97 The effect of metabolizable protein intake in finishing diets on feeding behavior of steers.

The objective of this study was to evaluate the effect of metabolizable protein intake (MP) in finishing cattle diets (10% forage) on feeding behavior. One-hundred thirty-two steers (initial BW: 316 kg; final BW 594 kg) were stratified by initial BW across five pens and randomly assigned to one of four dietary treatments (626, 906, 1209 and 1444 g/d MP intake; n = 33 per treatment). A visit was defined as each time the Insentec system detected a steer at the feed bunk. A meal was defined as eating periods by intervals no longer than 7 min. A quadratic effect for visits and meals per day was observed (P < 0.01) with steers fed 1209 g/d MP treatments having the least visits and meals per day. In addition, there was a quadratic effect for DMI (P < 0.01) with steers fed 1209 g/d MP having the greatest intake per day. Time eating per visit responded quadratically (P = 0.05) with time increasing from 626 to 906 g/d MP and plateaued thereafter. There was a linear increase (P < 0.01) in time eating per meal and per day with increasing MP intake. A quadratic effect (P < 0.03) was observed for DMI per visit, meal, and minute with steers fed 1209 g/d MP having the greatest DMI. In summary, steers fed 626 g/d MP had increased visits and meals per day. However, DMI per visit, meal, and minute was greater in steers fed 1209 g/d MP. These data indicate that MP supply (from deficient to excess) influences feeding behavior, potentially through chemostatic feedback mechanisms, in finishing cattle.