A study on the longevity of Black-and-White cows

M. M. Ignatova, Ts. H. Metodieva, Т. V. Ivanova

Abstract: The aim of the present study was to determine the longevity depending on the age at first calving
and the level of milk production (at first lactation) of the Black-and-White cows. The study included
1500 Black-and-White cows – daughters of 39 Holstein Friesian bulls. Data for milk production from
the first to the fifth lactation and the age at first calving were used. It was found that: The cows up to
25 months of age at the first calving were with the highest longevity and lifetime milk production. The
further increase of the age at first calving led to a decrease of the longevity and lifetime days in milk
of the Black-and-White cows; The cows with the lowest milk production at the first lactation were with the highest longevity; The increase in first lactation milk production had a negative influence on
the longevity.

Keywords: age at first calving; longevity; milk production; Productive live

Date published: 2020-09-15