Genetic parameters for somatic cell score and udder traits

Document Type : Research Paper

Authors

1 Institute of Agriculture, Water, Food and Nutraceuticals, Mah.C., Islamic Azad University, Mahabad, Iran. (Corresponding Author)

2 Institute of Agriculture, Water, Food and Nutraceuticals, SR.C., Islamic Azad University, Tehran, Iran

Abstract

Introduction: The aim of this study was to investigate Genetic parameters for somatic cell score and udder traits.
Methods: This study was conducted to estimate the genetic parameters and correlations between somatic cell score (SCS) and udder traits in 35,522 Holstein cows from 310 herds. The traits of fore udder attachment (FUA), udder depth (UD), suspensor ligament (SL), front teat placement (FTP) and rear teat position (RTP) were scored on a 9-point scale and rear udder width (RUW), rear udder height (RUH) and teat length (TL) were measured. Genetic parameters estimated using multivariate analysis by Wombat software.
Results: The models included fixed effects of herd, year, season of calving, evaluation code, lactation period and the random effect of animal. The heritability for teat length and udder depth were 0.09 and 0.23 respectively. Genetic correlations between rear udder width and height was 0.41, fore udder attachment and depth 0.67, front teat placement and rear teat position 0.60, rear teat placement and suspensor ligament 0.56, and udder depth and suspensor ligament 0.42.  The general means of all traits were lower than the ideal scores but results were within the scope of previous reports. Results suggest that little response to selection could be expected from these traits. Genetic correlation between udder type traits and somatic cell score was estimated in the range of 0.04-0.32.
Conclusion: The highest genetic correlation was observed between the strength of the suspensory ligament and the somatic cell score

Keywords

Medical Journal of Mashhad university of Medical Sciences
Volume 68, Issue 1
March and April 2025

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