|Hansen, G. - UNIVERSITY OF FLORIDA|
|Crockett, J. - UNIVERSITY OF FLORIDA|
|Olson, T. - UNIVERSITY OF FLORIDA|
Submitted to: American Society of Animal Science Southern Section Meeting
Publication Type: Abstract Only
Publication Acceptance Date: January 20, 2005
Publication Date: March 20, 2005
Citation: Riley, D.G., Hansen, G.R., Crockett, J.R., Olson, T.A., Chase, C.C. 2005. Florida crossbreeding research. American Society of Animal Science Southern Section Meeting. February 4-8, 2005, Little Rock AR. Paper No. 97. p.25. Technical Abstract: This review highlights the accomplishments of three University of Florida beef cattle research locations from the 1940s through the late 1980s. During that time, the Everglades Research and Education Center at Belle Glade, the Range Cattle Research and Education Center at Ona, and the Beef Research Unit at Gainesville conducted long-term crossbreeding research. These locations produced estimates of breed effects and heterosis for a variety of traits in Brahman and a number of other breeds. Most importantly, these facilities investigated the crossbred superiority (heterosis retained or expressed) in several crossbreeding systems, including terminal crosses, two- and three-breed rotations, and inter se matings (including F1 and 3/8 – 5/8 parents). In most of these studies, formal tests were not conducted, but results generally supported the dominance model of heterosis expression for most reproductive and calf growth traits. However, there was large loss of heterosis for weaning rate (almost 40% of that expressed by F1 cows with backcross calves) for 3/8 Brahman 5/8 Devon cows mated inter se at Belle Glade. There was almost a total loss of the heterosis expressed for 18-mo weight in 3/8 Brahman 5/8 Devon heifers at Belle Glade and for cow weight in F2, backcross, and three-breed cross (Brahman, Charolais, and Angus) cows at Ona. Early work in Florida also emphasized the complex interaction of reproductive performance with lactation status, age of cow, and nutritional plane in Brahman and Brahman-cross cows. There appears to be a negative autocorrelation between successive reproductive events that correspond with the age of the cow; it seems that reproductive performance in a given year could be effectively predicted with knowledge of the cow’s lactation status in the previous breeding season. This is especially important considering the high cost of heifer development, the late onset of puberty in Brahman heifers, and the longer gestation length of Brahman calves. This research has provided a framework for future investigations of Brahman crossbred superiority, especially for reproductive traits.