The association between the severity of ketosis and cyclicity in dairy cows.

Abstract

Hyperketonaemia (HK) is a frequently occurring condition in cows. Although most of the cases are subclinical. HK can cost a lot of money, because of decreased milkproduction, increased risk of fresh cow diseases, but what are the effects at the fertility of the cows? The aim of this study is to determine the effect of HK at the onset of cyclicity, namely: the interval of calving to resumption of cyclicity, the days in milk (DIM) first heat and the occurrence of cysts. This study used data from the Herd Navigator (Lattec I/S. Hillerørd. Denmark) from 35 farms in the Benelux between July 2018 and May 2020 and consisted of 4,175 cows. This data consists of frequent measurements of beta-hydroxybutyrate (BHB) in milk in the first 60 days after calving. The severity of ketosis parameter and the onset of ketosis were created from the BHB data (Unpublished data). The Herd Navigator also measured the progesterone. The progesterone levels determined the start of cyclicity, first heat and if a cow had a cyst. The severity of ketosis gave 90.1% more chance at a prolonged interval of calving to resumption of cyclicity. The severity of ketosis had an effect of +8 days at the first heat. The onset of ketosis had a reducing effect of 0.7% per day later at the interval of calving to resumption of cyclicity and a reducing effect of 0.1% per day later at the interval of calving to first heat. Severity and onset of ketosis had no effect at the number of cysts.