Effect of combinations of fish meat and feather meal on milk fatty acid content and nitrogen utilization in dairy cows
2003
Wright, T.C. | Holub, B.J. | Hill, A.R. | McBride, B.W.
The effect of supplemental fishmeal in combination with feathermeal at twodifferent proportions in the diet on milk docosahexaenoic acid (DHA) content was investigated.Recently, benefits to human health have been attributed to the consumption of this fatty acid,which is normally present in marine lipids. Six Holstein cows past peak lactation were used in aLatin square design with a 2 x 3 factorial arrangement of treatments. Fish- and feathermeals wereprepared as pellets at 4:1 and 1:4 combinations and offered at 3.75, 11.75, and 27% of the diet.The supplements were top-dressed onto a basal diet based on corn silage that was progressivelyreplaced by supplement. Nitrogen balance measures were made during the experiment because ofthe wide range in crude protein content of experimental diets. Milk protein content increasedwith level of supplementation in the diet reflecting the protein quality of the supplements used.There was overall higher milk DHA content when cows consumed the supplement containingmore fishmeal than feather meal. Milk DHA content increased in a quadratic fashion, as more ofeither supplement was included in the diet. Apparent transfer efficiency of DHA from diet tomilk declined with increasing amount of DHA in the diet. Results from this experiment suggestthat transfer of docosahexaenoic acid from diet to milk may depend on diet composition andquantity present in the diet.
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