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item Jenkins, Thomas
item Ferrell, Calvin

Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Proceedings
Publication Acceptance Date: 11/22/2005
Publication Date: 1/3/2006
Citation: Jenkins, T.G., Ferrell, C.L. 2005. Efficiency of feed utilization during the preweaning period among tropically adapted cattle. Symposium on Tropically Adapted Breeds, Southern Cooperative Series Bulletin 405, American Society of Animal Science Southern Section Meeting, p. 162-166.

Interpretive Summary: Included in a list of production resources for cow/calf operations would be attributes of the physical environment and management. The latter makes decisions regarding the allocation of available capital to produce a product whose revenues would exceed investment. Failure to utilize germplasm suitable for the typical attributes of a physical environment of a defined geographical region may negatively affect the return on investment. Utilization of germplasm that is adapted to the environment would decrease capital expenditures to modify the environment and could increase productivity. Commercial cow-calf producers whose enterprises are located in hot and humid areas with higher levels of internal and external parasite problems would benefit from access to germplasms that are fit within this type of environment. Crossbred cows containing tropically adapted germplasm were characterized for traits contributing to production efficiency during the preweaning period at MARC in south-central Nebraska. Relative to Angus/Hereford females, the efficiency of converting feed resources to weight gain during the preweaning period or weight weaned was higher in cows produced through matings with breeds suited to the tropical environment. This higher efficiency was evident even when higher cow feed intakes were observed for F1 cows from tropically adapted sire breeds cows.

Technical Abstract: Productivity of mature F1 cows from tropically adapted sire breeds produced by mating Angus and Hereford, Brahman (Cycle III and V) and Sahiwal (Cycle III), Nellore (Cycle IV), and Boran and Tuli (Cycle V) sires by AI or natural service to Angus and Hereford cows (AH) was measured. Comparisons were relative to Angus/Hereford F1. Daily milk yields were recorded via weigh-suckle-weigh. Brahman and Sahiwal F1 cows produced significantly more total lactation yield (TY), weight of calf weaned (WCW) and were more efficient (Eff, weight calf weaned/feed consumed by cow). These breed crosses exhibited 15.2% and 11.8% more TY, 18.8% and 13.1% more WCW and were 3.8% and 7.2% more Eff relative to AH cows (1,764 lb, 440 lb, 38.5 Eff). In Cycle IV, Nellore TY and WCW were greater (P < 0.05). Nellore crosses produced 4.8% more TY, 20% more WCW and were 14.2% more Eff at DMI for maximum weaning weight than AH (1,732 lb, 298 lb, 28 Eff). Cycle V mean TY for Brahman was greater (P < 0.05) than Tuli but neither differed (P > 0.10) from AH or Boran cross cows. Relative to AH (3,709 lb), Brahman, Boran and Tuli produced 6.9% and 1.9% more and 9.1% less TY; respectively. WCW of Brahman and Boran was greater (P < 0.05) than Tuli or AH which did not differ (P > 0.10). Brahman, Boran and Tuli produced 25.0%, 19.2%, and 4.2% more WCW than AH (372 lb). Brahman and Boran Eff exceeded (P < 0.05) Tuli which was greater (P < 0.05) than AH. Relative to Angus/Hereford (72.6), Brahman, Boran and Tuli F1s were 45%, 35%, and 15%; respectively, more Eff. F1 cows from tropically adapted sire breeds mated to non-adapted sires were more effective in converting food resources to weight of calf at weaning during the preweaning period during spring and summer months of a temperate climate.