• Home
  • E-Submission
  • Sitemap
  • Contact Us
Asian-Australas J Anim Sci. Search

CLOSE


Go to Top Go to Bottom
Asian-Australas J Anim Sci > Volume 10(1); 1997 > Article
Animal Reproduction and Physiology
Asian-Australasian Journal of Animal Sciences 1997;10(1): 75-78.
DOI: https://doi.org/10.5713/ajas.1997.75    Published online February 1, 1997.
Seasonal grouping in year-season animal model evaluation of Sahiwal cattle
M. S. Khan, A. Ali, S. Ali, M. Saleem
Abstract
Season is very important as it defines the contemporaries for sire and cow evaluation. An attempt is made for defining season for animal model evaluation of Sahiwal animals, using 1,227 records from 730 cows. Cows were required to have a lactation length of 305 days. Ten different combinations of months for two, four, five or other seasons were tried. The other fixed effect in the model was age defined within parity. The random effects were permanent environment and animal`s breeeding value along with the residual effects. A single trait animal model was used where all known relationships of an animal were incorporated in a relationship matrix. The error variance from the fitted model decreased as the number of year-season combinations increased, indicating a month-year model to be more appropriate. This, on the other hand, decreased the number of contemporaries for certain subclasses to a minimum of one, making the bull comparisons invalid. Use of a two season scenario, with winter (November through February) and summer (March through October) was better than the other combinations in terms of error variance of the fitted model and the number of lactations represented in any year-season subclass.
Keywords: Season; Animal Model; Sahiwal Cattle


ABOUT
SPECIALTIES
BROWSE ARTICLES
FOR AUTHORS AND REVIEWERS
Editorial Office
Asian-Australasian Association of Animal Production Societies(AAAP)
Room 708 Sammo Sporex, 23, Sillim-ro 59-gil, Gwanak-gu, Seoul
08776, Korea   TEL : +82-2-888-6558    FAX : +82-2-888-6559   
E-mail : jongkha@hotmail.com               

Copyright © 2019 by Asian-Australasian Journal of Animal Sciences. All rights reserved.

Developed in M2community

Close layer
prev next