Reduced Concentrate for Holstein First-Calf Heifers

Abstract

To examine the consequences of reducing annual concentrate in the diet of lactating first-calf heifers we fed forage (.63 urea-treated corn silage, .37 wilted grass silage) free choice during lactation and concentrate to appetite during wk 1 to 8 postpartum with ceilings of 1kg concentrate for each 2.5, 3.5, or 4.5kg milk produced on the preceding day. Concentrate actually consumed in wk 1 to 8 was totaled, and three times that amount was allocated over wk 9 to 44 postpartum by weekly, stepwise, percentage reductions common to all treatments. Reducing concentrate significantly decreased absolute intake of dry matter (primarily concentrate portion), milk yield, and income above feed cost. In wk 1 to 24 postpartum, for each kilogram decrease of daily intake of dry matter from concentrate, forage dry matter increased about .66kg and total intake of dry matter decreased about .33kg. Body weight, length of lactation, and milk composition were not significantly different among treatments. Heifers fed not more than 1kg concentrate for each 2.5kg milk during wk 1 to 8 postpartum consumed 2029kg concentrate and produced 6553kg milk for a lactation.