ABSTRACT

The present study was conducted to assess the relation between different production and reproduction traits in Sahiwal cattle. Data up to sixth parity related to different production and reproduction traits of Sahiwal cattle maintained at an organized herd of ICAR-National Dairy Research Institute, Karnal spread over a span of 29 years (1988–2016) were utilized. Various production and reproduction traits considered were 305-day milk yield (305DMY), total milk yield (TMY), lactation length (LL), dry period (DP), age at calving (AAC), calving to first insemination interval (CFI), days open/service period (DO), calving interval (CI) and pregnancy rate (PR) up to sixth parity. Genetic and phenotypic correlations between different production and reproduction traits were estimated in addition to analysis of graphs between these traits up to sixth parity in Sahiwal cattle. The genetic correlations of 305DMY, TMY and LL with DO and CI were positive. Likewise, the phenotypic correlations of 305DMY, TMY and LL with CFI, DO and CI were significantly positive suggesting that cows with high milk yield have longer calving to first insemination interval, days open and calving interval. These findings confirm antagonistic relation between production and reproduction traits. Therefore, reproduction traits should also be taken into consideration along with production traits for genetic evaluation, selection of superior germplasm as well as for formulating suitable breeding programs for sustainable genetic improvement of Sahiwal cattle.

Abbreviations: AAC, age at calving; CFI, calving to first insemination interval; CI, calving interval; 305DMY, 305-day milk yield; DP, dry period; DO, days open; LL, lactation length; TMY, total milk yield; PR, pregnancy rate

摘要

本研究旨在评估 Sahiwal 牛不同生产和繁殖性状之间的关系。使用了长达 29 年（1988 年至 2016 年）的 ICAR-国家乳业研究所有组织的畜群饲养的与 Sahiwal 牛不同生产和繁殖性状相关的六胎数据。考虑的各种生产和繁殖性状包括 305 天产奶量 (305DMY)、总产奶量 (TMY)、泌乳期 (LL)、干奶期 (DP)、产犊年龄 (AAC)、产犊至第一次授精间隔 (CFI) , 天开放/服务期 (DO), 产犊间隔 (CI) 和怀孕率 (PR) 直到第六胎。除了分析这些性状之间的图表外，还估计了不同生产和繁殖性状之间的遗传和表型相关性，直至 Sahiwal 牛的六胎。305DMY、TMY、LL与DO、CI的遗传相关性均呈正相关。同样，305DMY、TMY 和 LL 与 CFI、DO 和 CI 的表型相关性显着正相关，表明产奶量高的奶牛具有更长的产犊到第一次授精间隔、开放天数和产犊间隔。这些发现证实了生产和繁殖性状之间的拮抗关系。因此，在进行遗传评估时，还应考虑繁殖性状和生产性状，

缩写：AAC，产犊年龄；CFI，产犊至第一次授精间隔；CI，产犊间隔；305DMY，305天产奶量；DP，干燥期；DO，营业日；LL，泌乳长度；TMY，总产奶量；PR，怀孕率