Justification for Project:

Beef cattle production provides a large economic impact for many regions of the High Plains, Great Plains, and the Southern U.S.  These regions are locations of most of the cow-calf segment of the beef industry.  Improvement of commercial cow-calf performance in these regions of the United States has been due to breed complementary and utilizing genetics to improve calf performance, reproductive efficiency, carcass quality and maternal traits. This project will address several breeding and genetic aspects that are important to current and developing management strategies in these regions of the U.S.  A collaborative effort across locations in multiple states will be utilized due to limited resource situations of individual research universities and small university research herds of cattle. Genetic evaluation requires more sample size than individual research herds could provide. Combining the resources of the different states has great potential to augment the impact of the proposed research.

The overall goal of this project would be to address component traits with known environmental and genetic influence that impact productivity in cow-calf operations in the Southern, Great Plains and High Plains Regions. A thorough genetic evaluation of these adaptation-type traits may allow for previously unrecognized variation in beef cattle production systems to be identified. Many of the traits of interest are categorical in nature, and genetic evaluation could be complicated, but needs further study. This project will increase the global competitiveness of U.S. beef production and provide increased economic opportunities for cattle producers by improving their understanding of input and efficiency variability.

Objective Areas:

1. To evaluate adaptation of beef cattle to local production and environmental challenges.

Justification: Current information using modern cattle is needed so that cow-calf producers in the can make informed breeding decisions to profitably produce cattle under increasingly challenging environments. In the face of a changing global climate, these once temperate regions of the U.S. are becoming warmer.  Efficient cow-calf production will become increasingly dependent on heat tolerance, and at the same time, water sources may become scarce. These environmental changes may greatly impact gross performance and efficiency of beef production in these regions resulting in a less stable, and relatively more expensive protein supply if research is not conducted to identify adaptability for these environmental challenges. Production information is needed on local heat, humidity, and forage to identify how they may impact growth, carcass and fertility traits.  Hot temperatures and drought conditions are stressful enough to cattle production, but some areas of the upper South also deal with toxic endophyte infected tall fescue which amplifies heat stress conditions. It is important to provide current characterization of breeds that have potential to improve productivity in regions that have substantial environmental challenges.  Direct selection using estimated or predicted breeding values may represent another strategy for improvement of traits related to cow reproductive success and for calf survival.  Analyses of traits using data from across this region would permit accumulation of substantial numbers necessary for appropriate assessment and would expand application of results throughout this critical production area. We plan to document genetic components of thermotolerance pertaining to heat adaptive traits including sweat gland concentration, and hair coat shedding to improve sustainable beef cattle production.  Expected progeny differences and DNA testing are widely available in the U.S. beef industry. However, genetic improvement tools for economically relevant traits such as heat tolerance are less widely available and frequently are less accurate.

2. Estimate heterosis in Brahman-Bos taurus

Justification: Many cow-calf producers in the U.S. rely on breeding strategies that incorporate Bos indicus influence in breeding programs as both breed effects for adaptation and heterosis are advantages known to impact productivity. Breed comparisons are not static over time as these populations change due to selection strategies, and conclusions from breed comparisons at a single point in time during past research may not adequately explain current situations. Recent efforts are substantial to determine heterosis expressed by crosses of Bos indicus adapted breeds crossed with other traditional breeds in the U.S. but is early with emphasis mostly in the Great Plains (Engle et al., in press), and such information is needed by producers, especially in the South, to make the most appropriate choice of breeds to use in crossbreeding programs. It is important to characterize breeds that have potential to improve productivity in regions that have substantial environmental challenges.  Global warming will extend the adaptation and productivity for these breeds further north in the U.S. from the traditional area in the Southern U.S. to the Great Plains and High Plains regions.  Knowledge of heat tolerant breeds is limited compared to more established breeds. There is a need to estimate direct breed and additive genetic effects and heterosis resulting from crosses of Bos indicus influenced breeds bred to British and Continental breeds in specific production environments, especially in a genomics context. Characterization of heterosis levels between breeds will enhance breeding and production decisions and thereby profitability for cow-calf producers.  This characterization is necessary also to provide experimental setting for the application of genomics and DNA technology to this important improvement strategy.  Furthermore, non-additive gene interactions and epigenetic (non-traditional inheritance patterns) influences appear to be important for many body composition and health-related phenotypes in cattle, but investigation of these phenomena are novel and scarce in beef cattle. The intent in part of this project is to quantify these sources of variation in production systems utilizing Bos indicus-Bos taurus crosses regarding growth, health, and production efficiency related traits.

3. Estimate economically relevant traits as deviations from Angus across a United States North-South and East-West continuum.

Justification: In the past several years, new technologies have become available to identify individual genes throughout the bovine genome and independently assess their relationship to novel ERT in the beef cattle industry. To locate these genes, DNA markers (also known as genetic markers) have been developed to aid in locating and representation of genes that can positively or negatively affect the phenotype of a specific trait. Identification of genes with major effects would be beneficial for traits that are hard to measure and ones that are easily influenced by the environment, but this has not occurred, and marker-based improvement programs will be required. However, large populations of cattle of known genetic background are needed to fully characterize new and emerging genetic markers.  Current performance assessments are needed to enhance producer breeding decisions for traits related to cow production (birth weight, longevity, temperament, etc.), reproduction (fertility, heifer development), and carcass quality. There is limited characterization of the additive genetic control and prediction of breeding values for these important cow productivity traits. The effects of ERT’s on growth rate, meat quality and animal welfare and behavior need to be documented. Therefore, before engaging in a selection program to improve ERT’s, further research is needed to evaluate the genetic variation for these traits and the potential relationship between traits. Therefore, additional research is needed to determine the genetic variation that exists for these ERT’s and assess potential for genomic improvement.