Fertility in rams treated with clomiphene citrate


Wael M.B. Noseir, Ph.D.

(Theriogenology Department, Faculty of Veterinary Medicine, Alexandria University, Edfina, Behaira, Egypt.) (email; noseir@eudoramail.com) (Tel; 034259945 Egypt)



The effect of orally administered clomiphene citrate on the fertility of rams was studied. Semen and blood samples were collected from 10 mature and fertile Rahmani rams (control) twice per week for 3 weeks. Each ram was treated with 100mg-clomiphene citrate for 5 days. Semen and blood samples were collected again from the clomiphene citrate treated rams (CC treated) for the same period. Semen parameters (sperm motility, live sperm, and sperm concentration) were assessed in the two groups. Blood samples were subjected to radioimmunoassay for assessment of testosterone concentration in the control and CC treated rams. A reduction in the values of semen parameters was observed in the CC treated rams. Testosterone concentration was significantly decreased (approximately 50% from control rams) by clomiphene citrate treatment. It could be concluded that clomiphene citrate has a deteriorative effect on semen quality and testosterone concentration when it is orally administered to mature and fertile rams.


Key Words; Clomiphene, Clomiphene citrate, Rams, Fertility



Clomiphene citrate is a drug having augmenting influences on fertility. In the female, clomiphene affects fertility in a positive way by tricking the body into thinking that less estrogen is present than there really is, by blocking estrogen’s attachment to its receptor, and the body responds by releasing greater amounts of FSH that stimulates ovogenesis (IRMSSB, Unpublished data, 1997). In the male rats, it is effective in increasing the male’s serum level of LH and FSH, which stimulate testosterone and sperm production by the testes (Fertilitext, Unpublished data, 1997). In infertile male rats, clomiphene citrate treatment together with testosterone administration has maintained their fertility (Rej et.al., 1988). On the other hand, Sokol, et.al. (1988) have shown that clomiphene citrate is not a useful drug in the treatment of male infertility. Clomiphene citrate treatment in intact male rats was found to inhibit their reproduction (Brown and Chakraborty, 1988). The aim of this study is to determine whether clomiphene citrate can improve fertility of rams, measured by semen evaluation and serum testosterone concentration, or not.

Material and Methods

Ten Rahmani rams from Alexandria veterinary faculty farm were assigned for this study. Semen samples were collected from each ram (control) twice per week for 3 weeks. Blood samples were collected from each ram following semen collection. A period of rest (10 days) was given to the rams. Then each ram was given clomiphene citrate (CC) orally (Clomiphene, ADCO, Egypt) at a daily dose of 100mg for 5 days. Semen and blood samples were collected again from the CC treated rams.

Semen samples were collected by the electroejaculator. The percent of motile sperm, percent of live sperm, and sperm cells concentration (using haemocytometer method), were subjected for evaluation.

Blood samples were collected by jugular venipuncture. Serum samples were obtained by centrifugation (3000rpm/min for 15 minutes) for assessment of testosterone concentration by radioimmunoassay using a testosterone kits (Diagnostic Systems Laboratories, Texas, USA).

T-test (Norusis, 1986) was used for comparing the obtained data of semen analysis and serum testosterone concentration, before and after CC treatment.


The values of studied semen parameters (percentage of motile sperm, percentage of live sperm, and sperm cells concentration) before CC treatment were found within the normal range reported on Rahmani ram’s semen characteristics (table, 1). After CC treatment, these values showed a significant decrease (P £ 0.01), in the percentage of sperm motility and in the percentage of live sperm (table, 1). Moreover, there was a noticeable significant decrease (P £ 0.01) in sperm cells concentration after CC treatment.

A significant decrease (P £ 0.01) in testosterone concentration was noticed after CC treatment. Serum testosterone drop, after CC treatment, could be estimated to approach 50% below control value (table, 1).

















Table (1): Mean semen parameters and serum testosterone concentration in rams

before and after CC treatment




Before CC treatment

(control, n=60)

After CC treatment

(CC treated, n=60)

Percentage of sperm motility

75.62± 1.47a

52.50± 3.53b

Percentage of live sperm

79.37± 1.47a

66.62± 3.61b

Sperm concentration (million/ml)

2212.50± 387.96a

573.75± 53.05b

Testosterone concentration (ng/ml)

4.82± 0.89a

2.75± 0.53b

Means ± St.E.

Means with different letters in same row are significantly different (P £ 0.01).































Clomiphene citrate is a non-steroidal drug, it has a molecular formula of C26H28CINO.C6H8O7. It is capable of interacting with estrogen receptor containing tissues. The first endocrine event in response to clomiphene treatment in male rats is an increase in the release of pituitary gonadotrophin. Clomiphene citrate has been involved in many trials for the improvement of male fertility, but its beneficial effect is controversial (Shanis et.al., 1991). A significant improvement in semen volume, sperm density, and sperm motility was noticed in men treated with CC (Micic and Dotlic, 1985). Also a significant improvement in sperm counts occurred as a result of CC treatment in men (Soler Rosella et.al., 1980). On the contrary, Shanis et.al. (1991) have shown that in men there was a significant deterioration in sperm function as measured by percentage of morphologically normal sperm. Weissenberg et.al. (1992) have stated that in intact male rats LH and testosterone secretion were suppressed by clomiphene treatment. Hideki et.al. (1990) have demonstrated that infertile males with low FSH and LH plasma levels tended to respond to CC treatment, while those with elevated levels of FSH and LH did not have any improvement in semen quality.


Testosterone may be the hormone that makes the male but it is estrogen, the so called female hormone, that gives sperm its reproductive punch. Estrogen regulates fluid reabsorption in the efferent ductules of the male, and with out reabsorption the sperm remains diluted and incapable of maturation in the epididymis, so any block in the estrogen receptor’s function may result in infertility (Barlow, unpublished). In this work, the studied semen parameters in the CC treated rams were low along with a significant decrease in testosterone concentration. There was also a positive correlation between testosterone concentration and studied semen characteristics. A similar postulate was reported by Doshi et.al. (1994) who obtained a positive correlation between testosterone concentration, and total sperm count and sperm motility in buffalo-bulls treated with CC, indicating that low levels of testosterone was always associated with low values of semen characteristics. Brown and Chakraborty (1992) have suggested that clomiphene decreased the synthesis and/or release of gonadotrophins and also decreased serum LH and testosterone concentration in male rats.


The adverse effect of CC treatment on the fertility of rams, in the present study, may be attributed to its influencing effect on testosterone reduction (approximately 50%) and/or due to its antiestrogenic properties. It seems that good fertility response of clomiphene in mature males depends mainly on the presence of low fertility and/or deficiencies in serum gonadotrophins (Hideki et.al., 1990). While, simultaneous use of CC in normally fertile males could have a controversial effect. Therefore, CC treatment that could improve fertility in male infertile rats (Rej et.al., 1988) or infertile men (Micic and Dotlic, 1985), could also induce a deteriorative effects on semen characteristics when used in fertile rams. There is a still remains for investigation, a clomiphene good fertility response when administered to subfertile or infertile farm animals.





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