REPRODUCTIVE CONSEQUENCES OF AN X-AUTOSOME TRANSLOCATION IN A SWINE HERD

A survey was conducted on the chromosome makeup and breeding data of p igs housed at the Arkell Research Station, University of Guelph, to de termine the reproductive impact of a reciprocal translocation previous ly identified as t(Xp(+);14q(-)). Blood samples were cultured and chro mosome spreads were examined to identify carriers in the herd. Gonadal features of carrier boars and piglets and their age-matched normal co unterparts were studied, and the reproductive history of carrier sows, including the number of breedings required for conception, mean litte r size, prevalence of still births and malformations, and sex distribu tion among the piglets, was compared with that of normal (noncarrier) sows. Our observations on testicular histology confirmed that X-autoso me translocation-carrier boars are sterile and the analysis of reprodu ctive data showed that the most striking effects of t(Xp(+);14q(-)) on sows are the 50% increase in the number of breedings required for con ception and the over 25% reduction in litter size compared with that o f normal sows. The reproductive impact of this and similar translocati ons on the herd and on the swine industry in general is discussed.