Dr. Robert Tremblay
There is always more than enough work to do on any farm but especially on dairy farms. The uptake of automatic milking systems on so many farms is strong evidence of that. Researchers are now exploring to see if there are other management tools that might assist dairy farmers.
Looking after calves can be a big job. It takes a motivated person to do it well. Raising calves is complicated by the fact that calves are quite susceptible to suffer from respiratory disease when they are young. They respond better to treatment if they are treated at the first signs of pneumonia. This is one reason why calf scoring systems were developed. There is one (well two actually, the first then an improved version) from Wisconsin and one from the University of California. Both the first and second versions of the Wisconsin system are widely used. Studies using ultrasound of the chest have shown that the scoring systems improve detection of pneumonia although the scoring system is not perfect – it misses some calves with abnormal lungs.
Recently, researchers looked to see if there were ways to identify calves that are likely sick in group housing/group feeding management systems. Some calf feeders record feeder use by individual calves. The question is whether changes in feeding behaviour captured by the automatic feeder would reliably pick out the sick calves. The Wisconsin scoring system does not include ‘appetite’ as one of the things that are scored.
A research study on dairy calves in the U.K. investigated whether the data on feeder use and activity monitors showed much difference between sick and healthy calves. They looked at milk consumption, consumption per visit, feeding time, drinking speed and number of rewarded and unrewarded visits. For activity, they looked at lying time, the number of times that calves laid down and for how long. They found that sick calves were different in their feeding behaviour and in their lying behaviour. It was not clear that this information would reliably detect sick calves. Another study had investigated whether using data only from the automatic feeder (milk consumption, drinking speed, number of rewarded and unrewarded visits) could be used to pick out sick calves. It turned out that the data was not very accurate in picking out calves with pneumonia compared to the Wisconsin scoring system or in picking out calves that were sick from other illnesses either.
So, there is not yet a good system that is likely to be useful in picking out sick calves. That doesn’t mean that it might not be part of an ‘early warning’ system though. It is important to consider that there is no disease detection system yet that will detect all the sick calves. Even ultrasound of the chest may not find all the calves with pneumonia, but it does find more than any other method. Another management area of the dairy where researchers have looked to monitoring systems would make things easier is monitoring close‐up for the start of calving. A variety of approaches have been used and I’ll write about those next month.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.