GENETIC ANALYSIS OF PRODUCTION AND REPRODUCTION PERFORMANCES OF MECHERI SHEEP UNDER NORTH-WESTERN AGRO-CLIMATIC ZONE OF TAMIL NADU
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Date
2022
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Abstract
The primary condition required for improvement of animals through genetic selection is genetic variance. Understanding of non-genetic sources of variation in performance traits is critical for developing the most effective management strategies to support genetic progress. If the problems of inbreeding and lamb mortality are not addressed, the genetic superiority in animals may not result in profitability for farmers. Hence, this genetic evaluation study was carried out on Mecheri sheep for production and reproduction traits, along with inbreeding and survival analysis.
The data of Mecheri sheep maintained at Mecheri Sheep Research Station, Pottaneri from 1979 to 2018 were utilized in this study, which included production data of 2616 lambs and reproduction data of 559 ewes with 1373 lambings for genetic evaluation, 4168 sheep for pedigree evaluation and 3715 farm-born lambs for survival analysis. Least-squares analyses were conducted with general linear models to evaluate the performance of Mecheri sheep and to study the effect of non-genetic factors on production and reproduction traits. To estimate genetic parameters of performance traits, the animal models were fitted in REML and Gibbs samplers of Bayesian inference. Pedigree details of Mecheri sheep were analyzed to estimate inbreeding coefficient of the individual in the population. Kaplan-Meier and Cox proportional hazard analyses were conducted to study the survival of lambs.