|Faciola, Antonio - UNIV OF WISCONSIN-MADISON|
|Hristov, Alexander - PENN STATE UNIVERSITY|
|Pires, Jose - UNIV OF WISCONSIN-MADISON|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: March 10, 2008
Publication Date: July 7, 2008
Citation: Faciola, A.P., Broderick, G.A., Hristov, A.N., Pires, J.A. 2008. Effect of four levels of lauric acid on ruminal protozoa, milk production and composition in dairy cows [abstract]. Journal of Dairy Science. 91(suppl. 1):76. Technical Abstract: Ruminal protozoa (RP) are the main contributors to bacterial protein turnover in the rumen; therefore, reducing RP may improve N utilization. Medium-chain saturated fatty acids such as lauric acid (C12:0) have been shown to suppress RP. We tested lauric acid (LA) as a practical defaunating agent and assessed the effects of partial defaunation on N utilization, fermentation patterns, nutrient digestibility, milk production, and milk composition. Forty-eight Holstein cows (8 fitted with ruminal cannulae) were blocked by DIM into 12 blocks of four cows (2 blocks of cows with ruminal cannulas) and randomly assigned within blocks to four balanced 4 X 4 Latin square diet sequences. The basal diet contained (DM basis) 29% alfalfa silage, 36% corn silage, 7.5% high-moisture corn, 6% soybean meal, 8% dry molasses, 12% ground corn, vitamin and mineral premix, 15.5% CP, and 30% NDF. Diets differed in LA content: A) zero, B) 240, C) 480, and D) 720g/d. Each experimental period consisted of 21 d for adaptation, plus 7 d for data collection. Data were analyzed using the mixed procedure in SAS. LA was effective in reducing RP; however, it also decreased DMI. LA fed at 240 g/d did not reduce yield of milk or FCM; however, higher levels were detrimental to milk production and composition.