Starch–protein interaction in the rumen of weaned dairy calves

The objectives of this study were to investigate the effect starch and protein interaction on rumen environment, in situ digestion, total-tract digestibility nutrients weaned dairy calves between 8 16 wk age. Sixteen rumen-cannulated randomly divided into 4 dietary treatment groups with fed each treatment. diets had 2 levels [18%, low (LS), or 38%, high (HS)] [16%, (LP), 22%, (HP)] a dry matter (DM) basis calf grower: (1) LPLS, (2) LPHS, (3) HPLS, (4) HPHS. Calves for ad libitum intake (95% assigned grower 5% grass hay), refusals collected weekly. Total-tract collection procedures performed at 11 15 wk. Samples digestibility, hay (GH), soybean hulls (SBH), wheat middlings (WM), ground corn (GrC), meal (SBM) incubated 9 24 h. There was no calves. DM, neutral detergent fiber (NDF) acid (ADF) feed efficiency affected by both inclusion level diet. lower LS diets. Dry greater HP HS compared LP diets, respectively. Fiber (NDF ADF) less but Level did not affect DM NDF disappearance GH, increased SBH. High-starch decreased GH At 20 h after feeding, ruminal pH 0.51 unit higher HPHS LPHS. Total VFA proportion propionate versus LS, whereas acetate HS. SBM WM LPHS In our study, when HS, pH, digestion SBM, NDF, ADF increased. This provides evidence starch–protein recently Improvements suggest that are important 8- 16-wk-old