A comparison of progeny sired by high and low indexing Hampshire and Duroc central test station boars: progeny performance.

A 2-yr study compared progeny performance of high (HI) and low (LI) indexing central test station boars purchased in Iowa, Missouri, Nebraska and Oklahoma. Boars were evaluated for a National Swine Improvement Federation index recommended for central test stations. The 1st yr 22 Hampshire boars were mated to three- and four-breed Duroc, Yorkshire, Landrace and Spotted cross gilts. A disease outbreak the first farrowing season caused severe death loss and reduced performance. From 198 litters, 826 pigs completed their gain test. The 2nd yr 23 Duroc boars were mated randomly to gilts produced the previous year. From 181 litters, 1,070 pigs completed their gain test. No differences existed for postweaning average daily gain (ADG) and probe backfat thickness (PBF); however, progeny sired by HI Hampshire boars were an average of 5.66 units better for the index (I) compared with progeny of LI Hampshire boars. Gilt progeny of HI Duroc boars were .03 kg, .79 mm and 3.93 units greater for ADG, PBF and I, respectively, than LI Duroc-sired gilts. Barrow progeny of LI Duroc boars gained .01 kg/d faster, had .59 mm more PBF and were no different for I than barrows sired by HI Duroc boars. Maternal grandsire effects were important for Duroc-sired pigs, with gilts of HI maternal grandsires having .01 kg faster ADG, yet barrows of HI maternal grandsires had .02 kg slower ADG as compared with gilts and barrows having LI maternal grandsires, respectively.