Cytogenetic survey of breeding boars for chromosome abnormalities in the Canadian pig population
A cytogenetic survey was conducted on 98 breeding boars from 4 farms in Saskatchewan and Ontario to obtain an estimate of the frequency of chromosome abnormalities in the Canadian pig population. This frequency was estimated at 50% for the hypoprolific group (two translocations, rcp(1;6)(p22,q12) and rcp(10;13)(p13,q45), were found in boars siring small litters) and at 2.5% for the young group (one translocation, rcp(9;14)(p24;q27), was found in a boar selected but not yet used for breeding). A decrease in prolificacy of more than 40% was estimated for the 1/6 and 10/13 translocations and of 26% for 9/14 translocation after reproduction of the boar carrier. The percentage of stillbirth and repeat breeding was also calculated for the 1/6 and 9/14 translocations of 0.5%, 33% and 8.7%, 29%, respectively. All the rearrangements were highlighted using G-band techniques. To confirm the reciprocal characteristic of 10/13 and 9/14 translocations, the FISH technique was used. However, with the 9/14 translocation, an additional technique, immunostaining for synaptonemal complex, was required.