Effects of yeast culture (Saccharomyces cerevisiae) on prepartum intake and postpartum intake and milk production of jersey cows

Yeast cultures (Saccharomyces cerevisiae; YC) have been added to diets for dry and lactating dairy cows to attempt to improve ruminal fermentation, po tentially increasing dry matter intake (DMI) and milk yield. Jersey cows (1 4 primigravid and 25 multigravid) were fed total mixed rations prepartum an d postpartum that were either supplemented or not supplemented with YC. The YC was a dried product that was top-dressed at 60 g/d for approximately 21 d prepartum and 140 d postpartum. The DMI was increased by YC during both the last 7 d prepartum (9.8 vs. 7.7 kg) and during the first 42 d of lactat ion (13.7 vs. 11.9 kg). The treatment-by-day interaction was significant fo r DMI during the first 21 d postpartum, indicating that cows supplemented w ith YC increased DMI more rapidly than did nonsupplemented cows. A signific ant treatment-by-day interaction indicated that cows supplemented with YC l ost body weight less rapidly postpartum than did nonsupplemented cows. A si gnificant interaction of treatment by day indicated that cows supplemented with YC reached peak milk production more quickly than did nonsupplemented cows. However, total milk produced during the first 140 d of lactation did not differ. Concentrations of fat, protein, lactose, total solids, and urea N in milk, as well as somatic cell count, were not significantly affected by YC. Supplementation of YC increased DMI during the transition period and increased DMI postpartum.