We have all heard the common phrase “lions, tigers, bears, oh my!” from Dorothy’s fears of entering the forest and encountering the cowardly lion, but have you heard “apples, carrots, friends, oh my?” Similar to humans, dairy calves respond to novel or unknown stimuli and situations with caution due to the possibility of a threat or harm. Providing a form of social contact to calves has the potential to limit or decrease the behavioral responses surrounding novel stimuli. 

Dairy calves have to undergo a variety of changes in their first few months of life, including but not limited to: new environments, foods, and social companions. For example, socially housing dairy calves during early life, instead of housing them individually, is growing within the dairy industry, increasing calves’ exposure to new environments and other animals. Furthermore, weaning, where calves are reduced the amount of milk they are fed, is known to be a stressful event for calves as they transition from a milk-based diet to a fully grain-based diet. Taking all of this into account, we wanted to know how early life housing treatments affect the response to novelty following stressful events like weaning and social grouping? 

There is evidence across species that fearfulness and response to novelty is shaped by early life experiences, including housing and social contact [1,2]. Calves that were housed socially during early life were shown to have reduced avoidance to novel feeds, objects, and environments [3,4]. In this current study, University of Florida PhD student Emily Lindner and coauthors wanted to see how housing treatment impacted responses to novelty following a highly stressful event and the introduction into a new social group in dairy calves [5]. 

In this study, calves were housed either individually or in pairs of 2 from birth until 8 weeks of age (Figure 1). Beginning at week 7 of life, calves were weaning over a 10-day step down plan where milk allowance decreased gradually until no milk was provided. 2 days after the completion of weaning, calves were mingled between housing treatments into new groups of 4-6 calves (Figure 2). 3 days after introduction to group housing and the new social group (5 days after completion of weaning), calves were exposed to 2 different novel feeds, sliced carrots and chopped red apples, on 2 consecutive days. After the removal of the remaining starter in the feed trough, a pre-weighed amount (0.68kg or 1.5lbs) of novel feed was placed in the feed trough for an hour. Behavioral responses to the novel feeds were recorded and assessed to examine individual differences to novelty when presented in a social context (Figure 3). 

Researchers found that there were no differences in the time it took for calves to interact with the novel feeds, or the amount of attention directed towards the feed trough for either of the previous housing treatments. However, they found that calves that were previously individually housed prior to grouping spent more time at the feed trough, but were removed or displaced more frequently from the feed trough by other calves, compared to calves previously housed in pairs (Figure 4). Locomotor behaviors such as walking, running, and standing immobile were also similar between the previous housing treatments during the testing period.

Thus, the authors concluded that although there was no evidence to support effects of early social contact on avoidance of novel feeds, behavioral differences during the testing period were evident which could explain differences in response to social feeding. 

References:

1. Voelkl, B., Schrauf, C., and Huber, L. Social contact influences the response of infant marmosets towards novel food. 2006. Animal Behaviour. 72, 365–372. doi:10.1016/j.anbehav.2005.10.013.
2. Lukkes, J.L., Mokin, M.V., Scholl, J.L., and Forster, G.L. Adult rats exposed to early-life social isolation exhibit increased anxiety and conditioned fear behavior, and altered hormonal stress responses. 2009. Horm. Behav. 55, 248–256. doi:10.1016/j.yhbeh.2008.10.014.
3. Whalin, L., Weary, D.M., and von Keyserlingk, M.A.G. Short communication: Pair housing dairy calves in modified calf hutches. 2018.J. Dairy Sci. 101, 5428–5433. doi:10.3168/jds.2017-14361.
4. De Paula Vieira, A., de Passillé, A.M., and Weary, D.M. Effects of the early social environment on behavioral responses of dairy calves to novel events. 2012. J. Dairy Sci. 95, 5149–5155. doi:10.3168/jds.2011-5073.
5. Lindner, E.E., Gingerich, K.N., Utzig, S., and Miller-Cushon, E.K. Effects of social housing on dairy calf response to novelty shortly after weaning and grouping. 2023. JDS Communications. doi:10.3168/jdsc.2023-0446.

Emily Lindner is a PhD Candidate in the Animal Behavior and Welfare lab at the University of Florida. Her masters and PhD work has looked at the effects early life housing treatments have on the behavior, performance, and production of dairy cattle. 

[Edited by Isabelle McDonald-Gilmartin and Nicole Rodrigues]