Cows fed controlled energy during the close-up dry period had a shorter interval between calving and pregnancy than cows fed high energy during the close-up period. That was the conclusion of a University of Illinois investigation that analyzed results of seven experiments conducted between 1993 and 2010. Here is what the meta-analysis revealed:
- Cows on high-energy diets during the last four weeks before calving lost more body condition score in the first six weeks after calving than those fed controlled energy.
- Feeding controlled energy during the far-off dry period had a positive association with energy intake in the first six weeks after calving compared to high-energy diets fed during the far-off dry period.
- Cows fed controlled energy during the far-off dry period had lower NEFA (non-esterified fatty acid) concentrations during the first three weeks of lactation.
- High NEFA levels during the first week after calving were associated with a greater probability of disease.
- High plasma glucose during the third and fourth weeks after calving was associated with shorter days to conception compared to low glucose levels.
The researchers say that increased energy intake during the first couple weeks after calving and a lower incidence of disease help explain why cows fed controlled energy had a shorter interval between calving and pregnancy. They add that less body condition loss and slightly higher glucose concentrations during the early postpartum period also helped improve reproductive performance.
The results were reported in March at the 2012 Midwest meeting of the American Dairy Science Association in Des Moines, Iowa.
Source: ADSA/ASAS 2012 Midwest Meeting Abstracts (#29)