HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Santellano-Estrada, E. Articles by Ramírez-Valverde, R. Search for Related Content PubMed Articles by Santellano-Estrada, E. Articles by Ramírez-Valverde, R.

Inferring Genetic Parameters of Lactation in Tropical Milking Criollo Cattle with Random Regression Test-Day Models

E. Santellano-Estrada^*,,1, C. M. Becerril-Pérez^,2, J. de Alba, Y. M. Chang, D. Gianola, G. Torres-Hernández and R. Ramírez-Valverde^#

^* Facultad de Zootecnia, Universidad Autónoma de Chihuahua, Chihuahua, Chih. 31031, México
Campus Montecillo, Colegio de Postgraduados, 56230 Montecillo, Texcoco, Edo. de México, México
Asociación Mexicana de Criadores de Ganado Romosinuano y Lechero Tropical, Tuxpan, Veracruz 92801, México
Department of Dairy Science, University of Wisconsin-Madison, Madison 53706
^# Departamento de Zootecnia, Universidad Autónoma Chapingo, Chapingo 56230, México

¹ Corresponding author: esantellano{at}uach.mx

This study inferred genetic and permanent environmental variation of milk yield in Tropical Milking Criollo cattle and compared 5 random regression test-day models using Wilmink’s function and Legendre polynomials. Data consisted of 15,377 test-day records from 467 Tropical Milking Criollo cows that calved between 1974 and 2006 in the tropical lowlands of the Gulf Coast of Mexico and in southern Nicaragua. Estimated heritabilities of test-day milk yields ranged from 0.18 to 0.45, and repeatabilities ranged from 0.35 to 0.68 for the period spanning from 6 to 400 d in milk. Genetic correlation between days in milk 10 and 400 was around 0.50 but greater than 0.90 for most pairs of test days. The model that used first-order Legendre polynomials for additive genetic effects and second-order Legendre polynomials for permanent environmental effects gave the smallest residual variance and was also favored by the Akaike information criterion and likelihood ratio tests.

Key Words: random regression • lactation • genetic parameter • Tropical Milking Criollo