Hand-rearing dairy calves away from their dams may alter calf behavior development, especially social behavior. Traditionally, dairy producers have invested in individual hutches or pens to raise newborns to weaning, but pair or group housing systems are increasing in popularity and may potentially improve calf social behavior development. Research on calf behavior has shed light on the potential effects of individual versus pair or group housing. The objective of this publication is to provide a brief summary of the advantages and disadvantages of calf group housing for dairy producers and veterinarians considering this type of housing system. In particular, this publication focuses on calf behavior, health, and performance. Please consult WSU Extension Publication EM045E Dairy Calves and Their Environment: Improving Health, Welfare, and Performance for detailed information on dairy calf housing systems.
A calf reared by its dam in a natural environment spends its time either alone or with its dam until it is about one week old and begins interacting with other calves. Rearing dairy calves in individual hutches or pens from birth to weaning may have a detrimental impact on a calf’s social development (Bøe and Færevik 2003). Calves raised in pairs or groups demonstrate several favorable behaviors over calves raised individually. Some of these behaviors include decreased aggression, increased lying time, and an increased amount of time spent at the feeder. Decreases in aggressive behaviors improves not only animal and handler safety, but also minimizes the number of agonistic interactions and displacements (one animal forces another animal to move) that occur near feeding areas, which is a behavior commonly noticed when grouping or regrouping animals (Miller and Woodgush 1991). An increased amount of time spent at the feeder is associated with higher starter feed intakes and growth rates (De Paula Vieira et al. 2010). Group
During the first 90 days of life, approximately 23% of calves will develop one or more diseases. Diarrhea is more prevalent than respiratory disease during the first six weeks of life with most diarrhea cases reported during the first week (Svensson et al. 2003). Producers and veterinarians are concerned group housing will lead to even more calf health issues. A couple of studies (including Wells et al. 1996 and Kung et al. 1997) have found no differences in the number of treatments (treated with medications such as antibiotics) administered to calves or calf mortality rates when comparing calves in group housing versus individual housing; however, differences in health have been detected in other studies. Based on these studies, individually housed calves tend to have lower rates of respiratory disease (Cobb et al. 2014) and therefore lower treatment rates and decreased potential for the development of antibiotic resistance (Duse et al. 2015). Due to the lack of consistent results, a multitude of questions remains unanswered in regards to how pair or group housing impacts calf health. Table 2 highlights the effects of pair, group, or individual housing on calf health. For example, calves reared in pairs have a 13% lower heart rate when exposed to a novel environment than calves reared individually, indicating that pair-housed calves may cope with stressful situations more easily (Jensen and Larsen 2014).