Summary: Starch concentration did not affect milk yield or feed intake, but tended to increase blood ketones. Propionate producing DFM increased feed efficiency during early lactation. The combination of a high starch diet and DFM resulted in the greatest milk production, but the increase in milk production did not occur until week 5 of lactation.
Take home message: Low starch diets resulted in similar milk production in the first month of lactation compared to high starch diets. Fresh cow diets should optimize fiber digestion (good quality forage and avoid high starch diets). A pen dedicated to fresh cows allows producers to feed a diets specific to meet fresh cow needs.
Title: Effects of varying early lactation dietary starch concentration on first calf heifer performance and health.
Authors: Z. Sawall, T. Parrott, W. Weich, D. Lobao da Silva, and N.B. Litherland.
Objectives: To determine the effects of feeding 21 vs. 29% dietary starch on feed intake, milk yield, and body fat mobilization in first calf heifers.
Background: Heifers represent a very important group and their early lactation nutrition and management has a significant impact on their first lactation performance.
Summary: Varying dietary starch concentration did not alter feed intake. The high starch diet tended to increase yield of 3.5% fat corrected milk. High starch diets increased the risk of metritis, ketosis, and fatty liver after calving.
Take home message: Low starch diets in early lactation reduce the risk of ketosis and fatty liver, but may also decrease milk production. High starch diets might impact first calf heifers more than cows.
Title: Effects of supplemental sugar on fiber digestibility of corn silage.
Authors: D. Lobao da Silva and N. B. Litherland.
Objectives: To evaluate the effects of varying source of supplemental sugar on fiber digestibility of corn silage.
Summary: Pure sugars lactose and sucrose increased fiber digestibility over control. Due to their purity, both lactose and sucrose delivered the greatest amount of sugar indicating that the effect of sugar on rumen fiber digestion is dependent upon the concentration of sugar in the diet and also perhaps the chemical profile of the sugar.
Take home message: The effects of supplemental dietary sugar on rumen fiber digestibility are dependent upon the concentration of the sugar in the diet and the potential fiber digestibility of forage in the diet.