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MULTIVARIATE ANALYSIS OF MORPHOLOGICAL CHARACTERISTICS OF AWASSI SHEEP IN THE WEST BANK, PALESTINE.

Byline: Jihad M. Abdallah and Jamal Abo Omar

ABSTRACT

A field surveywasconducted to characterizelocal Awassi sheep in the West Bank, Palestine. A total of 130 sheep flocks were sampled over thirteen districts in the Southern, Central and Northern geographical regions. Body characteristics (qualitative and quantitative traits) were recorded on 130 rams aged 1 to 4 years and 520 ewes (first through fourth parities). Significant differences were found among regions in qualitative and quantitative traits. The multivariate analyses on quantitative traits identified five traits for rams and ten traits for ewes which were significant in discriminating Awassi sheep populations of the three regions. The largest squared Mahalanobis distances were found between the Southern and Northern regions (31.83 for rams and 49.51 for ewes) and the smallest distances were found between the Central and Northern regions (4.28 for rams and 5.23 for ewes) consistent with geographical distances.

Discriminant analysis showed that 85.4% of rams and 89.4% of ewes were correctly classified into their geographic areas with highest rates found for the Southern region (97.5% of rams and 100% of ewes were correctly classified). These results form the basis for the development of future characterization and conservation plans of Awassi sheep.

Keywords: Awassi sheep, Palestine, morphological characteristics, multivariate, discriminant analysis.

INTRODUCTION

Awassi sheep is a fat-tailed breed which is well adapted to harsh arid areas (Said et al., 1999) and is widespread in the Middle East(Epstein, 1985; Hailat, 2005; Tabbaa et al., 2001; Zarkawi et al., 1999). Besides Awassi, Assaf and Awassi x Assaf sheep are also raised in Palestine. Awassi sheep are characterized by their large fat-tail. Assaf breed has long thin tail and was developed by crossing Awassi with East Friesian sheep with original gene proportions of 5/8 Awassi and 3/8 East Friesian (Goot, 1986). Awassi x Assaf sheep are locally named "half-tailed" because they have distinctively smaller tail than Awassi. The Awassi population in the West Bank has been decreasing over recent years. In 2007, Awassi represented the major sheep breed (68%), while Assaf and Awassi x Assaf represented 32% (PCBS, 2007). In 2010, Awassi represented 54.5% of the total West Bank sheep population while Assaf and Awassi x Assaf accounted for 45%, (PCBS, 2011).

A more recent investigation by the Ministry of Agriculture(MoA, 2013, unpublished) found that Awassi only comprised about 20% of the total sheep population in the West Bank.This alarming trend emphasizes the need for an urgent conservation plan.

Characterization of indigenous livestock genetic resources are essential for planning national domestic animal diversity and conservation plans (FAO, 2012). Morphological characterization is the first step before performing molecular genetic characterization.

Severalauthors studied performance and morphological characteristics of Awassisheep in neighbor countries (Abdullah et al., 2015; Abdullah and Tabbaa, 2011; Alnimer et al., 2005; Al-Tarayrah and Tabbaa, 1999; Eliya and Juma, 1970; El-Sabeh and El-Najar, 1988; Galal et al., 2008; Gootwine and Pollot, 2000; Hailat, 2005; Kridli et al., 2009; Tabbaa, 1998; Tabaa, 2003; Tabbaa et al., 2001; Talafha and Ababneh, 2011). In Palestine, although some authors attempted to described milk production and reproductive performance of Awassi sheep (e.g., Abdallah, 1996 and Ahmad and Abdallah,2013),there is still a lack of information on morphological characteristics (both qualitative and quantitative) of this important breed. The main objectives of this study were to describe the qualitative and quantitative morphological characteristics of Awassi sheep of the West Bank and investigate if differences exist among geographical areas.

MATERIALS AND METHODS

Study Location: Palestine is composed of two provinces: the West Bank and Gaza Strip. The West Banks islocated 32 00 N, 35 15 E and has a total area ofabout 5900 km2. The altitude varies from - 408m to 1022m. It has warm to hot summers and mild to cold winters. It is composed of thirteen districts geographically grouped into three regions: the Southern region includes Yatta, Dora, Hebron and Betlehem; the Central region includes Jerusalem, Ramallah, Jericho, and Salfit; the Northern region includes Qalqilia, Nablus, Tulkarm, Jenin, and Tubas.

Sampling Procedure: Within each district, 10 flocks raising Awassi sheep were randomly selected (a total of 130 flocks were sampled). Five adult animals (four ewes and one ram) were selected from each flock for a total of 520 ewes and 130 rams (40 ewes and 10 rams from each district). Selected rams were more than one year old while ewes were selected if they have given at least one birth.Sampling of ewes in each herd was such that the four selected ewes in the same flock were of different parities.

Data Collection: The data were collected in late summerof 2015 by animal husbandry technicians and filled using questionnaires prepared for this purpose. Two on-farm training sessions were held for technicians before starting data collection. Information were obtained on flock size and composition (no of breeding and replacement animals), different breeds raised and proportion of Awassi in the flock, % of horned males and females at the flock level. Flock characteristics were obtained through observation of the flocks on site and questioning of farmers.The morphological characteristics studied and measurement methods were according to the FAO Animal Production Health Guidelines (FAO, 2012). Qualitative characteristics included body color, coat color pattern, presence of horns, horn shape and orientation, ear shape and orientation, head (facial) profile, and backline profile.

Quantitative morphometric characteristics included body length, chest girth, chest depth, height at withers, pelvic width, ear length, ear width,horn length, tail length, head length, headwidth,teat length, and scrotal circumference. Quantitative characteristics were measured using regular and flexible tapes calibrated in centimeters. Animals were measured while held in upright position on a flat floor.

Statistical Analyses: Qualitative variables were subjected to analysis in SPSS statistical package (SPSS, 2007). Frequencies were calculated by region and sex and Fisher's Exact test was used to test for differences in the distribution of qualitative characteristics among regions and between males and females. Statistical analyses on quantitative characteristics were carried out using the SAS/STAT package (SAS, 2002). Preliminary analyses showed significant differences between males and females and thus the data were analyzed separately by sex. Descriptive statistics for quantitative traits(means and coefficients of variation) were obtained using the MEANS procedure. The effects of region on measured traits were assessed using the GLM procedure fitting a model with region and age for rams (two classes: 1-2yr, and [greater than or equal to] 3yr) or parity (1 to 4) for ewes.

Initially, a stepwise discriminant analysis was performed using the STEPDISC procedure to identify variables which are important in discrimination among regions. These variables were then used in the SCANDISC and DISCRIM procedures to derive the canonical functions and compute the percentage of correct assignment of each animal to its sampling region.In the canonical analysis, squared Mahalanobis distances were obtained to test differentiation among regions.

RESULTS

Flock Characteristics: Characteristics of sampled sheep flocks are in Table 1. Overall average flock size was 127.8 heads (ranged from 17 to 596 heads). Average flock size was lowest for the Central districts (89.1 heads) and highest for the Northern districts (150.6 heads). Female to male ratio was about 20 ewes per ram and percent of replacements was about 18% in accordance with the worldwide breeding practices. Average percentage of horned animals at the flock level was about 70% for males and about 20% for females. All sampled flocks in the Southern region and 98% in the Northern region kept only Awassi breed, while 75% of sampled flocks in the Central districts raised Awassi x Assaf and 7.5% raised Assaf in their flocks besidesthe Awassi breed.

Qualitative Characteristics: Qualitative characteristics of Awassi sheep are presented by sex (Table 2) and by region (Table 3). Fisher's Exact test showed highly significant differences (P 0.05) for body color, coat color pattern, ear shape, and ear orientation. Highly significant differences were found among regions (P 0.05). Most of Awassi sheep sampled (71.95%) were of white body with brown heads (69.5 of ewes and 81.4% of rams) with plain coat color pattern (about 90%). However, the Northern region had lower percentage of white body and brown head sheep (62.2%) than the Southern and Central regions (79.4 and 76.4%, respectively). About 80% of rams were horned compared to about 25% of ewes.

The percentage horned was highest for the Southern region (61.3%) and lowest in the central region (19.9%). The percentages of horned males and females found at the individual level are in agreement with those found at the flock level.Horns of males were mostly spiral (52.0%) or curved (26.5%) in shape with backward orientation (88.1%). About two-thirds of males and females had semi-pendulous and pendulous ears. About half of ewes and rams had straight head profile and about one third had a convex head. However, 47.2% ofsheep in the Southern region had concave heads while these were nearly absent in the Central and Northern regions. About two-thirds of sampled Awassi sheep hada straight backline (64% of ewes and 74% of rams).

Quantitative Characteristics: Raw means and significance of region and age class (or parity) of quantitative characteristicsare in Table 4. Body measurements indicate that Awassi sheep are generally of medium size. As expected, rams had larger size than ewes (averages of body length, wither height, chest circumference, chest depth, and pelvic width were respectively 87.83, 90.12, 108.05, 54.58, 28.77 cm for rams and 78.39, 79.17, 99.87, 50.23, and 25.74 cm for ewes) and particularly longer horns (43.81 cm vs. 9.52 cm). Head length and head width were 28.72 cm and 11.89 cm for rams and 27.31 and 10.50 cm for ewes. Ear length and ear width were very similar in both sexes (20.45 and 10.88 cm for rams; 20.59 and 10.81 cm for ewes). Tail length averaged 28.52 cm for rams and 26.42 cm for ewes.Teat length averaged 4.38 cm and scrotal circumference averaged 33.18 cm.

Highly significant differences (P 0.05). For rams, differences among regions were highly significantin pelvic width, head length, headwidth, ear length, ear width, and tail length (P < 0.0001) and in chest girth and scrotal circumference (P 0.05).

No significant differences were found by age class (for rams) and parity was only significant for chest girth (P < 0.001), head length (P < 0.01) and ear length (P < 0.05). Least squares means of quantitative traits by region are in Table 5. The Southern region had higher means of head length, headwidth, ear length, ear width, and tail length than the Central and Northern regions for both rams and ewes but had the lowest means for chest girth, chest depth, pelvic width and scrotal circumference.

The stepwise discriminant analysis identified five traits for rams and ten traits for ewes (Table 6) which were significant discriminant traits among Awassi animals in different regions. These traits were then used in the canonical and discriminant analyses. Tail length, headwidth, and pelvic width had the highest discriminating power for both sexes as indicated by their high partial R2 and F values. This was also confirmed by the bi-dimensional plots constructed with the standardized canonical discriminant coefficients (Figures 1 and 2).

The canonical analysis on the data for ramsidentified two statistically significant (P < 0.001) canonical variables, CAN1 and CAN2. These functions respectively accounted for 95.5% and 4.5% of the total variation.The pair-wise squared Mahalanobis distances between areas(Table 7) were all highly significant (P < 0.0001).The squared distances found between the Southern region and each of the Central and Northern regions(16.44 and 31.83, respectively) were larger than that found between the Central and the Northern region (4.28). For ewes, twosignificant canonical functions were also identified (P < 0.001) accounting respectively for 96.9% and 3.1% of the total variation.Pair-wise squared Mahalanobis distances between areas (Table 7) were all highly significant (P < 0.0001).

The same trends found for rams were also found for ewes, i.e., higher distances between the Southern and Central region (27.06) and between the Southern and Northern regions (49.51) than between the Central and Northern regions (5.23). These results for males and females were confirmed by the Bi-dimensional plots constructed from CAN1 and CAN2 to illustrate the differentiation between regions (Figures 3 and 4).These plots show that the first canonical function (CAN1) separated well the sheep populations in the three areas. The multivariate statistics testing differences among sampling areas (Wilks' lambda, Pillai's trace, Hotelling-Lawley trace and Roy's greatest root) were all highly significant (P < 0.0001) for both sexes.

The correct assignment of rams to their geographic area(Table 8) ranged from 70% (for the Central region) to 97.5% (for the Southern region) with 85.4% of the total sample correctly assigned (overall error count estimate of 14.6%). For ewes, the correct classification rate ranged from 74.4% for the Central region to 100%for the Southern region (Table 9). The overall percentage of the female sample correctly classified was 89.4% (overall error count rate of 10.6%).Most misclassifications were between the Central and Northern regions (only one ram from the Southern region was incorrectly classified in the Central region and three ewes from the Central region were incorrectly classified in the Southern region).

Table 1. Main characteristics of sampled flocks1 raising Awassi sheep in the West Bank, Palestine.

Characteristic###Region 1###All

###Southern###Central###Northern###(n = 130)

###(n = 40)###(n = 40)###(n = 50)

###mean SD

Flock size 2###143.068.3###89.1 48.2###150.6115.4###127.890.8

Female to male ratio 3###19.17.0###20.89.4###21.99.8###20.99.1

% Replacement animals, 4###14.53.6###16.26.0###20.58.4###17.67.2

% Horned males###96.93.4###68.032.6###53.838.1###68.635.4

% Horned females###51.623.0###8.418.4###8.815.8###18.625.5

###% of flocks

proportion of Awassi breed in the flock

###<50%###0###30.0###0.0###10.3

###50-80%###0###45.0###2.0###16.2

###100%###100###25.0###98.0###73.5

% of flocks raising also Assaf breed###0###7.5###2.0###3.4

% of flocks raising also Awassi x Assaf###0###75###0###25.6

breed

Table 2. Frequency of class levels of qualitative characteristics of Awassi sheep by sex.

Characteristic###P value1###Ewes###Rams###Total

###(n = 520)###(n = 130)###(n = 650)

###% (Number)

Body color###0.057###White body, brown head###69.5 (357)###81.4(105)###71.95(462)

###White body, black head###6.6 (34)###3.1(4)###5.9 (38)

###White body and head###8.8(45)###7.8(10)###8.6(55)

###Black or black and white body,###10.1(52)###3.9(5)###8.9(57)

###black or black and white head

###Brown or brown and white###5.1(26)###3.9(5)###4.8(31)

###body, brown head

Coat color pattern###0.119###Plain###88.4(456)###94.6(122)###89.6(578)

###Patchy###8.3(43)###3.9(5)###7.4(48)

###Spotted###3.3(17)###1.6(2)###2.9(19)

Presence of horns###< 0.001###Horned###24.9(126)###79.1(102)###35.9(228)

###Polled###75.1(380)###20.9(27)###64.1(407)

Horn shape###< 0.001###Scurs###26.2 (33)###5.9(6)###17.1(39)

###Straight###34.9(44)###15.7(16)###26.3(60)

###Curved###24.6(31)###26.5(27)###25.4(58)

###Spiral###14.3(18)###52.0(53)###31.1(71)

Horn orientation###< 0.001###Lateral###16.0(20)###7.9(8)###12.4(28)

###Upward###42.4(53)###4.0(4)###25.2(57)

###Backward###41.6(52)###88.1(89)###62.4(141)

Ear shape###0.911###Rounded###61.5(308)###62.0(80)###61.6(388)

###Straight###38.5(193)###38.0(49)###38.4(242)

Ear orientation###0.833###Erect###1.2(6)###0.8(1)###1.1(7)

###Semi-pendulous###33.3(171)###32.0(41)###33.0(212)

###Pendulous###32.7(168)###36.7(47)###33.5(215)

###Carried horizontally###32.9(169)###30.5(39)###32.4(208)

Head profile###0.05###Straight###54.7(281)###51.2(66)###54.0(347)

###Concave###16.5(85)###11.6(15)###15.6(100)

###Convex###28.8(148)###36.4(47)###30.3(195)

###Ultra convex###0.0(0)###0.8(1)###0.2(1)

Backline profile###0.023###Straight###64.0(329)###74.0(94)###66.0(423)

###Slopes up towards rump###22.6(116)###14.2(18)###20.9(134)

###Slopes down from withers###7.6(39)###10.2(13)###8.1(52)

###Dipped or curved###5.8(30)###1.6(2)###5.0(32)

Table 3. Frequency of class levels of qualitative characteristics of Awassi sheep by region.

Characteristic###P value1###Southern###Central###Northern

###% (Number)

Body color###< 0.001###White body, brown head###79.4(158)###76.4(149)###62.2(155)

###White body, black head###5.5(11)###2.6(5)###8.8(22)

###White body and head###3.5(7)###6.2(12)###14.5(36)

###Black or black and white body,###6.5(13)###9.2(18)###10.4(26)

###black head

###Brown or brown and white body,###5.0(10)###5.6(11)###4.0(10)

###brown head

Coat color pattern###0.316###Plain###88.4(176)###91.9(181)###88.8(221)

###Patchy###7.0(14)###5.6(11)###9.2(23)

###Spotted###4.5(9)###2.5(5)###2.0(5)

Presence of horns###< 0.001###61.3###19.6###27.9

Horn shape###< 0.001###Scurs###5.7###13.5###39.7

###Straight###48.0###0###1.5

###Curved###33.3###16.2###16.2

###Spiral###13.0###70.3###42.6

Horn orientation###< 0.001###Lateral###18.7 (23)###5.7(2)###4.4(3)

###Upward###36.6 (45)###2.9(1)###16.2

###Backward###44.7(55)###91.4(32)###79.4

Ear shape###< 0.001###Rounded###98.0(193)###19.6(38)###65.7(157)

###Straight###2.0 (4)###80.4(156)###34.3(82)

Ear orientation###< 0.001###Erect###3.5(7)###0.0(0)###0.0(0)

###Semi-pendulous###91.0(181)###4.1(8)###9.3(23)

###Pendulous###5.5(11)###19.4(38)###67.2(166)

###Carried horizontally###0.0(0)###76.5(150)###23.5(58)

Head profile###< 0.001###Straight###44.7(89)###44.9(88)###68.5(170)

###Concave###47.2(94)###0.5(1)###2.0(5)

###Convex###8.0(16)###54.1(106)###29.4(73)

###Ultra convex###0.0(0)###0.5(1)###0.0(0)

Backline profile###< 0.001###Straight###52.0(103)###65.0(128)###78.0(192)

###Slopes up towards rump###48.0(95)###11.7(23)###6.5(16)

###Slopes down from withers###0.0(0)###17.3(34)###7.3(18)

###Dipped or curved###0.0(0)###6.1(12)###8.1(20)

Table 4. Raw means, coefficient of variation (CV), and significance (P values) of region and age class (or parity) for quantitativecharacteristics of rams and ewes of Awassi sheep.

Trait1,###Rams###Ewes

cm###Statistics###Significance of fixed###Statistics###Significance of Fixed###Sexual

###effects (P value)###effects (P value)###dimorphism

###Mean###CV###Region###Age###Mean###CV###Region###Parity###(m/f)

###class

BL###87.83###7.03###0.18###0.64###78.39###6.17###<0.0001###0.09###1.12

WH###90.12###7.40###0.70###0.55###79.17###8.83###0.0002###0.89###1.14

CG###108.05###5.78###0.009###0.36###99.87###7.42###<0.0001###<0.0001###1.08

CD###54.58###6.30###0.03###058###50.23###10.08###0.0008###0.09###1.09

PW###28.77###14.78###<0.0001###0.52###25.74###13.15###<0.0001###0.39###1.12

HL###28.72###10.92###<0.0001###0.59###27.31###11.91###<0.0001###0.001###1.05

HW###11.89###13.11###<0.0001###0.63###10.50###16.10###<0.0001###0.24###1.09

EL###20.45###11.23###<0.0001###0.68###20.59###11.83###<0.0001###0.02###0.99

EW###10.88###14.53###<0.0001###0.08###10.81###17.61###<0.0001###0.21###1.01

TL###28.52###23.78###<0.0001###0.45###26.42###26.73###<0.0001###0.85###1.08

HNL###43.81###46.14###0.08###0.82###9.52###68.69###0.21###0.55###4.60

SC###33.18###7.11###0.009###0.64

TTL###4.38###29.11###<0.0001###F###Wilks'###P ASCC

###entered1###Lambda###Lambda

###Rams

###1###TL###0.6785###103.41###< 0.0001###0.3215###< 0.0001###0.3393###< 0.0001

###2###PW###0.3872###30.65###< 0.0001###0.1970###< 0.0001###0.4174###< 0.0001

###3###HW###0.3868###30.28###< 0.0001###0.1208###< 0.0001###0.4884###< 0.0001

###4###CG###0.0825###4.27###0.0167###0.1108###< 0.0001###0.5191###< 0.0001

###5###BL###0.0721###3.54###0.0328###0.1031###< 0.0001###0.5473###< 0.0001

###Ewes

###1###TL###0.7502###746.25###< 0.0001###0.2498###< 0.0001###0.3751###< 0.0001

###2###HW###0.4214###180.61###< 0.0001###0.1445###< 0.0001###0.4681###< 0.0001

###3###PW###0.3263###119.89###< 0.0001###0.0974###< 0.0001###0.5219###< 0.0001

###4###HL###0.0950###25.94###< 0.0001###0.0881###< 0.0001###0.5274###< 0.0001

###5###TTL###0.0264###6.70###0.0014###0.0858###< 0.0001###0.5331###< 0.0001

###6###CG###0.0194###4.88###0.0080###0.0841###< 0.0001###0.5397###< 0.0001

###7###BL###0.0275###6.93###0.0011###0.0818###< 0.0001###0.5509###< 0.0001

###8###EW###0.0132###3.29###0.0382###0.0807###< 0.0001###0.5517###< 0.0001

###9###EL###0.0104###2.57###0.0773###0.0799###< 0.0001###0.5557###< 0.0001

###10###CD###0.0102###2.51###0.0822###0.0791###< 0.0001###0.5584###< 0.0001

Table 7. Squared Mahalanobis distances between regions for rams (above diagonal) and ewes (below diagonal).

Region###Southern###Central###Northern

###Analysis including all flocks

Southern###-----------###16.44***###31.83***

Central###27.06***###-----------###4.28***

Northern###49.51***###5.23***###----------

###Analysis excluding flocks raising Assaf or Awassi x Assaf sheep

Southern###-----------###52.49***###48.92***

Central###75.32***###-----------###1.58*

Northern###80.40***###2.01***###----------

Table 8. Percentage and number of observations classified in different regions for the male sample.

Region###Southern###Central###Northern###Total

###% (Number)

Southern###97.5 (39)###2.5(1)###0###100.0 (40)

Central###2.5 (1)###70.0 (28)###27.5(11)###100.0 (40)

Northern###0###12.0(6)###88.0(44)###100.0 (50)

Table 9. Percentage and number of observations classified in different regions for the female sample.

Region###Southern###Central###Northern###Total

###% (Number)

Southern###100.0 (159)###0.0 (0)###0.0 (0)###100.0(159)

Central###1.9 (3)###74.4(116)###23.7(37)###100.0(156)

Northern###0.0(0)###7.0(13)###93.0(173)###100.0(186)

DISCUSSION

The current study provided information on qualitative and quantitativecharacteristics of Awassi ewes and rams which would help characterize the breed in Palestine. In particular, body dimensions (e.g.; body length, wither height, chest girth, pelvic width, chest depth), areimportant to study the morphological structure of a breed (Tabbaa, 2003) and to discriminate among different breeds (Herera et al., 1996). Furthermore,they provide information on meat productivity (Al-Tarayrah and Tabbaa, 1999) because they have high positivecorrelations with body weight of the animal (Eliya and Juma, 1970;Gajbhiye and Johar, 1985)and carcass conformation and weight of lambs (Al-Jalili et al., 1987). Therefore, body dimensions can be used in designing breeding programs to improve meat production of Awassi sheep.

The estimates of body length found in the current studyfor Awassi sheep in Palestine were higher than those found for Awassi sheep in Jordan (Tabbaa, 1998) and Iraq (Eliya and Juma, 1970) but less than those found for Syrian Awassi (El-Sabeh and El-Najar, 1988). Estimates of wither height were higher than those found in Jordan and Syria (Tabbaa, 1998; El-Sabeh and El-Najar, 1988). Our estimates of chest girth were similar to those found for Awassi sheep in Jordan (Tabbaa, 1998) but larger than those found in other countries (Eliya and Juma, 1970 and El-Sabeh and El-Najar, 1988). Tabbaa (1998) reported similar estimates of pelvic width to those found in our study.

Awassi is a fat-tailed breed. Tabba(1998) studied fat-tail dimensions of Awassi sheep and found higher average values of tail length for ewes (31.2 cm) compared to rams (24.4 cm), contrary to the results of our study where rams had higher average tail length (28.5 cm) than ewes (26.4). According to Tabbaa (1998), the differences in tail dimensions in his study could be due to the selection ofa smaller fat-tail in rams and probably due to reserving fat during pregnancy for ewes. There is no indication that such selection is practiced in Palestine. Furthermore, the measures in our study were taken in late summer which corresponds to late breeding season and early pregnancy, while in the study of Tabbaa (1998) the measures were taken at lambing for ewes and during breeding season for rams.

The stepwise analysis identified five significant discriminatory traits (to discriminate among regions) for rams (tail length, pelvic width, head width, chest girth, and body length) and ten for ewes (tail length, headwidth, pelvic width, head length, teat length, chest girth, body length, ear width, ear length, and chest depth) with tail length, headwidth, and pelvic width showing the highest discriminating power for both sexes. Most of these traits were also significant contributors to discrimination among geographical regions in Spanish Assaf (Legaz et al., 2011) and Bengal (Banerjee, 2015) and Ethiopian (Melesse et al., 2013) indigenous sheep breeds.

The results of the multivariate analyses found in this study indicated adaptive morphological divergence between Awassi sheep populations raised in different geographical areas of the West Bank. Awassi rams and ewes kept in the Southern region have more distinct characteristics from those in the Central and Northern areas which are less different.Geographic proximity may have facilitated genetic exchange between the Northern and Central regions and to lesser extent between the Southern and Central regions.Very similar trends of geographic divergence were reported by Dekhili et al. (2013) for Algerian goat population of Setif.

Keeping mixed breeds in Awassi-raising flocks results in uncontrolled crossbreeding and may be the main reason for decreasing numbers of Awassi sheep over the past few years in Palestine. This is very alarming and emphasizes the urgent need for conservation and genetic improvement programs. By examining the characteristics of sampled flocks in Table 1, we see that 75% of flocks in the Central region and one flock in the Northern region keep also Assaf and Awassi x Assaf sheep while none of the sampled flocks in the Southern regionkeep any of these breeds. It is possible that this may have contributed to the divergence between the Central region and each of the Southern and Northern regions. To test this hypothesis, the data were reanalyzed excluding all flocks which raise Assaf and Awassi x Assaf sheep. The results showed that the distance between the Central and the Northern regions decreased but the distance between the Southern and Central regions increased (Table 7).

After excluding flocks raising other breeds from the data, all remaining flocks in the central region were from the district of Salfit which is geographically the closest district to the Northern region and farthest from the Southern region. This confirms that the geographical distance is the main reason for divergence of Awassi populations among different regions.

Conclusions: The current study presented qualitative and quantitative characteristics of local Awassi sheep in the West Bank, Palestine and described flockcharacteristics. These identified characteristics could be used as references and utilized to develop future conservation and breeding strategies for these breeds. The differences found among regions in these characteristics increases the necessity for genetic analysis to differentiate between subpopulations and link genetic differences to morphological differences.

Acknowledgments: The authors wish to thank the Middle East Regional Agricultural Programme (MERAP) for its generous financial support of the research presented in this paper. The authors express deep thanks to Mahmoud Fatafta,Iyad Badran, Naser Shuli and Muayed Salman for their valuable comments on the manuscript. The authors also thank the Ministry of Agriculture (MoA) for providing farmer lists and facilitating the field work. The authors highly appreciate the collaboration of the farmers who participated in this study.

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