Researchers at Kansas State University have found a correlation between the protein level of prepartum diets and subsequent milk production performance.

In the study, 75 Holstein cows were fed one of five different diets for 28 days before calving. The diets were formulated at different levels of protein — 9.7, 11.7, 13.7, 14.7 and 16.2 percent crude protein.

Here’s what they found:

  • Cows fed diets of 9.7 or 11.7 percent protein had higher calving difficulty scores than cows fed other diets.
  • Calf birth weights were similar with all diets.
  • Cows fed the 14.7 percent crude protein diet had less udder edema prepartum than cows in the other treatment groups. Postpartum edema was similar for all groups.
  • Cows fed the diet of 14.7 percent protein had the lowest incidence of subclinical ketosis and subclinical milk fever.
  • Peak milk yield and days to peak milk did not differ among treatment groups.
  • Cows fed the diets with 13.7 and 14.7 percent protein had the greatest response to BST.
  • Cows fed the diets with 13.7 and 14.7 percent protein had the highest yields of milk protein and milk fat.
  • Somatic cell count declined as dietary crude protein increased from 9.7 percent to 14.7 percent.

 In addition to the protein content of the diet, the researchers also compared different levels of non-fiber carbohydrate in the diet. Based on their research, they recommend a prepartum diet of 14.5 percent crude protein and 35 percent nonfiber carbohydrate.

The research was reported in the July 2002 issue of the Journal of Dairy Science.