Research Article

Effect of certain factors on the longevity and culling of cows

Małgorzata Jankowska, Anna Sawa, Justyna Kujawska

1. Acta Sci. Pol. Zootechnica, 13(2), 2014, 19‒30

Abstract. This study involved 1072 Polish Holstein-Friesian cows that were raised in 12 farms of the Kujawsko-Pomorskie province and culled between 2000 and 2012. Statistical calculations accounted for the effect of certain factors (age of cow at first calving, production level in the first lactation, housing system, herd size) on cow longevity (lifespan, length of productive life, number of calvings) and lifetime performance (GLM procedure of SAS) and proportion of culled cows (FREQ procedure of SAS). Increasing cow herd size had a negative effect (P ≤ 0.01) on longevity and lifetime performance. Likewise, efforts to maximize first lactation milk yield (> 10 000 kg milk) may shorten (P ≤ 0.05) the lifespan of the cows. Among the culled cows, as much as 90% were culled for reasons unplanned by breeders. Alarmingly, culling levels were particularly high (92%) in the largest herds (> 100 cows). Cows were culled mainly for infertility, and this reason for culling was particularly noticeable in cows that were oldest at first calving (> 30 months of age); yielded more than 10 000 kg of milk as primiparous cows; and were used in herds of 51–100 cows.

Keywords: cows, culling, determinants, Holstein-Friesian, longevity