The effects of different glucose precursors on milk production and composition in dairy cows

Abstract

The aim of this study is to investigate the effects of glucose precursors on blood parameters, milk yield and composition in dairy cows. For this study, 26 multiparous and 34 primiparous Holstein cows were used in randomized block design to evaluate the feeding glycerol (G), propylene glycol (PG), and water (C) from 7 d prepartum to 21 d in milk (DIM). Treatments were 300ml water (C), 450 ml glycerol (G), and 300 ml propylene glycol were drenched after morning feeding. Milk yields were recorded as daily, milk samples were analyzed for fat, protein, lactose from all cattle for two consecutive days every week compositions until the 100 DIM. In other hand, blood samples were taken for glucose at last week of gestation, day calving, week 1, 2 and 3 in postpartum. There was no difference between the groups in glucose levels. However, milk yield of C (35.06 L/day) group was 1 L higher than G (34.18 L/day) group and 1,5 L higher than PG (33.46 L/day) group (P<0,05). Milk fat was found to be higher in PG group cows (3.67%) compared to C (3.44%) and G (3.46%) cows (P<0.05). However, milk proteins of the C (3.32%) group were higher than the PG (3.15%) group. Milk yield and milk protein were found to be higher in the untreated C group than in the G and PG groups, and differences were found between the groups in terms of milk fat. It was concluded that there is a need for further investigation of the effects of glucose procurers such as G and PG, especially on the rumen.