Effects of Oral Administration of Clomiphene Citrate and Frequency of Ejaculation on Ejaculate Characteristics of Chickens

Abstract

The effects of clomiphene citrate (CC) and ejaculation frequency on semen characteristics of chickens were evaluated using 36 Black Nera cocks aged 24-28 weeks, and weighting 1.96kg to 2.39kg in a 4 x 3 factorial experiment, with clomiphene citrate dose at four levels (0mg, 5mg, 10mg and 15mg/kg body weight) and ejaculation frequency at three levels (once a week, twice weekly and thrice weekly) as factors. Ejaculate volume and colour, sperm motility, sperm concentration and total sperm per ejaculate generally increased progressively with increase in CC administration, with the 15mg CC group being significantly (P<0.05) higher than the control and 5mg CC groups. CC dose had no significant (P>0.05) effect on semen pH and morphologically abnormal sperm. Percent sperm motility increased significantly (P<0.05) while sperm concentration declined progressively for cocks ejaculated two and three times per week respectively, the difference between one and three ejaculations per week being significant (P<0.05). Semen volume, colour and pH as well as proportions of live and abnormal sperm were unaffected (P>0.05) by frequency of ejaculation. Ejaculation frequency, at each level of CC application, had no significant (P>0.05) effect on semen volume, semen colour score, sperm motility and total sperm per ejaculate. However, 15mg CC in combination with three ejaculations per week resulted in the highest numerical values of these characteristics, and in the lowest proportion of morphologically abnormal sperm. It was concluded that oral administration of 15mg CC kg^-1 body weight alone or in combination with frequent ejaculations significantly improved semen output, sperm motility and % live sperm, and reduced the proportion of morphologically abnormal sperm in the cocks.

Keywords: chickens, clomiphene citrate, cocks, ejaculate, ejaculation frequency, semen