This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Towne, G Articles by Kemp, K E Search for Related Content PubMed PubMed Citation Articles by Towne, G Articles by Kemp, K E Agricola Articles by Towne, G Articles by Kemp, K E

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1990 October; 56(10): 3174-3178

Dynamics of ruminal ciliated protozoa in feedlot cattle.

Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600.

ABSTRACT

Fluctuations in ciliated protozoan concentrations were monitored in 40 individually fed crossbred heifers that were stepped up to an 85% concentrate diet either slowly (12 days) or rapidly (3 days), with or without monensin (30 ppm). Ruminal fluid was withdrawn from all animals by stomach tube at the start of the study, after each group reached full feed, and at 14-day intervals thereafter throughout the finishing period until termination (day 119). Neither monensin nor speed of step-up affected (P greater than 0.10) total protozoan concentrations, ruminal pH, or lactic acid concentrations. Average protozoan concentrations peaked on day 5, progressively declined until day 56, and then increased (P less than 0.05), suggesting an adaptation to ruminal conditions. Concentrations of Isotricha spp. were higher (P less than 0.05) on the final two sampling dates than at any other time. After day 28, Entodinium, Isotricha, and Polyplastron were the only surviving genera. Protozoa were not detected in 11 heifers on day 42 and day 56, but only two animals were defaunated on day 119, indicating either exogenous or endogenous refaunation. Average protozoan concentrations were not different (P greater than 0.25) between ruminal samples collected by stomach tube the day before slaughter (2.8 x 10(5)/g) and digesta samples collected the next day (1.6 x 10(5)/g). In feedlot cattle, defaunation apparently is transitory and individual animals harbor a dynamic protozoan population that fluctuates in response to changing ruminal conditions.

This article has been cited by other articles:

• Nagaraja, T. G., Titgemeyer, E. C. (2007). Ruminal Acidosis in Beef Cattle: The Current Microbiological and Nutritional Outlook. J DAIRY SCI 90: E17-E38 [Abstract] [Full Text]  
• Firkins, J. L., Hristov, A. N., Hall, M. B., Varga, G. A., St-Pierre, N. R. (2006). Integration of Ruminal Metabolism in Dairy Cattle. J DAIRY SCI 89: E31-E51 [Abstract] [Full Text]  
• Sylvester, J. T., Karnati, S. K. R., Yu, Z., Morrison, M., Firkins, J. L. (2004). Development of an Assay to Quantify Rumen Ciliate Protozoal Biomass in Cows Using Real-Time PCR. J. Nutr. 134: 3378-3384 [Abstract] [Full Text]  
• Schwartzkopf-Genswein, K. S., Beauchemin, K. A., Gibb, D. J., Crews, D. H. Jr., Hickman, D. D., Streeter, M., McAllister, T. A. (2003). Effect of bunk management on feeding behavior, ruminal acidosis and performance of feedlot cattle: A review. J ANIM SCI 81: E149-158 [Abstract] [Full Text]