Chiasma counts and non-disjunction frequencies in a normal ram and in rams carrying the Massey I (t1) Robertsonian translocation.

Testicular material from a normal ram (54XY), three rams heterozygous (53XYt1) and one ram homozygous (52XYt1t1) for the Massey I (t1) translocation was examined. The autosomal non-disjunction in the normal ram was 2.0% compared to a mean of 6.1% in the heterozygous animals. In the homozygous animal there were adhesions of the tunica vaginalis to the cauda epididymidis and extensive spermatogenic arrest.