ON-FARM PRODUCTIVE, AND FEEDLOT PERFORMANCE EVALUATION OF WOLLO HIGHLAND SHEEP BREED AND THEIR F1 CROSSBREDS OF AWASSI AND WASHERA SHEEP IN ETHIOPIA
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Date
2018-06
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Abstract
The study was done, at on-farm productivity, and feedlot performance evaluation of Wollo highland sheep breed and their F1 crossbreds of Awassi and Washera sheep in Ethiopia. The main objectives of the research was identify flocks size and composition, reproductive performance, breeding objective, and strategies, on-farm lamb growth rate and on-station productive performance evaluation. Data collection conducted via questionnaire survey, focus group discussions, flock monitoring, on-station feeding trial, and carcass yield evaluation. The three genotypes used, based on their locations, available ram breed type and breeding strategies, agro-ecological similarity and their sheep production system. The main smallholder sheep producers’ traits of interest were growth rate, body size, and weaning rate in the order of their importance. The higher random mating breeding strategies were characterised in Wollo highland genotype flocks (38.6%). Whereas, village community based control breeding strategy was higher in Awassi and Washera genotype flocks with 35.8 and 35.3%, respectively.The private controlled breeding strategies (43.7%) higher in Wollo highland genotype flocks. Washera F1 crosses designated for fast weaning rate, good body size, marketing age, age at first lambing, good temperament, and large litter size traits. The mean number of lambs, ewes, matted and pregnant ewes per flock comprised significant variation between the three genotypes (P<0.05) and higher with Wollo highland breed flocks. The number of services per conception has significant variation between genotypes’ flock(P<0.05) and higher in the Wollo highland breed flocks (1.4±0.2). Age at first mating, age at first lambing, single birth, twin birth, weaning rate and lambing interval significantly different (P<0.001) between genotypes. Comparatively higher fertility rate recorded in the Awassi genotypes (89.8%) and lower mortality rate recorded in Wollo highland breed flocks. Lamb mortality due to disease and drought was higher in the Washera genotype flocks (32.2%) and lower in Wollo highland breed flocks (26.0%). Yearling lamb growth rate performance was the linear function with the age of lambs . Awassi F1 crosses had significantly havier (P<0.001) birth and 6th month of weight gain than Washera crossbreds. On-farm average body weight at 3rd, 9 th and 12 th months and effect of birth type between Awassi and Washera crosses were comparable each other. However, significant difference with Wollo highland breed lambs (P<0.001). The effect of parity, sex and their interaction also does not have significant effect on on-farm lamb growth performance. The males pre-weaning average daily weight gain greater than females for entire genotypes. However, the female post-weaning average daily weight gains greater than males for Awassi and Washera crossbreds. Body weight, body length, chest girth, back width, chest width, height at withers and rump height, hip width and hip length measurement traits had positive and significant (P<0.05) correlation with age and body weight gain of lambs. The average daily weight gain (ADG), total body weight change and final body weights of the supplemented group of each genotypes were significantly higher than (P<0.05) non-supplemented group. Hence, the supplemented and non-supplemented Awassi crossbreds had higher average daily weight gain followed by supplemented Wollo highland breed. Between genotypes there is significant difference (P<0.05) was observed for rib-eye area, empty body weight, hot and cold carcass weight and cold carcass dressing percentage. Wollo highland breed showed compensatory growth pattern daily weight gain at experimental period. This indicated, without nutritional requirement restriction, Wollo highland breed breed can increase a comparable weight gain with their F1 crossbred lambs. Whatever resource is available more economically, it will be advantageous to identify those breeds of which are more efficient meat producers and efficiency to produce saleable products. Therefore, the effect of genotype and feeding type had profound factors to enhance weight gain response in lamb growth performance. Washera genotype might have better nutrient utilization and conversion rate and resulted better carcass and non-carcass fat content. The quality and accessibility to the better grazing management system of natural pasture in wet season can satisfy the maintenance and weight gain requirement of lambs.
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PhD Thesis
Keywords
Reproductive, productive, breeding objective, supplementation