43 Cow Performance and Lameness Are Affected by Housing in Drylots vs Pasture During the Summer

Abstract The objective was to compare the performance of cows housed in drylots or on pasture. Spring-calving, Simmental × Angus cow-calf pairs (n = 108; 77 ± 18 days postpartum) were stratified by age, body weight (BW), body condition score (BCS), calving date, and calf sex. Cows were allotted into six groups which were randomly assigned to drylot or pasture. Drylot cows were limit-fed a ration consisting of corn silage, dried distillers grain, corn stalks, cracked corn, and a corn-based supplement to meet protein and energy requirements. Cows on pasture were rotationally grazed with access to free-choice mineral. Cows were artificially inseminated on day 0. Cow BW, BCS, hair coat scores, locomotion scores, and lameness treatments were evaluated throughout the 110-day experiment. Milk production and composition were evaluated on day 56. Data were analyzed using the MIXED and GLIMMIX (binary data) procedures of SAS. Artificial insemination and overall pregnancy rates did not differ (P ≥ 0.79) between groups. Drylot cows were 22 and 51 kg heavier (P ≤ 0.02) than pasture cows on days 83 and 110, respectively. Drylot cow BCS was greater (P = 0.03) on day 110. Hair coat scores were more desirable (P = 0.03) in drylot cows than pasture cows on day 110. Drylot cows had greater (P = 0.04) milk production than pasture cows. Pasture cows had greater (P ≤ 0.03) milk protein content and milk urea nitrogen. Although locomotion scores did not differ (P ≥ 0.45) on days 0 and 34, they were less desirable (P = 0.02) for the drylot cows on day 110. A greater (P = 0.02) percentage of drylot cows (33%) were treated for lameness than pasture cows (7%). Housing cows in drylots increased BW, BCS, and milk production, but resulted in poorer locomotion scores and increased lameness treatments.