Performance and ruminal fermentation of second-trimester pregnant beef cows fed short-season high-moisture corn stover or barley greenfeed during winter in western Canada
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Résumé en langage clair
Results from this study show that stover from short-season corn with corn dried distillers’ grains with solubles supplementation can be used as an alternative feed source to barley greenfeed in extensive winter grazing conditions for dry, multiparous, pregnant cows but additional supplementation may be required to prevent reductions in body energy status as indicated by poorer performance of cows fed baled corn dried distillers grains. Special care must be taken to minimize environmental loss and mitigate freezing and spontaneous heating when short-season corn stover is baled. Additional research into the most appropriate corn stover feed presentation (swaths, bales, etc.) and preservation in western Canadian conditions is warranted.
Résumé
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.