Page 12 - BBLP ejournal2018.docx

วารสารเทคโนโลยีชีวภาพการผลิตปศุสัตว์

Estimates of Genetic Parameters for Dairy Crossbred Female Fertility Traits

2/
3/
Sayan Buaban Jureeratn Sanpote Monchai Duangjinda
1/

Abstract

The objectives of this study were to estimate genetic parameters for various fertility traits on Thai dairy
crossbred heifers and cows population using univariate and bivariate analysis with animal model and to compare

the parameter estimates of fertility traits which are ordered categorical and binary traits with Threshold animal
model (TAM) and Linear animal model (LAM). The data from the Bureau of Biotechnology and Animal production,

DLD calving between 2002 and 2015were used. The data for univariate and bivariate analysis consisted of 71,515
and 82,633records (1.81 records per cow) on heifers and cows, respectively whereas the data for bivariate analysis

for each trait in heifers and cows were 148,269 records from 50,804 heads. The investigated traits were: age at
first service (AFS), age at first calving (AFC), days from calving to first service (DTFS), days from first service to

conception (DFTC), days from calving to conception or days open (DO), calving interval (CI), number of services
per conception (NSPC) and conception at first service (FSC), pregnancy within 56 dafter first service (P56) and

pregnancy within 90 dafter first service (P90). Virgin heifers had better fertility performance than cows. Estimated
heritabilities for the most of the fertility traits were 0.07 or less except for AFS (0.18) and AFC (0.17). Moreover,

the estimated genetic correlations among fertility traits within parity indicated that selection for heifers/cows with
shorten DFTC or DO would achieve the largest genetic progress in the ability to conceive and maintain pregnancy

in both heifers and cows. Therefore, DFTC or DO could be used as one of the best indicators for heifer/cow fertility
and could be complemented by more highly heritable other traits such as AFS (in heifers) and DTFS or NSPC (in

cows) in term of fertility index that would enable efficient selection for better fertility. Additionally, genetic
correlations for the same fertility traits between heifers and cows were low to moderate and far from 1. This

indicated that fertility traits of heifers and cows were different. Therefore, they should be considered as different

traits in genetic evaluation.

Keywords: genetic parameters, fertility traits, dairy crossbred, Thailand

Registered No. : 54(1)-(54:03)0208-026
1/ Bureau of Biotechnology in Livestock Production, Department of Livestock Development, Bangkadee,

Pathumthani, 12000

2/ Livestock Academic Development Group, Department of Livestock Development, Payathai, Ratchathevi,
Bangkok, 10400

3/ Department of Animal Science, KhonKaen University, Meaung, KhonKaen 40002

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