Genetic Evaluation of Gir Cattle for Success Rate to Conception using GLIMMIX Model

Background: The objective of this study was to assess the genetic and phenotypic parameters associated with the success rate to conception using 90-days non-return rate (NRR90F), conception Rate (CR) and number of insemination to conception (INS) traits in service bull. Methods: A total of 2590 insemination including 1776 first time insemination was carried out during the period of 2018-2020 in the Gir cattle distributed in the semi-arid region of RajasthanNRR90F and CR were analysed as binary variable and INS as multi-nominal trait. Generalized linear models were used to for the evaluation of non-genetic factors and generalized linear mixed models for genetic effects. Result: The average success rate of artificial insemination was estimated as 0.35 for NRR90F and 0.41 for CR. Further, cumulative logit link function was used to analyse the number of successful insemination to conception (INS) and cumulative estimates was observed as 0.95 for two number of insemination to conception. Period and season were the non-genetic factors that influenced the traits studied. Decreasing trend was observed over the period for success of insemination for all studied traits. Summer season showed highest odd ratio and estimated as 1.213 for NRR90F, 1.388 for CR and 1.440 for INS with reference to autumn season. Heritability was estimated as 0.015 for NRR90F, 0.028 for CR and 0.086 for INS.