GENETIC AND ENVIRONMENTAL TRENDS FOR FIRST LACTATION MILK TRAITS IN THE SOUTH-AFRICAN AYRSHIRE BREED

Authors
HALLOWELL GJ VANDERWESTHUIZEN J VANWYK JB
Citation
Gj. Hallowell et al., GENETIC AND ENVIRONMENTAL TRENDS FOR FIRST LACTATION MILK TRAITS IN THE SOUTH-AFRICAN AYRSHIRE BREED, South African journal of animal science, 28(1), 1998, pp. 38-45
Citations number
11
Categorie Soggetti
Agriculture,"Agriculture Dairy & AnumalScience
Journal title
South African journal of animal science → ACNP
ISSN journal
03751589
Volume
28
Issue
1
Year of publication
1998
Pages
38 - 45
Database
ISI
SICI code
0375-1589(1998)28:1<38:GAETFF>2.0.ZU;2-G
Abstract
Estimated breeding values and genetic trends were obtained in Ayrshire cattle by using DFREML procedures for 9050 first lactation records ca lving down from 1977 to 1992. Environmental trends were calculated as the difference between the phenotypic and genetic values. The Ayrshire breed showed a positive trend of 19 kg per year for milk yield, with similar trends for fat and protein yield, while the trends for fat and protein percentage were negative.