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ARS Home » Plains Area » Miles City, Montana » Livestock and Range Research Laboratory » Research » Publications at this Location » Publication #153718
Title: EFFECTS OF HYPERMUSCULARITY ON BEEF PRODUCTION

Author
item Macneil, Michael
item SHORT, R - RETIRED ARS
item Grings, Elaine

Submitted to: Research Update for Fort Keogh Livestock and Range Research Laboratory
Publication Type: Popular Publication
Publication Acceptance Date: 10/1/2002
Publication Date: 1/15/2003
Citation: MACNEIL, M.D., SHORT, R.E., GRINGS, E.E. EFFECTS OF HYPERMUSCULARITY ON BEEF PRODUCTION. RESEARCH UPDATE FOR FORT KEOGH LIVESTOCK AND RANGE RESEARCH LABORATORY. p. 66-67. 2003.

Interpretive Summary: Beef production in the United States is a billion-dollar industry that produces too much fat. Small amounts of fat are needed to maintain acceptable palatability. Because consumers demand enough fat to enhance palatability, beef is marketed in a system that pays premiums for fat. However, most cattle produced contain nearly twice the 3 to 7% carcass fat estimated as optimal by several researchers. This excess fat production is inefficient. Ironically, excess fat is also a major obstacle in consumer acceptance. Whether based on fact or perception, consumers are anxious about effects of eating too much saturated fat. Therefore, beef production systems that decrease fat and maintain a desirable level of palatability need to be developed. Thus, Hereford-based production systems produce high-quality beef with few associated problems and are adaptable to a wide range of conditions. Increased production of lean beef can be accomplished by using breeds such as Limousin and Piedmontese as terminal sires.

Technical Abstract: Objectives were to determine 1) effects on traits measured from birth to slaughter in calves from sire breeds that differ inpotential for lean tissue growth but have similar mature weight andd 2) the gene action of the mutant Piedmontese myostatin allele. Hereford (H), Limousin (L), and Piedmontese (P) sires (20 to 25 per breed) were bred at random to crossbred cows to produce F1 calves that were inter se-mated within sire breed to produce F2 calves. Piedmontese-cross calves were genotyped for the G-A transition mutation at the myostatin locus characteristic of P (msP). Genotypes were classified on the basis of having zero (P0), one (P1), or two (P2) copies of msP. Limousin-cross calves had heavier birth and weaning weights, gained faster, had more muscle, less fat, larger pelvic area, and more efficient feed conversion than Hereford-cross calves. Normal-muscled Piedmontese-cross calves were similar to Hereford-cross calves except that they required less assistance at birth in heifer dams, had less fat, gained slower, were less efficient, and had larger pelvic area. Addition of msP alleles (P1 and P2) consistently increased muscle through hyperplasia, decreased fat, and increased adjusted efficiency. We conclude that differences in muscularity affect most traits, and when differences in muscularity include the msP allele, there is an incremental, but not equal, change in most traits with the addition of each copy of the msP allele. Advantages of L could be captured through normal crossbreeding and selection schemes but with some caution because of potential problems from increased variability. Advantages of P could be best captured through more complex breeding and selection programs that would lessen potential negative impacts and through marketing systems that do not penalize for very low fat.