title: Effect of a high-palmitic acid fat supplement on milk production and apparent total-tract digestibility in high- and low-milk yield dairy cows.
abstract: The effect of a high-palmitic acid fat supplement was tested in 12 high-producing (mean = 42.1 kg/d) and 12 low-producing (mean = 28.9 kg/d) cows arranged in a replicated 3 × 3 Latin square design. Experimental periods were 21 d, with 18d of diet adaptation and 3 d of sample collection. Treatments were (1) control (no supplemental fat), (2) high-palmitic acid (PA) supplement (84% C16:0), and (3) Ca salts of palm fatty acid (FA) supplement (Ca-FA). The PA supplement had no effect on milk production, but decreased dry matter intake by 7 and 9% relative to the control in high- and low-producing cows, respectively, and increased feed efficiency by 8.5% in high-producing cows compared with the control. Milk fat concentration and yield were not affected by PA relative to the control in high- or low-producing cows, although PA increased the yield of milk 16-C FA by more than 85 g/d relative to the control. The Ca-FA decreased milk fat concentration compared with PA in high-, but not in low-producing cows. In agreement, Ca-FA dramatically increased milk fat concentration of trans-10 C18:1 and trans-10, cis-12 conjugated linoleic acid (>300%) compared with PA in high-producing cows, but not in low-producing cows. No effect of treatment on milk protein concentration or yield was detected. The PA supplement also increased 16-C FA apparent digestibility by over 10% and increased total FA digestibility compared with the control in high- and low-producing cows. During short-term feeding, palmitic acid supplementation did not increase milk or milk fat yield; however, it was efficiently absorbed, increased feed efficiency, and increased milk 16-C FA yield, while minimizing alterations in ruminal biohydrogenation commonly observed for other unsaturated fat supplements. Longer-term experiments will be necessary to determine the effects on energy balance and changes in body reserves.
authors.affiliation: Department of Animal Science, Penn State University, University Park 16802.
authors.forename: D E
authors.initials: DE
authors.lastname: Rico
authors.affiliation: Department of Animal Science, Penn State University, University Park 16802.
authors.forename: Y
authors.initials: Y
authors.lastname: Ying
authors.affiliation: Department of Animal Science, Penn State University, University Park 16802. Electronic address: kjh182@psu.edu.
authors.forename: K J
authors.initials: KJ
authors.lastname: Harvatine
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena / Q000187:drug effects; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements / Q000032:analysis; D004063:Digestion / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D007774:Lactation; D008892:Milk / Q000187:drug effects / Q000378:metabolism*; D019308:Palmitic Acid / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D019308:Palmitic Acid
keywords: dairy cow; milk fat; nutrient digestibility; palmitic acid