Comparison of corn and barley with and without ruminal buffer in supplements fed in wheat straw-based diets to beef steers.
Ruminal fiber digestion is often decreased by supplementation of readily fermentable carbohydrates. Five ruminally cannulated beef steers were used in a 5 x 5 Latin square design to evaluate the effects of grain type (corn vs barley) and ruminal buffer (Na sesquicarbonate; 0 vs 1.2% of dietary DM) on ruminal digestion and fermentation in wheat straw-based diets. Grain supplements were 30% of the dietary DM. The 2 x 2 + 1 factorial arrangement of treatments included a control supplement that consisted primarily of soybean meal. Diets were fed once daily and were formulated to be 10% CP (DM basis). In situ DM (ISDMD) and NDF (ISNDFD) disappearance of wheat straw was measured at 0, 8, 16, 24, 32, 40, and 96 h incubation. To examine the effects of time after supplementation, 8-h incubations were performed at 0 to 8, 4 to 12, 8 to 16, 12 to 20, and 16 to 24 h after supplementation. Corn diets resulted in lower (P < .05) ISDMD for the 12- to 20- and 16- to 24-h periods than did barley diets. Averaged across 8-h intervals, the control treatment had greater ISDMD (P < .01) and ISNDFD (P < .05) than the grain treatments. Treatment differences were not observed for ISDMD and ISNDFD after 8 h of incubation. Ruminal fluid pH for barley diets was greater at 0, 16, and 20 h and less at 4 h after feeding than for corn diets (treatment x hour; P < .01). Propionate concentration was greater (P < .05) for corn than for barley diets.(ABSTRACT TRUNCATED AT 250 WORDS)
Reynolds
W K
WK
Department of Animal and Veterinary Science, University of Idaho, Moscow 83843.
Hunt
C W
CW
Moen
T
T
Loesche
J A
JA
D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D002021:Buffers; D002417:Cattle / Q000502:physiology*; D004043:Dietary Fiber / Q000378:metabolism; D004063:Digestion; D004435:Eating; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation; D005527:Food, Fortified; D001467:Hordeum; D006863:Hydrogen-Ion Concentration; D008297:Male; D012417:Rumen / Q000737:chemistry / Q000382:microbiology / Q000502:physiology; D014908:Triticum; D003313:Zea mays
D002021:Buffers; D004043:Dietary Fiber; D005232:Fatty Acids, Volatile; D000641:Ammonia