The effect of selected non-genetic factors on key fertility indices in high-yielding Montbéliarde cows
Ewa Januś, Danuta Borkowska
Abstract. The aim of the study was to analyse the effect of non-genetic factors on fertility in high-yielding Montbéliarde cows. The length of the rearing period for the Montbéliarde heifers in the herd analysed was found to depend on their origin and on the season in which they were born. Their average age at first calving was 908 days, with imported heifers calving for the first time on average 168 days later than native heifers. Heifers born in autumn months gave birth earliest, while those born from March to May calved latest. The acclimatization process may have negatively affected reproductive performance, as longer calving-to-first-service intervals (CFSI), service periods (SP), calving-to-conception intervals (CCI), and calving intervals (CI) were noted in the imported cows. Delayed first calving in heifers significantly increased the calving-to-first-service interval. In successive lactations a general downward trend was observed in the length of CFSI, SP, CCI and CI. Reproductive efficiency was significantly reduced by 305-day milk yield exceeding 10~000 kg FPCM. Hence, in the case of record productivity in the Montbéliarde breed, as in Holstein-Friesians, reduced fertility must be expected.
Keywords: cows, fertility indices, high yield, Montbéliarde