title: Milk trait heritability and correlation with heterozygosity in yak.
abstract: 382 yak cows were examined for milk yield, fat, protein and lactose contents. Six polymorphic loci, alphas1-CN, kappa-CN, beta-CN, beta-Lg, alpha-La and MUC-1, were scored by PAGE electrophoresis for each individual. The values of milk yield, fat, protein and lactose content were 247.13 kg, 5.81%, 5.18% and 4.93%, respectively. Based on the 6 polymorphism loci, the average heterozygosity of the yak population was 0.1794. Calculated by the marker-based method, heritability estimates for milk yield, fat, protein and lactose contents were 0.353 +/- 0.093, 0.316 +/- 0.101, 0.415 +/- 0.098 and 0.481 +/- 0.035, respectively. The relatively high or medium heritability of these traits indicate that it is feasible to rely directly on them in breeding for the improvement in a relatively short period. The significant linear regression between heterozygosity and fat percentage with a positive slope (R = 0.0420) indicated that inbreeding affected milk fat content in this population.
authors.affiliation: College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, PR China. xpjiang@mail.hzau.edu.cn
authors.forename: X P
authors.initials: XP
authors.lastname: Jiang
authors.forename: G Q
authors.initials: GQ
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.forename: Y J
authors.initials: YJ
authors.lastname: Mao
authors.forename: Y Z
authors.initials: YZ
authors.lastname: Xiong
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle / Q000235:genetics*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D040582:Inheritance Patterns; D007785:Lactose / Q000032:analysis / Q000235:genetics*; D016014:Linear Models; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: D008894:Milk Proteins; D007785:Lactose