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Heat and moisture production of modern swine.

INTRODUCTION

As animal care practices have changed over time, pigs (raised almost exclusively outdoors 60 years ago) are now reared predominately in indoor confinements. This change has led to improvements in food safety, manure management, animal handling, performance, and well-being. Raising pigs indoors requires both engineering and animal expertise. Many years of research have been dedicated to building design, environmental management, and improving the understanding of building and animal interactions. Important criteria in facility designs are animal total heat production (THP) and moisture production (MP) rates, which vary with genetics, nutrition, and thermal environment.

Intensive swine production requires a building environmental control system. Ideally, the control system is designed for management of primary environmental variables such as temperature, humidity, air velocity, and aerial contaminants. These desired indoor conditions vary with local climate, facility design, management, animal population, and phase of production. In order to effectively control environmental conditions within the facility, ventilation rates and supplemental heating needs were determined based on THP and MP values.

Temperature and humidity control are important, not only to maximize animal well-being and production, but also to prolong the life of the structure. Environmental temperature and animal size effects on THP and MP values can be found in published standards (ASABE 1986; ASHRAE 2005). The standards are based on data from Ota et al. (1975) and Bond et al. (1959). Significant changes in swine housing systems, swine genetics, and nutrition have occurred since that time. To manage these parameters, the design values in the control system must reflect current animal genetics, nutrition, and housing characteristics.

Literature Review

Since the publishing of current standards for THP and MP values, genetic potential has changed. Current trends in pork production have yielded leaner and faster growing pigs. According to the National Pork Board (2001, 2012), dressing percentage (ratio of carcass weight to live weight) has steadily increased from 69.5% in 1960 to 74.8% in 2011. Retail meat yield has also increased 10.3% from 1974 to 2011. The most significant change reported was the decrease in lard yield. In 1960, lard yield was 14.6 kg (32.21 lb), or 13.6% of live weight, but by 1988 this had dropped to 4.8 kg (10.61 lb), or 1.9% of the weight. Lard yield has not been reported since 1988.

In a literature review published by Brown-Brandl et al. (2004), fasting heat production (FHP) was compared from four studies published from 1936 to 2002 (Breirem 1936; Holmes and Breirem 1974; Tess et al. 1984; Noblet 2002). Fasting heat production is the amount of heat produced by an animal without access to feed; this measurement compares the changes in genetics without nutritional variance. Comparisons of nonlinear regression equations revealed significant increases. Using the predicted FHP for 50 and 100 kg pigs from Tess et al. (1984) and Noblet (2002). FHP has increased on average 18.1% in those 18 years. (See Table 1.)

An additional component of THP is feed consumption. This additional heat originates from the activity of eating, digestion, and absorption and utilization of nutrients. Therefore, an ad-lib fed pig will have a higher THP rate than a limit-fed or fasted counterpart. Close and Mount (1978) illustrated the changes in heat loss for different temperatures and feed intakes.

Additionally, if the dietary amino acid profile is closely matched to the pig's requirements, the THP of the animal is minimized. Any excess amino acids result in unproductive heat generation to deaminate the extra amino acids. As protein is an expensive ingredient, nutritionists have changed from formulating diets based on total protein to an approach based on balanced amino acid profiles specific to animal requirements.

Heat production is minimized at thermoneutral conditions. Literature data were summarized in an article that included data from fed (unfasted) animals (Brown-Brandl et al., 2004). Brown-Brandl et al. (2004) developed two equations to illustrate the changes in THP with changes in genetics over time. Equation 1 is the prediction equation for THP of growing-finishing pigs prior to 1988. Data from seven independent studies were used in this analysis ([R.sup.2] = 0.886; P < 0.0001).

THP (W/kg)= 16.11 [w.sup.-0.44] (1a)

where THP is heat production in W/kg and w is live body weight in kg.

THP (Btu/lb x day) = 848 [w.sup.-0.44] (1b)

where THP is heat production in Btu/lb day and w is live body weight in lb.

Equation 2 is the prediction equation for THP of recent genetic lines (1988 to present). Data from a total of seven independent studies were used in this analysis ([R.sup.2] = 0.827; P<0.0001).

THP (W/kg) = 14.11 [w.sup.-0.38] (2a)

where THP is heat production in W/kg and w is live body weight in kg.

THP (W/kg) = 743 [w.sup.-0.38] (2b)

where THP is heat production in Btu/lb day and w is live body weight in lb.

The International Commission of Agricultural Engineering (CIGR) formed a working group on climatization of animal houses. The group established guidelines for animal heat and moisture production for designing ventilation and heating equipment for animal houses. Their 1992 report was published in the CIGR Handbook of Agricultural Engineering (CIGR 1999) and was updated in 2002 (CIGR 2002). Those data are also included in the comparisons of results of this study.

A comparison of the three equations is shown in Figure 1. It seems that the newer genetic lines have a maximum increase in THP of approximately 15%. However, according to the analysis by Brown-Brandl et al. (2004) there is little difference in the two groups of data at the lower end of this weight range.

The CIGR equation using the constants given in Pedersen (2002) seems to overpredict THP for lighter pigs; however, this equation is comparable to the 1998-2004 prediction equation for the heavier mass range.

As environmental temperature changes from thermoneutral conditions, animals respond by adapting their behavior, feed intake, and THP. Figure 2, a graph adapted from Esmay and Dixon (1986), shows the general relation of THP to increasing temperature. The exact shape of the curve and lower and upper critical temperatures depend on several parameters including age, feed intake, and prior thermal conditioning (Figure 3).

Brown-Brandl et al. (2004) analyzed literature THP and MP data and developed equations that delineated THP of pigs at various weights exposed to multiple temperatures. Data were divided into two categories: prior to 1988 (representing older moderate-lean growth genetics) and from 1988 to 2004 (representing newer, high-lean growth genetics). The effect of genetic potential is shown by Equations 3 and 4.

Prior to 1988 ([R.sup.2] = 0.739; P < 0.0001): log(THP[W/kg]) = 1.178 - 0.008 [t.sub.a] -0.338 log(w) (3a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

log(THP[Btu/lb x day]) = 3.007 - 0.0044 [t.sub.a] - 0.338 log(w) (3b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

1988 to present ([R.sup.2] = 0.798; P < 0.0001):

log(THP [W/kg]) = 1.189 - 0.005 [t.sub.a] -0.345 log(w) (4a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

log(THP [Btu/lb x day]) = 2.9668 - 0.1888 [t.sub.a] -0.345 log(w) (4b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

These equations predict an increase of 12.4% to 35.3% in THP for the newer genetic lines. According to these predictions, the largest differences are observed at higher temperatures. These data would support the idea that newer genetic lines may have a lower upper critical temperature than the older genetic line, as suggested by Nienaber et al. (1997).

Therefore, the objectives of this study were to determine THP and MP rates of modern swine with respect to weight and environmental temperature and to determine facility-level MP with different waste-handling practices.

MATERIALS AND METHODS

Calorimeter Studies

A series of four indirect calorimeter studies were conducted to assess THP and MP of modern swine (0.5 Landrace, 0.25 Duroc, and 0.25Yorkshire) at various production stages (Table 2). All pigs were selected on the basis of weight and health status and randomly assigned to either one of 30 pens (Experiments 1 and 2) or 24 pens (Experiments 3 and 4). The pens were 1.3 m x 1.3 m (4.3 ft x 4.3 ft) each with 6 pens per chamber. In Experiment 1, a total of 30 barrows (castrated males) at a nominal weight of 42.3 [+ or -] 1.3 kg (93.1 [+ or -] 2.9 lb) were individually penned in five chambers and were exposed to one of five air temperatures (16, 20[degrees]C, 24[degrees]C, 28[degrees]C, 32[degrees]C; 60.8[degrees]F, 68[degrees]F, 75.2[degrees]F, 82.4[degrees]F, 89.6[degrees]F). In Experiment 2,30 individually penned gilts (female pigs before first litter) weighing 44.6 [+ or -] 3.1 kg (98.1 [+ or -]

6.8 lb) were randomly assigned to one of five environmental temperatures (16[degrees]C, 20[degrees]C, 24[degrees]C, 28[degrees]C, 32[degrees]C; 60.8[degrees]F, 68[degrees]F, 75.2[degrees]F, 82.4[degrees]F, 89.6[degrees]F). In Experiment 3,96 piglets (0.5 Landrace, 0.25 Duroc, and 0.25 Yorkshire) averaging 6.4 [+ or -] 1.2 kg (14.1 [+ or -] 2.6 lb) were assigned in 4 pigs/pen to 24 pens at one of four environmental temperatures (20[degrees]C, 25[degrees]C, 30[degrees]C, 35[degrees]C; 68[degrees]F, 77[degrees]F, 86[degrees]F, 95[degrees]F). In Experiment 4, 48 pigs weighing 21.6 [+ or -] 0.44 kg (47.5 [+ or -] 0.97 lb) were randomly assigned in 2 pigs/pen to 24 pens at one of four environmental temperatures (18[degrees]C, 23[degrees]C, 28[degrees]C, 32[degrees]C; 60.8[degrees]F, 68[degrees]F, 75.2[degrees]F, 82.4,[degrees]F 89.6[degrees]F). After a minimum of 14 days (7 days during Experiment 3) of adaptation to the assigned environmental temperature, pens of pig(s) were moved to adjacent indirect calorimeters operated at the same environmental temperature and humidity where THP and MP rates were quantified for a 21-h period. Each day, one pen of pigs (1-4 pigs/pen) from each of four chambers was moved to the calorimeters. Calorimetry measurements were taken three days per week. After the calorimetry measurements were completed, the temperature treatment was changed in such a way that all groups of pigs were exposed to multiple temperature treatments during the experiment (Table 2). A 12-h photoperiod (6:00 a.m. to 6:00 p.m.) was provided with incandescent lighting in all chambers and calorimeters.

Pigs had ad-libitum access to feed and water at all times. For Experiments 1 and 2, feed intake was monitored in the chambers using a weighing load cell. Data were recorded every 30 seconds as described in Nienaber et al. (1996). The weighing feeders were used to monitor feed consumption for each pig to assure that all pigs ate at least 1 kg (2.2 lb) of feed for the four days prior to the calorimeter testing and to identify any potential health problems. Precalorimeter test feed intake was based on a four-day average feed intake using this system. Smaller pigs in Experiments 3 and 4 required different feeders that were not mounted on the load cells.

Quantification of THP and MP was completed in the four multiple temperature indirect calorimeters as described in Brown-Brandl et al. (2011). On each day of calorimetric quantification, four pens (4 piglets, nursery study; 2 pigs, growing study; or 1 barrow/gilt, finishing studies) were moved from their resident pen into a predetermined calorimeter set at the same temperature and humidity as their respective chamber. Animals were weighed before and after each calorimeter run. A known amount of fresh feed was added to the feeder after the animal was placed in the calorimeter. Feed was removed and weighed and the calorimeter pen was cleaned after each run. Calorimeter runs began at 10:30 a.m. and ended at 7:30 a.m. the following morning. Approximately one hour was needed to move, weigh pigs, and clean the pens. Then two hours were needed to allow the gas concentrations to equilibrate within the calorimeters.

Two cumulative gas samples from each calorimeter and one fresh air sample were collected over the 21-h runtime and analyzed as a daily batch sample. Additionally, dynamic samples at 10-minute intervals were analyzed during the calorimeter runs. Gases were analyzed for oxygen ([O.sub.2]), carbon dioxide (C[O.sub.2]), and moisture ([H.sub.2]O) concentrations. Total heat production was calculated using the total liters of [O.sub.2] consumed and C[O.sub.2] produced. These totals were calculated by the difference between incoming and outgoing concentrations and multiplied by the total pressure- and temperature-corrected volume of air. The respiratory quotient (RQ) was calculated from the ratio of C[O.sub.2] production to [O.sub.2] consumption. Moisture production was calculated using a similar method of quantifying the change in moisture concentration between incoming and outgoing air, with the additional weight of condensate from cooling coils being added to the total. A complete explanation of calculations can be obtained from Nienaber and Maddy (1985).

Each calorimeter's accuracy was verified by burning a known amount of 100% ethanol alcohol. All calorimeter chambers were verified to be within a target goal of 98.5[degrees]% to 101.5% accuracy. This procedure was completed before each first experiment. All calorimeters were again verified to be within the expected accuracy range after each study was completed.

Heat, moisture production, and RQ data were analyzed using the general linear model procedure in SAS/STAT[R] (SAS 2010). Effects of weight, calorimeter feed intake, number of times through the calorimeter, and ambient temperature were tested. A second analysis was completed using the general linear model procedure in SAS/STAT[R] to develop a prediction equation for THP and MP based on weight and ambient temperature. The third analysis was completed to discern differences in dynamic THP responses. This analysis was a repeated measures analysis and was conducted to test the effects of time (average hourly THP) and ambient temperatures.

Facility-Level Heat and Moisture Production

The study was conducted over 19 months in one growing/finishing facility and one wing of the farrowing facility at the U.S. Meat Animal Research Center, Clay Center, NE to quantify facility-level THP and MP of swine and their surroundings from weaning to slaughter weight and through late gestation, farrowing, and lactation (piglets were weaned between 20 and 27 days). Production phase, sex of the animals, weight ranges, and herds used in the analyses are summarized in Table 3.

Site Description: Nursery, Finishing, and Gestating

The facility measured 19.1 m x 11.0 m (35 x 62.5 ft) with a capacity of approximately 500 pigs at 10 kg (22 lb) to 200 pigs at 130 kg (287 lb), respectively. The facility was divided into 16 pens (eight on the north wall and eight on the south wall) used for the study and two wellness pens (i.e., for housing pigs needing special attention or treatment). The pens were partially slatted. The finishing facility had three exhaust fans, all on the east end wall (Figure 3), including two 0.76 m (30 in.) fans, and one 0.6 m (24 in.) fan. Air entered through the west end wall and was moved through a polytube (0.61 m [24 in.]) to achieve more uniform distribution of air temperature across the pens. Two 73.25 kW (250,000 Btu/hr) unvented heaters were placed in the facility (one over each group of pens). Fluorescent lighting was used with 12 h light and 12 h dark. Herds were fed corn/soybean mash diets. Water was supplied through two nipple drinkers in each pen. The nipple drinkers as well as a sprinkler head were used over the slatted floor area of each pen. The sprinklers were used primarily to keep floor areas clean of defecation by running 45 seconds every 10 minutes (7.5% of the day).

Site Description: Farrowing

One room of the three farrowing rooms was monitored in this study. The rooms were connected with a central hall that acted as an air-preconditioning area. The total farrowing facility measured 21.3 m x 28.6 m (70 ft x 94 ft), with each room being 8.8 m x 19.5 m (29 ft x 64 ft) and containing 19 individual farrowing crates. The farrowing crates had coated-metal mesh flooring to allow manure to fall into the flushing pit underneath. Each room had two exhaust fans on the west end wall (Figure 4), one 0.6 m (24 in.) and one 0.76 m (30 in.). Air entered through the east wall and was moved through a polytube (0.46 m [18 in.]) to achieve more uniform distribution of air temperatures across the crates. The preconditioning air hallway had one 73.25 kW (250,000 Btu/h) vented heater and an air-inlet area of 7.3 m x 1.2 m (7.3 ft x 4 ft). Evaporative cooling pads (102 mm or 4 in. thick) were located in front of the air inlets to provide cooling in the summer. Fluorescent lighting was used with 12 h light and 12 h dark. Sows were fed corn/soybean mash diets and piglets were supplemented with corn/soy based creep feed the week prior to weaning. Water was supplied through two nipple drinkers in each crate--one for the sow and one for piglets.

Measurement System

Concentrations of C[O.sub.2] and dew-point temperature near the inlet and the exhaust fan were measured continually with C[O.sub.2] and dew-point sensors (GMP222, Vaisala, Woburn, MA; DewTrakII, Edge Tech, Marlborough, MA). Concentrations of [O.sub.2],C[O.sub.2], and methane (C[H.sub.4]) were measured on a weekly basis. Samples were accumulated in Mylar bags from a continuous sampling stream and were analyzed after 24 hours. Heat production was calculated using indirect calorimetry methods (Nienaber and Maddy 1985; Brown-Brandl et al. 2011). [O.sub.2] and C[O.sub.2] were measured within 100 ppm. RQ was calculated by dividing the volume of C[O.sub.2] produced by the volume of [O.sub.2] consumed.

All sampling pumps and valves, data acquisition, and instrumentation for this study were kept in an enclosure in the east end of the house. The enclosure was supplied with fresh air from outside to provide a positive pressure system in an effort to minimize entrance of dust from indoor air.

The building ventilation rate (VR) was determined from in situ calibrated fan curves with 1.2 m (48 in.) fan assessment numeration systems (FANS) (Gates et al. 2004). Individual fan curves were established for each ventilation stage. The runtime of fans was recorded continuously with inductive current switches (Muhlbauer et al., 2011). Fan runtime along with the corresponding building static pressure (model 264, Setra, Boxborough, MA) were recorded every second. Using the calibration curves for each fan stage with the above data, an overall building VR was calculated. All data were collected with a data acquisition system (NI-DAQmx, National Instruments, Austin, TX). To capture the dynamics of fan and heater operations, all data were processed on a per-second basis.

Determination of Facility-Level MP and the Relationship of MP and LHP

The facility-level MP, including latent heat of the pigs and moisture evaporation from waste handling, sprinkle cooling, and heater combustion, was calculated from the following mass-balance equation:

MP = [rho]Q([W.sub.o] - [W.sub.a]) (5)

where MP = moisture production rate (g x [H.sub.2]O x [s.sup.-1] [lb x [H.sub.2]O x [h.sup.-1]]); [W.sub.o], [W.sub.a] is humidity ratio of outlet and inlet air, respectively (g x [g.sup.-1] [lb x [lb.sup.-1]]); Q is building ventilation rate ([m.sup.3] x [s.sup.-1] [[ft.sup.3] x [hr.sup.-1]]); [rho] = air density (g x [m.sup.-3] [lb x [ft.sup.-3]]).

LHP = MP ([h.sub.fg]) (6)

where LHP = latent heat production (W, Btu x [hr.sup.-1]); MP = moisture production rate (g x [H.sub.2]O x [s.sup.-1] [lb x [H.sub.2]O x [hr.sup.-1]]); [h.sub.fg] = latent heat of vaporization (2429 x J x [g.sup.-1] [1045 Btu [lb.sup.-1]]).

To analyze facility-level production and quantify various sources of moisture generation, the facility was run in three scenarios: (1) heater combustion in an empty, clean facility; (2) impact of sprinkler cooling in an empty, dirty facility; and (3) entire facility at full pig capacity.

In the first scenario, heater combustion and respective MP rates were determined. This was done in an empty facility with a higher setpoint temperature and lower VR. Natural gas usage was determined by gas meter (AL-800, Elster American, Nebraska City, NE). This scenario provided an initial verification of the measurement system by verifying C[O.sub.2] production and [O.sub.2] consumption based on stoichiometric equation and the amount of consumed natural gas. Based on the same stoichiometric relationship for complete combustion, the mass water vapor produced was related to the measured natural gas combusted, in order to gain an accurate MP rate for heaters independent of the facility.

In the second scenario, moisture generation was quantified while varying sprinkler runtime at two temperatures. The facility was again empty; however, the facility had not been cleaned from the previous study to provide more realistic surface areas for evaporation. For this setup, two indoor temperatures (17[degrees]C and 20[degrees]C [63[degrees]F and 68[degrees]F]) were set and MP was measured. Heater runtime was determined and the related moisture produced was removed from the facility-level production rates. This provided valuable estimated evaporation rates from leaks, stuck nipple drinkers, and the pit as well as sprinklers. Because the sprinkling system was made on site, buckets were placed under six of the nozzles to capture the water volume. Although these are not precise specifications, this does provide some information on the rate of water flowing from the sprinkler system. Individual nozzles averaged 43 [+ or -] 4.4 g x [H.sub.2] O[s.sup.-1] (341 [+ or -] 4.4 lb x [H.sub.2]O x [h.sup.-1]). Sprinkler runtime was varied at 0, 1, 3, 5, 7.5, or 10 minutes out of every 10-minute interval. Each test was run for at least 24 hours. After adjusting to the next setting, the facility was given at least 2 hours before the next sampling level. If the facility was stepping from a longer sprinkler runtime to a shorter runtime, sampling was delayed until the following day to allow wet areas time to dry. One of the 7.5-minute tests did not successfully collect data for a full 24 hours and was, therefore, removed from the results.

In the third scenario, the facility was operated with herds of pigs in either the growing or finishing phase. For this paper, swine over 40 kg (88 lb) were considered finishing pigs and those between 20 and 40 kg (44-88 lb) were considered growing pigs. During the course of the study five herds went through the facility. Although there were some inherent limits in temperatures, based on seasons monitored, data from all production phases were sorted into four temperature ranges: (1) [less than or equal to] 21.1[degrees]C (70[degrees]F); (2) 21.1[degrees]C-23.9[degrees]C (70[degrees]F-75[degrees]F); (3) 23.9[degrees]C-26.7[degrees]C, 75[degrees]F-80[degrees]F; (4) > 26.7[degrees]C (80[degrees]F).

RESULTS AND DISCUSSION

Calorimeter Experiments

Four calorimeter experiments were conducted: (1) finishing barrows, (2) finishing gilts, (3) nursery piglets, and (4) growing pigs. Table 4 summarizes the calorimeter temperature, THP, LHP, MP, feed intake (FI), and RQ as affected by temperature treatment (Table 4a SI units, Table 4b I-P units).

During all calorimeter experiments, pigs were affected by temperature. During the first two experiments (finishing barrows and gilts), THP decreased with temperature until 28[degrees]C (82.4[degrees]F) and then increased slightly at 32[degrees]C (89.6[degrees]F). A similar response was observed during the fourth experiment, with THP decreasing as temperature increased. However, no slight increase was observed in growing pigs. This increase in THP is observed when animals are heat stressed and cannot adequately adapt to environmental conditions (Esmay and Dixon 1986). An animal adapts to an increase in temperature by decreasing FI and increasing LHP (Midwest Plan Service 1987). In these three studies (Experiments 1,2, and 4) these FI decreases and LHP increases were observed at higher temperatures.

In Experiment 3, nursery piglets, a similar trend in THP and LHP was observed. There was a slight decrease in THP between 20[degrees]C and 25[degrees]C (68[degrees]F and 77[degrees]F) and another decrease between 30[degrees]C and 35[degrees]C (86[degrees]F and 95[degrees]F). However, during this experiment no differences in FI were o served between temperature treatments. Latent heat production was similar at 20[degrees]C and 25[degrees]C (68[degrees]F and 77[degrees]F), but was significantly higher at 30[degrees]C and 35[degrees]C (86[degrees]F and 95[degrees]F).

Each of the four calorimeter experiments yielded two equations, one for THP and one for LHP. The THP equations (7-10) are logarithmic and calculate HP (W/kg [Btu/lb day]) using ambient temperature ([t.sub.a], [degrees]C [[degrees]F]) and animal body weight (w, kg [lb]). These equations are useful when calculating HP for a specific weight and temperature.

Nursery pigs (6-20 kg):

Log(THP [W/kg]) = 0.715 - 0.0025 [t.sub.a] + 0.0211 log(w) (7a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

Log(THP [Btu/lb x day]) = 2.3375 - 0.0139 [t.sub.a] + 0.0211 log(w) (7b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Growing pigs (20-45 kg):

Log(THP [W/kg]) = 1.288 - 0.005 [t.sub.a] -0.371 log(w) (8a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

Log(THP [Btu/lb x day]) = 3.075 - 0.00277 [t.sub.a] 0.371 log(w) (8b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in[degrees]F, and w is live body weight in lb.

Gilts (45-120 kg):

Log(THP [W/kg]) = 1.555 - 0.0063 [t.sub.a] - 0.54 log(w) (9a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

Log(THP [Btu/lb x day]) = 3.2379 - 0.0035 [t.sub.a] - 0.54 log(w) (9b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Barrows (45- 120 kg):

Log(THP [W/kg]) = 1.792 - 0.0074 [t.sub.a] - 0.632 log(w) (10a)

where THP is heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

Log(THP [Btu/lb x day]) = 3.7109 - 0.00411 [t.sub.a] - 0.632 log(w) (10b)

where THP is heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

General observations can be made from these equations. The specific THP decreases with weight of the pigs. Younger pigs have a more stable specific THP over the weight range and temperature than later production phases. This same observation can be made using the current standards (ASHRAE 2001). Growing pigs and finishing barrows and gilts showed distinct differences between weights and temperatures. Specific THP decreased as the temperature and/or weight increased. Finishing pigs tend to be more impacted by temperature than lighter pigs (Figure 5), which was expected because lighter pigs are more advantageous in dissipating body heat due to higher surface to volume ratio. Again, similar observations can be made using the current standards (ASHRAE 2001).

The current study has consistently higher THP than the standards, except for the nursery piglets. Previous studies had shown the impact of weaning age on THP of nursery-age pigs. Specifically THP of piglets weaned at 10-16 days (Cairne and Pullar 1957; Harmon et al. 1997; McCracken and Caldwell 1980; McCracken and Gray 1984) averaged 29% higher than THP of piglets weaned at 22-28 days (Le Dividich et al. 1980; McCracken and Gray 1984; Ota et al. 1975). This difference in THP could be attributed to adaptation to solid feed--the more the feed is consumed, the higher the THP (Close and Mount 1978).

Latent heat production has a similar response to temperature across all weight ranges in that LHP increases with increasing temperature (Figure 6). The LHP determined during this portion of the study is not reflective of whole facility LHP. Many factors other than the animal's MP contribute to the facility-level MP, including the heaters if unvented and sprinklers or misters if available, water wasted from the drinkers, and the waste-handling process. The calorimeter LHP accounts for the animal, wastewater from the drinkers, and a small portion of evaporation from urine and feces. However, the true facility MP needs to be developed from facility level measurements.

Latent heat production was observed to be a function of animal weight and temperature as well. Equations 11-14 can be used to calculate the LHP for each of the weight ranges.

Nursery pigs (10-20 kg):

LHP = -2.26 + 0.194 [t.sub.a] + 0.0679 w - 0.0034 [t.sub.a] w (11a)

where LHP is latent heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

LHP = -213.34 + 4.013 [t.sub.a] + 2.718 w - 0.0320 [t.sub.a] w (11b)

where LHP is latent heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Growing pigs (20-45 kg):

LHP = -1.64+ 0.173 [t.sub.a] + 0.021 w-0.0016 [t.sub.a] w (12a)

where LHP is latent heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is weight in kg.

LHP = -176.28 + 3.578 [t.sub.a] + 0.840 w - 0.0150 [t.sub.a] w (12b)

where LHP is latent heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Barrows (45 - 120 kg):

LHP = -0.64 + 0.117 [t.sub.a] + 0.0019 w - 0.00054 [t.sub.a] w (13a)

where LHP is latent heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is weight in kg.

LHP = -101.75 + 2.420 [t.sub.a] + 0.196 w - 0.0051 [t.sub.a] w (13b)

where LHP is latent heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Gilts (45- 120 kg):

LHP = -0.46 + 0.077 [t.sub.a] + 0.0029 w - 0.00032 [t.sub.a] w (14a)

where LHP is latent heat production in W/kg, [t.sub.a] is ambient dry-bulb temperature in [degrees]C, and w is live body weight in kg.

LHP = -68.41 + 1.593 [t.sub.a] + 0.146 w -0.00301 taw (14b)

where LHP is latent heat production in Btu/lb day, [t.sub.a] is ambient dry-bulb temperature in [degrees]F, and w is live body weight in lb.

Facility-Level Measurements

The summaries of the facility-level studies conducted in the growing/finishing building were listed in Tables 5 and 7. Weight ranges were identified to correspond to those used in the calorimeter studies for ease of comparison. Facility THP was similar to the calorimeter studies, where specific THP and LHP were highest for the smallest pigs and decreased with weight through finishing. However, the gestating gilts had a higher THP than finishing pigs. Generally the flush system had a higher LHP than the simulated pit with the LHP of flush system being approximately 19% higher than that of the simulated pit. As the pigs grew, the flush system was operated more often, resulting in increasing LHP, 14% higher than the simulated pit in nursery pigs and 31% in gestating gilts. Note that the difference was not observed in late-finishing pigs. This could be due to the higher ambient temperature of the simulated pit measurements (simulated pit: [t.sub.a] = 23.5[degrees]C [74.3[degrees]F], flushing pit: [t.sub.a] = 20.7[degrees]C [69.3[degrees]F]). During the late-finishing phase, 12 days were above 24[degrees]C (75.2[degrees]F), 11 of which were measured as a simulated pit.

Heat production did vary between the flush and simulated pit operation. This difference was speculated to arise from the body weight distribution with higher body weight relating to lower THP per unit of body weight.

Data for the farrowing facility is summarized in Table 6. The gilts/sows were generally moved into the facility 5 to 7 days prior to parturition. Data collection was started 4 days later; therefore, on a normal cycle, 2 days of preparturition data were collected. Data were then divided into weeks based on the date of that the first sow to give birth in the facility. While sow weight was relatively constant, piglet weight gain accounted for the change in weight over the time period.

Heat production increases with increasing piglet size. In contrast, LHP is fairly constant over time with the only increase occurring at parturition. THP and LHP for farrowing are reported on an energy per mass basis, where weight accounts for the weight of the sow plus the weight of the litter. Note in Table 6, day 22 to move-out appears to be lower because the assumed weight is sow and litter, but sows were often moved out prior to piglets.

The facility-level THP and LHP are summarized in Table 7 for 4 temperature ranges. It should be noted that data collected during the finishing phase were during the fall season; therefore, the lowest temperature range was not achieved until late finishing. Also, the temperatures reported are daily averages and do not represent diurnal ranges. Average diurnal temperature ranges are shown in Figure 7. Generally, facility-level THP data are in agreement with data for the calorimeter experiments. However, nursery piglet THP measured in the facility at temperatures below 26.7[degrees]C (80[degrees]F) was approximately 45% higher than the calorimeter measurements. This difference can be explained by considering several factors. First, average temperature does not reflect the cooler nighttime hours when the piglets would likely have higher THP. Second, the building was filled over a 3-week period; there fore, piglets were at different ages and had different thermal requirements. The facility had half concrete slab and half concrete slats, whereas the calorimeters had plastic creep flooring. These two distinct flooring types have very different thermal conductivities and therefore, impact the thermal requirements of piglets (Mount 1967). The fourth and final factor is the size of the group of piglets in the pen. The larger group could have had an increase in activity due to social interaction and rank establishment among the young pigs. Therefore, it is believed that the THP and LHP values obtained during the facility-level runs are more representative of the expected THP and LHP in commercial settings.

Moisture Production Comparison

An effort was made to quantify MP from animal and non-animal sources because facility-level MP is dependent not only on the animals but also on evaporation from other surfaces and water vapor production from the combustion in unvented heaters.

In the case of the heaters, the MP is an assumed rate based on a stoichiometry relationship. The natural gas meter shows consistent volume of gas being consumed in the heaters per operational time, and the rate of complete combustion is assumed to be the same throughout the monitoring period. Based on C[O.sub.2] consumption, the MP is at a constant rate of 2.76 g [H.sub.2]O vapor per second (21.91 lb/h) of heater operation.

The other nonanimal source of moisture is the moisture from building surfaces. To evaluate the potential MP in the empty facility, including the sprinkling system as well as everyday leaks, drips, and pit evaporation, data were collected in an empty facility with a range of sprinkler operational time at two temperatures. MP increases with increasing temperature and sprinkler operational time. However, once the sprinklers are near 50% operation, the facility reaches its maximum MP rate. The facility's daily sprinkler operation was approximately 10% throughout all the experiments in the grow-finish facility. A linear equation was developed for MP based on temperature and is listed below.

MP = 0.1798 [t.sub.a] - 1.4664 (15a)

where MP is moisture production in g/s and [t.sub.a] is dry-bulb temperature in [degrees]C.

MP = 0.7911 [t.sub.a] -37.086 (15b)

where MP is moisture production in lb/hr and [t.sub.a] is dry-bulb temperature in [degrees]F.

To consider the effectiveness of the values for MP from sources other than animals, a comparison was made. In each production phase, four days were carefully chosen across the range of sampled temperature in the facility to ensure that the entire temperature range was represented. The heater MP was calculated based on heater runtime and empty facility MP calculated based on Equation 15 using average daily facility temperature. Specific MP of the pigs was calculated based on Equations 11-14. The sum of heater, facility, and pig MP were compared with the measured facility-level MP values. A positive difference between the sum of MP components and the measured facility-level MP indicates an underestimation of the calculated components, while a negative percent difference indicates an overestimation. The average of four days in each production phase is shown in Table 8. The MP for the nursery pigs was considerably underestimated (51%) by the components relative to the facility-level measurements. This is in agreement with the higher facility-level THP and LHP compared to the calorimeter experiments discussed above. Growing pigs MP values matched well between the two measurement methods. The finishing pig MP was based on the assumption that the barn was 50% barrows and 50% gilts, which is a close approximation. Overall, the finishing pigs' equated sum matched well with the measured facility values. However, when broken down by weight range, the early finishing pigs MP was underestimated, while the late-finishing pigs overestimated MP. This might be due to either facility temperature, with the early finishing having a higher temperature and, therefore, more potential for evaporation, or due to limitations in the pig LHP equations at the two weight extremes.

Circadian Patterns

As described above, THP was measured at 10-min intervals in the calorimeter trials. All observations used in the HP analyses were used to evaluate the variation in HP over time. All 10-min readings were adjusted by the ratio of the average 10-min reading to the overall average measurement for each calorimeter test period. This is because THP as measured over the total 21-h of calorimeter study is a more accurate measurement due to closely calibrated instruments. Accuracy is quantified in system tests by the burning of alcohol (maximum error of 1.5%). The dynamic 10-min measurements utilize the same analyzers, air volume meters, and associated line temperature and pressure sensors; however, barometric pressure changes can lead to erroneous [O.sub.2] concentration readings over time. Comparison of those averages and the adjustment ratios were within 5%. For the facility-level heat and LHP the one-second C[O.sub.2] and dew-point measurements were used to calculate THP and LHP with [O.sub.2] consumption assumed from a constant RQ established by the given week's bag sampling.

Those corrected calorimeter readings were summarized as hourly THP and are shown in Figures 7, 8, and 9 over the 21-h period from 10:30 a.m. through 7:30 a.m. the following morning (times were chosen to match the start and stop time of the calorimeters). Lights were turned off at 6 p.m. (between the 7th and 8th hour measurement) and turned on again at 6 a.m. (between 19th and 20th hour measurement). Values for facility-level THP and LHP were averaged hourly, providing 24 points. To provide visual ease of comparison, the 24 hourly facility-level averages were plotted on the same time basis as the calorimeter using 10:30 as time 0 (Figures 7, 8, and 10). In this facility, lights were turned off at 7 p.m. (between the 8th and 9th hour from time zero) and came on at 7 a.m. (between 20th and 21st hr). Because these facility-level measurements did not require any additional handling of the pigs, the adjustment of time zero does not affect interpretation of the circadian pattern plotted.

Nursery piglets show no differences with temperature treatments; therefore only one THP is plotted (Figure 7) for all temperatures. However, THP of finishing gilts and barrows, as demonstrated in the calorimeter experiments, showed strong temperature effects (P < 0.01). Specifically THP under the 16[degrees]C and 20[degrees]C (61[degrees]F and 68.2[degrees]F) treatments was greater than that under the higher temperatures. Similarly, in the facility-level experiments, both finishing sexes showed higher daytime THP in the 24[degrees]C (75.4[degrees]F) treatment, while THP was similar to that under the higher temperatures during dark periods. Growing pigs show a higher THP across the whole 21-h period in the 18[degrees]C (64.6[degrees]F) treatments compared to higher temperature treatments. A common trend, across all temperatures and phases of production in the calorimeter circadian data, is the late afternoon increases in THP. It is obvious that the pigs had active feeding during this late afternoon period, with the largest changes observed at the lower temperatures. In the warmer treatments, finishing gilts and barrows showed greater THP increase in early morning hours (with lights on). Responses were likely due to changes in eating behavior (Nienaber et al. 1990) and total time spent being active (Pedersen and Rom 2000).

Unlike with the calorimeter data, facility-level data were summarized as a whole across all temperatures due to higher variability and limited data in certain temperature ranges. Facility-level measurements did provide circadian LHP patterns. Overall, these patterns did correspond well with calorimeter values. Facility nursery pigs showed an earlier peak in THP compared to the calorimeter results, perhaps due to different feeding behaviors. Similarly, the THP values are higher across all hours of the day. Growing and early-finishing pigs in the facility demonstrated a late afternoon THP spike similar to that in calorimeter patterns. Late-finishing pigs exhibited a slightly different circadian pattern in that they had a steep spike in THP and LHP occurring early in the morning, and a more gradual spike in late afternoon. This outcome might have resulted from the corresponding behaviors (i.e., increased early morning feeding and gradually less activities in the afternoon for these larger animals). It is interesting to note that the LHP in all phases of production tend to follow the THP values.

The lighted hour increases in THP and LHP can be quantified as a percent increase over the dark hours. The calorimeter lighted hour THPs were 0.8%, 4.9%, 7.2%, and 5.6% greater than dark THPs for nursery piglets, growing pigs, finishing gilts, and finishing barrows, respectively. The facility THP exhibited increases of 13.5%, 22.1%, 21.4%, and 16.7% for the nursery piglets, growing pigs, early finishing pigs, and late finishing pigs, respectively. The values for the pigs in the facility showed a larger difference between lights on and off than the values for the pigs in the calorimeter. It is hypothesized that this difference is due to the activity level of the group-penned animals in the facilities. Facility-level LHP shows similar increases of 13.4%, 34.1%, 27.2%, and 12.4% for nursery piglets, growing pigs, early finishing pigs, and late finishing pigs, respectively.

Another difference between the calorimeter and facility-level experiments was the circadian temperature patterns in the facility. Where the calorimeters control incoming air temperature, the facility is dependent on climatic conditions. As expected, warmer average daily temperature range corresponds to larger ranges of temperature during the 24-h period. During warmer conditions, maximum ventilation can no longer remove enough heat because ambient air is near or above the facility setpoint temperature. This drives up temperatures in the early afternoon, and only with the cooler night temperatures will the facility temperature begin to drop (Figure 11).

Based on the temperature response by temperature range, the LHP should be highest in the highest temperature range and decrease with decreasing temperatures. However, the days averaged in the plot for each temperature range are not weighted equally by the phase of production. Figure 12 plots the circadian LHP for each temperature range. Both the 23.9[degrees]C-26.7[degrees]C (75[degrees]F-80[degrees]F) and the >26.7[degrees]C (>80[degrees]F) temperature ranges show large increases in LHP in the warmer hours compared to the cooler temperature ranges, indicating animals are using respiration and evaporation for cooling. While the LHP of the 23.9[degrees]C-26.7[degrees]C (75[degrees]F- 80[degrees]F) and the >26.7[degrees]C (>80[degrees]F) overlap in the warmest part of the day, the LHP in cooler hours is higher in the 23.9[degrees]C-26.7[degrees]C (75[degrees]F- 80[degrees]F) temperature range. This is due to the 23.9[degrees]C-26.7[degrees]C (75[degrees]F-80[degrees]F) range being weighted more evenly across all phases of production, while the >26.7[degrees]C (>80[degrees]F) range is heavily weighted towards finishing pigs.

SUMMARY AND CONCLUSIONS

It was determined that there was a need to complete a systematic upgrade of the swine heat and moisture production standards. In order to complete this upgrade, a series of four calorimeter studies (nursery, growing, finishing gilts, and finishing barrows), and six facility-level studies (nursery, growing, early finishing, late finishing, gestating gilts, and farrowing sows and litters) were conducted. It was found that THP of modern pigs is 16% higher than the current standards indicate. Changes in THP from the current standards ranged from 10% lower to 32% higher. The largest differences were observed for finishing pigs at the lower temperatures. The THP of nursery pigs was not impacted by temperature and was slightly lower than the standards indicate, possibly due to the weaning age of the piglets, the piglet adaptation to solid feed, and the activity level of the small group. For a given body weight, nursery pigs with younger weaning age tends to have higher THP.

The facility-level experiments allowed for THP information to be collected on gestating gilts and farrowing sows and litters. The literature, data, and standards are lacking in this area. It was noted that gestating gilts had a much higher THP than what would be anticipated from heavy gilts (122% increase over heavy finishing pigs). During the four-week period of a farrowing cycle (from preparturition through the week before weaning), THP steadily rose from 1.89 w/kg (70.2 Btu/lb x day) to 3.77 W/kg (140.2 Btu/lb x day). LHP followed the same trend.

The facility-level THP matched well with the calorimeter data, except for the nursery piglets. The nursery piglet THP was higher in the facility-level measurements (6.64 W/s [247.2 Btu [lb.sup.-1] [day.sup.-1]]) than in calorimeter (4.73 W/s [176.1 Btu [lb.sup.-1] [day.sup.-1]]), with discrepancy presumably attributable to differences in temperature and activity levels. Although not in disagreement with the calorimeter data, there were noticeable differences between the early and late-finishing production phase. Heat production was 40% higher in the early-finishing phase. The size of the animals, hence metabolic body weight, was substantially higher in the late-finishing phase and activity level is generally thought to be lower in larger pigs. This trend was not seen in the calorimeter data due to the experimental design.

Latent heat production (LHP) or MP data are used to set the minimum ventilation in a barn to ensure moisture control during wintertime conditions. The LHP determined in the calorimeter is a good indication of animal LHP and gives some clear guidance to predicting LHP given animal weight, population, and the temperature of the facility. However, it does underestimate the facility LHP, which is a sum of the MP from unvented heaters, water wastage, sprinkle-cooling system, and waste-handling facility. In the small barn that the experiment was conducted in, MP of an empty barn was a significant contribution of the total MP and averaged approximately 3 g/sec (24 lb/hr). This number was generated from a barn with sprinkle cooling and partially slatted floors; changes to these parameters could significantly change this value. A good approximation of this value for a facility would be 1.9 kg/day per [m.sup.2] of the animal area (0.4 lb [day.sup.-1] [ft.sup.-2]); this is in addition to the LHP of the animals. Using this facility value and the LHP equations, predicted LHP from this study was 28% higher than the values in the standards and ranged from -10% to 47%. The nursery piglets were the only phase that predicted below the current standards.

Circadian patterns of both the facility and the calorimeter experiments show a clear change in THP throughout the day. The calorimeter data consistently had a large peak in the late afternoon prior to lights going out. Facility data have a similar trend; however, the difference between light and dark periods was greater in the facility data than in the calorimeter data. The LHP follows similar circadian patterns as the THP.

These studies show an increase in heat and moisture production across weight ranges and temperatures. The collected data include values for gestating gilts and farrowing sows/litters that were previously unavailable. These updated THP and MP values are essential for designing new and managing current swine facilities.

DISCUSSION

Masaya Ishihara, Azbil Corporation, Tokyo, Japan: Why did you choose a 21-hour period for continuous heat production measurement? Would 24 hours be more natural?

Tami M. Brown-Brandl: A 24-hour cycle would be the best. However, changing animals and allowing the calorimeter to equilibrate took approximately 3 hours (45-60 minutes to change animals and the remaining time to equilibrate the chamber).

So, we felt it was extremely important to start at the same time each day to ensure the pigs were moved at the same time in the diurnal cycle.

This paper is based on findings resulting from ASHRAE Research Project RP-1475.

ACKNOWLEDGMENTS

The authors would like to thank Dale Janssen for gas analysis; Ty Post, Todd Boman, and John Holman for care of the animals; and Jan Watts for help in the preparation of this manuscript. This research was funded in part from a grant from ASHRAE.

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Tami M. Brown-Brandl

Associate Member ASHRAE

Hong Li

Morgan D. Hayes

Roger A. Eigenberg

Hongwei Xin

John P. Stinn

John A. Nienaber

Timothy Shepherd

Tami M. Brown-Brandl and Roger A. Eigenberg are agricultural engineers, Morgan D. Hayes is a research associate, and John A. Nienaber is a research collaborator at the USDA-ARS Meat Animal Research Center, Clay Center, NE. Hongwei Xin is a professor and director of Egg Industry Center, John P. Stinn is a graduate research assistant, and Timothy Shepherd is an assistant scientist in the Department of Agricultural and Biosystems Engineering, Iowa State University Ames, IA. Hong Li is an assistant professor in the Department of Animal and Food Science, University of Delaware, Newark, DE.

Table 1. Calculated Fasting Heat Production (FHP) from Four Studies
(1936 to 2002)

Source                50 kg                 100 kg
                     (110 lb) Pigs         (220 lb) Pigs

                       FHP,        %         FHP,         %
                      W/Pig       Change      W/Pig      Change
                     (Btu/hPig)    from    (Btu/h Pig)    from
                                   1936                   1936

Breirem(1936)        69 (237)       --      103 (351)      --
Holmes and           83 (284)      19.0     119 (405)     15.5
  Breirem(1974)
Tess et al. (1984)   103 (352)     48.7     147 (502)     43.1
Noblet (2002)        112 (383)     61.7     184 (627)     78.4

Table 2. Overview of Calorimeter Experiments

Experiment #     Sex     Total Number of   Weight Range,
                         Pigs (Pigs/Pen)      kg (lb)

1. Barrows     Barrows       30 (1)           45-120
                                              100-265
2. Gilts        Gilts        30 (1)           45-120
                                              100-265
3. Nursery      Mixed        96 (4)            6-20
                                               13-45
4. Growing      Mixed        48 (2)            20-40
                                               45-88

Experiment #      Temperatures,       Number of Temperature
                    [degrees]C         Treatments Each Pen
                   ([degrees]F)            Experienced

1. Barrows      16, 20, 24,28, 32               5
               (60, 68, 75, 82, 90)
2. Gilts        16, 20, 24,28, 32               5
               (60, 68, 75, 82, 90)
3. Nursery        20, 25, 30, 35                2
                 (68, 77, 86, 95)
4. Growing        18, 23, 28, 33
                 (64, 73, 82, 91)               2

Table 3. Overview of Facility Level Experiments

Experiment                   Sex      Weight Range,       Groups
                                         kg (lb)        Included in
                                                         Analysis

1. Nursery Piglets          Mixed     10-20 (22-44)          2
2. Growing Pigs             Mixed     20-40 (44-88)          2
3. Early Finishing Pigs     Mixed    40-80 (88-176)          2
4. Late Finishing Pigs      Mixed   80-130 (176-286)         1
5. Gestating Gilts          Gilts   130-155 (286-341)        1
6. Farrowing Gilts/Sows *   Sows    175-340 (385-750)        6

Experiment                    Average
                            Population

1. Nursery Piglets              513
2. Growing Pigs                 416
3. Early Finishing Pigs         371
4. Late Finishing Pigs          295
5. Gestating Gilts              80
6. Farrowing Gilts/Sows *    18 sows +
                            150 piglets

* Fairowing weight is for sow + litter

Table 4a. Summary of Results of the Calorimeter Experiments
in SI Units

                   Temperature   Average [T.sub.db],
                       TRT           [degrees]C

Experiment 1           16         15.7 [+ or -] 0.4
  Finishing            20         19.4 [+ or -] 0.4
  Barrows Weight       24         23.7 [+ or -] 0.4
  59-118 kg            28         27.5 [+ or -] 0.6
                       32         31.5 [+ or -] 0.7
Experiment 2           16         16.0 [+ or -] 0.6
  Finishing            20         19.7 [+ or -] 0.6
  Gilts Weight         24         24.7 [+ or -] 0.5
  54-113 kg            28         27.8 [+ or -] 0.5
                       32         31.4 [+ or -] 0.4
Experiment 3           20         19.6 [+ or -] 0.6
  Nursery              25         24.6 [+ or -] 0.6
  Piglets Weight       30         29.3 [+ or -] 0.6
  9-16 kg              35         33.9 [+ or -] 0.6
Experiment 4           18         17.5 [+ or -] 0.6
  Growing Pigs         23         22.5 [+ or -] 0.6
  Weight 27-39         28         27.1 [+ or -] 0.6
  kg                   33         32.2 [+ or -] 0.6

                             THP,                      LHP,
                             W/kg                      W/kg

Experiment 1        2.82 [+ or -] 0.11 (a)    0.60 [+ or -] 0.04 (a)
  Finishing         2.80 [+ or -] 0.09 (a)    0.96 [+ or -] 0.05 (b)
  Barrows Weight    2.37 [+ or -] 0.05 (b)    1.03 [+ or -] 0.05 (c)
  59-118 kg         2.19 [+ or -] 0.08 (c)    1.26 [+ or -] 0.07 (d)
                    2.27 [+ or -] 0.09 (b)    1.81 [+ or -] 0.09 (e)
Experiment 2        2.60 [+ or -] 0.04 (a)    0.49 [+ or -] 0.06 (a)
  Finishing         2.55 [+ or -] 0.04 (a)    0.74 [+ or -] 0.06 (b)
  Gilts Weight      2.34 [+ or -] 0.04 (b)    0.90 [+ or -] 0.06 (c)
  54-113 kg         2.22 [+ or -] 0.04 (c)    1.14 [+ or -] 0.05 (d)
                   2.21 [+ or -] 0.05 (b,c)   1.57 [+ or -] 0.07 (e)
Experiment 3        4.95 [+ or -] 0.11 (a)    1.63 [+ or -] 0.11 (a)
  Nursery          4.68 [+ or -] 0.11 (a,b)   2.24 [+ or -] 0.13 (b)
  Piglets Weight   4.74 [+ or -] 0.10 (a,b)   2.93 [+ or -] 0.14 (c)
  9-16 kg           4.55 [+ or -] 0.12 (b)    3.93 [+ or -] 0.14 (d)
Experiment 4        4.18 [+ or -] 0.10 (a)    1.26 [+ or -] 0.13 (a)
  Growing Pigs      4.07 [+ or -] 0.09 (a)    1.56 [+ or -] 0.13 (a)
  Weight 27-39      3.79 [+ or -] 0.10 (b)    2.21 [+ or -] 0.13 (b)
  kg                3.66 [+ or -] 0.10 (b)    2.98 [+ or -] 0.16 (c)

                          MP, g x                     FI,
                    [H.sub.2]O/kg x day              kg/day

Experiment 1       21.3 [+ or -] 1.4 (a)    2.12 [+ or -] 0.15 (a,b)
  Finishing        34.2 [+ or -] 1.8 (b)     2.32 [+ or -] 0.10 (b)
  Barrows Weight   36.3 [+ or -] 1.8 (c)     1.90 [+ or -] 0.10 (b)
  59-118 kg        44.5 [+ or -] 2.5 (d)     1.59 [+ or -] 0.09 (b)
                   64.4 [+ or -] 3.2 (e)     1.08 [+ or -] 0.08 (c)
Experiment 2       17.4 [+ or -] 2.1 (a)     2.03 [+ or -] 0.1 (a)
  Finishing        26.6 [+ or -] 2.1 (b)     1.91 [+ or -] 0.1 (a)
  Gilts Weight     32.0 [+ or -] 2.1 (c)     1.76 [+ or -] 0.1 (a)
  54-113 kg        40.5 [+ or -] 1.8 (d)     1.42 [+ or -] 0.1 (b)
                   55.8 [+ or -] 2.5 (e)     0.83 [+ or -] 0.1 (c)
Experiment 3       58.0 [+ or -] 3.9 (a)       0.61 [+ or -] 0.06
  Nursery          79.7 [+ or -] 4.6 (b)       0.58 [+ or -] 0.06
  Piglets Weight   104.2 [+ or -] 5.0 (c)      0.58 [+ or -] 0.06
  9-16 kg          139.8 [+ or -] 5.0 (d)      0.61 [+ or -] 0.07
Experiment 4       44.8 [+ or -] 4.6 (a)     1.44 [+ or -] 0.10 (a)
  Growing Pigs     55.5 [+ or -] 4.6 (a)     1.26 [+ or -] 0.10 (a)
  Weight 27-39     78.6 [+ or -] 4.6 (b)     1.24 [+ or -] 0.10 (a)
  kg               106.0 [+ or -] 5.7 (c)    0.95 [+ or -] 0.09 (b)

                              RQ

Experiment 1        1.08 [+ or -] 0.01 (a)
  Finishing         1.13 [+ or -] 0.01 (b)
  Barrows Weight    1.09 [+ or -] 0.01 (a)
  59-118 kg         1.07 [+ or -] 0.01 (a)
                    1.02 [+ or -] 0.01 (c)
Experiment 2        1.03 [+ or -] 0.01 (a)
  Finishing        1.06 [+ or -] 0.01 (b,c)
  Gilts Weight     1.05 [+ or -] 0.01 (a,c)
  54-113 kg         1.06 [+ or -] 0.01 (b)
                    1.06 [+ or -] 0.01 (b)
Experiment 3          1.00 [+ or -] 0.02
  Nursery             0.99 [+ or -] 0.02
  Piglets Weight      1.02 [+ or -] 0.01
  9-16 kg             1.02 [+ or -] 0.02
Experiment 4          1.06 [+ or -] 0.01
  Growing Pigs        1.08 [+ or -] 0.01
  Weight 27-39        1.08 [+ or -] 0.01
  kg                  1.05 [+ or -] 0.01

(a,b,c) Means within a single column with differing
superscripts are significantly different (P < 0.05).

Table 4b. Summary of Results of the Calorimeter Experiments
in I-P Units

                   Temperature   Average [T.sub.db]
                       TRT          ([degrees]F)

Experiment 1           60             60.3 0.7
  Finishing            68        66.9 [+ or -] 0.7
  Barrows Weight       75        74.7 [+ or -] 0.7
  130-260              82        81.5 [+ or -] 1.1
                       90        88.7 [+ or -] 1.3
Experiment 2           60        60.8 [+ or -] 1.1
  Finishing            68        67.5 [+ or -] 1.1
  Gilts Weight         75        76.5 [+ or -] 0.9
  120-250              82        82.0 [+ or -] 0.9
                       90        88.5 [+ or -] 0.7
Experiment 3           68        67.3 [+ or -] 1.1
  Nursery              77        76.3 [+ or -] 1.1
  Piglets Weight       86        84.7 [+ or -] 1.1
  20-35 lb             95        93.0 [+ or -] 1.1
Experiment 4           64        63.5 [+ or -] 1.1
  Growing Pig          73        72.5 [+ or -] 1.1
  Weight 60-86         82        80.8 [+ or -] 1.1
  lb                   91        90.0 [+ or -] 1.1

                      THP (Btu/lb x day)        LHP (Btu/lb x day)

Experiment 1          105.0 [+ or -] 4.1      22.3 [+ or -] 1.5 (a)
  Finishing         104.2 [+ or -] 3.4 (a)    35.7 [+ or -] 1.9 (b)
  Barrows Weight    88.2 [+ or -] 1.9 (b)     38.4 [+ or -] 1.9 (c)
  130-260           81.5 [+ or -] 3.0 (c)     46.9 [+ or -] 2.6 (d)
                    84.5 [+ or -] 3.4 (b)     67.4 [+ or -] 3.4 (e)
Experiment 2        96.8 [+ or -] 1.5 (a)     18.4 [+ or -] 2.2 (a)
  Finishing         94.9 [+ or -] 1.5 (a)     27.6 [+ or -] 2.2 (b)
  Gilts Weight      87.1 [+ or -] 1.5 (b)     33.5 [+ or -] 2.2 (c)
  120-250           82.7 [+ or -] 1.5 (c)     42.4 [+ or -] 1.9 (d)
                   82.3 [+ or -] 1.9 (b,c)    58.5 [+ or -] 2.6 (e)
Experiment 3        184.3 [+ or -] 4.1 (a)    60.7 [+ or -] 4.1 (a)
  Nursery          174.2 [+ or -] 4.1 (a,b)   83.4 [+ or -] 4.8 (b)
  Piglets Weight   176.5 [+ or -] 3.7 (a,b)   109.1 [+ or -] 5.2 (c)
  20-35 lb          169.4 [+ or -] 4.5 (b)    146.3 [+ or -] 5.2 (d)
Experiment 4        155.6 [+ or -] 3.7 (a)    46.9 [+ or -] 4.8 (a)
  Growing Pig       151.5 [+ or -] 3.4 (a)    58.1 [+ or -] 4.8 (a)
  Weight 60-86      141.1 [+ or -] 3.7 (b)    82.3 [+ or -] 4.8 (b)
  lb                136.3 [+ or -] 3.7 (b)    110.9 [+ or -] 6.0 (c)

                     MP (lb x [H.sub.2]O/           FI (lb/day)
                          lb x day)

Experiment 1       0.021 [+ or -] 0.001 (a)   4.67 [+ or -] 0.33 (a,b)
  Finishing        0.034 [+ or -] 0.002 (b)    5.11 [+ or -] 0.22 (b)
  Barrows Weight   0.036 [+ or -] 0.002 (c)    4.19 [+ or -] 0.22 (b)
  130-260          0.045 [+ or -] 0.003 (d)    3.51 [+ or -] 0.20 (b)
                   0.064 [+ or -] 0.003 (e)    2.38 [+ or -] 0.18 (c)
Experiment 2       0.017 [+ or -] 0.002 (a)    4.48 [+ or -] 0.22 (a)
  Finishing        0.027 [+ or -] 0.002 (b)    4.21 [+ or -] 0.22 (a)
  Gilts Weight     0.032 [+ or -] 0.002 (c)    3.88 [+ or -] 0.22 (a)
  120-250          0.041 [+ or -] 0.002 (d)    3.13 [+ or -] 0.22 (b)
                   0.056 [+ or -] 0.003 (e)    1.83 [+ or -] 0.22 (c)
Experiment 3       0.058 [+ or -] 0.004 (a)      1.35 [+ or -] 0.13
  Nursery          0.080 [+ or -] 0.005 (b)      1.28 [+ or -] 0.13
  Piglets Weight   0.104 [+ or -] 0.005 (c)      1.28 [+ or -] 0.13
  20-35 lb         0.140 [+ or -] 0.005 (d)      1.35 [+ or -] 0.15
Experiment 4       0.045 [+ or -] 0.005 (a)    3.17 [+ or -] 0.22 (a)
  Growing Pig      0.056 [+ or -] 0.005 (a)    2.77 [+ or -] 0.22 (a)
  Weight 60-86     0.079 [+ or -] 0.005 (b)    2.73 [+ or -] 0.22 (a)
  lb               0.106 [+ or -] 0.006 (c)    2.09 [+ or -] 0.20 (b)

                              RQ

Experiment 1        1.08 [+ or -] 0.01 (a)
  Finishing         1.13 [+ or -] 0.01 (b)
  Barrows Weight    1.09 [+ or -] 0.01 (a)
  130-260           1.07 [+ or -] 0.01 (a)
                    1.02 [+ or -] 0.01 (c)
Experiment 2        1.03 [+ or -] 0.01 (a)
  Finishing        1.06 [+ or -] 0.01 (b,c)
  Gilts Weight     1.05 [+ or -] 0.01 (a,c)
  120-250           1.06 [+ or -] 0.01 (b)
                    1.06 [+ or -] 0.01 (b)
Experiment 3          1.00 [+ or -] 0.02
  Nursery             0.99 [+ or -] 0.02
  Piglets Weight      1.02 [+ or -] 0.01
  20-35 lb            1.02 [+ or -] 0.02
Experiment 4          1.06 [+ or -] 0.01
  Growing Pig         1.08 [+ or -] 0.01
  Weight 60-86        1.08 [+ or -] 0.01
  lb                  1.05 [+ or -] 0.01

(a,b,c) Means within a single column with differing superscripts
are significantly different (P < 0.05).

Table 5a. Summary of THP and LHP Data Taken in the Facility Level
Studies. Growing/Finishing/Gestating Facility was Tested with Two
Waste Handling Treatments (Flushing/Simulated Pit) (SI Units)

                         Growing/Finishing Facility

                       Nursery Piglets        Growing Pigs

Weight Range (kg)           10-20                20-40
Simulated Pit
  Days in Analysis            13                   10
    Weight (kg)       13.9 [+ or -] 0.3    27.8 [+ or -] 1.8
    Temperature       26.1 [+ or -] 0.5    25.6 [+ or -] 0.7
      ([degrees]C)
    THP (W/kg)        6.18 [+ or -] 0.41   3.19 [+ or -] 0.20
    LHP (W/kg)        4.95 [+ or -] 0.20   2.95 [+ or -] 0.25
Flush System
  Days in Analysis            8                    6
    Weight (kg)       13.5 [+ or -] 1.4    30.2 [+ or -] 4.7
    Temperature       25.4 [+ or -] 0.4    25.6 [+ or -] 0.5
       ([degrees]C)
    THP (W/kg)        7.40 [+ or -] 0.41   4.27 [+ or -] 0.79
    LHP (W/kg)        5.71 [+ or -] 0.28   3.59 [+ or -] 0.49
Average
  Days in Analysis            21                   16
    Weight (kg)       13.7 [+ or -] 0.5    28.7 [+ or -] 1.9
    Temperature       25.8 [+ or -] 0.4    25.6 [+ or -] 0.5
      ([degrees]C)
    THP (W/kg)        6.64 [+ or -] 0.32   3.60 [+ or -] 0.32
    LHP (W/kg)        5.24 [+ or -] 0.18   3.19 [+ or -] 0.24

                      Growing/Finishing Facility

                       Early Finishing       Late Finishing
                             Pigs                 Pigs

Weight Range (kg)           40-80                80-130
Simulated Pit
  Days in Analysis            19                   27
    Weight (kg)       62.6 [+ or -] 2.5    104.5 [+ or -] 3.4
    Temperature       27.6 [+ or -] 0.4    23.5 [+ or -] 0.4
      ([degrees]C)
    THP (W/kg)        1.73 [+ or -] 0.08   1.33 [+ or -] 0.08
    LHP (W/kg)        1.22 [+ or -] 0.18   0.82 [+ or -] 0.05
Flush System
  Days in Analysis            21                   14
    Weight (kg)       57.5 [+ or -] 2.6    120.6 [+ or -] 2.6
    Temperature       26.8 [+ or -] 0.5    20.7 [+ or -] 0.6
       ([degrees]C)
    THP (W/kg)        2.11 [+ or -] 0.12   1.03 [+ or -] 0.12
    LHP (W/kg)        1.62 [+ or -] 0.15   0.81 [+ or -] 0.04
Average
  Days in Analysis            40                   41
    Weight (kg)       59.8 [+ or -] 1.8    109.1 [+ or -] 2.7
    Temperature       27.1 [+ or -] 0.4    21.7 [+ or -] 0.4
      ([degrees]C)
    THP (W/kg)        1.94 [+ or -] 0.08   1.24 [+ or -] 0.07
    LHP (W/kg)        1.40 [+ or -] 0.12   0.82 [+ or -] 0.03

                      Growing/Finishing
                           Facility

                           Mid-Late
                       Gestating Gilts

Weight Range (kg)          135-150
Simulated Pit
  Days in Analysis            7
    Weight (kg)       148.0 [+ or -] 0.4
    Temperature       20.4 [+ or -] 0.3
      ([degrees]C)
    THP (W/kg)        2.95 [+ or -] 0.50
    LHP (W/kg)        1.35 [+ or -] 0.30
Flush System
  Days in Analysis            6
    Weight (kg)       137.8 [+ or -] 0.4
    Temperature       20.4 [+ or -] 0.2
       ([degrees]C)
    THP (W/kg)        3.04 [+ or -] 0.70
    LHP (W/kg)        1.85 [+ or -] 0.53
Average
  Days in Analysis            13
    Weight (kg)       143.3 [+ or -] 1.5
    Temperature       20.4 [+ or -] 0.2
      ([degrees]C)
    THP (W/kg)        2.99 [+ or -] 0.37
    LHP (W/kg)        1.59 [+ or -] 0.27

* Mean ([+ or -] Standard Error [SE])

Table 5b. Summary of THP and LHP Data Taken in the
Facility Level Studies. Growing/Finishing/Gestating
Facility was Tested with Two Waste Handling Treatments
(Flushing/Simulated Pit) (I-P Units)

                                Growing/Finishing
                                    Facility

                                 Nursery Piglets

Weight Range (lb)                     10-20

Simulated Pit
  Days in Analysis                     13
    Weight (lb)                 30.6 [+ or -] 0.7
    Temperature ([degrees]F)    78.9 [+ or -] 0.9
    THP (Btu/lb x day)         230.1 [+ or -] 15.3
    LHP (Btu/lb x day)         184.3 [+ or -] 7.4
Flush System
  Days in Analysis                      8
    Weight (lb)                 29.7 [+ or -] 3.1
    Temperature ([degrees]F)    77.8 [+ or -] 0.7
    THP (Btu/lb x day)         275.5 [+ or -] 15.3
    LHP (Btu/lb x day)         212.6 [+ or -] 10.4
Average
  Days in Analysis                     21
    Weight (lb)                 30.2 [+ or -] 1.1
    Temperature ([degrees]F)    78.5 [+ or -] 0.6
    THP (Btu/lb x day)         247.2 [+ or -] 11.9
    LHP (Btu/lb x day)         195.1 [+ or -] 6.7

                                Growing/Finishing
                                    Facility

                                  Growing Pigs

Weight Range (lb)                     20-40

Simulated Pit
  Days in Analysis                     10
    Weight (lb)                 61.2 [+ or -] 4.0
    Temperature ([degrees]F)    78.1 [+ or -] 1.3
    THP (Btu/lb x day)         118.8 [+ or -] 7.4
    LHP (Btu/lb x day)         109.8 [+ or -] 9.3
Flush System
  Days in Analysis                      6
    Weight (lb)                66.4 [+ or -] 10.3
    Temperature ([degrees]F)    78.1 [+ or -] 1.0
    THP (Btu/lb x day)         159.0 [+ or -] 29.4
    LHP (Btu/lb x day)         133.7 [+ or -] 18.2
Average
  Days in Analysis                     16
    Weight (lb)                 63.3 [+ or -] 4.2
    Temperature ([degrees]F)    78.1 [+ or -] 0.9
    THP (Btu/lb x day)         134.0 [+ or -] 11.9
    LHP (Btu/lb x day)         118.8 [+ or -] 8.9

                                Growing/Finishing
                                     Facility

                               Early Finishing Pigs

Weight Range (lb)                     40-80

Simulated Pit
  Days in Analysis                      19
    Weight (lb)                 137.7 [+ or -] 5.5
    Temperature ([degrees]F)    81.6 [+ or -] 0.7
    THP (Btu/lb x day)          64.4 [+ or -] 3.0
    LHP (Btu/lb x day)          45.4 [+ or -] 6.7
Flush System
  Days in Analysis                      21
    Weight (lb)                 126.5 [+ or -] 5.7
    Temperature ([degrees]F)    80.2 [+ or -] 1.0
    THP (Btu/lb x day)          78.6 [+ or -] 4.5
    LHP (Btu/lb x day)          60.3 [+ or -] 5.6
Average
  Days in Analysis                      40
    Weight (lb)                 131.8 [+ or -] 4.0
    Temperature ([degrees]F)    80.8 [+ or -] 0.6
    THP (Btu/lb x day)          72.2 [+ or -] 3.0
    LHP (Btu/lb x day)          52.1 [+ or -] 4.5

                                Growing/Finishing
                                    Facility

                               Late Finishing Pigs

Weight Range (lb)                    80-130

Simulated Pit
  Days in Analysis                     27
    Weight (lb)                229.9 [+ or -] 7.5
    Temperature ([degrees]F)    74.3 [+ or -] 0.8
    THP (Btu/lb x day)          49.5 [+ or -] 3.0
    LHP (Btu/lb x day)          30.5 [+ or -] 1.9
Flush System
  Days in Analysis                     14
    Weight (lb)                265.3 [+ or -] 5.7
    Temperature ([degrees]F)    69.3 [+ or -] 1.0
    THP (Btu/lb x day)          38.3 [+ or -] 4.5
    LHP (Btu/lb x day)          30.2 [+ or -] 1.5
Average
  Days in Analysis                     41
    Weight (lb)                240.5 [+ or -] 6.0
    Temperature ([degrees]F)    71.0 [+ or -] 0.7
    THP (Btu/lb x day)          46.2 [+ or -] 2.6
    LHP (Btu/lb x day)          30.5 [+ or -] 1.1

                                  Growing/Finishing
                                       Facility

                               Mid-Late Gestating Gilts

Weight Range (lb)                      135-150

Simulated Pit
  Days in Analysis                        7
    Weight (lb)                   325.6 [+ or -] 0.9
    Temperature ([degrees]F)      68.7 [+ or -] 0.5
    THP (Btu/lb x day)           109.8 [+ or -] 18.6
    LHP (Btu/lb x day)            50.3 [+ or -] 11.2
Flush System
  Days in Analysis                        6
    Weight (lb)                   303.2 [+ or -] 0.9
    Temperature ([degrees]F)      68.7 [+ or -] 0.4
    THP (Btu/lb x day)           113.2 [+ or -] 26.1
    LHP (Btu/lb x day)            68.9 [+ or -] 19.7
Average
  Days in Analysis                        13
    Weight (lb)                   315.9 [+ or -] 3.3
    Temperature ([degrees]F)      68.7 [+ or -] 0.3
    THP (Btu/lb x day)           111.3 [+ or -] 13.8
    LHP (Btu/lb x day)            59.2 [+ or -] 10.1

* Mean ([+ or -] SE)

Table 6a. Farrowing Facility THP and MP from
Preparturition Until Weaning (SI Units)

                             Preparturition

Days Monitored                      6
Weight Sow, kg             183.2 [+ or -] 7.42
Weight Piglet, kg/piglet           --
Weight Sow + Litter, kg            --
THP, W/kg                  1.89 [+ or -] 0.28
LHP, W/kg                  1.27 [+ or -] 0.37

                               Birth-Day 7

Days Monitored                      29
Weight Sow, kg              182.8 [+ or -] 2.5
Weight Piglet, kg/piglet    1.92 [+ or -] 0.08
Weight Sow + Litter, kg     208.9 [+ or -] 8.7
THP, W/kg                  2.55 [+ or -] 0.20 *
LHP, W/kg                  2.09 [+ or -] 0.27 *

                                 Day 8-14

Days Monitored                      17
Weight Sow, kg              175.0 [+ or -] 2.0
Weight Piglet, kg/piglet    3.98 [+ or -] 0.15
Weight Sow + Litter, kg     221.5 [+ or -] 9.6
THP, W/kg                  3.80 [+ or -] 0.20 *
LHP, W/kg                  1.81 [+ or -] 0.20 *

                                Day 15-21

Days Monitored                      28
Weight Sow, kg              176.8 [+ or -] 1.7
Weight Piglet, kg/piglet    5.54 [+ or -] 0.12
Weight Sow + Litter, kg     248.8 [+ or -] 9.6
THP, W/kg                  3.77 [+ or -] 0.19 *
LHP, W/kg                  2.03 [+ or -] 0.17 *

                              Day 22-Weaning

Days Monitored                      10
Weight Sow, kg              177.8 [+ or -] 3.0
Weight Piglet, kg/piglet    6.78 [+ or -] 0.13
Weight Sow + Litter, kg    282.6 [+ or -] 19.5
THP, W/kg                  3.28 [+ or -] 0.16 *
LHP, W/kg                  1.62 [+ or -] 0.28 *

* THP per kg of sow + litter

Table 6b. Farrowing Facility THP and MP from
Preparturition Until Weaning (I-P Units)

                              Preparturition

Days Monitored                       6
Weight Sow, lb              402.9 [+ or -] 16.2
Weight Piglet, lb/piglet            --
Weight Sow + Litter, lb             --
THP, Btu/lb-day             70.2 [+ or -] 10.4
LHP, Btu/lb-day              47.2 [+ or -] 14

                                Birth-Day 7

Days Monitored                      29
Weight Sow, lb              402.2 [+ or -] 5.6
Weight Piglet, lb/piglet    4.22 [+ or -] 0.18
Weight Sow + Litter, lb     459.5 [+ or -] 8.7
THP, Btu/lb-day             95.1 [+ or -] 7.3 *
LHP, Btu/lb-day            77.8 [+ or -] 10.0 *

                                  Day 8-14

Days Monitored                       17
Weight Sow, lb               387.2 [+ or -] 4.4
Weight Piglet, lb/piglet     8.75 [+ or -] 0.32
Weight Sow + Litter, lb     487.3 [+ or -] 21.1
THP, Btu/lb-day             141.5 [+ or -] 7.3 *
LHP, Btu/lb-day             67.4 [+ or -] 7.3 *

                                 Day 15-21

Days Monitored                       28
Weight Sow, lb               388.9 [+ or -] 3.8
Weight Piglet, lb/piglet    12.19 [+ or -] 0.26
Weight Sow + Litter, lb     547.4 [+ or -] 21.0
THP, Btu/lb-day             140.2 [+ or -] 7.2 *
LHP, Btu/lb-day             75.7 [+ or -] 6.2 *

                               Day 22-Weaning

Days Monitored                       10
Weight Sow, lb               391.2 [+ or -] 6.6
Weight Piglet, lb/piglet     14.91 [+ or -] 0.29
Weight Sow + Litter, lb      621.8 [+ or -] 42.9
THP, Btu/lb-day             122.00 [+ or -] 6.3 *
LHP, Btu/lb-day             60.2 [+ or -] 10.4 *

* THP per kg of sow + litter

Table 7a. Summary of Facility-Level THP and LHP of Nursery, Growing,
and Finishing Pigs Exposed to Various Temperature Ranges (SI Units)

                            <21.1[degrees]C   21.1[degrees]C-
                                              23.9[degrees]C

Nursery        Days               --                 3
  Piglets      Weight, kg         --               16.7
               THP, W/kg          --           7.34 [+ or -]
                                                   0.07
               LHP, W/kg          --           5.35 [+ or -]
                                                   0.11
Growing Pigs   Days               --                 2
               Weight, kg         --               34.1
               THP, W/kg          --           2.32 [+ or -]
                                                   0.38
               LHP, W/kg          --           1.94 [+ or -]
                                                   0.14
Early          Days               --                 4
  Finishing    Weight, kg         --               44.1
  Pigs         THP, W/kg          --           2.53 [+ or -]
                                                   0.12
               LHP, W/kg          --           2.12 [+ or -]
                                                   0.09
Late           Days               15                14
  Finishing    Weight, kg        120.0             117.7
  Pigs         THP, W/kg     0.98 [+ or -]     1.14 [+ or -]
                                 0.12              0.11
               LHP, W/kg     0.81 [+ or -]     0.82 [+ or -]
                                 0.07              0.05

                            23.9[degrees]C-   >26.7[degrees]C
                            26.7[degrees]C

Nursery        Days               14                 4
  Piglets      Weight, kg        13.2              13.3
               THP, W/kg     7.04 [+ or -]     4.75 [+ or -]
                                 0.30              0.82
               LHP, W/kg     5.36 [+ or -]     4.76 [+ or -]
                                 0.22              0.59
Growing Pigs   Days                9                 5
               Weight, kg        29.0              26.0
               THP, W/kg     3.83 [+ or -]     3.69 [+ or -]
                                 0.51              0.42
               LHP, W/kg     3.17 [+ or -]     3.74 [+ or -]
                                 0.29              0.42
Early          Days               16                22
  Finishing    Weight, kg        56.2              65.3
  Pigs         THP, W/kg     1.99 [+ or -]     1.79 [+ or -]
                                 0.15              0.09
               LHP, W/kg     1.39 [+ or -]     1.26 [+ or -]
                                 0.16              0.15
Late           Days               10                 2
  Finishing    Weight, kg        86.6              95.8
  Pigs         THP, W/kg     1.62 [+ or -]     1.64 [+ or -]
                                 0.03              0.08
               LHP, W/kg     0.80 [+ or -]     0.86 [+ or -]
                                 0.07              0.50

                                Average

Nursery        Days               21
  Piglets      Weight, kg        13.7
               THP, W/kg     6.64 [+ or -]
                                 0.32
               LHP, W/kg     5.24 [+ or -]
                                 0.18
Growing Pigs   Days               16
               Weight, kg        28.7
               THP, W/kg     3.60 [+ or -]
                                 0.32
               LHP, W/kg     3.19 [+ or -]
                                 0.24
Early          Days               40
  Finishing    Weight, kg        59.8
  Pigs         THP, W/kg     1.94 [+ or -]
                                 0.08
               LHP, W/kg     1.40 [+ or -]
                                 0.12
Late           Days               41
  Finishing    Weight, kg        109.1
  Pigs         THP, W/kg     1.24 [+ or -]
                                 0.07
               LHP, W/kg     0.81 [+ or -]
                                 0.03

* Note: gestating gilt data was collected in the spring
and daily average temperatures were within 2[degrees]C;
and therefore, were not included in this table.

Table 7b. Summary of Facility Level THP and LHP of Nursery,
Growing, and Finishing Pigs Exposed to Various Temperature
Ranges (I-P Units)

                                 <70[degrees]F    70[degrees]F-
                                                   75[degrees]F

Nursery        Days                    --               3
  Piglets      Weight, lb              --              36.7
               THP, Btu/lb-day         --         273.2 [+ or -]
                                                       2.7
               LHP, Btu/lb-day         --         199.2 [+ or -]
                                                       4.8
Growing Pigs   Days                    --               2
               Weight, lb              --              75.0
               THP, Btu/lb-day         --         86.5 [+ or -]
                                                       14.2
               LHP, Btu/lb-day         --         72.4 [+ or -]
                                                       5.2
Early          Days                    --               4
  Finishing    Weight, lb              --               97
  Pigs         THP, Btu/lb-day         --         94.1 [+ or -]
                                                       4.5
               LHP, Btu/lb-day         --         78.7 [+ or -]
                                                       3.3
Late           Days                    15               14
  Finishing    Weight, lb             264             258.9
  Pigs         THP, Btu/lb-day   36.6 [+ or -]    42.4 [+ or -]
                                      4.3              4.0
               LHP, Btu/lb-day   30.1 [+ or -]    30.7 [+ or -]
                                      2.4              1.8

                                 75[degrees]F-    >80[degrees]F
                                  80[degrees]F

Nursery        Days                    14               4
  Piglets      Weight, lb              29              29.3
               THP, Btu/lb-day   261.9 [+ or -]   176.9 [+ or -]
                                      11.3             30.5
               LHP, Btu/lb-day   199.4 [+ or -]   177.1 [+ or -]
                                      8.1              21.8
Growing Pigs   Days                    9                5
               Weight, lb             63.8             57.2
               THP, Btu/lb-day   142.5 [+ or -]   137.5 [+ or -]
                                      18.9             15.5
               LHP, Btu/lb-day   118.1 [+ or -]   139.1 [+ or -]
                                      10.7             15.6
Early          Days                    16               22
  Finishing    Weight, lb            123.6            143.7
  Pigs         THP, Btu/lb-day   74.2 [+ or -]    66.7 [+ or -]
                                      5.6              3.4
               LHP, Btu/lb-day   51.6 [+ or -]    46.9 [+ or -]
                                      5.9              5.8
Late           Days                    10               2
  Finishing    Weight, lb            190.5            210.8
  Pigs         THP, Btu/lb-day   60.1 [+ or -]    61.2 [+ or -]
                                      1.3              3.0
               LHP, Btu/lb-day   29.9 [+ or -]    31.8 [+ or -]
                                      2.6              18.5

                                    Average

Nursery        Days                    21
  Piglets      Weight, lb             30.1
               THP, Btu/lb-day   237.3 [+ or -]
                                      0.32
               LHP, Btu/lb-day   5.24 [+ or -]
                                      0.18
Growing Pigs   Days                    16
               Weight, lb             63.1
               THP, Btu/lb-day   122.2 [+ or -]
                                      16.2
               LHP, Btu/lb-day   109.9 [+ or -]
                                      10.5
Early          Days                    40
  Finishing    Weight, lb            131.6
  Pigs         THP, Btu/lb-day   78.35 [+ or -]
                                      4.5
               LHP, Btu/lb-day   59.1 [+ or -]
                                      5.0
Late           Days                    41
  Finishing    Weight, lb             240
  Pigs         THP, Btu/lb-day   54.6 [+ or -]
                                      2.7
               LHP, Btu/lb-day   30.8 [+ or -]
                                      7.6

* Note: gestating gilt data was collected in the spring and
daily average temperatures were within 3.6[degrees]F; and
therefore, were not included in this table.

Table 8a. Comparison of Computed MP Rates of Heater, Facility, and
Pigs Compared to Measured Values (SI Units)

Phase of       Facility          Facility         Heater     Empty
Production    Temperature        Population      MP, g/s   Facility
                Range,           and Weight                 MP, g/s
              [degrees]C

                                #         kg

Nursery        23.6-28.5       539       14.8     0.23       3.17
Growing        21.6-28.0       421       27.4     0.12       3.08
Early          22.2-30.1       360       58.5     0.001      3.25
  Finishing
Late           19.2-26.1       320       100.9    0.04       2.57
  Finishing
Overall        19.2-30.1       340       79.7     0.02       2.91
  Finishing

Phase of       Pigs     Sum of Heater,    Facility         %
Production    MP, g/s    Facility and    Values, g/s   Difference
                          Pigs, g/s

Nursery        7.99         11.40           17.06        50.68
Growing        10.18        13.38           13.91         5.00
Early          12.63        15.88           17.04        10.86
  Finishing
Late           11.74        14.35           10.74        -23.67
  Finishing
Overall        12.18        15.12           13.89        -6.41
  Finishing

Table 8b. Comparison of Computed MP Rates of Heater,
Facility, and Pigs Compared to Measured Values (I-P Units)

Phase of             Facility      Facility      Heater MP,    Empty
Production          Temperature    Population      lb/h       Facility
                      Range,       and Weight                 MP, lb/h
                    [degrees]F

                                   #     lb

Nursery              74.7-83.5    539   32.5       1.86       25.11
Growing              71.0-82.6    421   60.2       0.96       24.36
Early Finishing      72.2-86.4    360   128.6      0.01       25.77
Late Finishing       66.8-79.1    320   221.9      0.34       20.39
Overall Finishing    66.8-86.4    340   175.3      0.17       23.08

Phase of            Pigs    Sum of Heater,   Facility   % Difference
Production           MP,     Facility and    Values,
                    lb/h      Pigs, lb/h       lb/h

Nursery             63.28        90.3         135.2        50.68
Growing             80.63       105.9         110.1         5.00
Early Finishing     99.99       125.8         135.0        10.86
Late Finishing      92.96       113.7          85.0        -23.67
Overall Finishing   96.48       119.7         110.0        -6.41
COPYRIGHT 2014 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE)
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2014 Gale, Cengage Learning. All rights reserved.

Article Details
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Author:Brown-Brandl, Tami M.; Li, Hong; Hayes, Morgan D.; Eigenberg, Roger A.; Xin, Hongwei; Stinn, John P.
Publication:ASHRAE Transactions
Article Type:Report
Geographic Code:1USA
Date:Jan 1, 2014
Words:14477
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