title: Effect of 2- versus 6-day collections for the determination of ruminal and postruminal digestion in steers.
abstract: Abomasally fistulated steers (500 kg) were used to determine the effect of length of collection period (2 vs 6 days) on total, ruminal and postruminal digestibilities of organic matter, starch and protein. Twice daily, four steers were fed steam-processed flaked grain and three steers were fed dry-rolled sorghum grain in an 82% grain diet. Dysprosium was used as an indicator. Abomasal and fecal samples were collected at 12-hr intervals for 6 days or every 4 hr for 2 days, providing 12 samples per collection period. Nutrient contents of feed, abomasal and fecal samples were similar during both collection periods. Except for total digestibility of crude protein in the dry-rolled grain diet, ruminal, postruminal and total digestibilities of organic matter, starch and protein did not differ between the 2- and 6-day collection periods. Standard deviations for nutrient concentration and digestion coefficients were similar for the two collection periods within both the steam-processed flaked and dry-rolled treatments. Results indicate that sampling six times daily for 2 days provided representative samples for partitioning organic matter, starch and protein digestibilities in abomasally fistulated steers that had been adapted to collection procedures.
mesh_terms: D000018:Abomasum / Q000502:physiology*; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004063:Digestion; D008297:Male; D013048:Specimen Handling / Q000662:veterinary*; D013997:Time Factors