Research findings: Pair housing calves

Dr Sophie Mahendran discusses her research comparing individual and pair housing calves on dairy farms in the UK.

• Pair housing reduced the risk of premature exit from the herd
• Pair-housed calves experienced less pre-weaning disease
• Individual calves had reduced odds of udder health issues, potentially linked to increased cross sucking in pair housing
• No effect of pre-weaning housing on average daily liveweight gain or fertility
• No effect on 305-day milk yield. However, given that more pair-housed calves survived to the end of first lactation, as a group, they produced more milk compared to individually housed calves

This study followed 100 calves over 6 months, housed in outdoor hutches. One group of 19 calves were housed individually, one group of 40 calves were housed in pairs from birth, and another group of 39 calves were housed individually and then pair housed at 3 weeks old.

This study found:

• Increased concentrate intake in pair-housed calves
• Regrouping (which occurred at 8 weeks old) was stressful and caused a growth check
• No difference in growth rates

Low volumes of milk fed on this farm (3 L, twice a day) may have limited growth rates. 

This study followed 164 individually housed and 280 pair-housed Holstein Friesian calves until the end of their first lactation.

It aimed to investigate how individual or pair housing may affect first lactation. Data was collected from accelerometers, observed behaviours, fertility data and milk recording data.

Survival rate

Seventy-four per cent of pair-housed heifers reached the end of first lactation compared to only 64% of individually housed heifers.

Overall, only 70% of all heifers reached the end of their first lactation, demonstrating significant loss and economic impacts.

Dr Mahendran highlights heifer survival as an area for improvement across the UK herd.

Disease

Pair-housed heifers had less disease incidences during the pre-weaning period. Thirty-three per cent of pair-housed calves had disease events compared with 67% of individually housed calves.

This shows that calf sickness is unlikely to increase if farms move from individual to pair housing. Housing type did not affect disease incidence after weaning, except for udder diseases.

Activity

Individually housed calves spent approximately 30 minutes more every day lying down, suggesting more boredom and a lack of interaction compared to pair-housed calves.

Individually housed calves also spent longer with their head outside of the pen, likely looking for social interaction.

Weight gain

Calves have excellent feed conversion efficiency at an early age, and it’s important to capitalise on this efficiency with a high-quality feeding regime.

Housing type did not affect pre-weaning average daily liveweight gain, but this may have been affected by limited milk being fed (3 L, twice a day).

Fertility

There was no effect of housing type on heifer fertility. Both individual and pair housed calves had similar ages at first service, number of services and likelihood of achieving first calving.

Milk yield

There was no difference in the total milk yield for the first lactation. However, in Study 1, when survival rate was considered, pair-housed calves produced 973 L more milk than individually housed calves.

Cross sucking

Pair-housed calves spent approximately 30 minutes more cross sucking than individually housed calves. This included inanimate objects such as buckets and pen walls as well as the other calf.

Environmental enrichment can help to reduce this behaviour, but research shows success is variable. Housing design, space and milk allowance may have more of an impact on cross-sucking.

Udder health

Pair-housed calves had an increased likelihood of udder issues, including:

• Mastitis
• High somatic cell counts
• Blind quarters

These issues were observed in 29.4% of pair-housed calves and 17.7% of individually housed calves. It was difficult to identify if this was a consequence of cross-sucking or other effects.

This page supports a webinar hosted by AHDB and the Calf Action Network.