Influence of an early exposure to the calving pen on lying behavior at calving and avoidance distance of dairy heifers

Dairy heifers are confronted with a number of changes in their environment before their first parturition. In this study, we examined the influence of an early exposure to a calving pen 4 weeks prepartum, combined with increased human–animal contact, on behavior around calving and avoidance distance of heifers. Data were collected on 65 Brown Swiss heifers on five Swiss dairy farms. On each farm heifers were randomly assigned to two treatment groups. Thirty-four treated heifers were singly housed for 24h in the calving pen 4 weeks before expected calving, a procedure that also involved handling by a human. Heifers of the control group (n=31) were housed for the first time in the calving pen on the days before and during parturition. Lying behavior was recorded using data loggers, and a human avoidance test involving a familiar and an unfamiliar person was conducted 4 weeks prepartum and 1 week postpartum. Additionally, interventions during parturition were logged. Neither the proportion of time spent lying observed for either 48 or 12h around birth nor the number of lying bouts observed for 48 around birth differed significantly between treated and control heifers (all P>0.20). In the period of 6h before to 6h after calving, the number of lying bouts decreased with number of days that heifers had spent in the calving pen before parturition for the treated heifers and increased for the control heifers (interaction P=0.019). The avoidance distance was higher for the unfamiliar than for the familiar person (P<0.001), tended to decrease from before to after calving (P=0.07), and did not differ between treated and control heifers (P=0.14). There was no significant difference in the risk of an intervention between treated and control heifers (P=0.24). In conclusion, these results do not provide evidence that an early exposure of dairy heifers to the calving pen had a positive effect on their lying behavior around parturition and avoidance distance. However, additional time in the calving pen pre-partum seemed to have a calming effect as reflected by the number of lying bouts in the treated but not the control heifers.