Relationship between body weight and level of fat supplementation on fatty acid digestion in feedlot cattle

• Published in: Journal of animal science 2003-11, Vol.81 (11), p.2653-2659
• Main Authors: Plascencia, A, Mendoza, G.D, Vasquez, C, Zinn, R.A
• Format: Article
• Language: English
• Subjects: Animal Feed; Animal productions; Animals; Biological and medical sciences; body weight; Body Weight - physiology; Cattle; Cattle - growth & development; Cattle - metabolism; Detergents; diet; Dietary Fats - administration & dosage; Dietary Fiber - metabolism; Dietary supplements; Digestion; Digestive system; dry matter intake; duodenum; experimental design; Fatty acids; Fatty Acids - metabolism; feedlots; Fundamental and applied biological sciences. Psychology; Holstein; intestinal absorption; Male; Nutritive Value; Random Allocation; rumen; Rumen - metabolism; rumen fermentation; starch; Starch - metabolism; stearic acid; steers; Terrestrial animal productions; Vertebrates; Weight; yellow grease
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/2003.81112653x

Eight Holstein steers with cannulas in the rumen and proximal duodenum were used in a split-plot design experiment to evaluate the interaction of body weight (175 vs. 370 kg) and level of fat supplementation (0, 3, 6, and 9% yellow grease) on characteristics of digestion and feeding value of fat in finishing diets. Dry matter intake was restricted to 2% of BW. There were no interactions between BW and level of fat supplementation (P > 0.10) on ruminal or total-tract digestion. Level of supplemental fat decreased (linear, P < 0.01) ruminal digestion of OM and NDF, and increased (linear, P < 0.05) ruminal N efficiency. There were no treatment effects (P > 0.10) on postruminal digestion of OM, NDF, and N. There tended to be an interaction (P < 0.10) between BW and level of fat supplementation on postruminal starch digestion. Increasing level of fat supplementation increased postruminal digestion of starch in heavier steers but did not affect starch digestion in lighter steers. There were no interactions (P > 0.10) between BW and level of fat supplementation on postruminal fatty acid digestion. Increasing level of fat supplementation decreased (linear, P < 0.01) postruminal fatty acid digestion, which was due to a decreased (linear, P < 0.01) postruminal digestion of C16:0 and C18:0. Supplemental fat decreased (linear, P < 0.01) total-tract digestion of OM and NDF. The estimated NEm (Mcal/kg) of yellow grease averaged (linear, P < 0.01) 6.02, 5.70, and 5.06 for the 3, 6, and 9% of level supplementation, respectively. We conclude that intestinal fatty acid digestion (FAD, %) is a predictable function (r2 = 0.89; P < 0.01) of total fatty acid intake per unit body weight (FAI, g/kg BW): FAD = 87.560 − 8.591FAI. Depressions in fatty acid digestion with increasing level of intake were due primarily to decreased intestinal absorption of palmitic and stearic acid. Level of fatty acids intake did not appreciably affect intestinal absorption of unsaturated fatty acid. Changes in intestinal fatty acid digestion accounted for most of the variation in the NE value of supplemental fat.