Evaluation of health and ruminal variables during adaptation to grain-based diets in beef cattle.
Health and ruminal variables were intensively measured during adaptation to grain-based diets in 6 beef cattle with fistulated rumens. The cows had been maintained on prairie grass hay-supplemented diets, and were converted to a grain-based finishing ration by feeding each successive diet (diets 1-4, respectively) for a period of 7 days. Each cow was evaluated and samples were obtained 3 times each day for the first 5 days that each diet was fed. Health variables monitored were rectal temperature, pulse, respiratory and rumen motility rates, fecal consistency, demeanor, blood pH, and blood glucose and L (+) lactate concentrations. Ruminal variables monitored were pH and glucose, DL-lactate, and volatile fatty acid concentrations of rumen contents. Data were analyzed by use of a multivariate ANOVA. We determined that most of the health variables were within reference range limits throughout the adaptation period; however, analysis of pulse and respiratory rates indicated that diets 2 and 4 were stressful. Although blood pH continually decreased during feeding of the 4 diets (7.38 to 7.30), blood L (+) lactate and glucose concentrations had large increases only within diet 4. The pH of ruminal contents decreased progressively from 6.8 to 5.3. Rumen glucose concentration was low (< mumol/ml), except with diet 4 in which values were 8 times higher than for other diets. By the end of the study, the ruminal contents of all animals were acidic (pH < 5.5), and, on the basis of higher than background amounts of ruminal glucose and DL-lactate, it was determined that rumen microbial equilibrium had not yet been achieved.(ABSTRACT TRUNCATED AT 250 WORDS)
Leedle
J A
JA
Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5602, USA.
Coe
M L
ML
Frey
R A
RA
D000064:Acclimatization; D000085:Acetates / Q000032:analysis; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000502:physiology*; D004032:Diet; D002523:Edible Grain; D005260:Female; D005285:Fermentation; D005527:Food, Fortified; D005766:Gastrointestinal Contents; D005947:Glucose / Q000378:metabolism; D006304:Health Status; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000032:analysis; D008460:Meat; D011422:Propionates; D012417:Rumen / Q000502:physiology* / Q000601:surgery; D013997:Time Factors
D000085:Acetates; D007773:Lactates; D011422:Propionates; D005947:Glucose