A cytogenetic study was undertaken on the chromosomal makeup and breeding data of 29 boars housed in a Canadian pig farm. Blood cultures were made and chromosome spreads were examined, searching for carriers of chromosomal abnormalities. The investigation revealed that twenty-six individuals had a normal karyotype and 3 (10.3%) carried the following aberrations: (a) two 1/6 translocations in two - unrelated - individuals, (b) one reciprocal translocation rcp(10;13). The litter size of the two boars carrying the 1/6 translocation was, on average, 6.5 and 5.8, respectively. The mean size of the litter sired by the boar carrying the rcp(10;13) was 6.0. As compared with the average litter size (11.0) sired by the normal boars in the herd, the translocations described here seemed to be responsible for ~35% decrease in prolificacy.

W. A. King

Papers

Cytogenetic screening of a canadian pig breeding unit