Document Type : Research Paper
Author
Assistant Professor, University of Tehran, Aborayhan Campus
Abstract
In order to estimate the genetic parameters for days from calving to first service (DFS) in Iranian Holstein cattle by using repeatability, multiple-trait (MT) and random regression (RR) models, 159,482 records of parities 1 to 6 collected during 1981 to 2013 and distributed over 33 large Holstein herds were used. Bayesian information criterion of MT model was lower than other models and Bayesian factor of MT model was significant compared to other models (P< 0.05). Estimates of heritability of DFS with RR model decreased from parity 1 (0.09±0.01) to parity 6 (0.03±0.01). Estimated heritability by MT model decreased from parity 1 (0.08) to parity 5 (0.04) and increased in parity 6 (0.10). The obtained heritability using repeatability model was 0.055±0.01. Genetic correlations between DFS in different parities were reduced continuously with increasing distance between parities in RR and MT models. Overall, the result of this study indicate that multiple trait model performs better than other models in estimation of genetic parameter for DFS.
Keywords
- Fatehi J and Schaeffer LR (2003) Data management for the fertility project. Report to the technical Committee of the Canadian Genetic Evaluation. From http://cgil.uoguelph.ca/dcbgc/Agenda0303/FatehiReport.pdf.
- Ghiasi H, Pakdel A, Nejati-Javaremi A, Mehrabani-Yeganeh H, Honarvar M, Gonzalez-Recio O, Carabano MJ and Alenda R (2011) Genetic variance components for female fertility in Iranian Holstein cows. Livestock science. 139: 277–280.
- González-Recio O and Alenda R (2005) Genetic parameters for female fertility traits and a fertility index in Spanish dairy cattle. Journal of Dairy Science. 88: 3282–3289.
- Gutierrez GA (2010) Estimates of genetic parameters for female fertility traits from a dairy selection experiment for fat plus protein by using random regression and linear-threshold animal models. Iowa State University, USA, Ph.D. Dissertation
- Jamrozik J, Fatehi J, Kistemaker GJ and Schaeffer LR (2005) Estimates of genetic parameters for Canadian Holstein female reproduction traits. Journal of Dairy Science. 88(6): 2199-2208.
- Jorjani H (2007) There and back again: a tale of choosing female fertility traits. Interbull Bull. 37: 148–151.
- Kass RE and Raftery AE (1995) Bayes factors. Journal of the American Statistical Association. 90(430): 773-795.
- Menendez-Buxadera A, Carabaño MJ, Gonzalez-Recio O, Cue RI, Ugarte E and Alenda R (2013) Reaction norm of fertility traits adjusted for protein and fat production level across lactations in Holstein cattle. Journal of Dairy Science. 96: 4653-4665.
- Meyer K (2004) Scope for a random regression model in genetic evaluation of beef cattle for growth. Livestock Production Science. 86(1): 69-83.
- Nishida A, Aziz MA, NishidaS and Suzuki K (2006) Modelling number of services per conception of Japanese Black cattle by random regression. Journal of Animal Breeding and Genetic.123, 56-63.
- Nobre PRC, Misztal I, Tsuruta S, Bertrand JK, Silva LOC and Lopes PS (2003) Analyses of growth curves of Nellore cattle by multiple-trait and random regression models. Journal of Animal Science. 81(4): 918-926.
- Schaeffer LR (2004) Application of random regression models in animal breeding. Livestock Production Science. 86(1): 35-45.
)