Effect of feeding an energy supplement to dairy cows pre- and postpartum on intake, milk yield, and incidence of ketosis

Seventy-five dry multiparous Holstein cows housed in a tie stall facility on a commercial dairy, were blocked and assigned randomly to treatments to evaluate the effect of feeding a dry energy supplement for 21 days prepartum and 21 days postpartum on animal performance. The energy supplement contained 45% beet pulp, 22% sugarcane molasses, 17% propylene glycol, and 16% calcium propionate (DM basis). The sugars in molasses were mainly glucose and sucrose. Forages and concentrates were fed separately and comprised 67 and 33% (DM basis), respectively, of the diet for dry cows and 46 and 54%, respectively, of the diet for lactating cows. In addition, each cow received 908 g per day of ground corn (85% DM; control), 454 g per day of ground corn and 454 g per day of the energy supplement (86% DM), or 908 g per day of the energy supplement on an as fed basis. Feeding the energy supplement had no effect on DM intake among dry or lactating cows, or effect on incidence of ketosis among lactating cows. Milk yield during week 1–4 postpartum by cows fed ground corn (43.9 kg per cow per day) was lower (P=0.073) than by cows fed the diets containing the energy supplement at the low (46.3 kg per cow per day) and high levels (44.5 kg per cow per day). After the feeding of the energy supplement was discontinued after week 3, milk yield by cows previously fed the energy supplement at the low (53.4 kg per cow per day) and high levels (52.7 kg per cow per day) was greater (P=0.006) than that by cows fed ground corn (50.1 kg per cow per day). Cows previously fed the energy supplement at either level also had higher yield of milk fat (P=0.027) and protein (P=0.061) than cows fed ground corn. Feeding an energy supplement containing beet pulp, sugarcane molasses, propylene glycol, and calcium propionate to Holstein cows improved milk yield, especially when fed at the low level.