title: Genetic analysis of the rates of conception using a longitudinal threshold model with random regression in dairy crossbreeding within a tropical environment.
abstract: This study was designed to: (i) estimate genetic parameters and breeding values for conception rates (CR) using the repeatability threshold model (RP-THM) and random regression threshold models (RR-THM); and (ii) compare covariance functions for modeling the additive genetic (AG) and permanent environmental (PE) effects in the RR-THM. The CR was defined as the outcome of an insemination. A data set of 130 592 first-lactation insemination records of 55 789 Thai dairy cows, calving between 1996 and 2011, was used in the analyses. All models included fixed effects of year × month of insemination, breed × day in milk to insemination class and age at calving. The random effects consisted of herd × year interaction, service sire, PE, AG and residual. Variance components were estimated using a Bayesian method via Gibbs sampling. Heritability estimates of CR ranged from 0.032 to 0.067, 0.037 to 0.165 and 0.045 to 0.218 for RR-THM with the second, third and fourth-order of Legendre polynomials, respectively. The heritability estimated from RP-THM was 0.056. Model comparisons based on goodness of fit, predictive abilities, predicted service results of animal, and pattern of genetic parameter estimates, indicated that the model which fit the desired outcome of insemination was the RR-THM with two regression coefficients.
authors.affiliation: The Bureau of Biotechnology in Livestock Production, Department of Livestock Development, Patumtani, KhonKaen, Thailand.
authors.forename: Sayan
authors.initials: S
authors.lastname: Buaban
authors.affiliation: Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Kuchida
authors.affiliation: Department of Life Science and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
authors.forename: Mitsuyoshi
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Life Science and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Masuda
authors.affiliation: Department of Animal Science, Khon Kaen University, Meaung, KhonKaen, Thailand.
authors.forename: Wuttigrai
authors.initials: W
authors.lastname: Boonkum
authors.affiliation: Department of Animal Science, Khon Kaen University, Meaung, KhonKaen, Thailand.
authors.forename: Monchai
authors.initials: M
authors.lastname: Duangjinda
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D002417:Cattle / Q000235:genetics* / Q000502:physiology; D003612:Dairying; D066264:Datasets as Topic; D005260:Female; D005306:Fertilization / Q000235:genetics* / Q000502:physiology*; D059647:Gene-Environment Interaction; D006824:Hybridization, Genetic; D007314:Insemination / Q000502:physiology*; D007774:Lactation; D008297:Male; D008957:Models, Genetic; D015233:Models, Statistical; D012044:Regression Analysis; D014329:Tropical Climate
keywords: conception rate; crossbred dairy cattle; random regression; threshold model