Department of Agriculture, Minab Higher Education Center, University of Hormozgan, Bandar Abbas, Iran.
Trop Anim Health Prod. 2024 Oct 1;56(8):309. doi: 10.1007/s11250-024-04124-6.
The study's objectives were to assess the genetic parameters of reproductive characteristics in Sangsari sheep. A data set of reproductive information with pedigree details from 1995 to 2016 was used. Studied traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB), litter mean weight per lamb weaned (LMWLW), total litter weight at birth (TLWB) and total litter weight at weaning (TLWW). Test significance of the environmental factors to be included in the model was conducted using the general linear model procedure of the SAS program. All traits were significantly affected by the year of lambing and ewe age at lambing (P < 0.01). The AI-REML procedure of the Wombat program was used to evaluate genetic parameters. A series of bivariate animal models were employed to calculate genetic (r) and phenotypic (r) correlations between traits. The total least square means ± standard error of LSB and LSW were 1.04 ± 0.05 and 0.96 ± 0.03, while LMWLB, LMWLW, TLWB, and TLWW were 3.12 ± 0.08, 15.40 ± 0.13, 3.28 ± 0.04, and 19.31 ± 0.16 kg, respectively. The estimates of h were relatively low (P < 0.01) and ranged from 0.063 ± 0.028 for LSW to 0.181 ± 0.063 for TLWW. Repeatability estimates varied from 0.101 for LSW to 0.241 for TLWW. The sire service effects for LMWLB, TLWB, and TLWW were 0.012 ± 0.004, 0.023 ± 0.006, and 0.039 ± 0.009, respectively. The traits studied showed a greater magnitude of genetic correlation than phenotypic correlation, with values ranging from - 0.59 (LSB-LMWLB) to 0.87 (LMWLB-TLWB). It appears that focusing on TLWW for selection could result in more significant improvements in the reproductive performance of Sangsari ewes.
本研究旨在评估桑萨里绵羊繁殖特征的遗传参数。使用了 1995 年至 2016 年的繁殖信息数据集，包括系谱详细信息。研究的性状包括初生窝产仔数（LSB）、断奶窝产仔数（LSW）、每头羔羊出生平均体重（LMWLB）、每头羔羊断奶平均体重（LMWLW）、初生总窝重（TLWB）和断奶总窝重（TLWW）。使用 SAS 程序的一般线性模型程序对要包含在模型中的环境因素的测试显著性进行了检验。所有性状均受产羔年份和母羊产羔年龄的显著影响（P<0.01）。使用 Wombat 程序的 AI-REML 过程评估遗传参数。采用一系列双变量动物模型计算性状间的遗传（r）和表型（r）相关关系。LSB 和 LSW 的总最小二乘平均值±标准误差分别为 1.04±0.05 和 0.96±0.03，而 LMWLB、LMWLW、TLWB 和 TLWW 分别为 3.12±0.08、15.40±0.13、3.28±0.04 和 19.31±0.16 kg。h 的估计值相对较低（P<0.01），范围从 LSW 的 0.063±0.028 到 TLWW 的 0.181±0.063。重复率估计值从 LSW 的 0.101 到 TLWW 的 0.241 不等。LMWLB、TLWB 和 TLWW 的 sire 服务效应分别为 0.012±0.004、0.023±0.006 和 0.039±0.009。研究的性状表现出遗传相关性大于表型相关性，数值范围从 -0.59（LSB-LMWLB）到 0.87（LMWLB-TLWB）。似乎专注于 TLWW 的选择可能会导致桑萨里母羊繁殖性能的更大改进。
