Range and Livestock Research Site Logo
ARS Home About Us Helptop nav spacerContact Us En Espanoltop nav spacer
Printable VersionPrintable Version     E-mail this pageE-mail this page
Agricultural Research Service United States Department of Agriculture
Search
  Advanced Search
 
Programs and Projects
Subjects of Investigation
Home
CurrentNutrientContent
Range Comparison Pictures
Animal
Range
Publications
Weed Calculator
 

Research Project: REDUCING COST OF EFFICIENT BEEF PRODUCTION

Location: Range and Livestock Research

Title: Improving Reproductive Performance: Long and Short Term

Authors

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 11, 2011
Publication Date: March 17, 2011
Citation: Geary, T.W., Roberts, A.J. 2011. Improving Reproductive Performance: Long and Short Term. Proceedings of the XV Course on New Approaches to Production and Reproduction in Cattle. Pp. 370-385. Uberlandia, Brazil, March 17, 2011.

Interpretive Summary: Several papers have been written during the past 50 years to include strategies to improve short term (current year) reproductive performance in beef cows, but very few papers have revealed strategies that improve long term reproductive performance as measured by longevity in a cowherd. The information in the present paper includes short term strategies (including heifer development, dystocia management, nutritional management, early weaning, and hormonal manipulation of estrous cycles) and long term strategies (including genetic selection and epigenetic control) to improve herd reproductive performance and guidelines when both should be used to obtain the maximal benefit.

Technical Abstract: Improvements in reproductive performance for beef herds can be classified as short term (current year) or long term (lifetime production) and can be applied to and measured in individual animals or the entire herd. In other species, results show that rearing young animals under caloric restriction increased lifespan. An objective of the current study was to determine the effects of restricted feeding (80% of adequate) in utero and during pubertal development on reproductive performance and longevity. Data was collected over an eight year period in cows that were culled from the herd if they failed to have a calf at their side at the beginning of the breeding season or were not pregnant after the end of the breeding season. Heifers reared on reduced nutrient availability consumed 27% less feed and were lighter at the onset of breeding at approximately 14 months of age, but were more efficient in conversion of feed to gain. Reproductive performance during their first breeding season was not different than heifers fed the adequate diet. During the first 3 years of production, retention was greater for adequate fed cows than restricted cows. However, a greater retention is being observed in restricted fed cows that were restricted in utero. Cows that were nutritionally restricted in utero are heavier and in better body condition at the start of breeding in their 5th year. Taken together, these data indicate an epigenetic effect on metabolic efficiency based on in utero nutrition. Short term strategies that could be used to decrease the decline in retention of nutritionally restricted heifers include providing additional nutrient supplementation during and after their first pregnancy, hormonal induction of estrous cycles, and early weaning of calves. Genetic selection for earlier age of puberty and crossbreeding are other long term strategy to improve reproductive performance and longevity. The mechanisms by which crossbreeding improve reproductive performance warrant further study.

   

 
Project Team
Roberts, Andrew - Andy
Alexander, Leeson - Lee
Waterman, Richard
Petersen, Mark
Geary, Thomas
 
Publications
   Publications
 
Related National Programs
  Food Animal Production (101)
 
 
Last Modified: 05/25/2013
ARS Home | USDA.gov | Site Map | Policies and Links 
FOIA | Accessibility Statement | Privacy Policy | Nondiscrimination Statement | Information Quality | USA.gov | White House