Effects of feeding textured soy protein (TSP), in liquid form (through esophageal groove), or solid form (throughout concentrate) were studied in a Latin-square changeover 4 x 4 design. Four Holstein steers fitted with ruminal cannulas were used, weighting 100 kg of live weight at the beginning of the trial, to evaluate treatments consisting of increasing TSP levels in liquid form (0%, 33%, 66% and 100%) offered through nipple-pail, and decreasing levels in concentrate to keep the same amount of nitrogen in the diet. Twenty-one days subperiods were used, the first sixteen for diet's adaptation, constituted by Coast-Cross (Cynodon dactylon) hay, concentrate mixture and the liquid portion of diet. At twentieth day ruminal material was sampled to analyze ammonia nitrogen as well pH control at 0, 2, 3, 4, 5 and 6 hours after first feed. Also were checked the esophageal groove closure reflex using a liquid marker (polyetylene glycol - PEG) collected directly from the rumen. Esophageal groove reflex was more effective in the highest liquid protein level treatment, showing lower concentrations of ruminal PEG. Ammonia nitrogen measures agreed with this observation, since there was a decrease in its concentration with the increase of the liquid supplement level. There were no effects of the feeding form in calves weight gains.
polietileneglicol; protein supplementation way; textured protein; soy protein
