Canola Meal Versus Cottonseed Meal as the Protein Supplement in Dairy Diets

Abstract

Four trials were conducted to evaluate effects of incorporating cottonseed meal or canola meal in dairy diets. In Experiment 1, 36 Holstein cows, 12 first lactation and 24 second or more lactations, were in two groups fed complete mixed diets containing either cottonseed meal or canola meal as the protein supplement. Yields of milk and milk components and feed intake were not affected by protein supplement. In Experiment 2, 6 Holstein cows in first lactation were fed diets of Experiment 1 in two periods of 3 wk to evaluate effects of protein supplement on milk composition. Protein supplement did not affect fat, lactose, ash, total solids, total nitrogen, casein nitrogen, whey protein nitrogen, or nonprotein nitrogen content in milk. Diets of Experiment 1 were fed to four rumen-fistulated heifers (Experiment 3) for changes of ruminal fluid characteristics. Ruminal fluid samples were collected at –1, 2, 4, and 8 h postfeeding. Volatile fatty acid and ammonia concentrations of ruminal fluid were not different for protein supplement. In Experiment 4, in situ disappearance of nitrogen and dry matter of protein sources in the rumen of a Holstein cow was studied. Disappearance of nitrogen and dry matter of protein supplements from nytex nylon bags was similar. © 1986, American Dairy Science Association. All rights reserved.