A barrier can reduce competition over teats in pair-housed milk-fed calves

The objectives of this study were 1) to assess whether a barrier placed between 2 teat buckets would reduce displacements at the teat buckets during milk-feeding events, 2) to determine whether the length of the barrier would influence this effect, and 3) to determine whether the quantity of milk provided to the calves would further affect competitive behavior. In both experiments, male and female Holstein calves were housed in pairs and fed milk in adjacent teat buckets. Experiment 1 included 12 pairs of calves provided with either 8 or 5 L of milk/d and compared the effect of a short barrier placed between the 2 teat buckets (B) with the effect of no barrier (C) in a crossover design with 4 periods of 10 d each. Three pairs of calves on each of the 2 milk allowances were given the treatments in the order B, C, C, B, whereas the other 3 pairs were given the treatments in the order C, B, B, C. The short barrier reduced the frequency of switches between teat buckets but did not affect the latency to initiate switching behavior. Calves provided 5 L of milk/d ingested their ration faster and had a shorter latency to initiate switching behavior, but their frequency of switching per milk-feeding event was not higher than that of calves fed 8 L. Experiment 2 examined the effect of the length of barriers placed on both sides of the teat buckets. Forty-eight calves had either long (100 cm), short (46 cm), or no barriers throughout the milk-feeding period. Three barriers (all of the same size) were placed in each pen; one was placed between the 2 teat buckets, another was placed on the right-hand side of the right bucket, and another was placed on the left-hand side of the left bucket. The long barriers doubled the latency to initiate switching behavior and greatly reduced the frequency of switching. Moreover, no calves were able to displace a calf successfully while it was consuming milk from a teat bucket when the buckets were separated by the long barriers. In conclusion, barriers between teat buckets can reduce competition for milk among pair-housed calves, but the effects were strongest when using long barriers, which separated the teat buckets as well as the front half of the calf during a feeding event.