Effects of pre-calving desensitization with brushing on postpartum behavior and physiology in Zebu heifers

Résumé fourni par la source

The management of primiparous heifers presents a significant challenge for pasture-based milk production systems with Zebu cattle in tropical regions. This study evaluated animal welfare indicators, specifically behavioral and physiological parameters, in Zebu heifers exposed to different pre-calving desensitization protocols and assessed the subsequent postpartum effect in 35 Gyr and Girolando heifers. Animals were assigned to either a control or a desensitized group, the latter undergoing 23 days of structured handling to promote habituation and learning to the milking environment. Data were analyzed using mixed-effects models and Fisher’s exact tests, supplemented by Principal Component Analysis (PCA) to assess the interplay between multiple parameters. PCA identified three main components: a handling reactivity axis (defined by physical tension, movement, and rectal temperature), heart rate, and cortisol levels. Desensitized heifers exhibited significant reductions in physical tension, movement, heart rate, and udder temperature ( P <0.05). When evaluating the progression throughout the protocol, a significant decrease from the beginning to the end was detected in movement, surface and core temperatures, flight speed, and fecal cortisol ( P <0.05). Notably, the protocol facilitated calf-free milk ejection in Girolando heifers ( P <0.05), although milk yield remained unaffected by the intervention ( P >0.05). These findings demonstrate that prepartum desensitization effectively promotes a state of physiological and behavioral relaxation during early lactation. Consequently, implementing parlor habituation as a standard management practice is recommended to enhance the welfare and operational efficiency of Zebu-derived dairy herds.

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