The effect of the glycerol pellet supply on dairy cows during the close-up dry period

Abstract

This study examined the effects of the glycerol pellet supply during the close-up dry period in dairy cows. The peripartum metabolic status, postpartum disease, milk yield, and recovery of reproductive function were examined in 41 dry Holstein cows. Daily doses of 200 g of glycerol pellets containing 40 % glycerol (Gly group, n＝20) or 200 g of placebo pellets without glycerol (Cnt group, n＝21) were orally administered 21 days before the expected calving date through parturition. The rumen fill score (RFS) before calving did not change in the Gly group, but the RFS decreased gradually as the calving day approached (P<0.05) in the Cnt group. In the Gly group, the β-hydroxybutyrate acid (BHBA) blood concentration during 2 weeks prepartum was lower (P<0.05), and the body condition score (BCS) during 2 weeks prepartum (P<0.05) and 4 weeks postpartum (P＝0.06) was higher. In addition, blood non-esterified fatty acid concentration during 4 weeks postpartum was tended to be higher (P＝0.09) and blood γ-glutamyl transpeptidase activity at 4 and 4.5 week postpartum was higher (P<0.05) in Gly group than in Cnt group. The number of cows that developed ketosis after parturition did not differ between groups, although the Gly group cows with ketosis tended to have lower blood BHBA concentrations (P＝0.07). There were no differences in the milk yield and recovery of reproductive function after parturition between groups. Administering 40 % glycerol pellets to dairy cows during the close-up dry period may help to maintain feed intake, improve hepatic lipidosis, proper maintaining of BCS, and alleviate ketosis symptoms.