Calving area selection and prepartum behavior of dairy cows managed outdoors with access to artificial and natural shelters during winter

Introduction Before calving, dairy cows may seek a secluded area to express maternal behavior. Pasture-based systems may facilitate this behavior by allowing cows to move away from the group, but little is known about calving location selection and prepartum exploratory behavior in outdoor paddocks during winter. We therefore evaluated calving area selection and prepartum exploratory behavior in dairy cows with access to sheltered and open areas. Methods Forty-eight prepartum dairy cows (17 nulliparous, 31 multiparous) were enrolled in an 8,450 m 2 paddock with access to three potential calving areas: natural shelter (NS; area with bushes and trees with straw bedding, 440 m 2 ), artificial shelter (AS; three structures with three walls and straw bed, 18 m2 each), and open paddock (OP; 7,956 m 2 ). Continuous video monitoring recorded calving locations (n = 36), while prepartum exploratory behavior was assessed using 10-min instantaneous scan sampling from video recordings during the 24 h before calving (n = 23). Results Of the total sample (n = 36), 38.9% of cows calved in NS, 16.7% in AS, and 44.4% in OP. Multinomial logistic regression showed that higher lactation number was associated with lower odds of calving in NS versus OP (OR = 0.587; 95% CI = 0.365 – 0.943; p = 0.028). Cumulative rainfall increased the odds of calving in the AS (OR = 1.195; 95% CI = 0.980 – 1.456; p = 0.078); and a higher calf-to-dam weight ratio tended to be related to greater odds of calving in NS (OR = 3.047; 95% CI = 0.000 – 9.288; p = 0.050). Descriptive analysis of exploratory behavior showed that cows calving in AS and NS spent approximately one-third of the 24 h prepartum period in their respective calving areas (6.33 ± 4.02 h/d and 7.82 ± 3.68 h/d, respectively), with visits appearing to concentrate during the hours closest to parturition. Discussion Our results indicate that dairy cows allocated outdoor during winter select sheltered and open areas to calve, and that the selection of sheltered areas was associated with individual and winter weather conditions. As parturition approached, the use of sheltered areas increased, as was observed descriptively.