The bovine clitoris
Keywords: clitoris, bovine, anatomy
The bovine clitoris is the homolog of the penis in males. In cattle it is a small structure; far smaller relative to the size of a cow than the equine clitoris relative to a mare.
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Also, unlike the situation in mares, where the clitoris has three or more deep sinuses that harbor various pathogens (including T. equigenitalis), the bovine clitoris is simple, with a shallow, partially circumferential sinus (see image) that appears to play no major role in harboring reproductive pathogens such as Campylobacter fetus and Trichomonas fetus.
In beef animals, several studies have shown that short periods of clitoral stimulation immediately after A.I. will increase fertility modestly but significantly. The physiology behind this is not well understood but it has been linked to increased motility of the uterus. It is natural to speculate that increased motility is mediated by oxytocin but that has not been shown to be the case. Instead a local neural pathway has been suggested. Nevertheless, some hormonal involvement may be involved because the LH surge and ovulation may occur earlier in stimulated than non-stimulated cows. Interestingly, data on clitoral stimulation show that beneficial effects have only been demonstrated in older cows, not heifers. In dairy cows, the value of clitoral stimulation remains controversial; it has not been shown to be valuable yet it is still practiced by some A.I. technicians
Because the clitoris is a homolog of the penis and penile size is somewhat dependent on androgens, clitoral enlargement is a valuable sentinel for illegal use of anabolic steroid use in veal calves.
References:
Randel R.D. et al. 1973. Effect of clitoral massage after artificial insemination on conception in the bovine. J. Anim. Sci. 40: 1119-1123
Short, R.E. et al. 1979. Effect of clitoral stimulation and length of time to complete AI on pregnancy rates in beef cattle J. Anim. Sci. 49:647-650
Cooper, M.D. et al. 1985 Uterine Contractions and Fertility Following Clitoral Massage of Dairy Cattle in Estrus J. Dairy Sci. 68: 703-708
Lunstra, D.D. er al. 1983. Clitoral stimulation and the effect of age, breed, technician, and postpartum interval on pregnancy rate to artificial insemination in beef cattle.Theriogenology. 19: 555–563
Groot, M.J. and den Hartog, J.M.P 1990 Histological Changes in the Genital Tract of Female Veal Calves Implanted with Naturally Occurring Anabolic Steroidsclitoris for androgenic activity can be useful in tracing illegal anabolic treatment of female veal calves with combination preparations.
J.Vet.Med.Series A 37: 775–786
