QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart 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 Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McCarthy, F. D. Articles by Hawkins, D. R. Search for Related Content PubMed PubMed Citation Articles by McCarthy, F. D. Articles by Hawkins, D. R.

Muscle Protein Turnover in Cattle of Differing Genetic Backgrounds as Measured by Urinary N^r-Methylhistidine Excretion¹

Department of Animal Science, Michigan State University, East Lansing, MI 48824

N^r-methylhistidine (N^rMH) was used as an index for muscle protein degradation and this index was utilized to evaluate degradation rates in young growing cattle. Initially, two Charolais crossbred heifers, 12 months of age, were used to measure the recovery of radioactivity in the urine for a 120-hour period after intravenous injection of [¹⁴C]N^rMH. Of the radioactivity injected into the animals, 89.7% was recovered after 120 hours. With rate and amount of clearance as the criteria, the excretion of N^rMH in urine appears to be a valid index of muscle protein degradation in cattle. Eight steers of two genetic types were used to evaluate the effect of frame size on turnover rates of muscle proteins with N^rMH as an index. Large frame cattle (LG) excreted more N^rMH per day (P < 0.03) throughout the trial. Total daily creatinine excretion was less for small frame (SM) cattle (P < 0.02) showing an increase with time (P < 0.01) in LG and SM cattle. N^rMH-to-creatinine ratios showed a decline with time. Fractional breakdown rates (FBR) and fractional synthesis rates (FSR) appeared to parallel each other with rates tending to decrease with age. No differences were observed between LG and SM cattle for FBR, FSR or fractional growth rate (FGR).

KEY WORDS: • N^r-methylhistidine • fractional turnover rates • muscle protein turnover • frame size • steers

¹ Michigan Agricultural Experiment Station Journal Article Number 10770.

² Present address: Department of Animal Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061.

³ Author to whom reprint requests should be addressed.

Manuscript received 3 March 1983.

This article has been cited by other articles:

				J. M. Kelzer, P. J. Kononoff, A. M. Gehman, L. O. Tedeschi, K. Karges, and M. L. Gibson Effects of feeding three types of corn-milling coproducts on milk production and ruminal fermentation of lactating Holstein cattle J Dairy Sci, October 1, 2009; 92(10): 5120 - 5132. [Abstract] [Full Text] [PDF]

				B. N. Janicek, P. J. Kononoff, A. M. Gehman, and P. H. Doane The Effect of Feeding Dried Distillers Grains Plus Solubles on Milk Production and Excretion of Urinary Purine Derivatives J Dairy Sci, September 1, 2008; 91(9): 3544 - 3553. [Abstract] [Full Text] [PDF]

				A. M. Gehman, P. J. Kononoff, C. R. Mullins, and B. N. Janicek Evaluation of Nitrogen Utilization and the Effects of Monensin in Dairy Cows Fed Brown Midrib Corn Silage J Dairy Sci, January 1, 2008; 91(1): 288 - 300. [Abstract] [Full Text] [PDF]