Effect of age at first calving on productive parameters in Costa Rican Jersey cows.
DOI:
https://doi.org/10.15517/am.v24i1.9796Keywords:
milk production, first lactation, age at first calving, Jersey.Abstract
The objective of this work was to quantify the effect of age at first calving (AFC) on milk production in the first and second lactation of specialized diary Jersey cows. Records of 28 367 cows belonging to 545 specialized dairy herds, registered in the software VAMPP Bovino 3.0 between January 2000 and December 2010, were used. Descriptive statistics and linear mixed models were performed. The AFC average was 29.35 months (SD: 6.77), with a trend to increase during the study period. A significant effect of the AFC was observed on milk production (kg/305d) in the first two lactations (P<0.0001); in the first lactation, cows with AFC < 25.8 months or between 25.8 and 41.0 months produced -275.81 and -167.70 kg/305d (P<0.0001) than those with AFC >41 months. Cows without retained placenta (RMF) produced +450 kg/305 d (P= 0.0022) than those with RMF. On the other hand, the inbreeding coefficient and type of birth had no effect on milk production. In the second lactation, the independent variables affected the milk production similarly to first lactation; however, the age at second calving did not affect the subsequent production. This study demonstrates the linear effect of AFC on first and second lactation milk production; thus, AFC seems to have an effect not only on first lactation, but also in the productive performance of second lactation.
Downloads
Downloads
How to Cite
Issue
Section
License
1. Proposed policy for open access journals
Authors who publish in this journal accept the following conditions:
a. Authors retain the copyright and assign to the journal the right to the first publication, with the work registered under the attribution, non-commercial and no-derivative license from Creative Commons, which allows third parties to use what has been published as long as they mention the authorship of the work and upon first publication in this journal, the work may not be used for commercial purposes and the publications may not be used to remix, transform or create another work.
b. Authors may enter into additional independent contractual arrangements for the non-exclusive distribution of the version of the article published in this journal (e.g., including it in an institutional repository or publishing it in a book) provided that they clearly indicate that the work was first published in this journal.
c. Authors are permitted and encouraged to publish their work on the Internet (e.g. on institutional or personal pages) before and during the review and publication process, as it may lead to productive exchanges and faster and wider dissemination of published work (see The Effect of Open Access).
