Pair housing of neonatal calves encourages both positive feeding patterns and improved socialization
When farmers choose either individual or paired housing for their neonatal calves, they weigh many factors which ultimately come down to one question: Which is best for their calves' growth and health? Much of the recent research on calf housing has sought to answer this question by suggesting that pair housing of neonatal calves may indeed improve both growth and welfare by encouraging greater feed intake, by supporting and encouraging the development of normal social behaviours, and by reducing stress and helping with weight gain at the time of weaning. Until recently, most of this research had focused on tracking solid feed intake. However, in 2015, Jensen, et al. found that calves paired socially and on enhanced milk-feeding programmes, responded greater to social stimuli than those with low allowances of milk, and thus increased their starter intakes even more. But what of the impact of social housing in calves with free access to both solid feed and milk? A 2015 joint study from the University of Florida and the University of Guelph, sought to find out.
In the study which spanned 13 weeks, 20 Holstein bull calves were assigned to individual (IH= 10 calves) or paired housing (PH = 10 calves) from birth. All calves were offered grain concentrate and milk replacer ad libitum. After being weaned gradually by the end of week seven, the 10 IH calves were paired up as well. All calf pairs were then offered a complete pelleted diet, ad libitum, for the rest of the study. Meal frequency and meal duration, as well as frequency and duration of synchronized feeding were monitored. Preference tests were also conducted to assess if calves preferred to eat alone or with their partner pair within sight.
Positive outcomes of pair housing both before and during weaning
The results point strongly to the fact that the PH calves had significantly higher solid feed intakes during the milk feeding stage than IH calves, with the gap increasing over time. At week six, the week before weaning, average dry matter intake (DMI) was 170 grams per day for the PH calves vs. 62 grams per day for the IH calves. PH calves also had more frequent solid-feed meals (8.0 per day vs. 4.6 per day for IH calves). Milk replacer intakes, while identical in terms of amount in both treatments (9.8 Litres per day), was spread out over smaller, more frequent meals with the PH calves than the IH calves. During the weaning phase, PH calves continued to consume more dry matter (460 g per day vs. 200 g per day) and had greater ADG than the IH calves (0.67 kg per day vs. 0.41 kg per day).
Pair housing has positive outcomes post weaning too
While DMI and ADG did not differ between treatments after weaning, feeding behaviour did. While all calves were now pair housed, the calves who were so from birth continued to have more frequent meals with shorter duration. Additionally, in the preference tests, the calves who were PH from birth chose to spend more time feeding (both competitively and not) in the presence of their pen mates than the previously IH calves, who preferred to spend more time alone.
Implications for herd management
It seems that early social environments help shape meal patterns and that these patterns can and do persist after weaning. Additionally, this research shows that social housing influences both milk and solid feed meal patterns. The increase in solid feed intake by the PH calves corresponded to greater ADG, thereby suggesting that social housing may in fact be especially beneficial when milk is fed at an elevated plane of nutrition, pre-weaning, by supporting a smooth transition and aiding in higher solid feed-intake. This study also suggests that calves reared with social contact prior to weaning continue to prefer to feed socially after weaning. These findings do indeed have significant implications for herd management, especially since most dairy cows feed in groups post weaning.