Milk production and composition, and body measurements of dairy cows receiving intramuscular injections of folic acid and vitamin B-12 in commercial dairy herds
Duplessis, M., Girard, C.L., Santschi, D.E., Lefebvre, D.M., Pellerin, D. (2014). Milk production and composition, and body measurements of dairy cows receiving intramuscular injections of folic acid and vitamin B-12 in commercial dairy herds. Livestock Science, [online] 167(1), 186-194. http://dx.doi.org/10.1016/j.livsci.2014.06.022
The purpose of this study was to measure the effects of a supplementation in folic acid and vitamin B-12 given before calving and in early lactation on milk production and components within the first 60 days in milk (DIM) as well as the 305-d yield, and on indicators of energy balance for dairy cows in commercial dairy herds. A total of 805 dairy cows (271 primiparous and 534 multiparous) in 15 commercial dairy herds were involved. From February to December 2010, every 2. mo and within each herd, cows were assigned, according to parity, predicted 305-d milk production, and calving interval to receive weekly intramuscular injections (5 mL) of either (1) saline 0.9% NaCl (Control) or (2) 320. mg of folic acid+10. mg of vitamin B-12 (Vitamins). Treatments began 21. d (SD 8) before the expected calving date and lasted until 60 (SD 4) DIM. For the first 60. DIM, average milk yield was 35.0. kg/d and was not affected by treatment. On average, milk fat concentration was decreased in early lactation for cows in the vitamin group as compared with control, from 42.1 to 40.3 g/kg whereas milk protein concentration was increased by the supplement, from 30.9 to 31.5 g/kg. Milk lactose and milk urea nitrogen concentrations were unaffected by treatment. No treatment effect was found on 305-d milk and protein yields. The vitamin supplement reduced 305-d milk fat yield in primiparous cows as compared with controls whereas no treatment effect was observed for multiparous cows. As indicators of energy balance, the fat:protein ratio was decreased by 0.06 and body condition score losses after calving tended to be smaller for cows in the vitamin group as compared with control. The decrease of the fat:protein ratio by the vitamin supplement was greater in primiparous cows than in multiparous cows. Cows receiving the vitamin supplement lost less body weight (estimated by heart girth circumference) during the first 60 DIM than control cows. Estimated body weight losses of 22.8 and 30.3 kg were recorded for vitamin and control cows, respectively. The observed reduction in estimated body weight loss coupled with a reduction of the fat:protein ratio without effect on milk yield suggest that supplementary folic acid and vitamin B-12 could have an effect on energy partitioning in early lactation. © 2014.