Dairy farmers under certain retailer aligned contracts are required to rear their calves in pairs. While initially there were reservations about housing calves in pairs due to the risk of cross-suckling, disease transmission and the practicality of milk feeding, there are definitely benefits to be had.

The main positives around pairing calves are improved growth rates, with heavier calves at weaning and calves performing better post-weaning with less of a growth check. Higher starter feed intakes are also evident and there is anecdotal evidence from farmers that the calves seem to cope better when they go into group housing.

The following table shows the benefit in growth and feed intake of early pairing calves as opposed to later pairing, as well as a comparison with individually housed calves.

Growth rate was higher when calves were paired at day six, and starter feed intake at ten weeks of age was nearly double that of individually housed calves. Performance was also improved over calves that were paired later at 43 days of age.

Housing Average daily gain up to 10 wks (kg/day) Starter feed intake at 10 wks (kg/day)

Individual 0.76 1.09

Paired at day 6 0.89 2.20

Paired at day 43 0.73 1.26

Source: Costa et al, 2015. Journal of Dairy Science

Behavioural studies with paired and individually housed calves have shown that rearing calves in pairs allows social facilitation; calves learn off each other and are faster to locate and use feeders in new surroundings. These calves were more dominant and spent more time eating in competitive group housed situations. They also showed less stress at weaning, with fewer vocalisations.

While there has been the argument that pairing calves could lead to more disease transmission compared to being housed individually, it is thought that calf immunity, good hygiene, ventilation and adequate feeding have a greater impact on susceptibility to disease than housing type. Respiratory disease and scours are not consistently associated with group housing.

The other barrier against pairing calves is the concern around cross-suckling behaviour. However, research shows that there is less cross-suckling with calves that are better established on solid feed and have better access to high quality feed.

Therefore, ensure that starter feed is offered early on in life (ideally from day one) so that good intakes are being achieved, especially when calves are starting to be weaned. Other suggestions to reduce the risk of cross suckling are:

• Feed milk from a teat instead of an open bucket;

• Provide higher volumes of milk if possible and access to milk for more times throughout the day (e.g. a third feed). Sucking behaviour is closely linked to motivation to drink milk;

• Provide a dry teat for calves to suck upon;

• Carry out a more gradual weaning process.

The influence of consumer perception of dairy farming cannot be ignored, and pairing calves will be seen as a positive from an animal welfare perspective, with the calves being able to socially interact with each other. It is recommended that calves should be paired as early as possible, with certain milk contracts stipulating calves should be paired by 21 days of age.

For more information on calf rearing visit the Farm Advisory Service website: https://www.fas.scot/livestock/dairy-cattle/calf-and-heifer-reading/