Feeding a controlled-energy diet in the close-up period is a strategy that is gaining currency. And a study published in last September’s Journal of Dairy Science backs it up.

Researchers from the University of Illinois did a statistical analysis of seven studies that looked at the association between prepartum energy intake and reproductive performance. On average, cows fed a controlled-energy diet (with less than or equal to the recommended amount) during the close-up period became pregnant about 10 days sooner than cows fed a high-energy diet. Perhaps it is because cows fed a controlled-energy diet prepartum eat more after calving than cows fed a high-energy diet.

“We want the cow to eat as much as possible just after calving because then she is going to be healthier,” says U of I animal sciences researcher Phil Cardoso.

In addition to having fewer days to pregnancy, the cows fed a controlled-energy diet during the last three weeks prepartum lost less body condition in the first six weeks postpartum and had slightly greater plasma glucose concentrations, which may contribute to improved reproductive performance.

“A strategy of (controlled energy) prepartum may have a favorable impact on both health and reproductive performance,” Cardoso and his colleagues concluded in the JDS article. “Research evaluating the effect of (controlled energy) diets prepartum on more specific reproduction variables, such as progesterone concentrations, ovarian function, time to first ovulation, and embryonic death, is needed,” they wrote.  

Read abstract.