D. F. Jones*,
W. P. Weiss* 1,
T. C. Jenkins+
*The Ohio State University Department of Animal Sciences
+Department of Animal, Dairy, and Veterinary Sciences, Clemson University
This experiment was designed to determine the effects of fat source on blood neutrophil (PMN) function, digestibility, and production. Four diets (23% alfalfa silage, 31% corn silage, and 46% concentrate) with either 0 or 3% of the DM as tallow, fish oil, or fish oil treated with ethanolamine to prevent rumen biohydrogenation were formulated. Based on milk fatty acid data, protection of fish oil with ethanolamine was not complete. Thirty-two Holstein cows in late lactation were arranged in eight blocks and fed diets for 28 days. Digestibility was determined by total collection. Viability of PMN was not different for any of the four treatments. Phagocytic index (the ability of PMN to phagocytize Staphylococcus aureus) was significantly higher for cows fed fish oil compared with cows fed the other three treatments. The survival index (S. Aureus surviving within the PMN) was not different among treatments. The apparent digestibility of DM, NDF, and fatty acids was not different among the three sources of fat. These results indicate fish oil may improve the ability of PMN to phagocytize S. aureus. The treatment of fish oil with ethanolamine did not affect the digestibility of fish oil; however, protection was low.
1For more information, contact at: The Ohio State University, Ohio Agricultural Research and Development Center, 314 Gerlaugh Hall, 1680 Madison Avenue, Wooster, OH 44691; 330-263-3622; e-mail: weiss.6@osu.edu