Location: Livestock and Range Research Laboratory
Project Number: 3030-31000-018-000-D
Project Type: In-House Appropriated
Start Date: Oct 23, 2017
End Date: Oct 22, 2022
Objective 1: Evaluate effects of heifer development and winter supplementation protocols that differ in level and type of harvested feed inputs on the sustainability of beef production systems, including annual reproductive success, lifetime productivity, and progeny performance. Component 1: Problem Statement 1A, 1B Objective 2: Establish postweaning heifer development protocols that provide opportunities for improved fertility and differential forage utilization. Component 1: Problem Statement 1A, 1B Objective 3: Integration of phenomics and genomics data to dissect the genetic basis of reproductive and growth traits in beef cattle. Component 1: Problem Statement 1A, 1B Component 2: Problem Statement 2A, 2B, 2D Objective 4: Study the effect of environment, management and genetic interaction on range beef cattle production. Component 1: Problem Statement 1A, 1B Component 2: Problem Statement 2B, 2D We have proposed a series of experiments that will contribute to the alleviation of rate limiting factors that compromise beef production efficiency by: 1) Collectively increasing knowledge of the phenotypic and genetic interplay between nutrition and lifetime reproductive efficiency (Objectives 1, 2, 3 and 4) thus facilitating the economic optimization of feed level and identification of germplasm that is of less risk of reproductive failure when feed level is reduced; 2) Developing strategies that will provide producers management approaches to better utilize forage and better cope with yearly environmental variation (Objective 1, 2, and 4); 3) Further identifying phenotypic and genomic factors controlling fertility in bulls and establishment and maintenance of pregnancy in females thus leading to targets for managerial interventions that increase pregnancy rate, decrease replacement rate and reduce cost associated with producing replacement females (Objective 1, 3, and 4); 4) Prioritizing weighting of phenotypic and genotypic traits influencing production at the time selection decisions occur (typically at approximately one year of age) targeting lifetime performance (Objectives 1, 2, 3, and 4) thus facilitating selection of breeding stock for efficient low-cost production. Work needed to accomplish our objectives is multi-disciplinary and contributions from more than one scientist are expected in order to bring each objective to fruition.
Feed consumption and replacement of cows, culled for reproductive failure, are two primary determinants of beef production efficiency. Our overarching goal is to develop strategies and technologies to alleviate these limitations. Sufficient nutrient intake resulting in adequate body energy stores are believed essential for reproduction. Thus, producers are challenged to match nutritional environment, which is subject to seasonal and annual variation, and various genotypes to obtain sustainable reproduction and retention rates. Our approach is, of necessity, long-term and multi-disciplinary, involving both basic and applied aspects of genetics, nutrition, and physiology in a semi-arid grazing production system. This proposal brings to fruition ongoing research and establishes investigations of genetic by environmental interactions and physiological mechanisms limiting reproductive success. Four distinct cattle populations (an intercross of Charolaise (25%), Red Angus (50%) and Tarentaise (25%), Line 1 Hereford, purebred Angus, and Hereford-Angus herd) will be used to facilitate assessment of genetic factors affecting fitness (hybrid vigor). Distinct nutritional environments differing in provision of harvested or grazed forage will be tested to challenge the nutrition-reproduction interface to reveal roles of genetic, physiological, and management factors influencing feed utilization and lifetime productivity. Identification of genetic, nutritional, and physiological mechanisms that limit or contribute to beef production efficiency will facilitate early in life selection and management of replacement animals most fit for particular production environments. This research will result in the establishment of evidence based beef female development and management protocols that provide producers options for dealing with annual environmental variations.