Increasing daily exercise of dairy cattle in the dry period can induce fat metabolism before calving. This may help to reduce the risk for ketosis and fatty liver disease in early lactation – specifically for cows with high body condition scores. Therefore, if you encounter fat cows in a dry cow pen: make them walk!
At the start of lactation, dairy cow energy metabolism needs to adapt to the high requirements of milk production. Fat mobilisation supports milk output, but mobilisation may get out of hand in cows with too much body reserves at calving. Cows that are fat at calving therefore have a higher risk to encounter metabolic disorders like ketosis or fatty liver disease. In an experiment funded by the Dutch Dairy Board we tested whether physical exercise in the dry period could support the process of adaptation to lactation.
In short, a group of 16 cows was subjected to a training schedule of 45 minutes of walking, twice daily from dry-off until calving, while 16 others did not receive this training. Half of the cows had a high body condition score at dry-off (BCS ≥ 3.5), while others had lower BCS. Cow performance was monitored during the dry period and the first six weeks of lactation.
The results show that physical exercise during the dry period does not result in a higher milk yield after calving, but can reduce the risk for metabolic disorders like ketosis and fatty liver disease. The difference was most clear in dairy cows that have a high body condition score at dry-off. Dairy cow feeding strategies normally incorporate measurements to prevent over-conditioning towards the end of lactation. Some cows however may still slip by and have a higher condition score than desired. Those cows are prone to metabolic disease, but physical exercise in the dry period may help to prevent such problems.
More information can be found in Wageningen UR Livestock Research report 795 (in Dutch).