Performance and ruminal fermentation of second-trimester pregnant cows when fed short-season high-moisture corn stover or barley greenfeed during winter in western Canada

This study evaluated performance and ruminal fermentation for cows fed short-season high-moisture shelled corn stover with corn dried distillers’ grains with solubles (COR) or barley greenfeed (BAR) that was either swathed (S-COR; S-BAR; Experiment 1) or baled (B-COR; B-BAR; Experiment 2) as winter-feeding systems. In Experiment 1, cows were randomly assigned to S-COR or S-BAR and fed for 52 d in the fields where crops were grown. Body weight (BW), subcutaneous rib and rump fat, and body condition score (BCS) were measured, with no differences detected between treatments (P > 0.05). However, S-COR had lower estimated dry matter intake (DMI) than S-BAR (P ≤ 0.03). In Experiment 2, cows were assigned to B-COR or B-BAR for 42 d and fed in field paddocks. Cows fed B-COR had lesser (P ≤ 0.01) DMI, final BW, rib fat, rump fat, and BCS than B-BAR, with no differences (P > 0.05) for ruminal pH. Total SCFA concentration was greater (P ≤ 0.05) on d 21 for B-BAR than B-COR, but not on d 42. Under western Canadian conditions COR may reduce DMI and performance of pregnant cows suggesting that additional preservation and supplementation strategies should be investigated.