Lateralized behaviour of dairy cows and calves during nursing and suckling

Parent–offspring interactions play an important role in offspring survival. Although there is evidence that these interactions are predominantly guided by the right hemisphere, little is still known about the factors that shape this lateralized processing. This study therefore aimed to explore lateralized behaviour of dairy cows and calves during nursing and suckling, respectively, focusing on the development during the first days after birth and the effects of calf sex, dam parity, and allosuckling. Video observations were made of the calf suckling and dam nursing behaviour of 59 group-housed dam-calf pairs from birth to four days after. Calves showed a significant bias to initiate suckling from the left side. Analysed separately, only males showed a significant left bias to initiate suckling. Furthermore, daily analyses showed that calf suckling and dam grooming during nursing were significantly left biased on the first day only. Although nursing interruptions by the cow were also left biased on the first day, most of the findings suggest that left lateralized dam-calf interactions could be associated with heightened maternal care. Such knowledge could help to identify appropriate maternal behaviour in livestock production systems that rely on maternal investment to raise healthy offspring, like cow-calf contact systems.