Effects of ejaculation frequency and breed on semen characteristics and sperm output of rabbits

each ejaculated at frequencies of 1\m=x\12 hr, 1\m=x\24hr and 2\m=x\48hr. Ejaculate volume and sperm concentration were lower (P<0\m=.\01)at 1\m=x\12 hr than at either of the other two frequencies. Daily sperm output did not differ significantly among the three frequencies. Dutch-type rabbits had a significantly lower daily sperm output than New Zealand Whites. Grégoire, Bratton & Foote (1958) found that increasing the ejaculation fre¬ quency of rabbits from once weekly to once daily resulted in decreases of 50% in sperm concentration and 40 % in ejaculate volume. Weekly sperm output, however, was almost 400 % greater at the higher frequency. Desjardins, Kirton & Hafs (1965) compared the sperm output of twelve rabbits each collected at four frequencies. Weekly sperm output (x 10~6) averaged 273 with one ejacu¬ late weekly, 519 with one ejaculate collected daily except Sundays and 619 when two successive ejaculates were collected each Monday, Wednesday and Friday. The present study was designed to determine an ejaculation frequency which would maximize sperm output and to study breed differences in semen characteristics. Three groups, each consisting of two Dutch-type and three New Zealand White rabbits over 1 year old, were used in a change-over design. Body weight averaged 2-40 kg for Dutch-type and 3-88 kg for New Zealand White rabbits. Ejaculation frequencies tested with each rabbit were: one ejacu