TY - JOUR
T1 - Evaluation of protein flow to the duodenum in dairy cattle by the in sacco method
AU - Arieli, A.
AU - Mabjeesh, S.
AU - Tagari, H.
AU - Bruckental, I.
AU - Zamwell, S.
PY - 1993/6
Y1 - 1993/6
N2 - In situ evaluation of the amount and composition of duodenal crude protein flow was examined in a 4×4 Latin square study using four lactating Holstein cows fitted with ruminal and duodenal cannulas. Dietary supplemental CP sources, making up 40% of the dietary CP, were: soybean meal, cottonseed meal, corn gluten meal or urea. Duodenal flow of organic matter (OM) and CP was determined in vivo by means of constant infusion of Yb and Cr, and was predicted in situ from rumen degradation. Purines were used as microbial markers. The two methods of estimating ruminally undegraded protein ranked the diets similarly. Microbial CP (1.9 to 2.1 kg/d) was estimated to make up 57% to 68% of the duodenal CP flow in the experimental diets. Efficiency of microbial protein synthesis were 201 (SEM 16) g CP/kg OM truly digested in the rumen, and 224 (SEM 18) g CP/kg OM disappearing in the rumen. Data are interpreted to suggest that the in situ method enables a prediction of total protein flow to the duodenum which is comparable to that obtained using the in vivo method. The added practicality of the former method renders it advantageous.
AB - In situ evaluation of the amount and composition of duodenal crude protein flow was examined in a 4×4 Latin square study using four lactating Holstein cows fitted with ruminal and duodenal cannulas. Dietary supplemental CP sources, making up 40% of the dietary CP, were: soybean meal, cottonseed meal, corn gluten meal or urea. Duodenal flow of organic matter (OM) and CP was determined in vivo by means of constant infusion of Yb and Cr, and was predicted in situ from rumen degradation. Purines were used as microbial markers. The two methods of estimating ruminally undegraded protein ranked the diets similarly. Microbial CP (1.9 to 2.1 kg/d) was estimated to make up 57% to 68% of the duodenal CP flow in the experimental diets. Efficiency of microbial protein synthesis were 201 (SEM 16) g CP/kg OM truly digested in the rumen, and 224 (SEM 18) g CP/kg OM disappearing in the rumen. Data are interpreted to suggest that the in situ method enables a prediction of total protein flow to the duodenum which is comparable to that obtained using the in vivo method. The added practicality of the former method renders it advantageous.
KW - Cow, Dacron bag
KW - Duodenal protein
KW - Microbial yield
UR - http://www.scopus.com/inward/record.url?scp=38249001367&partnerID=8YFLogxK
U2 - 10.1016/0301-6226(93)90098-3
DO - 10.1016/0301-6226(93)90098-3
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AN - SCOPUS:38249001367
SN - 0301-6226
VL - 35
SP - 283
EP - 292
JO - Livestock Production Science
JF - Livestock Production Science
IS - 3-4
ER -