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United States Department of Agriculture

Agricultural Research Service

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Reproduction Research Unit (RRU)


The goal of the RRU is to increase reproductive efficiency in swine by decreasing the number of breeding-age females required to produce a given number of offspring. Developing and maintaining animals for breeding is a significant cost in the production of swine, and inefficiencies exist at several stages of the reproductive process.  Improvements in reproductive efficiency would reduce costs, increase profitability and reduce meat prices paid by the U.S. consumer.


Reproduction research in the RRU at the U.S. Meat Animal Research Center includes efforts to improve female components of reproduction, including puberty attainment (gilt development), embryo-fetal development, the birth process, preweaning survival (collectively number of piglets weaned per sow), and rebreeding performance and retention in the breeding herd (sow productive lifetime). The RRU combines traditional endocrine and physiology studies with modern genomic, proteomic, and molecular biology techniques to provide an integrated approach to the complex problem of reproductive efficiency in livestock. Genetic and genomic analysis of swine, using a range of both common and novel phenotypic traits, is a significant part of this effort. This effort is focused on developing genetic markers for quantitative traits for reproduction as well as growth, skeletal structure, behavior (temperament, feeding and drinking behavior), and meat quality.


Recent research successes of the unit include:

  • Genetic markers for a poor stress response syndrome within the dystrophin gene have been developed. The syndrome is similar to forms of muscular dystrophy in humans, and pigs with the syndrome are being explored as a biomedical model for this disease.
  • Results from studies of the Meishan pig have suggested that differences in glycogen metabolism in piglets may influence preweaning survival.
  • Genetic loci affecting age at puberty and failure of puberty in gilts have been defined.
  • The "immunoglobulin immunocrit" was developed to assess whether piglets acquire sufficient colostrum during the neonatal period.

Staff Scientists


G.A. Rohrer - Research Geneticist, Acting Research Leader effective September 05, 2016


B.A. Freking - Research Geneticist


B. N. Keel - Research Biologist


C.A. Lents - Research Physiologist


J.R. Miles - Research Physiologist


D.J. Nonneman - Molecular Biologist


L.A. Rempel - Research Physiologist


J.L. Vallet - Research Physiologist, National Program Leader for NP101 effective September 05, 2016

Last Modified: 8/23/2017
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