title: Ruminal characteristics, microbial populations, and digestive capabilities of newly weaned, stressed calves.
abstract: Eight ruminally fistulated steers, 7 to 8 mo old, were used in a completely randomized, 2 x 2 factorial experiment to determine the effects of energy density and protein source in receiving diets on in situ DM, NDF, and N disappearance, concentrations of ruminal bacteria, protozoa, ammonia, and pH. Two energy densities (1.80 and 1.48 Mcal/kg of NEm) and two protein sources (spray-dried blood meal [SDBM] and soybean meal [SBM]) were compared. Fistulated steers were weaned, transported by truck, and held in a sale barn before their arrival at the feedlot. On d 0 (day of arrival at the feedlot), DMI was 62% of DMI on d 7 after arrival. Overall, feeding a high-energy diet resulted in lower (P < .01) in situ DM disappearance (DMD) of orchardgrass than feeding a low-energy diet at both 24 and 48 h. In situ 24-h DMD averaged 46.6% on d-3 and 41.6% on d 0, whereas 48-h in situ DMD on d -3 and 0 averaged 58.2 and 58.6%, respectively, indicating the ruminal microbial population was not inhibited in its ability to digest available substrate. Additionally, there were no differences (P > .10) in 48-h in situ NDF disappearance between d -3 and 0 (58.8 vs 57.8%), respectively. No differences (P > .10) occurred in the concentration of total bacteria, or cellulolytic bacteria, due to feed and water deprivation. Concentration of total protozoa was lower (P < .05) on d 0 than at any other time. Entodinium averaged 72.5% of genera before weaning, and more than 90% of genera found on all treatments by d 21. Diplodinium and Epidinium percentages tended to decline after weaning. Isotricha concentrations were low and Dasytricha were eliminated after d 7. In conclusion, the concentration of ruminal bacteria and the ability to digest available substrate were not decreased immediately after weaning, trucking, and 24 h of feed and water deprivation.
authors.affiliation: Department of Animal Science, Ohio Agricultural Research and Development Center.
authors.forename: F L
authors.initials: FL
authors.lastname: Fluharty
authors.forename: S C
authors.initials: SC
authors.lastname: Loerch
authors.forename: B A
authors.initials: BA
authors.lastname: Dehority
mesh_terms: D000641:Ammonia; D000818:Animals; D001419:Bacteria / Q000302:isolation & purification; D002417:Cattle / Q000502:physiology*; D002418:Cattle Diseases / Q000503:physiopathology; D004043:Dietary Fiber; D004044:Dietary Proteins / Q000008:administration & dosage; D004063:Digestion / Q000502:physiology*; D004435:Eating / Q000502:physiology; D004734:Energy Metabolism; D056890:Eukaryota / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008297:Male; D009584:Nitrogen; D011897:Random Allocation; D012417:Rumen / Q000382:microbiology / Q000469:parasitology / Q000502:physiology*; D013312:Stress, Physiological / Q000503:physiopathology / Q000662:veterinary*; D013997:Time Factors; D014886:Weaning
chemical_list: D004043:Dietary Fiber; D004044:Dietary Proteins; D000641:Ammonia; D009584:Nitrogen