Epsilon Archive for Student Projects

Abstract

Milk production has steadily increased during the recent decades, both in yield and milk solids. However, a higher milk production can be associated with reproductive problems resulting in challenges with fertility. A traditional 12 month calving interval (CI) with a voluntary waiting period (VWP) of 50-60 days is because of this harder to achieve, especially if the cow is sick postpartum. The aim of this thesis was therefore to evaluate if cows, sick during the first 30 days postpartum, that are given a longer VWP, and also a longer CI, will need fewer inseminations before getting pregnant. It was also hypothesized that those cows would have a higher total milk yield. A literature review and statistical analysis of data was carried out, the data was available from previous trials. The findings showed no difference between an extended (EXT) VWP and a conventional (CONV) VWP when it comes to dry days. The total lactation milk yield and 305 days milk yield was higher for cows on an EXT VWP plan. Milk yield per day of CI was higher for cows on an EXT plan but did not differ significantly. Neither did number of inseminations (NINS), cows on an EXT plan required 1.7 inseminations and cows on a CONV plan needed 2.1. First service conception rate (FSCR) was higher for cows on an EXT plan at 69% compared to cows on a CONV plan were 61% of the cows required more than one insemination to get pregnant. These results indicate that primiparous cows that express signs of sickness during the first 30 days postpartum can benefit from receiving an EXT plan, to what extent is likely to vary greatly depending on herd and their management.