Abstract
This study aimed to derive additional fertility traits from service data and estimate their genetic parameters for their possible inclusion in the South African Holstein cattle breeding programs. Service records (n = 64,464) were collected from 18 South African Holstein herds using on-farm automated milk recording systems. Using a multivariate model, the data were used to estimate heritabilities and correlations among several fertility traits. The pedigree data consisted of information on 18,592 animals born between 1981 and 2013. Heritability estimates observed were low to moderate (0.02 ± 0.00 to 0.24 ± 0.00), indicating that there is some genetic basis for the explored fertility traits to warrant selection. The genetic correlations observed between fertility traits were generally favorable, with some high correlations between age at first service (AFS) and services per conception for heifers (SPCh) (0.73 ± 0.00) and between days from calving to first service (CFS) and services per conception for cows (SPC) (0.90 ± 0.01). Positive genetic correlations indicate that improvement in one trait is coupled with a correlated genetic increase in another trait. The studied fertility traits could be used in addition to AFC and CI to serve as a basis for the selection of reproduction in dairy cattle to minimize selection bias.
Funder
National Research Foundation
Subject
General Veterinary,Animal Science and Zoology
Reference50 articles.
1. Genetic relationships between production traits and reproductive performance in Holstein dairy cows
2. The Productive Lifetime of the Dairy Cow
http://www.milkproduction.com/Library/Editorial-articles/The-productive-lifetime-of-the-cow/
3. The incorporation of fertility indices in genetic improvement programmes
4. Expected Genetic Gain from Newly Developed Selection Indices for South African Holstein Cattle;Banga;Proceedings of the 10th World Congress of Genetics Applied to Livestock Production,2014
5. Selection Indices in Holstein Cattle of Various Countries