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This trial was conducted to determine the effect of the addition of 2 or 4% oleic acid to an hydrogenated fat coating applied to an experimental supplement with 55 or 58% lysine sulfate on ruminal escape and intestinal absorption of Lys. Two lactating Holstein cows (103 d in milk and 45.1 kg/d of milk) previously fitted with ruminal and duodenal cannulas were individually housed and fed a corn silage-based ration. In situ and mobile bag techniques were utilized to evaluate the 4 test products. Twenty bags of each product were incubated for 16 h in each cow to determine ruminal escape. After ruminal incubation, products were repackaged, soaked in pepsin/HCl solution for 2 h, inserted into the duodenum, and subsequently collected in the feces. The percentage of dry matter and fat escaping the rumen decreased as oleic acid increased from 2 to 4% or as the proportion of supplemental Lys increased. An interaction was observed because of a greater reduction of N and Lys escaping ruminal fermentation and flowing to the small intestine for the product with 58% supplemental Lys and 4% oleic acid compared with the other products. No differences were observed in intestinal digestibility of dry matter, N, Lys, or fat or in the amount of Lys digested in the small intestine. Increasing the proportion of oleic acid in the coating applied to supplemental Lys increased ruminal degradation. The extent of the degradation increased as the proportion of Lys in the product increased., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Forty Holstein cows were used in an 8-wk randomized trial to evaluate the effects of feeding combinations of forages with improved fiber digestibility on performance during early lactation. Treatments were arranged as a 2 x 2 factorial to include silage from normal (NCS) or brown midrib (BMR) corn silage with or without 10% Tifton 85 bermudagrass hay (T85). In a simultaneous digestion trial, degradation and passage kinetics and ruminal fermentation parameters were evaluated in a 4 x 4 Latin square design trial using late-lactation Holstein cows fitted with ruminal cannulas. Dry matter intake (DMI) and neutral detergent fiber (NDF) intake were greater with BMR than with NCS; however, milk yield and composition were similar among corn silage types. Inclusion of T85 reduced milk yield but supported higher milk fat percentage, resulting in similar yields of energy-corrected milk. Blood glucose concentrations were higher for BMR compared with NCS, and inclusion of T85 increased blood urea N concentrations. Treatments did not alter liquid or solid phase passage rates or rumen turnover. Corn silage type did not affect ruminal pH or volatile fatty acid concentrations, but inclusion of T85 increased pH and molar proportion of acetate but decreased butyrate. Molar proportions of propionate were greater for NCS and T85 compared with BMR and T85, resulting in an interaction. Results of this trial indicate that combinations of forages with improved fiber digestibility can be used to support intake and performance of cows during early lactation., (Copyright 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)