Control energy intake during the dry period
Proper dry cow feeding management is a critical component to achieving transition success. There is a substantial body of evidence that demonstrates that manipulation of the dry diet(s) can have a substantial impact on subsequent health and lactational performance.
In regards to energy, excessive energy intake may predispose the cows to greater tissue insulin insensitivity and greater nonesterified fatty acid (NEFA) mobilization and increased risk of metabolic disorders. Currently, controlled-energy dry cow diets are recommended for use in one- or two-group management systems. The goal is to provide sufficient energy to meet daily needs while not supplying excessive energy intake relative to requirements. Cows will easily consume > 150% of their energy requirement on corn silage based diets. Typically this is too much energy. The controlled-energy diets typically incorporate low-energy feedstuffs (e.g. straw, grass hay, or haycrop silage). Inclusion of these feedstuffs allow cows to consume feed ad libitum without over consuming energy. The cows eat to rumen fill.
Recently, the effect of energy intake during the dry period on reproductive performance in the subsequent lactation was evaluated using pooled data from 7 studies conducted at the University of Illinois. The individual studies did not have the statistical power necessary to examine reproductive measures. However, by pooling the data across studies there was enough statistical power to make conclusions regarding days to pregnancy. The treatments applied during the dry period were categorized as either controlled-energy (≤ 100% of NEL requirement; ~12 Mcal/d) or high-energy (>100% of NEL requirement; ~20 Mcal/d). Holstein cows used in the analysis averaged 77 lb of milk and 1335 lb of body weight at 4 weeks in lactation.
Far-off energy intake did not affect days to pregnancy. However, cows fed high-energy diets rather than controlled-energy diets during the close-up period had a significantly longer time to pregnancy (167 vs. 157 days). Interestingly, the cows fed high-energy diets lost more body condition during the first 6 weeks of lactation and had greater NEFA concentrations at week 1 of lactation. Dry matter intake during the first 4 weeks of lactation tended to be lower for cows fed the high-energy diet than the controlled-energy diets (33.9 vs. 36.3 lb, respectively). Cows that were classified at 1 week of lactation as thin (BCS ≤ 2.75) had a longer time to pregnancy (170 days) than cows that were more conditioned (BCS 3 to 3.75; 148 days). The improved reproductive performance in the cows fed the controlled-energy diets appears to be attributable in part to improved energy status during early lactation. Now we have one more positive reason to feed controlled-energy diets to our dry cows.
By Heather Dann, from the Miner Institute Farm Report