Genetic parameters for test day somatic cell score in Brazilian Holstein cattle

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Costa, CN (Author) Other; Santos, GG (Author) Other; Cobuci, JA (Author) Other; thompson, g (Author) ICBAS; carvalheira, j (Author) ICBAS

Journal

Title: Genetics and Molecular Research

Vol. 14

ISSN: 1676-5680

Publisher: Fundacao de Pesquisas Cientificas de Ribeirao Preto

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 0 Citations

Other information

Authenticus ID: P-00K-2H6

DOI: 10.4238/2015.december.29.21

Abstract (EN): Selection for lower somatic cell count has been included in the breeding objectives of several countries in order to increase resistance to mastitis. Genetic parameters of somatic cell scores (SCS) were estimated from the first lactation test day records of Brazilian Holstein cows using random-regression models with Legendre polynomials (LP) of the order 3-5. Data consisted of 87,711 TD produced by 10,084 cows, sired by 619 bulls calved from 1993 to 2007. Heritability estimates varied from 0.06 to 0.14 and decreased from the beginning of the lactation up to 60 days in milk (DIM) and increased thereafter to the end of lactation. Genetic correlations between adjacent DIM were very high (>0.83) but decreased to negative values, obtained with LP of order four, between DIM in the extremes of lactation. Despite the favorable trend, genetic changes in SCS were not significant and did not differ among LP. There was little benefit of fitting an LP of an order >3 to model animal genetic and permanent environment effects for SCS. Estimates of variance components found in this study may be used for breeding value estimation for SCS and selection for mastitis resistance in Holstein cattle in Brazil.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 11