FROM THE FARM REPORT: REFINEMENT OF PAIRING CALVES

There have been several studies evaluating the effectiveness of pair-housing calves in the preweaning period. Justification for keeping calves separate have been to reduce disease transmission and individualized care, less competition for milk, and limiting cross-suckling. All of these in theory should also support improved performance (less morbidity, mortality, and more growth) in the preweaning period. Previous studies that have evaluated pairing have shown positive effects on this management practice in the preweaning period. Cattle are social animals so there is thought that isolation in early life can limit the calf’s development. The benefits of pair housing have been shown to be improved solid feed intake, growth and reduced stress. It also helps with calves’ fear of new feeds and improves the affective state and cognitive development of these animals. A limitations with previous studies is that they’ve been underpowered in evaluating the health of animals paired at different ages, with most focusing on behavior, growth and intake. Most studies have also only compared two time-points of pairing which might be a challenge in determining the most appropriate time to group calves because of the main health challenges in the preweaning period. Those are: diarrhea, which often affects calves in the first three weeks of life and then Bovine Respiratory Disease (BRD) which has the highest risk 1 month of age or later. However, to wait to pair and avoid these periods of highest risk might miss the most optimal time to get the benefits of pairing.

A recent study published in the Journal of Dairy Science (108:2839-2855) evaluated three different pairing ages on performance, health, and behavior. They used 140 calves (70 pairs) to pair early (6-7 days of age), intermediate (29-30 days of age) and late (49-50 days of age). All calves were weaned at 78 days of age. Calves were fed and managed similarly. Calves were fed pasteurized waste milk with milk replacer (22% CP, 17% Fat) to achieve 14% total solids. The allowance of milk went from 4 L/d to 8 L/d after two weeks and was reduced over four weeks to facilitate weaning.

The mortality rate was low (<1.5%) with no difference in mortality across treatment. There was no difference in diarrhea or incidence of bovine respiratory disease (BRD). However, calves paired at 30 days of age did have BRD 11 days earlier compared to late-paired calves. Early-paired calves exhibited fewer idle behaviors and more exploratory behaviors compared to intermediate or late paired calves. Early-paired calves had higher odds of engaging in social behavior, while there was no difference between intermediate or late-paired calves. Calves that were grouped earlier exhibited more allogrooming (grooming others).

During two time periods of the preweaning period, cross-suckling was evaluated. The first compared calves that were paired early versus intermediately. There were no differences between these two groups. And the second period compared all three groups. Furthermore, the researchers did not detect any differences in cross-sucking behaviors between all three treatment groups. However, they did note that calves paired either at the intermediate or late timepoint did exhibit more non-nutritive oral behaviors.

Age at pairing did not impact growth up to 30 days of age and calves averaged ~1 kg/d (2.2 lb). However, at 50 days of age early calves had higher average daily gain compared to late-paired calves. An interesting finding was that the early-paired calves had more consistency in their growth compared to the other groups, which would be helpful in managing more consistent animals within a group. Starter intake was twice as high for early-paired calves in the first two weeks of life, and this continued as these calves consumed more starter for the first 30 days of life compared to late-paired calves.

Overall, this study adds to the support of pair housing calves. It further demonstrates that there is a critical time to pair calves, which is likely within the first three weeks of age. There appeared to be limited benefits of pairing calves at 30 days compared to pairing calves at 50 days of age. Health challenges are likely something you will have to continue to manage in a calf rearing system but there could be benefits of pairing that might further benefit calves as they get started in your program.

— Sarah Morrison

morrison@whminer.com