Ali Ilyas, Muhammad Suhail Syed, Shafiq Muhammad
Department of Livestock Management and Animal Breeding & Genetics, Faculty of Animal Husbandry and Veterinary Sciences, the University of Agriculture, Peshawar, Pakistan.
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China.
Reprod Domest Anim. 2019 Jul;54(7):1026-1033. doi: 10.1111/rda.13458. Epub 2019 May 27.
Inheritance of economic traits and their genetic correlation was studied in different breeds and their various grades (crossbred's cattle) under the subtropical condition. Data on principal parameters comprising 10 years, that is 2004-2014, were utilized for the present study. Different grades of dairy cows comprising Holstein Friesian (HF), Sahiwal x Friesian (SxHF), Jersey (J), Jersey x Achai (JxAC) and Achai (AC) were included in the study. Heritability estimates and genetic correlations of some important productive and reproductive traits were worked out. Heritability estimates of certain economic traits were found to be: birthweight, 0.32 ± 0.181; age at maturity, 0.11 ± 0.136; age at first calving, 0.19 ± 0.162; days open, 0.09 ± 0.121; calving interval, 0.14 ± 0.211; dry period, 0.11 ± 0.124; lactation length, 0.04 ± 0.212 and lactation yield, 0.46 ± 0.206. Genetic correlation showed that body weight was significantly and positively correlated with lactation length (0.30) and lactation yield (0.81), while negatively correlated with age at maturity, age at first calving, days open, calving interval and dry period (-0.09, -0.07, -0.16, -0.34 and -0.002, respectively). Calving interval was positively and significantly correlated with the dry period (0.56), lactation length (0.72) and lactation yield (0.37). Moderate to higher heritability estimates with adequate genetic variance was found for body weight and lactation yield. The moderate to higher heritability estimates of birthweight in the present study revealed that this important trait might be considered in selection criteria.
在亚热带条件下，对不同品种及其不同等级（杂交牛）的经济性状遗传及其遗传相关性进行了研究。本研究利用了2004年至2014年这10年期间的主要参数数据。研究纳入了不同等级的奶牛，包括荷斯坦弗里生牛（HF）、萨希瓦尔×弗里生牛（SxHF）、泽西牛（J）、泽西×阿柴牛（JxAC）和阿柴牛（AC）。计算了一些重要生产和繁殖性状的遗传力估计值和遗传相关性。某些经济性状的遗传力估计值如下：出生体重，0.32±0.181；成熟年龄，0.11±0.136；初产年龄，0.19±0.162；空怀天数，0.09±0.121；产犊间隔，0.14±0.211；干奶期，0.11±0.124；泌乳期长度，0.04±0.212；泌乳量，0.46±0.206。遗传相关性表明，体重与泌乳期长度（0.30）和泌乳量（0.81）呈显著正相关，而与成熟年龄、初产年龄、空怀天数、产犊间隔和干奶期呈负相关（分别为-0.09、-0.07、-0.16、-0.34和-0.002）。产犊间隔与干奶期（0.56）、泌乳期长度（0.72）和泌乳量（0.37）呈显著正相关。体重和泌乳量的遗传力估计值为中等至较高，且具有足够的遗传方差。本研究中出生体重的中等至较高遗传力估计值表明，在选择标准中可能应考虑这一重要性状。
