Relationship between age at first calving and longevity

ZAVADILOVÁ, L. & ŠTÍPKOVÁ, M. Vztah věku krav při prvním otelení a dlouhověkosti krav. Náš chov, 2011, roč. 71, č. 5, s. 29-30.{INTLINK}
ZAVADILOVÁ, Ludmila and ŠTÍPKOVÁ, Miloslava. Relationship between age at first calving and longevity. Náš chov, 2011, vol. 71(5), p. 29-30. ISSN 0027-8068.
Year2011
CathegoryPublication in specialized journals
Internal link11046.pdf
Abstract

Survival analysis was used to estimate the effect of the age at the first calving on the functional longevity of Holstein cows. The data set consisted of 709 495 cows. The model included the time-dependent effects parity and stage of lactation, effect of herd, year and season, herd size, class of milk production within herd and year and effect of age at the first calving. The highest risk of culling was found for the youngest cows. The risk of culling increased with the higher age at the first calving.