In dairy cows, one problem often leads to another. The falling domino scenario is particularly the case around calving time. Over-conditioning can lead to ketosis that can lead to a displaced abomasum. And metabolic problems after calving can mean reduced reproductive performance later. The underlying causes that start the sequence of problems can be many and often several in combination.
In the June 2011 issue of the Journal of Dairy Science, researchers Cook and Calderon at the School of Veterinary Medicine, University of Wisconsin-Madison, published a study looking at the impact of lameness on both cow behavior and metabolic status around the time of calving.
This study took place on a commercial dairy with a high incidence of lameness. The researchers recorded the number and length of times that cows laid down and the total time spent lying down, before and after calving. They also took blood samples before and after calving once per week while they were in the hospital or fresh pens. Samples from after calving were analyzed for beta-hydroxybutyrate (BHB), a chemical that is a measure of ketosis in cows.
This article focuses on the relationship of ketosis to lameness, but the lying time results may help to explain that relationship. The bottom line is that cows with moderate or severe lameness in the dry period were at a significantly greater risk of ketosis.
Blood serum results for cows that were classified as moderately to severely lame had an average measurement of 1165 for BHB. Twenty-six percent of cows had a BHB measurement greater than 1400, the cutpoint used in blood serum to define subclinical ketosis. The average for cows classified as slightly lame was 697 and the average for cows not lame was 687. These cows were at low risk for the development of ketosis.
Interestingly, there was no relationship between lameness and pre-calving levels of NEFA (non-esterified fatty acids). Elevation of this blood component is an indicator of fat mobilization before calving and subsequent ketosis. In this study, the ketosis occurred in spite of NEFA levels, which may say more about the impact of lameness on the cow after calving.
It was also found that lame cows had more episodes lying down and a greater total time, approximately 2 hours more, spent lying. This seems to make sense that they would want to get off their feet and yet that they would be uncomfortable and would get up and down more often. In addition, though eating behavior and intake was not measured in this study, cows that spend more time lying down may eat less, and therefore, consume less energy and be more likely candidates for ketosis.