T144 A miniature condition in Brahman cattle is associated with a single nucleotide mutation within the growth hormone gene. B. L. McCormack1, C. Agca1, C. C. Chase, Jr.2, T. A. Olson3, T. H. Elsasser4, A. C. Hammond5, T. H. Welsh, Jr.*6, and M. C. Lucy1, 1University of Missouri, Columbia, 2USDA, ARS, Brooksville, FL, 3University of Florida, Gainesville, 4USDA, ARS, Beltsville, MD, 5USDA, ARS, ...

Abstract Thermal stress in subtropical regions is a major limiting factor beef cattle productions with around $370 million being lost annually due to reduced performance. About 45% of the United States are southern and southeastern states where tropical climates most prevalent. Cattle utilize sweating dispense their excess heat allowing them return thermoneutral zone. The objective this study w...

Adult females of the tick Boophilus decoloratus were removed from 6 breeds of cattle on 2 farms in the Northern Transvaal. Highest numbers of female ticks were collected from Simmentaler, followed by Santa Gertrudis, Bonsmara, Afrikaner, Brahman and Nguni. Resistance levels of each breed to B. decoloratus was positively correlated with the amount of Bos indicus genes in the breed, with the exce...

The objectives of this work were to estimate heterosis and breed genetic effects for carcass quantity, quality, and palatability traits of steers (Bos spp.) produced from matings of Romosinuano, Brahman, and Angus cattle. Steers (n = 464) were weaned at 7 mo of age and transported to the Southern Great Plains where they grazed winter wheat for 6 mo and were then fed a finishing diet until seria...

Effects and interactions of calpain-system tenderness gene markers on objective meat quality traits of Brahman (Bos indicus) cattle were quantified within 2 concurrent experiments at different locations. Cattle were selected for study from commercial and research herds at weaning based on their genotype for calpastatin (CAST) and calpain 3 (CAPN3) gene markers for beef tenderness. Gene marker s...

Studies involving different cattle genetic types evaluated under temperate and subtropical environmental conditions have revealed important genotype × environment interactions for most preweaning traits. A longterm study involving different lines of Hereford cattle evaluated under temperate (Miles City, MT) and subtropical (Brooksville, FL) environments revealed important genotype × environment...

The objective of this study was to evaluate the growth curves of females to determine if mature size and relative rates of maturation among breeds differed. Body weight and hip height data were fitted to the nonlinear function BW = f(age) = A - Be(k×age), where A is an estimate of mature BW and k determines the rate that BW or height moves from B to A. Cows represented progeny from 28 Hereford,...