Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2001
Publication Date: 7/1/2001
Citation: MACNEIL, M.D., SHORT, R., GRINGS, E.E. CHARACTERIZATION OF TOPCROSS PROGENIES FROM HEREFORD, LIMOUSIN, AND PIEDMONTESE SIRES. JOURNAL OF ANIMAL SCIENCE. 2001. v. 79. p. 1751-1756. Interpretive Summary: Effective use of genetic differences between breeds is key to efficient production of beef with attributes that satisfy consumers. Breeds used in rotational crossbreeding systems should be of similar mature size and composition to maximize calf survival and avoid inter-generational variability in attributes of beef produced. Hereford, Limousin, and Piedmontese are of approximately equal mature size and yet may vary in body composition at a given degree of maturity. However, direct comparisons among these three breeds were not found. Within breeds such as Hereford, Limousin, and Piedmontese, of similar mature size and growth rate, ample variation exists in body composition at approximately equal degree of maturity. This suggests opportunity to use breed resources with complementary genetic potentials for carcass characteristics in rotational crossbreeding systems without creating problems with inter-generational variation in birth weight, calving difficulty, or resultant neonatal mortality.
Technical Abstract: The objective of this research was to compare progenies of Hereford (H) (n=23), Limousin (L) (n=24), and Piedmontese (P) (n=24) sires. Male calves were either left intact or castrated at about 2 mo of age. Calves remained with their dams until weaning at an average age of 179 d. Male calves were then individually fed a growing ration until they reached 386 kg and then fed a finishing ration either 90 or 132 d. They were then slaughtered at a commercial abattoir and carcass data collected. Female calves were group-fed and used to examine nutritional effects on age at puberty. Data were analyzed using an animal model and REML. Hereford-sired calves had shorter gestation periods and weighed less at birth than L- or P-sired calves. Calving difficulty of H- and L-sired calves was less than P-sired calves. Limousin-sired calves tended to grow more rapidly than H-sired calves. By the finishing phase, L- and H- sired calves had greater average daily gains than P-sired calves. Differences in dry matter intake among breeds of sire were relatively small. Differences in carcass weight, ribeye area, fat depth, and percentage kidney, pelvic, and heart fat resulted in stratification of USDA yield grade between breeds of sire. Differences in percentage primal cuts were similar to those for USDA yield grade. Hereford-sired calves had more marbling than progeny of L or P sires. However, force necessary to shear cores from steaks of P-sired calves was less than for progeny of L or H sires. Hereford- and P-sired heifers were younger at puberty than L-sired heifers. Within breeds of similar mature size and growth rate, ample variation exists in age at puberty and body composition at approximately equal degree of maturity.