Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/23/2004
Publication Date: 5/21/2004
Citation: Jenkins, T.G., Ferrell, C.L. 2004. Preweaning efficiency for mature cows of breed crosses from tropically adapted Bos indicus and Bos taurus and non-adapted Bos taurus breeds. Journal of Animal Science. 82:1876-1881.
Interpretive Summary: Commercial cow calf producers whose enterprises are located in hot and humid areas need access to tropically adapted breeds or breed crosses. Presently, the prevalent breed crosses in use in these areas contain tropically adapted Bos indicus to meet the challenge of the production environment. Calves from these cows are frequently discounted at the market because of perceived problems with carcass tenderness. There is a need to identify tropically adapted breed resources without the problems with carcass tenderness. The current evaluation of production characteristics important to weaned calf enterprises provided evidence that the productivity of mature cows produced by mating Tuli sires to non-adapted Bos taurus were comparable to F1 Angus/Hereford females; however, neither of these sire breed of cow (SBC) groups were equal in performance to the Bos indicus tropically adapted breeds. These results suggest the Tuli breed may represent a viable alternative to Bos indicus breeds for use as a maternal breed cross to reduce the potential loss in meat quality attributes sometimes found in progeny from maternal breed crosses containing Bos indicus germplasm but at a cost of cow herd performance relative to the Bos indicus crossbred cows.
Technical Abstract: Production data were collected on mature cows, produced by mating Angus and Hereford (pooled AH) non-tropically adapted Bos taurus (NBT), Brahman (Bh) and Boran (Br) (tropically adapted Bos indicus, TBI), and Tuli (Tu, tropically adapted Bos taurus, TBT) sires by AI or natural service to Angus and Hereford cows. These cows were mated to Charolais bulls for the purpose of this study. Within each sire breed of cow, cows were randomly assigned to one of three feeding rates, 49 or 76 g/weight**0.75 DMI and ad lib (10 to 12-cows/feeding rate group) with weekly individual animal feed consumption recorded. Lactation yields were recorded via weigh-suckle-weigh protocol at approximately 14, 28, 56, 84, 112, 140, 168 and 196 d post partum for each cow/calf pair. Means for milk yield at peak lactation (PY), total milk yields (TY), calf birth weight (BW), age adjusted weaning weights (AWW), preweaning daily gain (DG), and feed efficiency (FE) were estimated. Mean PY (kg/d) for Bh (10.3 ± 0.36) was greater (P < 0.05) than Tu (9.0 ± 0.31) but neither breedcross differed (P > 0.10) from AH (10.0 ± 0.31) or Br (9.9 ± 0.31). Mean TY (kg, 212 d) for Bh (1802 ± 68) was greater (P < 0.05) than Tu (1532 ± 59) but neither breedcross differed (P > 0.10) from AH (1686 ± 58) or Br (1718 ± 58). The BW (kg) of Bh (39 ± 1.1), Br (39 ± 0.9), and Tu (42 ± 0.9) were similar (P > 0.10) but the BW of AH (44 ± 0.9) was heavier than Bh and Br (P < 0.05). Preweaning daily calf gain (g/d) and AWW (kg) of Bh (813 ± 28, 212 ± 6.1) and Br (766 ± 24, 202 ± 5.1) were similar (P > 0.10) and both differed (P < 0.05) from AH (589 ± 24, 169 ± 5.2) and Tu (634 ± 24, 176 ± 5.3) which were similar (P > 0.10). Efficiency estimates (g AWW/kg DMI of cow) for Bh (88 ± 2.5) and Br (85 ± 2.1) exceeded (P < 0.05) Tu (74 ± 2.1) and AH (73 ± 2.1) which did not differ (P > 0.10). Bos indicus breed crosses exhibited greater PY and TY, lower BW, greater DG and AWW and higher FE than Bos taurus breed crosses (P < 0.05). Means estimates for TY, DG, AWW and FE were higher (P < 0.05) for cows sired by bulls from tropically adapted breeds and the BW was less (P < 0.10). The TBT exhibited lower TY and BW than NBT (P < 0.05) and tended to be more efficient (P < 0.10) than NBT. The efficiency of crossbred cows produced from matings with a tropically adapted Bos taurus breed did not differ from Angus/Hereford F1 females but neither equaled the efficiency of crossbred cows produced using Bos indicus breeds.