Effects of vitamin E and different energy sources on vitamin E status, milk quality and reproduction in transition cows

We investigated whether vitamin E supplementation and supplemental energy s ources (fat or starch) influenced plasma and milk levels of vitamin E, and reproductive and other parameters in 28 Italian Friesian multiparous dry co ws. From 14 days before expected calving to 7 days after, the animals were assigned to either basal diet (containing 1000 IU/day of vitamin E) or an e xtra 1000 IU/day of vitamin E (total 2000 IU). In addition they received ei ther 0.5 kg/day of corn or 0.2 kg/day of calcium soaps. Plasma samples were collected 4 days before expected calving and 4 days after calving and anal ysed for alpha -tocopherol and cholesterol. Milk yield as well as the compo sition, somatic cell count (SCC) and alpha -tocopherol of milk were determi ned 7 and 14 days after calving. Milk yield and composition were unaffected by treatments. SCC was significantly lower in (SCC Log 4.62 versus Log 5.1 , P < 0.01) 2000 IU/day animals than in the 1000 IU/day group. Milk <alpha> -tocopherol was higher (P < 0.001) in animals receiving 2000 IU/day (1.11 v s. 0.65 <mu>g/ml, P < 0.01). Plasma <alpha>-tocopherol in animals receiving 2000 IU/day was also higher (P ( 0.001) than in cows receiving 1000 IU/day (4.85 vs. 3.25 mug/ml), but was not affected by dietary energy source. Num ber of services and days to conception were lower (P < 0.01) in the 2000 IU vitamin E supplemented cows. To conclude, dietary vitamin E supplementatio n to periparturient dairy cows increased plasma and milk vitamin E, decreas ed SCC in milk, and improved fertility but different energy sources had no effect on any measured variable.