Breeding Programs To Facilitate AI

With the development of larger and more specialized production units there has also been the development of breeding programs better suited to the use of Al than the traditional two or three breed rotational crosses. Although a program utilizing Fl sows and terminal boars can be readily adapted to Al, a program utilizing a rotational sow line and a terminal boar line is probably best suited for Al in small to medium sized herds. Either a two or three breed rotation could be used for the sow line. A three breed rotation will result in a higher level of hybrid vigor. The top producing sows from the total herd can be selected to be bred Al (to the next breed of boar in the rotation) for production of replacement females. The remainder of the sows would be bred to terminal boars for commercial production. This permits a high degree of selection pressure on reproductive performance for the females selected to produce replacements. The terminal boar can be a pure line, an Fl, or a two breed rotation. The following diagram illustrates a rotaterminal crossing system:

DIAGRAM OF A ROTATERMINAL BREEDING SYSTEM

Recent research indicates that the greatest improvement in sow productivity in a commercial herd results from the selection pressure placed on reproductive traits for the boars utilized to produce the replacement females. Thus, there is a large demand for semen from boars with superior EPDs and indexes for maternal traits. SGI sires have consistently proven to be the industry leaders as documented by the Yorkshire and Landrace Across-Herd Sire Summaries. As a result, the use of maternal line semen by commercial producers has been the largest growth area in the SGI Al Center during the past several years.