Printer Friendly

Effects of chilled drinking water on performance of laying hens during constant high ambient temperature.


Water is involved in every aspect of poultry metabolism. From a physiological perspective, water consumed by the bird is used for nutrient transportation, enzymatic and chemical reactions in the body, lubrication of joints and organs, and body temperature regulation (Fairchild and Ritz, 2006). At normal temperatures, poultry consume at least twice as much water as feed. When heat stress occurs, water consumption will double to quadruple (Carter and Sneed, 1987).

Poultry production efficiency is adversely affected by high ambient temperature and humidity. Several studies have been conducted on the effects of high environmental temperature and humidity on the performance of different poultry species, including broilers (Cooper and Washburn, 1998; Shim et al., 2006; Zulkifli et al., 2007; Yu and Bao, 2008), broiler breeders (Mc Daniel et al., 1995; Chung et al., 2005), young chickens (Henken et al., 1983), and laying hens (Miller and Sunde, 1975; Arima et al., 1976; Emery et al., 1984; Muiruri and Harrison, 1991; Whitehead et al., 1998; Mashaly et al., 2004), and have found that high environmental temperatures have deleterious effects on hen's productivity.

Laying hens are susceptible to heat stress for several reasons; their metabolic heat production is high (Blem, 2000), because there is little heat dissipation by convection and radiation, and in addition, hens have no sweat glands (Etches et al., 1995; Dawson and Whittow, 2000). Heat stress on laying hens depresses egg production (Arima et al., 1976; Muiruri and Harrison, 1991; Whitehead et al., 1998; Mashaly et al., 2004), egg weight (Miller and Sunde, 1975; Balnave and Muheereza, 1997), shell quality (Miller and Sunde, 1975; Arima et al., 1976; Emery et al., 1984; Mahmound et al., 1996), body weight (Scott and Balnave, 1988) and is generally accompanied by a reduction in feed intake, which could reduce egg production.

To alleviate the effects of heat stress on laying hens, several approaches have been examined over the years (Deaton et al., 1981; Smith, 1981; Carr and Carter, 1985; de Andrade et al., 1977; Balnave and Muheereza, 1997; Wolfenson et al., 2001; Awoniyi, 2003; Balnave, 2004; Seven, 2008). These are include: roof insulation, orientation of buildings to maximize natural ventilation, installation of fans to increase ventilation, evaporative cooling, and improving dietary nutrient requirements. The approaches to facilitate heat conduction, which are not used commercially in poultry farms, include provision of water-cooled floor-level perches inside the cages (Muiruri and Harrison, 1991; Reilly et al., 1991), immersion of hens' legs in cool water (van Kampen, 1988), and provision

of cool drinking water (Beker and Teeter, 1994; van Kampen, 1988).

There is little published information available regarding the effect of drinking water temperature on modern layers during heat exposure (Xin et al., 2002). Some layer farmers in South Korea have fed groundwater at 16[degrees]C (Sung, 1993) to laying hens subjected to heat stress and asserted that cool drinking water improves egg production of laying hens on summer days over 30[degrees]C. This study was conducted to evaluate the effect of 16[degrees]C chilled drinking water to the productivity of laying hens under 30[degrees]C constant ambient temperature.


Animal housing and management

The layers were randomly housed in a battery type metal wire cages. The dimensions of each cage was 60 x 60 x 40 cm each cage (6 layers/cage), having 3 floors with 12 division in each floor. Each floor were divided into two blocks and placed in a controlled chamber (4 x 4.2 x 2.6 m) with 30[degrees]C constant temperature. Each individual bird cage was equipped with a feeding and drinking station. For the chilled drinking water group (CDWG), water at 16.0[+ or -]0.5[degrees]C passed through from the chiller directly into the cup and nipple waterer (Jeon et al., 2006). Six birds in each cage were given 1 kg commercial feed daily (Table 1). Leftovers were collected and weighed the following day for feed intake analysis.

Experimental design

Total of seventy-two 123-day-old Hy-line brown layers weighing 1.3 to 1.7 kg were divided into two groups. Each group was replicated into six, and there were six hens in each replication. The first group (UDWG) was given unchilled drinking water (23.0[+ or -]2.5[degrees]C) and the second group (CDWG) was given chilled drinking water (16.0[+ or -]0.5[degrees]C). Water was available ad libitum. The hens brought from the experimental poultry house to the chambers were allowed a three-week adaptation period before the experiment. The hens were kept at 30[degrees]C constant temperature with approximately 50% relative humidity and were exposed to 17 h of light a day.

Data and sample collection

Feed intake was determined by collecting and weighing the leftovers in each cage the next day before feeding. Daily values for each replication were further averaged into weekly intervals. Egg production and egg quality were also determined on weekly basis. Eggs were collected and recorded daily at 3 pm. At the end of the week, the collected eggs were pooled and analyzed for each cage, basis for the egg quality analysis (egg weight, shell weight, egg shell strength, shell thickness (FHK, Japan), egg shell color, yolk color, and Haugh unit (TSS, England)). Eggs were weighed, and the shell strength was determined by a shell-breaking method shell strength analyzer (QC-SPA, TSS, England). Albumen height and Haugh Unit were evaluated with albumen height gauge (TSS-QCH, TSS, England). The device measures Haugh Unit by the method of Haugh (1973). Using the individual weight of each egg and the weight of its components, yolk percentage, albumen percentage and shell percentage were determined. Eggshell weight was determined after drying. At the end of the experiment, blood analyses were also conducted in an attempt to explain the observed differences. Blood analyses was done by collecting blood sample from 3 randomly selected hens from each treatment and transferred it into the reagent disc which were analyzed for approximately 12 minutes on a compact portable analyzer (VetScan, Germany).

Statistical analysis

The data were subjected to analysis of variance (ANOVA) using software (SAS, 1999) to compare the effects of providing chilled drinking water and unchilled drinking water on productivity of laying hens under high ambient temperature. We chose p<0.05 as the minimum acceptable level of significant, except for the blood analysis which we used a significant level of p<0.10 due to relatively small sample sizes. Results are presented as mean, standard deviation, and coefficient of variance.


The feed intake of laying hens that were given chilled drinking water under constant high ambient temperature was significantly higher (p<0.01) than that of the laying hens given unchilled drinking water (Table 2). This means that, providing chilled drinking water for laying hens under heat stress increases feed consumption. This finding was also observed in previous studies of Glatz (1997), Janssen and Musharaf (1984), Leeson and Summers (1975). In addition, Teeter et al. (1987) reported that KCl drinking water fortification increased feed consumption and growth rate when the temperature of consumed water was lower than the broiler's body temperature, and that lowering the water temperature without salt addition to stimulate water intake also proved to be beneficial. Puma et al. (2001) reported that broilers increased their feed and water intake under warm environmental conditions (35[degrees]C) when they were provided cooler drinking water in the range of 2032[degrees]C. Moreover, Degen and Kam (1998) concluded that roosters prefer cool drinking water than warm drinking water in both summer and winter. However, Xin et al. (2002) reported when 6 laying hens per treatment were given drinking water of 15, 19, 23, or 27[degrees]C under a diurnal air temperature of 27[degrees]C to 38[degrees]C feed intake was most for laying hens in the 23[degrees]C drinking water group. The differences between the observations of Xin et al. (2002) with the previous studies (Glatz, 1997; Puma et al., 2001) and our present results may be due to small sample size, age, and type of bird used, or due to the experimental methodology that was being applied.

The laying hens in the CDWG produced significantly more (p<0.001) eggs than those in the UDWG (Table 3). It seems that increasing the feed intake positively affect the intake of calcium and thus, egg production. Xin et al. (2002) also reported that decreased feed consumption during hot weather negatively affects the intake of calcium and other nutrients. Thus, in the present research, we hypothesized that increases in feed consumption increased calcium intake (Figure 1) and other nutrients needed for the productivity of heat-challenged hens. Furthermore, Mahmoud et al. (1996) suggested that alterations in pH balance, status of [Ca.sup.2+], and diminished ability of duodenal cells to transport calcium could be critical factors in the detrimental effects of heat stress on egg production, egg shell characteristics and skeletal integrity that are often documented in laying hens. Bar et al. (2002) reported that increasing dietary [Ca.sup.2+] from 24-25 to 36-40 gk/g improved egg production, shell weight, shell thickness, and decreased mortality.


Our assumption was also supported by our blood calcium concentration results. We observed that the blood calcium concentration in laying hens of the CDWG was 11.72% higher than the UDWG counterparts (p<0.10). Blood phosphorus concentration of laying hens in CDWG, was 12.53% higher than UDWG, although it was not statistically significant (p>0.10). Calcium is needed for bone and eggshell formation (Scanes et al., 2004), and calcium metabolism is involved in an array of factors, including phosphorus, micronutrients, vitamin D3, other hormones, and respiration (Silversides and Scott, 2001). A dietary phosphorus content of 4.5 g/kg appears to be sufficient for maintaining egg production and shell quality in aged laying hens given 36-40 g/kg calcium (Bar et al., 2002).

We observed that providing chilled drinking water to laying hens under high ambient temperature, did not show any direct influence on egg weight (Table 4) or egg quality (Table 5). According to Emery et al. (1984) the reduction in egg weight and shell thickness observed at cyclic temperatures were not simply results of a reduction in nutrient intake at high temperatures but also the direct affect of heat stress on the hens. This conclusion by Emery et al. (1984) was noted in pair-feeding layers under different temperature regiments, and suggested that feed intake alone will not rectify an egg weight or shell quality problem that might exist in the summer months. However, Deaton et al. (1986) reported that a difference in feed or nutrient intake was the causative factor for reduced egg weight. Contrary to the results of the present study, Xin et al. (2002) reported that egg weight of laying hens given 23[degrees]C and 27[degrees]C drinking water was heavier than that of hens given 15[degrees]C and 19[degrees]C drinking water under a diurnal air temperature of 27[degrees]C to 38[degrees]C. The differences could be due to the sample size, age, and type of bird used, or to the experimental methodology that was being applied. It was reported that egg weight is influenced by strain, age of the breeder flock and age at photostimulation (TAS, 2008). They reported that as the bird ages, the average egg weight initially increases. Accordingly, the average hen egg weight is determined by the age of the breeder hen, not by the time following photostimulation. This means that if a flock is photostimulated at younger age than the normal 29-30 weeks, the first eggs laid will be smaller. Conversly, if the flock is photostimulated at a later age, its first egg will be heavier. They added that the rate of egg production can have impact on egg size, whereby poor egg production tend to produce heavier eggs. Furthermore, factors such as high environmental temperatures (above 25[degrees]C), non-standard lighting regimes, and nutritional factors can affect egg size in laying hens.

The study showed that the feed intake and egg production of laying hens given chilled drinking water under constant high ambient temperature were significantly higher than those of the laying hens given unchilled drinking water. However, no significant differences were observed in egg weight or in egg quality. Calcium concentrations were higher in the CDWG birds than in the UDWG birds. Higher calcium concentrations may contribute to increased egg production of laying hens in the CDWG. In conclusion, providing chilled drinking for laying hens under high ambient temperature, improved their feed intake and egg productivity.


This research was supported by the MIC, Korea, under the ITRC support program supervised by the IITA (IITA-2008-(C1090-0801-0047)).

Received September 25, 2008; Accepted February 21, 2009


Arima, Y., F. B. Mather and M. M. Ahmad. 1976. Response of egg production and shell quality to increases environmental temperature in two age groups of hens. Poult. Sci. 55:818-820.

Awoniyi, T. A. M. 2003. The effect of housing on layer-chicken's productivity in the 3-tier cage. Intl J. Poult. Sci. 2(6):438-441.

Balnave, D. 2004. Challenges of accurately defining the nutrient requirements of heat stressed poultry. Poult. Sci. 83:5-14.

Balnave, D. and S. K. Muheereza. 1997. Improving egg shell quality at high temperature with dietary sodium bicarbonate. Poult. Sci. 76:558-593.

Bar, A., V. Razaphkovsky and E. Var. 2002. Re-evaluation of calcium and phosphorus requirements in aged laying hens. Br. Poult. Sci. 43(2):261-269.

Beker, A. and R. G. Teeter. 1994. Drinking water temperature and potassium chloride supplementation effects on broiler body temperature and performance during heat stress. J. Appl. Poult. Res. 3:87-92.

Blem, C. R. 2000. Energy balance. Pages 327-341 in: Sturkie's Avian Physiology. 5th ed. (Ed. G. C. Whittow). Academic Press, New York, NY.

Carr, L. and T. Carter. 1985. Housing and management of poultry in hot and cold climates. pp. 73-110 In: Stress physiology in livestock. Poult. Vol. 3 (Ed. M. K. Yousef) CRC Press, Boca Raton, FL.

Carter, T. A. and R. E. Sneed. 1987. Drinking water quality for poultry. PS&T Guide No. 42, Extension Poultry Science, North Carolina state University, Raleigh. NC.

Chung, M. K., J. H. Choi, Y. K. Chung and K. M. Chee. 2005. Effects of dietary vitamins C and E on egg shell quality of broiler breeder hens exposed to heat stress. Asian-Aust. J. Anim. Sci. 18:545-551.

Cooper, M. A. and K. W. Washburn. 1998. The relationship of body temperature to weight gain, feed consumption, and feed utilization in broilers under heat stress. Poult. Sci. 77:237-242.

Dawson, W. R. and G. C. Whittow. 2000. Regulation of body temperature. pp. 343-390. In: Sturkie's avian physiology. 5th ed. (Ed. G. C. Whittow). Academic Press, New York, NY.

de Andrade, A. N., J. C. Rogler, W. R. Featherston and C. W. Alliston. 1977. Interrelationships between diet and elevated temperatures (cyclic and constant) on egg production and shell quality. Poult. Sci. 56:1178-1188.

Deaton, J. W., F. N. Reece, J. L. McNauhton and B. D. Lott. 1981. Effect of differing temperature cycles on egg shell quality and layer performance. Poult. Sci. 60:733-737.

Deaton, J. W., F. N. Reece and B. D. Lott. 1986. Effect of summer cyclic temperatures versus moderate temperature on laying hen performance. Poult. Sci. 65:1649-1651.

Degen, A. and M. Kam. 1998. Roosters prefer cool drinking water in both summer and winter. Appl. Poult. Res. 7:258-262.

Emery, D. A., P. Vohra, R. A. Ernst and S. R. Morrison. 1984. The effect of cyclic and constant ambient temperatures on feed consumption, egg production, egg weight, shell thickness of hens. Poult. Sci. 63:2027-2035.

Etches, R. J., M. John and G. A. M. Verrinder-Gibbins. 1995. Behavioral, physiological, neuroendocrine and molecular responses to heat stress. pp. 31-66 In: Poultry production in hot climates (Ed. N. J. Daghir). CAB International, Cambridge, UK.

Fairchild, B. D. and C. W. Ritz. 2006. Poultry drinking water primer. Accessed Jun. 14, 2008.

Glatz, P. C. 1997. Ideal drinking water temperature for layers. Accessed Jun. 12, 2008 (Abstr).

Haugh, R. R. 1973. The Haugh Unit for measuring egg quality. US Egg Poult. Mag., 43:599-602.

Henken, A. M., A. M. J. Groote Schaarsberg and M. G. B. Nieuwland. 1983. The effect of environmental temperature on immune response and metabolism of the young chicken. Poult. Sci. 62:51-58.

Janssen, W. M. M. A. and N. A. Musharaf. 1984. Effects of water temperature and feed density on the performance of laying hens kept under thermal stress. pp. 1-12. In: Proc, Intl. Poultry Conf., Frankfurt, Germany.

Jeon, J. H., S. C. Yeon, Y. H. Choi, W. Min, S. Kim, P. J. Kim and H. H. Chang. 2006. Effects of chilled drinking water on the performance of lactating sows and their litters during high ambient temperatures under farm conditions. Livest. Sci. 105:86-93.

Leeson, S. and J. D. Summers. 1975. Cool water during heat stress results in more eggs. Poult. Digest. 34:369-370.

Mahmoud, K. Z., M. M. Beck, S. E. Scheideler, M. F. Forman, K. P. Anderson and S. D. Kachman. 1996. Acute high environmental temperature and calcium-estrogen relationship in the hen. Poult. Sci. 75:1555-1562.

Mashaly, M. M., G. L. 3rd Hendricks, M. A. Kalama, A. E. Gehad, A. O. Abbas and P. H. Patterson. 2004. Effect of heat stress on production parameters and immune responses of commercial laying hens. Poult. Sci. 83:889-894.

McDaniel, C. D., R. K. Bramwell, J. L. Wilson and B. Howarth, Jr. 1995. Fertility of male and female broiler breeders following exposure to elevated ambient temperatures. Poult. Sci. 74:1029-1038.

Miller, P. C. and M. L. Sunde. 1975. The effects of precise constant and cyclic environments on shell quality and other lay performance factors with leghorn pullets. Poult. Sci. 54:36-46.

Muiruri, H. K. and P. C. Harrison. 1991. Effect of peripheral foot cooling on metabolic rate and thermoregulation of fed and fasted chicken hens in a hot environment. Poult. Sci. 70:74-79.

Puma, M. C., H. Xin, R. S. Gates and D. J. Burnham. 2001. An instrumentation system for measuring feeding and drinking behavior of individual poultry. Appl. Eng. Agric. 17:365-374.

Reilly, W. M., K. W. Koelkebeck and P. C. Harrison. 1991. Performance evaluation of heat-stressed commercial broilers provided water-cooled floor perches. Poult. Sci. 70:1699-1703.

SAS. 1999. PC SAS Version 8.0 SAS Institute Inc., Cary, NC.

Scanes, C. G., G. Brant and M. E. Ensminger. 2004. Poultry minerals. pp. 86. In: Poultry science. 4th ed. Pearson Education, Inc., Upper Saddle River, New Jersey.

Scott, T. A. and D. Balnave. 1988. Comparison between concentrated complete diets and self-selection for feeding sexually-maturing pullets at hot and cold temperatures. Br. Poult. Sci. 29:613-625.

Seven, P. T. 2008. The effects of dietary propolis and vitamin C on performance, digestability, egg production and egg quality in laying hens under different environmental temperatures. Asian-Aust. J. Anim. Sci. 21:1164-1170.

Shim, K. S., K. T. Hwang, M. W. Son and G. H. Park. 2006. Lipid metabolism and peroxidation in broiler chicks under chronic heat stress. Asian-Aust. J. Anim. Sci. 19:1206-1211.

Silversides, F. G. and T. A. Scott. 2001. Effect of storage and layer age on quality of eggs from two lines of hens. Poult. Sci. 80:1240-1245.

Smith, W. K. 1981. Poultry housing problems in the tropics and subtropics. pp. 235-258 In: Environmental aspects of housing for animal production (Ed. J. A. Clark). Butterworths, London, UK.

Sung, I. H. 1993. Analysis of temperature variations in groundwater in the Taegu area. The Journal of Engineering Geology 3(3):267-278.

TAS. 2008. Egg weight. 20Weight.pdf Accessed Feb. 5, 2009.

Teeter, R. G., M. O. Smith, S. Sangiah and F. B. Mather. 1987. Effects of feed intake and fasting duration upon body temperature and survival of thermostressed broilers. Nutrition Reports International 35:531-537.

van Kampen, M. 1988. Effects of drinking water temperature and leg cooling on heat stress of laying hens (Gallus domesticus). J. Thermal. Biol. 13:43-47.

Whitehead, C. C., S. Bollengier-Lee, M. A. Mitchell and P. E. V. Williams. 1998. Alleviation of depression in egg production in heat stressed laying hens by vitamin E. pp. 576-578. In: Proceeding of 10th European Poultry Conference, Jerusalem, Israel.

Wolfenson, D., D. Bacharach, M. Maman, Y. Graber and I. Rozenboim. 2001. Evaporative cooling of ventral regions of the skin in heat-stressed laying hens. Poult. Sci. 80:958-964.

Xin, H., R. S. Gates, M. C. Puma and D. U. Ahn. 2002. Drinking water temperature effects on laying hens subjected to warm cyclic environments. Poult. Sci. 81:608-617.

Yu, J. and E. Bao. 2008. Effect of acute heat stress on heat shock protein 70 and its corresponding mRNA expression in the heart, liver, and kidney of broilers. Asian-Aust. J. Anim. Sci. 21:1116-1126.

Zulkifli, I., N. N. Htin, A. R. Alimon, T. C. Loh and M. Hair-Bejo. 2007. Dietary selection of fat by heat-stressed broiler chickens. Asian-Aust. J. Anim. Sci. 20:245-251.

W. M. Gutierrez, W. Min (1) and H. H. Chang (*)

Department of Animal Science, College of Agriculture and Life Sciences Gyeongsang National University, Jinju 660-701, Korea

(*) Corresponding Author: H. H. Chang. Tel: +82-55-7515510, Fax: +82-55-7567171, E-mail:

(1) College of Veterinary Medicine, Gyeongsang National University, Jinju 660-701, Korea.
Table 1. Composition of diets fed to laying hens

Ingredients (%) Composition

Corn 55.00
Wheat bran 9.70
Soybean meal 20.00
Corn gluten meal 5.00
Salt 0.30
Vitamin-mineral premix (1) 0.50
L-lysine 0.50
DL-methionine 0.50
Limestone 7.50
Tricalcium phosphate 1.00
Calculated nutrient composition (2)
ME (kcal/kg, %) 2740
Crude protein (%) 15.50
Lysine (%) 0.70
Methionine (%) 0.30
Calcium (%) 3.30
Phosphorus (%) 1.00

(1) Provided following nutrients per kg of diet: vitamin A, 123,000
IU; vitamin [D.sub.3,] 2,500 IU; vitamin E, 20 IU; riboflavin, 5.6 mg;
pyridoxine, 1.6 mg; vitamin [B.sub.12,] 14 mg; niacin, 30 mg;
panthothenic acid, 12 mg; folic acid, 1.0 mg; biotin, 0.12 mg.

(2) Calculated based on the feed ingredient composition data from
manufacturer's value.

Table 2. Feed intake (g/bird/7 d) of laying hens given unchilled
drinking water or chilled drinking water under heat stress

 CV p-
Experimental UDWG (1) CDWG (2) (5) value
period (wk) (n (3) = 36) (n = 36)
 Mean [+ or -] SD (4) Mean [+ or -] SD

1 599 [+ or -] 38 (4,B) 703 [+ or -] 17 (A) 4.5 0.0001
2 763 [+ or -] 72 837 [+ or -] 56 8.1 0.0739
3 745 [+ or -] 69 (b) 825 [+ or -] 36 (a) 7.0 0.0285
4 747 [+ or -] 42 (b) 820 [+ or -] 60 (a) 6.6 0.0352
Overall 713 [+ or -] 86 (B) 796 [+ or -] 70 (A) 10.4 0.0007

(1) UDWG = Unchilled drinking water group.

(2) CDWG = Chilled drinking water group.

(3) n = Nnumber of laying hens.

(4) Mean [+ or -] SD.

(5) CV = Coefficient of variance.

(A,B) Means with different superscripts in the same row differ with
statistical significance of p<0.01.

(a,b) Means with different superscripts in the same row differ with
statistical significance of p<0.05.

Table 3. Egg production (%) of laying hens given unchilled drinking
water or chilled drinking water under heat stress


Experimental UDWG (1) CDWG (2)
period (wk) (n (3 = 36)) (n = 36)
 Mean [+ or -] Mean [+ or -]
 SD (4) SD

1 73.4 [+ or -] 3.9 (4, b) 78.2 [+ or -] 4.1 (a)
2 75.4 [+ or -] 4.4 78.2 [+ or -] 5.9
3 68.7 [+ or -] 3.8 (B) 82.1 [+ or -] 7.2 (A)
4 69.0 [+ or -] 6.9 (b) 80.6 [+ or -] 3.9 (a)
Overall 71.7 [+ or -] 5.4 (B) 79.7 [+ or -] 5.4 (A)

 CV (5) p-value
period (wk)

1 5.3 0.0445
2 6.7 0.3344
3 7.6 0.0009
4 7.5 0.0050
Overall 7.2 0.0001

(1) UDWG = Unchilled drinking water group.
(2) CDWG = Chilled drinking water group.
(3) n = Nnumber of laying hens.
(4) Mean [+ or -] SD.
(5 CV = Coefficient of variance.)

(A,B) Means with different superscripts in the same row differ with
statistical significance of p<0.001.

(a,b) Means with different superscripts in the same row differ with
statistical significance of p<0.05.

Table 4. Egg weight (g) of laying hens given unchilled drinking
water or chilled drinking water under heat stress

 CV p-value
Experimental UDWG (1) CDWG (2) (5)
period (wk) (n (3) = 36)) (n = 36)
 Mean [+ or -] SD4 Mean [+ or -] SD

1 51.0 [+ or -] 3.44 51.4 [+ or -] 6.3 9.8 0.8244
2 48.2 [+ or -] 3.4 48.0 [+ or -] 4.9 8.7 0.2607
3 51.0 [+ or -] 3.4 51.4 [+ or -] 6.3 9.8 0.8244
4 51.8 [+ or -] 3.0 51.6 [+ or -] 2.9 5.7 0.6909
Overall 50.5 [+ or -] 3.5 50.6 [+ or -] 5.4 9.0 0.7367

(1) UDWG = Unchilled drinking water group.
(2) CDWG = Chilled drinking water group.
(3) n = Number of laying hens.
(4) Mean [+ or -] SD.
(5) CV = Coefficient of variance.

Table 5. Overall means of egg quality parameters of laying hens given
unchilled drinking water or chilled drinking water under heat stress


Parameters UDWG (1)(n (3)= 36) CDWG (2(n = 36))
 Mean [+ or -] Mean [+ or -]

Egg shell 5.47 [+ or -] 0.264 5.41 [+ or -] 0.33
(kg/cm (2))
Egg shell 36.65 [+ or -] 3.24 38.13 [+ or -] 2.31
([micro] m)
Egg shell color 23.31 [+ or -] 0.73 24.23 [+ or -] 0.92
Egg yolk color 6.50 [+ or -] 2.92 6.24 [+ or -] 2.93
Haugh unit 111.46 [+ or -] 15.15 103.03 [+ or -] 2.18

Parameters CV (5) p-value

Egg shell 6.7 0.7517
(kg/cm (2))
Egg shell 7.1 0.3056
([micro] m)
Egg shell color 5.4 0.6104
Egg yolk color 8.5 0.5785
Haugh unit 7.8 0.5642

(1) UDWG = Unchilled drinking water group.
(2) CDWG = Chilled drinking water group.
(3) n = Number of laying hens.
(4) Mean [+ or -] SD.
(5) CV = Coefficient of variance.
COPYRIGHT 2009 Asian - Australasian Association of Animal Production Societies
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2009 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Author:Gutierrez, W.M.; Min, W.; Chang, H.H.
Publication:Asian - Australasian Journal of Animal Sciences
Article Type:Report
Geographic Code:9SOUT
Date:May 1, 2009
Previous Article:Inclusion of dried bakery product in high fat broiler diets: effect on pellet quality, performance, nutrient digestibility and organ weights.
Next Article:Effects of Ligustrum lucidum fruits on growth performance, antioxidation and meat quality in arbor acres broilers.

Related Articles
Effects of dietary dihydropyridine supplementation on laying performance and fat metabolism of laying hens.
Quality of duck breast and leg meat after chilling carcasses in water at 0, 10 or 20[degrees]C.
Changes in behaviour of laying hens following beak trimming at hatch and re-trimming at 14 weeks.
Effects of dietary inclusion of palm kernel cake and palm oil, and enzyme supplementation on performance of laying hens.
The effects of dietary Turkish propolis and vitamin C on performance, digestibility, egg production and egg quality in laying hens under different...
Probiotics in drinking water alleviate stress of induced molting in feed-deprived laying hens.
Evaluation of [delta]-aminolevulinic acid on serum iron status, blood characteristics, egg performance and quality in laying hens.
Seasonal production performance of Angora rabbits under sub-temperate Himalayan conditions.
Extreme pipetting: soaking wet at Olympic National Park: Doreen Rumery, Laboratory Technical Manager and Quality Control Manager, and Bjoern Carle,...
An experimental study in passive cooling systems and investigation of their role in consumption and diminishing environmental pollutants.

Terms of use | Privacy policy | Copyright © 2018 Farlex, Inc. | Feedback | For webmasters