Escape protein supplementation of steers fed grass silage-based diets.
Beef steers (Trials 1 and 2, 280 +/- 2 kg; Trial 3, 330 +/- 2 kg) were fed diets of 67.5% wheat (Trial 1) or oat silage (Trials 2 and 3), 20.5% barley, and 12% supplement in randomized complete block design growth trials. Dietary treatments were graded levels of supplemental escape protein (EP) from corn gluten meal (Trial 1, 0 to 213 g/d escape protein) or animal by-products (1:1:1 DM mixture of blood, feather, and meat and bone meals, 0 to 223 or 0 to 317 g/d of escape protein in Trials 2 and 3, respectively) to titrate amounts needed to maximize steer live weight gain. As supplemental EP from corn gluten meal increased, steer live weight gain increased linearly (P < .001) and feed-to-gain decreased linearly (P < .001). Supplementation with 135 g/d of corn gluten meal EP (335 g/d of corn gluten meal) increased average daily gain from .76 to .91 kg/d. As supplemental EP from animal by-products increased, steer live weight gain increased quadratically (P < .05) and feed-to-gain decreased linearly (P < .01). Supplementation with 223 or 317 g/d of animal by-product EP increased live weight gain by .27 kg/d. Supplemental escape protein was needed to increase live weight gain of steers consuming ensiled forage diets due to low EP contents of silages (7, 3, and 23% of CP in Trials 1, 2, and 3, respectively) and barley (15, 27, and 22% of CP in Trials 1, 2, and 3, respectively) and limited microbial protein synthesis.
Nelson
M L
ML
Department of Animal Sciences, Washington State University, Pullman 99164-6351, USA.
D000818:Animals; D018554:Avena / Q000378:metabolism / Q000592:standards; D001688:Biological Products; D001769:Blood / Q000378:metabolism; D001835:Body Weight / Q000502:physiology; D002417:Cattle / Q000254:growth & development* / Q000378:metabolism* / Q000502:physiology; D004032:Diet / Q000662:veterinary*; D004044:Dietary Proteins / Q000032:analysis / Q000378:metabolism*; D019587:Dietary Supplements; D004063:Digestion / Q000502:physiology*; D005241:Feathers; D001467:Hordeum / Q000378:metabolism / Q000592:standards; D008297:Male; D008903:Minerals / Q000378:metabolism / Q000592:standards; D009584:Nitrogen / Q000378:metabolism*; D006109:Poaceae; D011897:Random Allocation; D014908:Triticum / Q000378:metabolism / Q000592:standards; D015430:Weight Gain / Q000502:physiology; D003313:Zea mays / Q000378:metabolism / Q000592:standards
D001688:Biological Products; D004044:Dietary Proteins; D008903:Minerals; D009584:Nitrogen; C027762:bone meal