Effect of a mechanical grooming brush on the behavior and health of recently weaned heifer calves

Abstract

Background Calf stress at weaning and during transition to group pens represents a concern in dairy operations. Favoring natural behaviors, such as grooming, may help on reducing this challenge. Our objective was to evaluate the effect of a mechanical grooming brush on behavior and health of recently weaned calves, after transferring from individual to group housing. Two treatment groups (control [CON, n = 81]; automated brush [AB, n = 81]) were compared enrolling Holstein heifers (94 ± 7 d old) that were monitored for 20 days. Four cohorts, considering one CON and one AB group (19–20 calves/pen/cohort) were enrolled sequentially. Each calf was weighed, clinically evaluated, and affixed with a 3-D accelerometer sensor attached to the ear at enrolment. Continuous measurements (min/h) were generated for the following behaviors: Not-active, active, highly active, eating, and ruminating. Cameras for continuous video recording were installed in each pen, and calves were weighted at the last day of the study (d 20). Behavioral data were summarized as daily averages (min/h). Data was examined using repeated measures analysis for nested factors, with day as the time unit. Results Overall, calves had their first interaction with the brush within 2.5 days with a mean (SE) of 7 (±9.6) h after being transferred to group pens. A significant effect was determined for the interaction day by treatment on the time spent not-active and eating. Average not-active time was greater in CON compared to AB (22.8 ± 0.82 min/h vs. 21.7 ± 0.82 min/h), while eating time was greater in AB compared with CON (7.01 ± 0.40 min/h vs. 6.43 ± 0.40 min/h). Treatment groups had a similar weight gain and time to the first disease. Conclusions We concluded that the use of a mechanical brush influenced behavior, reducing not-active time, while increasing eating time. The consequences of this change in activity require further investigation.

Measuring Calves' Usage of Multiple Environmental Enrichment Objects Provided Simultaneously

“…The motivation of the calves to use this device remained consistent throughout the experiment, suggesting that the use of rotating mechanical brushes might be sustained by the need for grooming or by the fact that they change from a static to a dynamic state when in use and that may make them more attractive. Our results are in line with Velasquez-Muñoz et al (18), who reported that brush use was stable across time in heifer and bull calves, observed from week 4 (pre-weaning) until week 7 (weaning). Moreover, we can speculate as Kohari et al (31) observed that calves incorporated elements of play behavior when they used movable rubbing or scratching objects, explaining the higher motivation for visiting the automated brush.…”

“…This finding is in accordance with previous studies that reported calves using a great variety of devices when they were available in pen (4,8). It was the case for automated brushes (6,14,18), stationary brushes (6,26), ropes (9, 13), hay (27), hanging balls (28), rubber chains, and "calf lollies" (PVC pipes capped on both ends filled with dry molasses) (26). All these examples evidence that young calves are curious and have a high motivation to explore their environment when they have the opportunity (28).…”

“…This finding could be explained by the circadian rhythm of bovine behavior [reviewed by Kilgour (25)], showing how cattle are generally less active and tend to rest more at night. A daily rhythm of calf activity has been described and shows a low activity level from 8:00 p.m. to 07:00 a.m. (18). Once the daily pattern of activities was established, the rest of the replications consisted of observations conducted only during the daytime.…”

“…In dairy cows, it has been observed that the brushes contribute to satisfying the natural need for grooming (rubbing and scratching), especially in places that are difficult to reach by the cow, and are associated with a cleaner body (12). In addition, brushes could be tools to monitor the health of animals because their use decreases when animals are sick [e.g., metritis (16), mastitis (17), and health in calves (18)], or to help determine whether they are under conditions of heat stress (19). In terms of production, the physical enrichment with brushes would increase the daily milk production.…”

Caring animals and the ways we wrong them

“…Artificial substitutes for care in farming range from cattle brushes that are offered to (at least partially) replace social grooming (e.g. Velasquez-Munoz et al 2019 ) to the administration of hormones that are associated with attachment to facilitate forced weaning (e.g. Rault et al 2015 ).…”