Semen Quality and the Gene for Rose Comb in the Domestic Fowl

THE low fertility characteristic of White Wyandottes is associated with rose comb and is expressed only by males homozygous (RR) for that comb type (Crawford and Merritt, 1963; Crawford and Smyth, 1964a). Presence of the gene for rose comb in the sperm cell does not decrease fertility of that cell; instead, the low fertility is caused by some deleterious effect of the RR male host body acting on the spermatozoa (Crawford and Smyth, 1964b). To determine whether this effect might be identified in the semen, several experiments have been conducted to compare qualities of semen and seminal plasma of males of RR, Rr, and rr comb genotypes. A possible reason for the low fertility of RR males is that some inadequacy might exist in their seminal fluids. One or more of the essential components may be absent or present in insufficient amounts preventing normal fertility from being expressed. Maw (1954) has described a condition of this nature, regulated…