| 초록 |
Four ruminally cannulated Holstein steers (BW $401.0{ pm}2.22kg$ ) fed TMR containing low protein (CP 9.63 %) as a basal diet were used to investigate the effects of cornell net carbohydrates and protein system (CNCPS) fraction enriched protein feeds on rumen fermentation and blood metabolites. The steers used in a $4{ times}4$ Latin square design consumed TMR only (control), TMR with rapeseed meal (AB1), TMR with soybean meal (B2) and TMR with perilla meal (B3C), respectively. The protein feeds were substituted for 30 % crude protein of TMR intake. For measuring ruminal pH, ammonia-N and volatile fatty acids (VFA), ruminal digesta was sampled through ruminal cannula at 1 h-interval after the afternoon feeding. Blood was sampled via the jugular vein after the ruminal digesta sampling. Different CNCPS fraction-enriched proteins did not affect (p gt;0.05) ruminal pH except B3C being numerically low compared with the other groups. Ammonia-N and VFA were not significantly different among the experimental groups. Numerically low ammonia-N appeared in the steers fed rapeseed meal even though it contained high soluble N composition (A and B1 fractions). The discrepancy is unclear; however this may be related to low protein level in the diet and/or low DM intake. Blood metabolites were not significantly affected by the protein substitution except for blood urea nitrogen that was significantly (p |
