Cows don’t consciously decide not to cycle. But when cows don’t cycle, they are certainly trying to tell us something.
One can have a quick evaluation of the effectiveness or a farm’s transition program by looking at the percent of cows cycling before 60 DIM. About 80% of the cows in a well run farm should be cycling before 60 DIM. A lower percent of cycling cows may be indicative of problems in the transition program.
In the chart below we can see “Fertility Summary” report from a Midwestern dairy. The cells circled in red show the percent of cows that have had a cycle by 60 DIM, first lactation and second and above lactation animals.
74.2% of first lactation cows cycle prior to 60 DIM versus 81.3% of second lactation and above cows. Obviously they have challenges in their transition program that affect first lactation cows more than the older cows.
The herd manager suspected that the source of the issue is the fact that the two year-olds are mixed in with older cows in the fresh pen. It appeared that the younger cows were not able to compete with the older cows. He decided to physically separate between the two-year-old population and the mature cows.
The two-year-old population responded very well to this change. Not only did their reproductive performance improve and more cows were showing heats, they also showed a significant increase in milk production.
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