IT seems reasonable to ask how the study of fish in hot climes, or the interaction between killer whales, leads to better management of a dairy herd.
A conversation with Professor Darren Croft, in the café alongside the Animal Behaviour Research Group at the University of Exeter, soon reveals intense enthusiasm for the transference of social information between species.
The science sways towards social network analysis, a method that views social groups as a dynamic network of connected individuals. Somewhere in the background there may be a depth of mathematical and statistical relationships but the napkins were not covered in lines and equations as the topic developed.
Proximity collar study
Late in 2015, the results of a study by Natasha Boyland, utilising proximity collars on a dairy herd, will be published. The collars use radio signals to determine social contact time between the cows and sourcing effective equipment has not been easy.
Various pieces of work, including studies involving cattle and wildlife (badgers in particular have been highlighted), have utilised radio collars but traditional products were found to be unreliable.
This setback has been overcome and the social structure of a cow group is being measured, which shows the varying relationships between each cow.
Grooming, for example, takes place regularly between certain cows indicating that this is a selective and not a random event. Noticing such things may enable the farmer to achieve greater reproductive performance, an improved body condition score, better mobility scores, improved milk yield and composition and reduced somatic milk cell count.
The trial is measuring stress hormones in faecal samples and the lower the stress the better the performance.
This particular trial has recruited additional herds that have started their programme of observation, but more herds are sought for a further study being developed.
Veterinary practices with an interest and possible trial herds should contact Dr Jenny Gibbons, DairyCo research and development manager: jenny. firstname.lastname@example.org.
Darren Croft makes the point that one of the advantages of studying warm water sh in shoals is that changes in social structure can quickly be assessed. Progressing the observations of shoal behaviour to a dairy herd raises interesting lines of possibility.
What, for example, is the effect of culling? If, from a stable group, one or more individuals are removed, does this have the potential to reduce the performance of the group? Some removals are planned due to infertility or low milk yield but it may be that the economic state of the individual cow is less of a limiting factor than that animal’s social contribution to the group.
In considering enforced culling due to disease testing (e.g. bTB) the impact of removing several animals from a yield group could require a major restructuring to return to a social balance.
Conversely, recognising a negative or disruptive influence from an individual could indicate the social benefit of removing that individual. If this sounds a little like the human equivalent of removing anti-social individuals from society, then there may be direct parallels to be drawn. This is all speculation but these studies are more than just fitting a few collars on cows and monitoring their movements and behaviour.
A social study in calves has already been completed. Sarah Bolt, in collaboration with Boyland, Gibbons and Croft, challenges the practice of housing calves individually until weaning. It is indicated that some 60% of calves are individually housed with the aim of reducing disease transmission.
Other work has shown that individual rearing impairs solid feed intake but the social study found no statistical difference in concentrate intake, daily liveweight gain and respiratory or faecal scores between groups.
Individual rearing, however, reduces the ability of a calf to cope with the challenges of weaning and regrouping. It may be that veterinary surgeons will need to review their recommendations and balance the risks of disease transmission between pairs of calves being reared together until weaning, against individual rearing.
Vocalisations by the calf are a distress response and individually housed calves vocalise four times more frequently at weaning than calves paired from day five after birth. The figures are interesting in themselves in that a calf vocalises over 160 times per hour when housed individually and 40 times when paired.
Calves paired from day 28 vocalise at a rate of 60 times an hour. Over 24 hours the calf increases vocalisation from near zero before weaning to 160 at the end of weaning. The vocalising falls after three days to around 20 per calf per hour. The term for future familiarity appears to be social buffering. The duration of time that calves have to socialise determines the degree of social buffering to stressors.
There is much concern about the welfare of young calves. The GB Cattle Health and Welfare Group has published that 172,000 cattle under one-year-old died on British farms in 2013, not including calves born dead. Pneumonia is identified as a major disease issue for calves under two months of age.
Repeatedly, veterinary surgeons have indicated that the best way to maintain health in calves is to “give them a good start” and issues of colostrum management have been routinely promoted. Social buffering may need to be added to the disease control routine.
Research has shown that the performance of mid-lactation cows alters when introduced to a new group. They spend less time feeding and are displaced more often from the feeder by other cows.
New cows introduced to a group were often displaced from cubicles and spent less time lying down. First lactation heifers benefit from being housed separately from older cows. Heifers take smaller bites and therefore spend additional time feeding. Grouping them separately provides more time for rumination with increased milk fat production and less body weight loss. Regrouping cows at quiet times of day (not close to feeding) may decrease the frequency of aggressive interactions.
The Exeter workers are considering the practical application of identifying positive social relationships with the benefit of reducing the disruptive effects of cow introduction and removal from groups. The relationship between cows is expected to be influenced by group size.
When the studies are published, the in-depth discussions and interpretations for specific herd management can begin, but so far the indications are to avoid overstocking, move cows in a small group rather than alone and limit the number of group moves.
It would be interesting to know whether stockmen already recognise the importance of social interaction within their herd and additionally whether they can quantify any related performance factors.
It has often been somewhat of a mystery why some cows are retained in a herd when they clearly have repeated health difficulties. It may just be that these individuals simply make other cows more relaxed and happy. Cows with a twinkle in their eye perhaps?