BREEDING & GENETICS
PIH-9
pork industry handbook
PURDUE UNIVERSITY • COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, INDIANA
Boar Selection Guidelines for Commercial Pork Producers
Authors:
Allan P. Schinckel, Purdue University
Charles J. Christians, University of Minnesota
Ronald O. Bates, University of Missouri
Reviewers:
Erik Cleveland, University of Hawaii at Hilo
Donn Damos, North Henderson, Illinois
Lynn Cole, Mt. Blanchard, Ohio
Dave Elftman, Kokomo, Indiana
The performance level of the commercial swine herd is determined by two things: genetics and environment. The genetic contribution is determined by the boars and gilts selected and the crossbreeding program used. The environment, (weather, housing, feeding, management, etc.) will enhance or hinder the genetic expression of performance traits. The purpose of this publication is to provide recommendations for selecting replacement boars.

Identification of Responsible Seedstock Suppliers
It is extremely important that you identify seedstock suppliers who can provide you with superior seedstock as a result of their genetic selection and herd health programs. Identification of progressive, responsible seedstock suppliers, is the only means by which your herd can consistently improve its production efficiency.

Genetic Improvement
The rate of genetic improvement in a commercial pork producer’s herd parallels the rate of genetic progress made by the seedstock suppliers (Figure 1). To make significant genetic progress for any economically important trait (growth rate, feed conversion, carcass merit, or litter size), performance records must be kept and superior animals selected to produce the next generation.

The top three lines (A, B, C) of Figure 1 show the expected improvement in genetic merit when the seedstock herds are making genetic progress. The genetic merit of commercial herds follows the progress made by the seed-stock herds. In those seedstock herds making genetic progress, the purchase of the highest-ranking boars available,
will enable the commercial herd to approach the genetic level of the seedstock herd.
Purchase of boars from seedstock herds where genetic improvement programs are not utilized (lines D and E) results in inconsistent genetic progress. This is because the genetic merit of the boars purchased is not improving.

Commercial herds which purchase average boars from genetically improved seedstock herds have an advantage over commercial herds which purchase the very top boars from unimproved herds. Average boars from genetically superior herds can be of higher genetic merit than above average boars in genetically average or below average herds. For this reason, identification of seedstock producers is of primary importance. Selection of individual boars from these producers is secondary.

When selecting seedstock suppliers, review their genetic improvement program. A sound genetic improvement program should include four features: (1) accurate, complete performance records including animal identification, consistent measurement of all boars and gilts (not on-again, off-again or limited, partial performance testing), and ranking of animals within defined contemporary groups; (2) assessment of the genetic merit of economically important traits (growth rate, feed efficiency, carcass merit, and reproductive performance) based on the individual's performance relative to its contemporary group and incorporating the performance of relatives; (3) indexes weighting traits relative to their economic importance in commercial pork production (the indexes should correctly rank the individuals relative to their intended use in crossbreeding systems); and (4) selection of the highest-ranking boars and gilts based on selection indexes. Seedstock producers should utilize selection indexes as their primary selection criteria. Some emphasis should also be given to physical
Cooperative Extension work in Agriculture and Home Economics, State of Indiana, Purdue University and U. S. Department of Agriculture cooperating. H. A. Wadsworth, Director, West Lafayette, IN. Issued in furtherance of the acts of May 8 and June 30, 1914. The Purdue University Cooperative Extension Service is an affirmative action/equal opportunity institution.