Abstract
The objectives were to compare the effects of housing cows in dry lots or pasture on cow performance and reproduction. Simmental × Angus (n = 108; 87 ± 11.5 d postpartum), lactating, spring-calving cows were stratified by age, BW, BCS, calving date, and sex of the calves and allotted to six groups. Groups were randomly assigned to 1 of 2 treatments: dry lot (DL) or pasture (PAST). The cows in dry lot were limit-fed a ration consisting of corn silage, dried distillers grains, corn stalks, corn, and soybean hulls to meet their protein and energy requirements. Cows on pasture were rotationally grazed and with free-choice mineral. On d 0, cows were synchronized and artificially inseminated (AI). On d 0, 33, 51, and 87, BW and BCS were measured. Cow AI and overall pregnancy were determined on d 35 and 88, respectively. On d 52, milk production was determined using the weigh-suckle-weigh technique. Body weight, BCS, and milk yield were analyzed using the MIXED procedure of SAS. Reproductive data were analyzed using the GLIMMIX procedure of SAS. On d 0 and 33, BW did not differ (P ≥ 0.38) between cows on in DL or on PAST. On d 51, DL cows tended (P = 0.07) to have greater BW than PAST cows. On d 87, DL cows had greater BW (P = 0.05) than PAST cows. The BCS, milk yield, and reproductive rates did not differ (P ≥ 0.12) between treatments. Housing cows in dry lots compared to pasture increased BW, but did not affect BCS, milk production, and reproduction.