Deribe Belay, Tesema Zeleke, Lakew Mesfin, Zegeye Asres, Kefale Alemu, Shibesh Mekonnen, Yizengaw Liuel, Belayneh Negus
Sirinka Agricultural Research Center, Woldia, Ethiopia.
Debre Birhan Agricultural Research Center, Debre Birhan, Ethiopia.
Transl Anim Sci. 2023 Apr 17;7(1):txad034. doi: 10.1093/tas/txad034. eCollection 2023 Jan.
This study aimed to evaluate the growth performance and Kleiber ratio (KR) and to determine the growth curve of Dorper × Tumele sheep under a smallholder management system. Growth and efficiency-related traits were analyzed by using the general linear model (GLM) procedure of SAS. Gompertz, Logistics, Brody, Monomolecular, and Negative exponential models were used to determine the growth curve, and growth curve parameters were estimated via the nonlinear regression model (NLIN) procedure of SAS. The overall least-squares means of the birth weight, weaning weight, 6-month weight, and yearling weight were 3.29, 13.7, 17.3, and 23.4 kg, respectively. Dorper × Tumele lambs grew faster during the preweaning period (115.3 ± 1.19 g day) than during the postweaning periods (44.1 ± 1.26 g day to 33.5 ± 1.13 g day). Likewise, a higher KR was observed during the pre-weaning age (16.1 ± 0.08 g/day/kg) than during postweaning periods (5.08 ± 0.13 g/day/kg to 3.10 ± 0.09 g/day/kg). Brody, a model without an inflection point was the best-fitted growth function for Dorper × Tumele sheep under a smallholder management system. The highest and lowest asymptotic weight was observed for Brody (23.8 ± 0.22 kg) and Logistics (20.7 ± 0.11 kg) models, respectively. The maturation rate ranged between 0.21 (Brody) and 0.66 (Logistics). Based on the Brody model, the correlation between asymptotic weight and maturity rate was -0.92. The growth parameter estimate in this study indicates that Dorper × indigenous sheep had a better speed to achieve mature weight and the early mature crossbred sheep are less likely to exhibit high adult weight. The rapid growth of crossbred sheep during the early period can provide more profit to the farmer by reducing the cost of sheep production inputs. Therefore, crossing Tumele with Dorper sheep and integrating with improved management would be suggested to improve productivity and profit from sheep production.
本研究旨在评估杜泊×图梅勒羊在小农管理系统下的生长性能和克氏比（KR），并确定其生长曲线。利用SAS的一般线性模型（GLM）程序分析生长和效率相关性状。采用Gompertz、Logistics、Brody、单分子和负指数模型确定生长曲线，并通过SAS的非线性回归模型（NLIN）程序估计生长曲线参数。出生体重、断奶体重、6月龄体重和周岁体重的总体最小二乘均值分别为3.29、13.7、17.3和23.4千克。杜泊×图梅勒羔羊在断奶前阶段（115.3±1.19克/天）比断奶后阶段（44.1±1.26克/天至33.5±1.13克/天）生长得更快。同样，断奶前年龄阶段的KR（16.1±0.08克/天/千克）高于断奶后阶段（5.08±0.13克/天/千克至3.10±0.09克/天/千克）。Brody模型（无拐点）是杜泊×图梅勒羊在小农管理系统下的最佳拟合生长函数。Brody模型（23.8±0.22千克）和Logistics模型（20.7±0.11千克）分别观察到最高和最低的渐近体重。成熟率在0.21（Brody）至0.66（Logistics）之间。基于Brody模型，渐近体重与成熟率之间的相关性为-0.92。本研究中的生长参数估计表明，杜泊×本地羊达到成熟体重的速度更快，早期成熟的杂交羊成年体重不太可能很高。杂交羊早期的快速生长可以通过降低绵羊生产投入成本为养殖户带来更多利润。因此，建议将图梅勒羊与杜泊羊杂交，并结合改进的管理措施，以提高绵羊生产的生产力和利润。
