Effect of crop residues in haylage-based rations on the performance of pregnant beef cows

Abstract

Seventy-one individually fed multiparous, pregnant crossbred beef cows [body weight (BW) ± SD; 730 ± 77.9 kg] were used to examine the effects of including crop residues in alfalfa/grass haylage-based rations on BW gain, fat deposition/loss and plasma metabolites. The haylage control ration (CON; n = 23) was modified to include either 40% (dry matter basis) wheat straw (WS; n = 24) or 40% corn stalklage (CS; n = 24). Cows were blocked by calving date and randomly assigned to each treatment and fed for 82 d leading up to the earliest calving date. On days 1, 40, and 82, cows were weighed, ultrasounded to measure subcutaneous backfat (BF) over the ribs, body condition scored (BCS) and plasma was collected. Calves from cows fed WS had greater (P = 0.02 ) weaning weights than cows fed CS, but did not differ (P = 0.23) from CON. CS cows had the lowest ADG (P < 0.03), lost the most body condition (P < 0.04), and had the lowest dry matter intake (P ≤ 0.001). These data indicate that diets containing crop residues can be used to dilute high-quality haylage rations for wintering beef cows; however, diets containing 40% corn stalklage used in this experiment may not be advisable, since cows lost BW and fat, and their calves had the poorest calf performance up to weaning. Key words: Beef cattle, wheat straw, winter feeding, corn stalklage, crop residues