Maximizing the number of offspring born per female is a key functionality trait in commercial-and/or subsistence-oriented livestock enterprises. Although the number of offspring born is closely associated with female fertility and reproductive success, the genetic control of these traits remains poorly understood in sub-Saharan Africa livestock. Using selection signature analysis performed on Ovine HD BeadChip data from the prolific Bonga sheep in Ethiopia, 41 candidate regions under selection were identified. The analysis revealed one strong selection signature on a candidate region on chromosome X spanning BMP15, suggesting this to be the primary candidate prolificacy gene in the breed. The analysis also identified several candidate regions spanning genes not reported before in prolific sheep but underlying fertility and reproduction in other species. The genes associated with female reproduction traits included SPOCK1 (age at first oestrus), GPR173 (mediator of ovarian cyclicity), HB-EGF (signalling early pregnancy success) and SMARCAL1 and HMGN3a (regulate gene expression during embryogenesis). The genes involved in male reproduction were FOXJ1 (sperm function and successful fertilization) and NME5 (spermatogenesis). We also observed genes such as PKD2L2, MAGED1 and KDM3B, which have been associated with diverse fertility traits in both sexes of other species. The results confirm the complexity of the genetic mechanisms underlying reproduction while suggesting that prolificacy in the Bonga sheep, and possibly African indigenous sheep is partly under the control of BMP15 while other genes that enhance male and female fertility are essential for reproductive fitness.

Ten Katahdin (KAT) sheep and 10 Spanish (SPA) goat wethers were used to develop a simple method to estimate dry matter intake (DMI) required for maintenance (DMI m) with feed restriction. Grass hay was fed in a 5-week maintenance phase, initially at 51 and 54 g/kg BW 0.75 for KAT and SPA, respectively, and then varied by 0-5% every 2-3 days to maintain constant body weight (BW). Individual wether DMI m was the intercept of regressing DMI against BW change in 2-and 3-day periods of weeks 3 and 4. In the subsequent 8 week, wethers consumed hay at 70% or 55% of their maintenance DMI m. Restricted DMI m was average DMI in week 8 when no individual wether intercept of regressing BW against day differed from 0. Maintenance DMI m was not influenced by animal type (52.0 and 49.6 g/kg BW 0.75 for KAT and SPA, respectively; SEM = 0.73). Animal type and restriction level tended (p = .084) to interact in restricted DMI m (34.1, 38.6, 30.7, and 39.0 g/kg BW 0.75 for KAT-55%, KAT-70%, SPA-55%, and SPA-70%, respectively; SEM = 1.03), suggesting greater ability of Spanish to lessen energy use with appreciable feed restriction. Correlation coefficients of 0.89, −0.06, 0.96, and 0.85 (p = .041, .927, .009, and .066, respectively) between DMI m in the two phases for KAT-55, KAT-70, SPA-55, and SPA-70, respectively, suggest preference for the 55% level for evaluating resilience to feed restriction. In conclusion, frequent determinations of BW and DMI can be used to compare DMI m of individual animals with restricted feeding.

Sheep population in Ethiopia is among the largest in East Africa and sub-Saharan Africa and it increased from 25.5 million in 2012 to 31.8 million in 2017 (FAOSTAT, 2017). Small ruminants are mainly kept by smallholder farmers and the rural poor. Sheep contribute substantially as a source of income, food (meat and milk), and industrial raw materials (skin and wool). In addition, sheep production has a socioeconomic and cultural function and contributes to risk mitigation during crop failures, increase property security, and serve as a form of investment (Tibbo, 2006). Ethiopia has a large and diverse sheep population which is divided to four groups based on morphological characteristics and geographic distribution: (a) Sub-Alpine short-fat-tailed, (b) Highland long-fat-tailed, (c) Lowland fat-rumped/tailed, and (d) Lowland thin-tailed groups (Gizaw, Komen, Hanotte, & Van Arendonk, 2008). Bonga sheep belong to the Highland long-fat-tailed group and have physical features characterized by long fat tail with straight tapering end (98.4%), hairy coat, large size, and predominantly plain brown in color (57.9%; Gizaw et al., 2011). Average adult body weights of female and male Bonga sheep are 32 and 48 kg, respectively (Edea, 2008), and the breed is considered among the large-sized sheep breeds in Ethiopia. Kaffa, Sheka, and Bench zones of Southern State are the home region of the Bonga sheep with 66% of the total population being reared in Kaffa zone (CSA, 2017). The reproductive performance of sheep in Ethiopia varies among breeds, types, and locations. Major traits differences include age at first lambing, litter size, lambing interval, and lifetime productivity of the ewe (Abate, 2016).

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