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On-Farm Phenotypic Characterization of Indigenous Sheep Types in Selale Area, Central Ethiopia | OMICS International
ISSN: 2157-7579
Journal of Veterinary Science & Technology

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On-Farm Phenotypic Characterization of Indigenous Sheep Types in Selale Area, Central Ethiopia

Bosenu Abera1, Kefelegn Kebede2, Solomon Gizaw3 and Teka Feyera4*

1Jigjiga University College of Dry Land Agriculture, Ethiopia

2Haramaya University College of Agriculture and Environmental Sciences, Ethiopia

3Debre Berhan Agricultural Research Center, Ethiopia

4Jigjiga University College of Veterinary Medicine, Ethiopia

*Corresponding Author:
Teka Feyera
Jigjiga University College of Veterinary Medicine
Ethiopia
Tel: +251 913199648
E-mail: [email protected]

Received date: April 12, 2014; Accepted date: May 31, 2014; Published date: June 10, 2014

Citation: Abera B, Kebede K, Gizaw S, Feyera T (2014) On-Farm Phenotypic Characterization of Indigenous Sheep Types in Selale Area, Central Ethiopia. J Veterinar Sci Technol 5:180. doi:10.4172/2157-7579.1000180

Copyright: © 2014 Abera B, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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Abstract

The study was conducted to physically characterize indigenous sheep types in Selale area, Debre Libanos and Wuchale districts, Central Ethiopia. A total of 560 mature sheep were sampled randomly for characterization of phenotypic traits. Majority of the ewes and rams in both districts had plain coat color pattern (58.21%) followed by patchy (33.33%). Majority of female and male sheep in the study areas had medium and smooth coat cover. All the sampled sheep population in both districts has characteristics of long fat tailed type. Body weight of female sheep in age group1(0PPI), age group2(1PPI) and age group 3(≥ 2PPI) were 24.3 ± 0.6 kg, 25.8 ± 0.5 kg and 28.7 ± 0.2 kg, respectively, and the values for males in the same age groups were 25.7 ± 0.3 kg, 31.9 ± 0.8 kg and 38.2 ± 2.0 kg, respectively. Wuchale sheep (27.9 ± 0.20 kg) were comparable with Debre Libanos sheep (27.6 ± 0.2 kg). Debre Libanos sheep had significantly higher linear body measurements (P<0.05) than Wuchale sheep population. Sex of the sheep had no significant (p>0.05) effect on the body weight, ear length and rump length. The interaction of sex and age group significantly (p<0.05) influenced all linear body measurements except ear length of the sheep. The interaction of age group and location was significant (p<0.05) for all linear body measurements. Heart girth and body length were found to be the most important variables for estimation of body weight in sheep. For any breed improvement program and to boost productivity of indigenous sheep, characterization is the baseline so; this preliminary work could be used to support genetic analyses to determine variation between and within these small populations.

Keywords

Characterization; Debre Libanos; Phenotypic traits; Selale; Sheep types; Wuchale

Introduction

Ethiopia is endowed with huge livestock resources of varied and diversified genetic pools with specific adaptations to a wide range of agro-ecologies. Farm animals as a whole are an integral part of the country’s agricultural system and are raised both in the highland and lowland areas. In developing countries, livestock production is mostly subsistence oriented and fulfills multiple functions that contribute more for food security [1,2]. The demand for livestock products is increasing due to the growing urban population, while farm areas are shrinking considerably as a result of an increase in the rural population [3].

Ethiopia is home for at least 9 breeds and 14 traditional sheep populations [4] with an estimated 25.9 million heads. Out of which about 73.1 percent are females, and about 26.9 percent are males [5]. Of the total sheep population, 75 percent is found in the highlands where mixed crop-livestock systems dominate, while the remaining 25 per cent of the sheep is found in the lowlands [6]. The main production from indigenous sheep populations in Selale area is meat, skin and manure.For planning of community based breeding strategy as well as setting up a useful sheep development program, the genetic and the phenotypic merit and production system of that particular breed is a must. It has been stressed that identification and characterization of livestock genetic resources and their production environment is vital for long-term genetic improvement and sustained use of available resources [7].

On farm characterization can serve as basis for the sustainable improvement and conservation of indigenous animal genetic resources, and has received increasing attention in determining the variation between and within pure breeds [8]. Thus, more comprehensive information specific to on-farm phenotypic characterization of indigenous sheep breeding should be made available. Hence, this study was attempted to physically characterize indigenous sheep types in Selale area, Central Ethiopia.

Materials and Methods

Study area

The study was conducted in Selale area, Debre Libanos and Wuchale district, central Ethiopia. Debre Libanos and Wuchale district are located at 85 km and 75 km north of the capital Addis Ababa, respectively. Debre Libanos is located in 38o58’ 33”E longitude and 9o 63’ 75’’N latitude with altitude ranging from 1500 to 2700 m.a.s.l. For Debre Libanos the maximum and minimum annual temperature is 230C and 150C, respectively. Its main rainy season occurs between May and September and the dry season lasts from October to April. Wuchale district is located in 38o 47’E longitude and 9o54’N latitude with maximum temperature of 250C and minimum of 30C. Similarly, the main rainy season of Wuchale district occurs between May and September and the dry season lasts from October to April. Clay and sandy soils are the major soil types of the zone. In both of the districts agricultural production is characterized by a mixed crop-livestock production system [9] (Figure 1).

veterinary-science-technology-Location-map-study

Figure 1: Location map of the study area.

Sampling procedure

Selection of the studied districts and peasant associations were done using multi-stage purposive sampling technique in consultation with zonal and district bureau of agriculture experts. Four Kebeles in Debre Libanos (Wakene, Sone, Dire Jibbo and Tere) and four Kebeles in Wuchale district (Jate, Harkiso, Adere Gordoma and Gora Keteba) were selected based on their suitability for sheep production, road access and willingness of the farmers to participate in the study. A total of 400 female (200 in Debre Libanos and 200 in Wuchale) and 160 male (80 in Debre Libanos and 80 in Wuchale) sheep were selected for body linear measurements.

Data collection

The standard breed descriptor list for sheep developed by FAO [10] was closely followed in selecting morphological variables. Qualitative traits like: coat color pattern, coat color type, hair type, head profile, ears, wattle, horn, ruff and tail were observed and recorded. Body measurements: Chest Girth (CG), Body Length (BL), Wither Height (WH), Rump width (RW), Ear Length (EL), Horn Length (HL), Tail Length (TL), Tail width (TW), Rump length (RL) and Scrotum circumference (SC) were measured using flexible measuring tape while weight was measured using suspended spring balance having 50kg capacity with 0.2kg precision. Each experimental animal was identified by sex, districts and age group. Adult sheep were classified into three age groups; 0PPI (zero pair of permanent incisor), 1PPI (one pair of permanent incisor) and 2PPI (two pair of permanent incisor. Linear body measurements were taken by restraining and holding the animals in a stable condition.

Data management and analysis

Statistical analyses were made separately for male and female animals on variables that varied on sex; otherwise the data were merged and analyzed together. Qualitative data from individual observation were analyzed following the frequency procedures of SAS version 9.1(2005). The General Linear Model (GLM) procedure of SAS was employed to analyze quantitative variables to determine effects of class variables (sex, district and dentition). The effects of class variables and their interaction were expressed as Least Square Means (LSM) ± SE. Due to the low number of males in each dentition class, analysis was done for both sexes independently. Within each sex, location and dentition were fitted as fixed factors. Pearson’s correlation coefficient between linear bodies measurements under consideration were computed for both of the sheep types within each sex.

Univariate and multivariate analysis

General linear model procedures (PROC GLM) of the SAS were employed for quantitative variables to detect statistical differences among sample sheep populations. Mean comparisons were made for variables showing significant differences between sample populations. The quantitative variables from female and male animals were separately subjected to discriminant analysis (PROC DISCRIM of SAS) and canonical discriminant analysis (CAN DISC) programme to ascertain the existence of population level phenotypic differences among the sample sheep populations in the study area.

Results and Discussions

Characterization of qualitative traits

The major qualitative traits of sample sheep population are presented in Table 1. Out of the sampled 390 sample sheep, 58.21 % were plain, 33.33% patchy and 8.46% had spotted coat pattern. Brown and white with brown dominant (24.87 %), brown with red dominant (16.92%), and white with black dominant (19.23%) coat color patterns were the dominant colors. Beside, brown (18.21%), black (4.36%), white (4.87%) and red (6.67%) coat were also observed in plain pattern and mixed in patchy or spotted patterns.

Character Attributes DebreLibanos Wuchale Overall
Sex Sex
Female Male Female Male  
N % N % N % N % N %
Coat colour pattern Plain 89* 57.42 21* 60.00 97* 64.67 20 40.00 227 58.21
Patchy 60 38.71 6 17.14 44 29.33 20 40.00 130 33.33
Spotted 6 3.87 8 22.86 9 6.00 10 20.00 33 8.46
X2_value 68.68 11.37 78.52 4.00ns  
Coat colour type White 7* 4.52 - - 6* 4.00 6 12.00 19 4.87
Black 10 6.45 - - 7 4.67 - - 17 4.36
Brown 23 14.84 8 22.86 32 21.33 8 16.00 71 18.21
Red 6 3.87 5 14.29 9 6.00 6 12.00 26 6.67
white and red with white dominant 5 3.23 - - 6 4.00 8 16.00 19 4.87
Brown and White with brown  dominant 43 27.74 6 17.14 40 26.67 8 16.00 97 24.87
Brown and red  with red  dominant 25 16.13 10 28.57 17 11.33 14 28.00 66 16.92
Black and white with black dominant 36 23.23 6 17.14 33 22.00 - - 75 19.23
X2_value 91.72  2.29 ns 74.21  5.20ns  
Toggle Present 44* 28.39 - - 31* 20.67 - - 75 19.23
Absent 111 71.61 35 100 119 79.33 50 100 315 80.77
X2_value 28.96 - 51.63 -  
         
Character Attributes DebreLibanos Wuchale Overall
Sex Sex
Female Male Female Male  
N % N % N % N % N %
Tail type Long fat tail 44* 92.90 30* 85.71 141* 94.00 50 100 365 93.59
Long thin tail 11 7.10 5 14.29 9 6.00 - - 25 6.41
X2_value  114.12 17.86 116.6 -    
Tail form Straight and tip down ward 104* 67.10 12 34.29 81 54.00 36* 72.00 233 59.74
Straight and twisted end 51 32.90 23 65.71 69 46.00 14 28.00 157 40.26
X2_value 18.12  3.46ns 0.96 9.68    
Ruff Present - - 26* 74.29 - - 44* 88.00 70 17.95
Absent 155 100 9 25.71 150 100 6 12.00 320 82.05
X2_value  -  8.26 - 28.88    
Ear form Rudimentary 24* 15.48 5 14.29 15* 10 8* 16 52 13.33
Semi-pendulous 131 84.52 30 85.71 135 90 42 84 338 86.67
X2_value 73.86 17.86 96.00 23.12    
Horn shape Straight 17 48.72 - - 11 44.00 - - 28 19.72
Curved 7 30.77 26 74.29 6 24.00 26 52.00 65 45.77
Spiral 8 20.51 9 25.71   8 32.00 24 48.00 49  
X2_value 5.69ns 8.26 1.52ns 0.08ns  

Table 1: Summary of the qualitative traits of female and male sheep in the study areas.

Majority of sheep population (80.77%) didn’t have toggle and majority (82.05%) lack ruff. Ear formation of sheep population was carried semi-pendulous (86.67%) followed by rudimentary (13.33%). Females were usually polled (74.84%) with 48.72% straight concerning horn shape. Males were characterized by curved horn shape (74.29%) and spiral horn shape (25.71%) in Debre Libanos while 52% and 48% in Wuchale district, respectively. In 67.10% of the female population the tail was straight down pointed while the rest 32.90% had twisted tail. In contrary to the female sheep population male had straight with twisted end (65.71%) while the rest (34.29%) straight with tip down ward.

Majority of the sheep (59.74%) in Wuchale and Debre Libanos districts had tails hanging straight downwards and 40.26 % of them had twisted end. The higher proportion of male sheep with long and straight downward pointed tail might be due to selection against twisted end tail animals and farmers preferences of straight downward pointed tail. It was noted that ruff was mainly sex and age dependent. They were totally absent in females and more readily observed in adult males as compared to young growing males. The chi-square testfor assumption of equal proportion of categorical variables in both Wuchale and Debre Libanos sample sheep population indicated that among the variables considered in this study coat pattern, coat color, toggle, tail type, tail conformation and ear form were found to significantly (P<0.05) differ within the sample sheep population.

Live body weight and linear measurements

The body weight and linear measurements for Debre Libanos and Wuchale sheep population at various ages are presented in Table 2. Least squares means of most of the quantitative variables were significant (P<0.05) between districts except body weight and Scrotal circumferences (Table 2). Results for body weight and linear measurements of Debre Libanos and Wuchale sheep revealed that Debre Libanos had significantly larger (P<0.05) linear measurements than Wuchale sheep population.

Effects  and level N BW CG BL WH RW EL TL TW RL SC
LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE
Over all 560 27.75 ± 0.2 75.34 ± 0.2 62.59 ± 0.2 65.43 ± 0.1 16.70 ± 0.1 9.49 ± 0.1 32.31 ± 0.2 11.38 ± 0.1 21.08 ± 0.1 21.90 ± 0.26
CV%   12.89 5.36 5.15 4.76 7.52 20.88 16.56 15.65 6.18 14.82
R2   0.27 0.33 0.24 0.21 0.19 0.02 0.07 0.51 0.12 0.015
Location   NS NS * * * * NS * * NS
D/Libanos 280 27.6 ± 0.2 75.05 ± 0.3 62.9 ± 0.2a 65.73 ± 0.2a 16.78 ± 0.1a 9.71 ± 0.1a 32.99 ± 0.3 12.45 ± 0.2a 21.38 ± 0.1a 21.50 ± 0.38
Wuchale 280 27.9 ± 0.2 74.31 ± 0.3 62.3 ± 0.2b 64.86 ± 0.2b 16.35 ± 0.1b 9.28 ± 0.1b 32.67 ± 0.3 11.85 ± 0.1b 20.88 ± 0.1b 22.30 ± 0.35
Sex   NS * * * * NS * * NS _
Female 400 27.96 ± 0.2 76.23 ± 0.2a 63.51 ± 0.2a 65.6 ± 0.2a 16.88 ± 0.1a 9.50 ± 0.1 31.63 ± 0.3a 10.33 ± 0.1a 21.23 ± 0.1 NA
Male 160 27.23 ± 0.4 73.13 ± 0.5b 60.30 ± 0.3b 65.0 ± 0.3b 16.24 ± 0.1b 9.48 ± 0.1 34.02 ± 0.4b 14.03 ± 0.2b 21.03 ± 0.1 21.90 ± 0.26

a,b,cmeans on the same column with different superscripts within the specified dentition group are significantly different (P<0.05); Ns = Non- significant (P>0.05); BW = Body weight; BL = Body Length; CG = Chest Girth; WH = Wither height; RW = Rump width ; EL = Ear Length; TL = Tail Length; TW = Tail width; RL= Rump length; SC = Scrotal Circumference; D/Libanos =Debre Libanos.

Effects and level N BW CG BL WH RW EL TL TW RL Sc
LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE
Age group 560 * * * * * Ns * * * *
0 PPI 156 25.43 ± 0.3c 71.50 ± 0.4b 59.83 ± 0.3c 63.59 ± 0.3b 15.91 ± 0.1b 9.32 ± 0.1 33.51 ± 0.4a 12.77 ± 0.2a 20.78 ± 0.1b 21.29 ± 0.3b
1 PPI 88 27.83 ± 0.5b 76.31 ± 0.6a 62.89 ± 0.4b 66.26 ± 0.4a 17.01 ± 0.2a 9.42 ± 0.2 33.50 ± 0.6a 12.25 ± 0.4a 21.40 ± 0.2a 24.10 ± 0.7a
2 PPI 316 28.87 ± 0.2a 76.97 ± 0.2a 63.87 ± 0.2a 66.12 ± 0.2a 17.00 ± 0.1a 9.60 ± 0.1 31.39 ± 0.3b 10.45 ± 0.1b 21.14 ± 0.1a 24.60 ± 1.3a
Sex by age group 560 * * * * * NS * * * -
Female,0PPI 30 24.3 ± 0.6d 73.13 ± 0.7c 61.16 ± 0.6b 62.63 ± 0.6d 16.34 ± 0.2c   8.97 ± 0.4 31.37 ± 0.8bc 10.13 ± 0.2c 20.47 ± 0.1d NA
Male,0 PPI 126 25.7 ± 0.3d 71.11 ± 0.4d 59.52 ± 0.3c 63.82 ± 0.3d 15.80 ± 0.1d   9.41 ± 0.2 34.0 3 ± 0.5a 13.40 ± 0.2b 20.86 ± 0.1cd 21.29 ± 0.3b
Female,1PPI 59 25.81 ± 0.5d 74.39 ± 0.6c 62.94 ± 0.5a 65.00 ± 0.4c 16.64 ± 0.1bc   9.27 ± 0.3 33.18 ± 0.6ab 10.34 ± 0.2c 20.94 ± 0.2cd NA
Male, 1 PPI 29 31.93 ± 0.8b 80.24 ± 0.7a 62.79 ± 0.7ab 68.83 ± 0.6a 17.75 ± 0.3a   9.72 ± 0.3 34.14 ± 1.1a 16.14 ± 0.6a 22.34 ± 0.4b 24.10 ± 0.7a
Female, 2 PPI 311 28.7 ± 0.2c 76.88 ± 0.2b 63.85 ± 0.2a 66.03 ± 0.2b 16.97 ± 0.0b   9.59 ± 0.1 31.36 ± 0.3b 10.34 ± 0.1c 21.09 ± 0.1c NA
Male,2 PPI 5 38.2 ± 2.0a 82.60 ± 1.6a 65.40 ± 1.7a 71.6 0 ± 2.2a 18.6 0 ± 0.7a  10.00 ± 0.0 33.20 ± 2.6ab 17.40 ± 0.8a 24.00 ± 1.6a 24.60 ± 1.3a

a,b,c,dmeans on the same column with different superscripts within the specified dentition group are significantly different (P<0.05); Ns = Non- significant (P>0.05); BW = Body weight; BL = Body Length; CG = Chest Girth; WH = Wither height; RW = Rump width ; EL = Ear Length; TL = Tail Length; TW = Tail width; RL= Rump length; SC = Scrotal Circumference; 0PPI = 0 Pair of Permanent Incisors; 1 PPI = 1 Pair of Permanent Incisors; 2PPI = 2 Pairs of Permanent Incisors; NA=Not applicable

Effects and level N BW CG BL WH RW EL TL TW RL Sc
LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE LSM ± SE
Age by location 560 * * * * * * * * * *
0PPI, D/ Libanos 70 25.11 ± 0.4c 71.03 ± 0.5c 59.85 ± 0.4c 63.57 ± 0.4c 16.02 ± 0.2c 9.41 ± 0.2ab 34.03 ± 0.6a 13.12 ± 0.3a 20.98 ± 0.2c 20.57 ± 0.38c
0 PPI, Wuchale 86 25.69 ± 0.4c 71.89 ± 0.5c 59.82 ± 0.3c 63.61 ± 0.4c 15.81 ± 0.1c 9.26 ± 0.2b 33.11 ± 0.6ab 12.48 ± 0.2ab 20.62 ± 0.2c 21.93 ± 0.34b
1PPI, D/ Libanos 42 26.73 ± 0.7b 75.95 ± 0.8b 62.67 ± 0.5b 66.57 ± 0.5a 17.23 ± 0.2ab 9.59 ± 0.3ab 32.81 ± 0.9ab 12.67 ± 0.6ab 21.79 ± 0.3a 24.20 ± 0.8a
1PPI, Wuchale 46 28.82 ± 0.7a 76.65 ± 0.7ab 63.11 ± 0.6b 65.97 ± 0.5ab 16.74 ± 0.2ab 9.26 ± 0.3ab 34.13 ± 0.7a 11.87 ± 0.5b 21.06 ± 0.2bc 24.00 ± 1.1a
≥2PPI,D/ Libanos 168 28.91 ± 0.3a 77.58 ± 0.5a 64.29 ± 0.2a 66.92 ± 0.2a 17.16 ± 0.1a 9.87 ± 0.2a 31.99 ± 0.5b 10.74 ± 0.1c 21.32 ± 0.1ab 24.60 ± 1.33a
≥2 PPI, Wuchale 148 28.83 ± 0.3a 76.28 ± 0.3b 63.40 ± 0.3b 65.20 ± 0.2b 16.86 ± 0.1b 9.30 ± 0.2b 30.71 ± 0.4c 10.12 ± 0.1d 20.94 ± 0.1c NA

Table 2: Least squares Means (± S.E.) for Body Weight (kg), and Linear body measurements (cm) as affected by district, sex, age group and their interactions.

Sex by age group: The interaction between sex and age group not significantly (p>0.05) affect ear length of the sheep. The remaining parameters of body measurements were affected by the sex-age interaction effect. Both females and males in age group 0(0PPI) had the same (p>0.05) body weight value but males in age group 1(1PPI) and ≥ 2PPI were heavier (p<0.05) than females in the same age group. Body weight of males in age group 0PPI (25.7 ± 0.3kg), age group 1PPI (31.9 ± 0.8kg) and age group ≥ 2PPI (38.2 ± 2.0kg) in the current study was higher than body weight of Menz males18.0 ± 0.28kg, (22.9 ± 0.39kg) and24.9 ± 0.67 in the same age group. Similarly, body weight of females in all age group in the current study was higher than the values reported for Menz ewes (19.1 ± 0.27kg) in the same age group [11].

Age by location: The interaction of age group and location was significant (p<0.05) for all parameters of body measurement used in the study. The result indicates the interaction of age group and location had strong effect on body weight and linear body measurements. Young (0PPI) sheep of DebreLibanos had similar (p>0.05) body weight with Wuchale sheep. The age group ≥ 2PPI also had similar (p>0.05) body weight 2 locations. However, Wuchale sheep (28.8 ± 0.7 kg) in age group 1PPI had heavier body weight than Debre Libanos (26.7 ± 0.7 kg). This implies that Debre Libanos sheep did not attain maturity at 2PPI. Body weight of the age group 1PPI of the two locations is larger than Tocha, Mareka and Konta sheep [12] and Menz sheep [11] in the same age groups.

Correlation between body weight and body measurements

The highest relationship between chest girth and body weight were observed in Debre Libanos female sheep (0.68) and in Wuchale male sheep (0.80).The highest correlation of chest girth with body weight than other body measurements was in harmony with other results of [11,13-15] and it can indicate that chest girth is the best variable for predicting live weight than other measurements (Table 3).

  CG BL WH RH RW TL TW RL BW
CG   0.39* 0.33* 0.42* 0.20* 0.13ns 0.08ns 0.18* 0.68*
BL 0.68*   0.29* 0.30* 0.08ns 0.11ns -0.06ns 0.08ns 0.38*
WH 0.66* 0.57*   0.84* 0.13ns 0.07ns 0.10ns 0.12ns 0.30*
RH 0.68* 0.56* 0.91*   0.15* 0.07ns 0.06ns 0.15* 0.37*
RW 0.60* 0.43* 0.40* 0.39*   0.08ns 0.40* 0.11ns 0.23*
TL -0.23* -0.08ns -0.23* -0.30* -0.15ns   0.19* 0.15* 0.22*
TW 0.64* 0.33* 0.33* 0.35* 0.54* -0.09ns   0.15* 0.22*
RL 0.59* 0.41* 0.46* 0.51* 0.39* -0.25* 0.22ns   0.26*
BW 0.73* 0.53* 0.62* 0.64* 0.42* -0.14ns 0.44* 0.53*  
SC 0.50* 0.43* 0.33* 0.37* 0.37 -0.11ns 0.40* 0.13ns 0.37*

Table 3: Correlation coefficients among body measurements and weight of females and males of indigenous Debre Libanos sheep (values above the diagonal are for females and below the diagonal are for males) (N=80 for male; N=200 for females).

Of the linear body measurements, chest girth with exception in Wuchale females had the highest correlation with body weight at all groups. In both Wuchale and Debre Libanos districts, the highest correlation coefficient between body weight andchest girth, body length, wither height and rump height were established in males (73%, 53%, 62%, 64%) for Debre Libanos and (80%, 73%, 72%, 75%) for Wuchale. The highest positive and significant correlation between body weight and chest girthsuggest thatthis variables couldprovide a good estimate for predicting live weight of these breed types (Table 4).

  CG BL WH RH RW TL TW RL BW SC
CG   0.71* 0.75* 0.75* 0.51* 0.31* 0.41* 0.51* 0.80* 0.32*
BL 0.57*   0.71* 0.75* 0.42* 0.39* 0.43* 0.49* 0.73* 0.23*
WH 0.26* 0.36*   0.95* 0.42* 0.42* 0.43* 0.53* 0.72* 0.23*
RH 0.28* 0.39* 0.90*   0.42* 0.46* 0.44* 0.53* 0.75* 0.28*
RW 0.33* 0.19* 0.26* 0.28*   0.08Ns 0.57* 0.45* 0.52* 0.16Ns
TL 0.07Ns 0.17* 0.18* 0.19* -0.08Ns   0.09Ns 0.38* 0.35* 0.17Ns
TW 0.17* 0.26* 0.16* 0.21* 0.09Ns 0.03Ns   0.34* 0.51* 0.23*
RL 0.34* 0.28* 0.27* 0.31* 0.43* 0.07Ns 0.20*   0.48* 0.13Ns
BW 0.50* 0.48* 0.32* 0.33* 0.24* 0.11Ns 0.11Ns 0.18*   0.30*

Table 4: Correlation coefficients among body measurements and weight of females and males of Wuchale sheep (values above the diagonal are for males and below the diagonal are for females) (N=80 for male; N=200 for females).

Multiple regression analysis

Table 5 shows that the number of variables entered in the model to predict the best fitted variable to estimate body weight and their contribution in terms of adjusted coefficient of determination (R2adj.), mallows Cp statistics, Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC) at different dentition and sex categories.

Age group Model   Parameters
Intercept β1 β2 β3 β4 R2 adjust.
Female              
0PPI CG+BL+WH+RW -53.95 ± 6.96 0.44 ± 0.08 0.31 ± 0.10 0.55 ± 0.10 -0.48 ± 0.25 0.83
1PPI CG -0.32 ± 7.68 0.35 ± 0.10       0.16
≥2 PPI CG+BL -15.12 ± 3.9 0.41 ± 0.05 0.18 ± 0.06     0.30
Overall CG+BL+WH -23.49 ± 4.00 0.44 ± 0.04 0.16 ± 0.05 0.11 ± 0.05   0.36
Male              
0PPI CG+BL+WH -26.25 ± 4.49 0.38 ± 0.06 0.23 ± 0.10 0.18 ± 0.08   0.57
≥1PPI CG + RH -61.74± 20.94 0.52 ± 0.19 0.72 ± 0.23     0.36
Overall CG+BL+RH -35.83 ± 4.27 0.43 ± 0.06 0.15 ± 0.09 0.33 ± 0.08   0.67

Table 5: Multiple regression analysis of live weight on different body measurements for ewe and ram by age group.

Small AIC, Cp and BIC value and higher adjusted R2 are included in regression equation. The independent variables were body length, chest girth; wither height, rump height, rump width, tail length, tail width and rump length. In addition to these variables scrotal circumference and horn length were considered for male population.In most cases heart girth was found to be the most important in accounting sizeable proportion of the changes in the body weight. Similarly, this measurement was reported for Afar, Menz, Bonga, Horro, Gumuz, Jarso, and Nedjo sheep [11,16-18]. Chest girth was more reliable in predicting body weight than other linear body measurements. Parameter estimates in multiple linear regression model showed that higher R2 adjusted was observed when more than one body dimensions were used in the multiple regression equation.

Conclusion

The present study conducted in Selale area of Central Ethiopia evidenced that most of the sheep in the study area had plain coat pattern, brown coat color, semi-pendulous ear orientation and long fat tailed with straight down pointed in females and twisted end in males. Sex of the sheep had no significant (p>0.05) effect on the body weight, ear length and rump length. Age group had significant effect (p<0.05) on body weight and other body measurements. Location was found to influence (P<0.05) body length, tail width, wither height, ear length and rump length. The interaction of sex and age group significantly (p<0.05) influenced all linear body measurements except ear length of the sheep. The interaction of age group and location was significant (p<0.05) for all linear body measurements. Of the linear body measurements, chest girth with exception in Wuchale females had the highest correlation with body weight at all groups. In the regression analysis carried out to predict body weight, heart girth was selected and explained more variation than other variables in all age groups of both males and females of Debre Libanos and Wuchale sheep population. For any breed improvement program and to boost productivity of indigenous sheep, characterization is the baseline. Therefore, this preliminary work could be used to support genetic analyses to determine variation between and within these small populations.

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