Calf bonding and bull presence modify dam-calf behaviors and estrous expression in buffaloes.

This study evaluated the effects of different buffalo-calf contact systems on the calf and dam behavior and examined whether buffalo-bull contact enhances estrous behavior in calf-bonded buffaloes. In Experiment 1, 24 buffalo-calf pairs were allocated to three treatments: no buffalo-calf or buffalo-bull contact (NBC-NBB), restricted buffalo-calf contact with fenceline buffalo-bull contact (RBC-FBB), and fenceline buffalo-calf and buffalo-bull contact (FBC-FBB). In Experiment 2, 24 additional pairs were assigned to restricted buffalo-calf contact with no buffalo-bull contact (RBC-NBB) or fenceline buffalo-calf contact with direct buffalo-bull contact (FBC-DBB). Calves in the FBC-FBB (Experiment 1) and FBC-DBB (Experiment 2) stood and achieved first successful suckling (via teat suckling or bottle feeding, depending on group) earlier than calves in other treatments (p < 0.05). These calves also spent more time eating and ruminating across all observation days (p < 0.05). Oral stereotypies (cross-suckling and licking inanimate objects) were nearly absent in fenceline contact calves. Buffalo dams in FBC-FBB and FBC-DBB showed longer eating and resting times from days 1 to 90 (p < 0.05), with higher rumination times on multiple observation days. In Experiment 1, estrous behavior frequencies were higher from day -2 to + 1 in FBC-FBB and RBC-FBB than in NBC-NBB (p < 0.05). In Experiment 2, all estrous behaviors occurred more frequently in FBC-DBB than in RBC-NBB (p < 0.05). In conclusion, calf-mother contact during the colostrum period, followed by fenceline interaction, was associated with reduced abnormal oral stereotypies (cross-sucking and object licking) and behavioral indicators consistent with improved welfare in buffaloes. In addition, the management systems incorporating bull biostimulation were associated with enhanced estrous behavioral expression, with splashed urination identified as a prominent biostimulatory response that may facilitate the identification of receptive females.