Journal of Animal Science, Vol 79, Issue 6 1370-1377, Copyright © 2001 by American Society of Animal Science

JOURNAL ARTICLE

Genotype x environment interactions for postweaning performance in crossbred calves grazing winter wheat pasture or dormant native prairie

W. A. Phillips, M. A. Brown, A. H. Brown Jr and S. W. Coleman
USDA-ARS, Grazinglands Research Laboratory, El Reno, OK 73036, USA. bphillip@grl.ars.usda.gov

Data from 403 calves from Angus, Brahman, and reciprocal-cross cows sired by Polled Hereford bulls were used to evaluate the impact of postweaning backgrounding forages on postweaning BW, gains, and carcass traits. Calves were born (spring of 1991 through 1994) and reared on either endophyte-infected tall fescue or common bermudagrass pastures. After weaning, calves were transported 360 km to the Grazinglands Research Laboratory, west of El Reno, OK, and, within breed and preweaning forage, were assigned to one of the following winter stocker treatments: 1) winter wheat pasture or 2) dormant native prairie plus supplemental CP. In March, winter stocker treatments were ended and calves were grazed as a single group on cool-season grasses until early July (1992, 1993, and 1994) or late May (1995), when the feedlot phase began. In the feedlot, calves were fed a high concentrate diet for an average of 120 d until a backfat thickness of > 10 mm was reached. Calves were shipped in truck load lots to Amarillo, TX (350 km), for processing and collection of carcass data. Averaged over calf breed group, calves wintered on wheat pasture gained faster (P < 0.01) during the stocker phase (0.71 vs 0.43 kg); had heavier (P < 0.01) final feedlot weights (535 vs 512 kg); lower feedlot (P < 0.01) ADG (1.37 vs 1.53 kg); heavier (P < 0.01) carcass weights (337 vs 315 kg); larger (P < 0.01) longissimus muscle (84.9 vs 81.8 cm2); higher percentage (P < 0.01) of kidney, heart, and pelvic fat (2.32 vs 2.26); and higher (P < 0.01) dressing percentage (62.2 vs 61.3) than calves backgrounded on native prairie. Maternal heterosis for stocker ADG was evident in calves backgrounded on native prairie but not on winter wheat (P < 0.10), but the two environments were similar in maternal heterosis for feedlot ADG and carcass traits. Calves wintered on native prairie were restricted in growth and expressed compensatory gain during the feedlot phase but not during the spring stocker phase. Dormant native grasses can be used to winter stocker calves excess to the winter wheat pasture needs, but ownership of these calves would have to be retained through the feedlot phase to realize any advantage of built-in compensatory gain. Finally, these data suggest that expression of maternal heterosis for weight gain is more likely in calves backgrounded on native prairie than in calves grazed on winter wheat.

This article has been cited by other articles:

				W. A. Phillips and G. W. Horn Intake and digestion of wheat forage by stocker calves and lambs J Anim Sci, September 1, 2008; 86(9): 2424 - 2429. [Abstract] [Full Text] [PDF]

				M. A. Brown, X. Z. Wang, F. Q. Gao, J. P. Wu, D. L. Lalman, and J. W. Holloway Postweaning Gains in Calves Sired by Six Sire Breeds Evaluated on Two Preweaning Forages and Two Postweaning Management Systems Professional Animal Scientist, June 1, 2008; 24(3): 224 - 231. [Abstract] [PDF]

				C. T. MacKown and B. F. Carver Fall Forage Biomass and Nitrogen Composition of Winter Wheat Populations Selected from Grain-Only and Dual-Purpose Environments Crop Sci., January 1, 2005; 45(1): 322 - 328. [Abstract] [Full Text] [PDF]

				T. G. Jenkins and C. L. Ferrell Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and unadapted Bos taurus breeds J Anim Sci, June 1, 2004; 82(6): 1876 - 1881. [Abstract] [Full Text] [PDF]

				M. J. Hersom, G. W. Horn, C. R. Krehbiel, and W. A. Phillips Effect of live weight gain of steers during winter grazing: I. Feedlot performance, carcass characteristics, and body composition of beef steers J Anim Sci, January 1, 2004; 82(1): 262 - 272. [Abstract] [Full Text] [PDF]

				W. T. Choat, C. R. Krehbiel, G. C. Duff, R. E. Kirksey, L. M. Lauriault, J. D. Rivera, B. M. Capitan, D. A. Walker, G. B. Donart, and C. L. Goad Influence of grazing dormant native range or winter wheat pasture on subsequent finishing cattle performance, carcass characteristics, and ruminal metabolism J Anim Sci, December 1, 2003; 81(12): 3191 - 3201. [Abstract] [Full Text] [PDF]