| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Division of Animal Science, University of New England, Armidale, New South Wales, Australia
2 Bovine Research Australasia, P.O. Box 660, Camden, New South Wales, Australia
3 Pfizer Pty. Ltd. 38-42 Wharf Rd., P.O. Box 57, West Ryde, New South Wales, Australia
The effects of virginiamycin, an agent active against Gram-positive lactic acid-producing bacteria, and NaHCO3 on ruminal and fecal Ph, rumen volatile fatty acid proportions, blood metabolites, and milk production and composition were assessed. This study was conducted over 28 d and involved 71 dairy cows that grazed predominantly ryegrass, oats, and clover, and that were fed 10 kg of concentrate pellets/d per head. The pellets contained (per kilogram) no dietary additive, 30 mg of virginiamycin, 20 g of NaHCO3, or 30 mg of virginiamycin and 20 g of NaHCO3 on a DM basis.
Ruminal pH tended to be higher in cows fed pellets containing virginiamycin (7.0 vs. 6.9; SED = 0.16). The results of in vitro incubation of ruminal fluid with glucose found the potential for L-lactic acid accumulation in ruminal fluid to be significantly lower in cows fed virginiamycin (15.5 vs. 35.3 mmol/L; SED = 2.98). Cows fed virginiamycin had significantly higher fecal pH (6.72 vs. 6.57; SED = 0.08) and produced more milk (23.94 vs. 23.32 kg/d) and more lactose than those not fed virginiamycin. No effects of NaHCO3 on fecal pH, in vitro potential for L-lactic acid accumulation in ruminal fluid, or milk production were observed, but ruminal pH tended to be higher and ruminal acetate proportion was greater for cows fed NaHCO3. Milk fat and milk protein percentage did not differ significantly as a result of dietary treatment. These data suggest that the inclusion of virginiamycin in the diet will reduce L-lactic acid accumulation in ruminal fluid and increase fecal pH in grazing dairy cattle fed concentrate supplements.
Key Words: virginiamycin • sodium bicarbonate • lactic acidosis • ruminal pH
Submitted on July 27, 1998
Accepted on March 11, 1999
This article has been cited by other articles:
|
|
 |
|
  J. Salinas-Chavira, J. Lenin, E. Ponce, U. Sanchez, N. Torrentera, and R. A. Zinn Comparative effects of virginiamycin supplementation on characteristics of growth-performance, dietary energetics, and digestion of calf-fed Holstein steers J Anim Sci, December 1, 2009; 87(12): 4101 - 4108. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Bramley, I. J. Lean, W. J. Fulkerson, M. A. Stevenson, A. R. Rabiee, and N. D. Costa The Definition of Acidosis in Dairy Herds Predominantly Fed on Pasture and Concentrates J Dairy Sci, January 1, 2008; 91(1): 308 - 321. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. H. Clayton and R. J. Blake Possible Errors in the Analysis of Lactic Acid and Volatile Fatty Acids in the Gastrointestinal Tracts of Pigs and Chickens Appl. Envir. Microbiol., April 1, 2005; 71(4): 2206 - 2207. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
