Abstract #M297

# M297
Effect of palmitic acid-enriched supplements with different levels of fatty acid peroxidation on short-term feed intake and production responses of lactating dairy cows.
Arnulfo Pineda*1, Adam L. Lock1, 1Michigan State University, East Lansing, MI.

We evaluated the short-term effects of feeding palmitic acid (PA)-enriched supplements with different levels of peroxidation on feed intake and production responses of dairy cows. Eight Holstein cows (147 ± 40 DIM, 44.6 ± 4.84 kg/d milk yield) were assigned randomly to treatment sequence in a replicated 4 × 4 Latin square design balanced for carryover effects. Cows received a common basal diet which contained (% DM) 29.1% NDF, 17.3% CP, and 28.6% starch. Fatty acid (FA) treatments contained different combinations of a commercially available PA-enriched supplement (PA-NORM) and a PA-enriched supplement with a high level of peroxidation (PA-HIGH) as follows: (1) control (CON) supplemented with 1.5% DM PA-NORM; (2) low peroxidation (LPO) supplemented with 1.0% DM PA-NORM and 0.5% DM PA-HIGH; (3) medium peroxidation (MPO) supplemented with 0.5% DM PA-NORM and 1.0% DM PA-HIGH; and (4) high peroxidation (HPO) supplemented with 1.5% DM PA-HIGH. Each 14-d period consisted of a 7-d washout during which all cows received CON followed by 7-d of feeding all treatment diets with the final 3 d used for data and sample collection. The statistical model included the random effect of cow and the fixed effects of FA treatment, period, and their interactions. The major FA in PA-NORM and PA-HIGH were C16:0 (82.2 and 93.8%), C18:0 (5.23 and 3.49%), and cis-9 18:1 (9.41 and 1.30%), respectively. Results in the text are presented in the following order: CON, LPO, MPO, and HPO. Fatty acid treatments did not affect DMI (29.4, 29.6, 30.7, and 30.5 kg/d; P = 0.13) or yields of milk (44.1, 44.2, 44.5, and 45.0 kg/d; P = 0.76), milk fat (1.65, 1.61, 1.62, and 1.68 kg/d; P = 0.13), or milk protein (1.44, 1.42, 1.44, and 1.47 kg/d; P = 0.69). There was no effect (P > 0.20) of treatment on BW, BCS, or yields of de novo, mixed, and preformed milk FA. Our results demonstrate that short-term feeding of PA-enriched supplements with high levels of peroxidation does not negatively affect DMI or production responses of mid lactation dairy cows.

Key Words: lipid peroxidation, fatty acid, milk production