Estimation of Genetic Parameters for 305 Days Milk Yields and Calving Interval in Xinjiang Brown Cattle

Xuefeng Fu,Kechuan Tian,Zhiqin Guo,Yachun Wang,Yuezhen Tian,Liming Cheng,Xinming Xu,Xixia Huang,Lili Lu,Jiqing Fang

doi:10.4236/as.2017.81004

Abstract

This study was conducted to estimate variance components and genetic parameters for 305 days mature equivalent milk yields (MEM) and calving interval (CAI) of registered Xinjiang Brown cattle. The total records were 3940 including 2579 for 305-day MEM and 1970 for CAI, which were collected from Xinjiang Urumqi Cattle Breeding farm in China with calving records from 1990 to 2008. Genetic parameters were obtained by multiple trait derivative-free restricted maximum likelihood (MTDFREML) using animal model. The model included year, season, parity and calving interval of calving for 305 days MEM, and year, season and parity of birth for CAI as fixed effects. Heritability for 305 days MEM was moderate (0.39) and in the same range of parameters estimated in management systems with medium production levels. Heritability of calving interval was small (0.02) as fertility traits for Xinjiang Brown cattle. Estimates of genetic and environmental correlations between 305 days MEM and CAI were 0.47 and 0.37, respectively. Estimates of genetic variation and heritability indicated that selection would result in genetic improvement of production traits. Estimates of both heritability and genetic variation for CAI were small, which indicates that genetic improvement would be difficult.

Highlights

The Xinjiang Brown cattle belong to the dual-purpose cow
Estimates of heritability and genetic variation for 305 days mature equivalent milk yields (MEM) in this study were moderate compared with major reports on Brown Swiss, Holstein populations and Simmental cattle
The results indicate that response to selection would be expected in Xinjiang Brown cattle

Summary

Introduction

They would establish selection index and estimate genetic progress in animal breeding plan [3]. Accurate heritability and genetic correlation estimates are required to predict expected selection response and to obtain predicted breeding values using animal mixed model and best linear unbiased prediction (BLUP) programs [2]. A measure of lactation yield is information needed for management and genetic evaluation in dairy cattle; monthly test day yields are used as basis for calculating whole lactation yields [8]. The test interval method (TIM) has become a standard method for this purpose; it is currently used to calculate dairy herd improvement (DHI) lactation and lactation-to-date totals [9]. The totals for the two portion of the test interval are added to obtain the interval totals

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Conclusion