Objective The purpose of this study was to estimate the genetic parameters and analyze the genetic trends of milk production traits in Chinese Simmental cattle in Xinjiang.
Methods DHI measurement data and pedigree data of Chinese Simmental cattle from 2008 to 2024 were collected from Xinjiang Hutubi Breeding Cattle Farm and Xinjiang Yili Chuangjin Ben Cattle Co., Ltd. The effects of calving year, calving season, parity, and farm on 305-d milk yield, milk fat percentage, milk protein percentage, somatic cell score, and milk urea nitrogen were analyzed using SAS 9.2 software. Genetic parameters of milk production traits were estimated using DMU software.
Results The heritability of 305-d milk yield, milk fat percentage, milk protein percentage, somatic cell score, and milk urea nitrogen of Chinese Simmental cattle in Xinjiang was 0.27, 0.14, 0.15, 0.12, and 0.08, respectively. Among them, milk urea nitrogen was a low heritability trait (h2<0.1), while 305-d milk yield, milk fat percentage, milk protein percentage, and somatic cell score were medium heritability traits (0.1<h2<0.3). The genetic trend of 305-d milk yield showed an upward trend. The genetic trends of milk fat percentage, milk protein percentage, and somatic cell score showed no obvious changes. The genetic trend of milk urea nitrogen showed a trend of first increasing and then decreasing.
Conclusion The genetic parameter estimation and genetic trend analysis of milk production traits in Chinese Simmental cattle in Xinjiang provide a theoretical reference for future genetic parameter estimation and selection index development in this breed.
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