On-farm evaluation of growth and reproductive performances of Washera and Gumuz sheep in northwestern Ethiopia: Basics for setting up breeding objectives/goals

Growth and reproductive performance traits are traits of economic importance for sheep selection and productivity improvement interventions. This study aimed at comparative evaluation of growth and reproductive performance traits of sheep in the highland and lowland agro-ecologies of northwestern Ethiopia. Data on growth performance traits were collected from 144 Washera (78 males and 66 females) lambs and 72 Gumuz (37 males and 35 females) lambs. Data on reproductive performance traits were collected from 260 Washera (130 rams and 130 ewes) sheep and 150 Gumuz (75 rams and 75 ewes) sheep. General linear model univariate procedure was employed to analyze the collected data. Breed, the interaction effect between breed and season of birth as well as the interaction effect between breed and type of birth all exerted very high significant effect (P<0.001) on live weight at all age groups. Breed type affected pre-weaning average daily weight gain significantly (P<0.01). Pre-weaning average daily weight gain of Washera (70 g/day) was found much better performance than 60 g/day of Gumuz. Breed type exerts significant (P<0.05) effect on age at first lambing, lambing interval, annual reproductive rate and number of lambs born per ewe life time. Average age at first lambing and lambing interval of Washera sheep were 11.69 months and 9.27 months, respectively. The corresponding values for Gumuz sheep were 12.51 months and 10.43 months, respectively. Production and reproduction performance values of traits varied across the two breeds and sexes as well. These values can be used to set up breeding objectives or goals for selective breeding of sheep giving special emphasis to growth traits believed to have medium heritability values.

Earlier to the study, data collection formats and procedures were reviewed and agreed by the research ethics review committee of Debre Markos University, Ethiopia (Ref. number DMU 10/2018 E.C). In addition, target group smallholder farmers provided their verbal informed consent to participate in this study. Besides, the data were analyzed namelessly; ethnicity and religious issues were not asked and recorded during data collection. Since domestication, sheep have become essential parts of farms across the world [1] 47 and comprises 16 percent of the total TLUs in sub-Saharan Africa [2]. In part it is because of 48 their ability to adapt to local environments [1]. Small ruminants represent only 7% of the 49 average total capital invested in livestock in the mixed crop-livestock production system, but about 40% of fresh skins and 92% of the value of semi-processed skin and hide export trade.

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The increased domestic and international demand for Ethiopian sheep and goats has 55 established them as important sources of Inland Revenue as well as foreign currency [3].
Therefore, integrated attempt with emphasis on prescribing and genetic enhancement is lowland crop-livestock sheep production systems, respectively [14]. Morphologically,

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Washera is a short fat tail, large body size, short-haired, predominantly brown, both males 77 and females are polled reared by Amhara and Agew communities. Washera is a good meat 78 producer under good environment [15]. Gumuz sheep is long thin tail, somewhat dwarf, 79 convex face profile, long pendulous ear, commonly plain brown or with patch coat color, 80 polled and reared by Gumuz and Amhara communities [14]. Gumuz sheep is adapted to heat crosses with exotic breeds are not well grounded due to the reason that many researchers has 90 tended to focus on-station performance evaluation rather than on farm condition [20]. Yet, This study was conducted in two districts, Burie and Mandura considered as potential 113 areas for Washera and Gumuz sheep breed types in North Western Ethiopia (Fig 1).

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According to altitudinal location, rainfall and crop yields, the agro-ecological zone of Burie is 115 highland and the agro-ecological zone of Mandura is lowland [21]. The necessary data on growth and reproductive parameters were collected from sheep 140 flocks managed under mixed -crop livestock farming system of Burie and Mandura districts.

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Data collection was carried out for two years from September, 2017 to October, 2018 G.C.

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Smallholders owning rams, ewes and lambs were asked for voluntarily for sparing their sheep Weight records at various ages were adjusted for actual age using different formulas used by 160 [25,26]. Average daily weight gain from weaning to 6 month age (g) Lamb survival rate was calculated by the formulae adopted from [28]: The result of this study indicated that there exists variation in growth rate between 252 Washera and Gumuz sheep populations. Table 1    The impact of reproduction on sheep and goat productivity is best estimated by the annual 319 reproductive rate [9]. Long-term studies carried out over periods of several years have shown 320 that the annual reproductive rate (number of young produced per breeding female per year) 321 varies from 1.5 to over two lambs [27]. This rate of reproduction results in part is from the 322 uncontrolled access of rams to ewes on a permanent basis and in part from the litter size ; in 323 that annual reproductive rate(ARR) is a function of litter size and parturition 324 interval(ARR=Liter size*365/ parturition interval. ARR of this study was calculated by a 325 formulae adopted from [27]. Hence; ARR was 2.12 and 1.71 lambs/ewe/year for Washera and Gumuz sheep, respectively.

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Lamb survival rate was calculated by the formulae used by [28]: sheep. The post-weaning growth rate of Washera sheep was comparable and even better than 387 some other indigenous breeds indicating its potential for meat (mutton) production for the 388 local and export markets [33]. For instance, post-weaning growth rate of Washera sheep 389 found by this study was 60 g/day, which was close to 63.4±4.0 of Bonga sheep [32]. The overall mean±SD value for average age of first mating for females was 6.93±1.54 394 months (207.9 days). These ewes were early maturing than Djallonké gimmers of Ghana 395 mated when they are 8 months (240 days) old [34].