Abstract #T227

# T227
Estimation of total fatty acid content and composition of feedstuffs for dairy cattle.
V. L. Daley*1, L. E. Armentano2, P. J. Kononoff3, J. M. Prestegaard4, M. D. Hanigan4, 1National Animal Nutrition Program (NANP), University of Kentucky, Lexington, KY, 2University of Wisconsin, Madison, WI, 3University of Nebraska-Lincoln, Lincoln, NE, 4Virginia Tech, Blacksburg, VA.

Predictions of total fatty acid (FA) and individual FA content of feeds are necessary for formulating diets based on essential FA requirements of dairy cows. Equations to predict total FA content from crude fat (EE) for different classes of feeds were developed using data from commercial laboratories. The FA composition of total FA for each feed was taken from the CNCPS library. Feed ingredients were grouped into 8 classes. All models were linear and fitted without an intercept. The data for forages were weighted using the inverse of the standard error. Regression coefficients for prediction of total FA from EE, and the mean FA composition are shown in Table 1. Estimates of FA content and composition of feed ingredients are useful to formulate diets for dairy cows when animal feed analysis laboratories are not available. Table 1. Fatty acid (FA) and FA composition (% of total FA) in different classes of feeds
ItemAnimal proteinPlant proteinEnergy sourcesGrainforage cropsBy-productsfeedsForages1Oil seedsOil
Feed ingredients, n1428351543571111
Observations, n6579182631816111142016490684056245426NR3
Regression coefficients2
FA composition
 C18:1 cis-925.5220.1820.2816.3217.122.6022.9043.03
 C18:1 trans1.560.55NR30.011.880.420.042.17
 C18:2 cis-9, cis-126.7148.8354.6542.2949.1019.1450.3624.54
 C18:3 cis-9, cis-12, cis-150.579.443.5313.566.4440.553.9710.45
1Forage grasses and legumes. 2Regression coefficients to estimate FA in feeds: FA (% of DM) = crude fat (% of DM) × slope. 3Not reported.

Key Words: feed, fatty acid composition, model