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Infertility –Temporary loss of fertility in male characterized by reduced number of viable spermatozoa in the ejaculate
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Nils Lagerlof divided the forms of infertility in males into 3 general categories
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- These above conditions are present in males of all species.
- The degree of each condition present in males varies considerably between species, breeds, families and individuals. There are many degrees, from mild to severe in each category of the various forms of infertility.
- Sometimes reduced sexual desire and ability to copulate may be associated with reduced fertility and poor quality semen but in most cases of infertility in males the two conditions are not related.
- In male animals semen collection is usually possible so that direct measurement of semen quality and other test may be applied to diagnose male infertility.
- In examining males for infertility or sterility,
- Accurate breeding and health records on the male and the herd should be obtained and examined.
- Secondly, there should be a careful, painstaking physical examination of the male including the observation of his mating behavior.
- Thirdly, one or more thorough semen examination by a trained veterinarian or qualified laboratory is necessary.
- To evaluate the nature of a male’s infertility and sterility so that proper recommendations for therapy, treatment or disposal of the animal may be made.
- The prognosis in nearly all forms of infertility or sterility in male animals should be guarded.
Potency
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Potency is the physical capability of the entire body to coordinate and performs the male’s normal role at coitus including erection, mounting, intromission and ejaculation.
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A lack of potency is observed in certain males in all species and is characterized by symptoms ranging from a complete lack of sexual interest and inability to copulate to a slight slowness or delay in the exhibition of libido, mounting and copulating.
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Libido is defined as the willingness and eagerness of a bull to attempt to mount and service .
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In the female animal reproductive behavior is relatively simple requiring only a willingness to stand to be mounted or an attitude of acceptance. This attitude is primarily under the control or influence of oestrogen which may be enhanced by progesterone.
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In the male animal reproductive behavior is more complex requiring identification, seeking out, teasing and then the performance of the complicated act of copulation. This is under the control or influence of testosterone and other central nervous system mechanisms.
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The components of the act of copulation consist of sexual excitement, courtship, erection, mounting, intromission, ejaculation, dismounting and refractoriness.
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There is a great variation in the duration of these components between species and individual males within a species. Mating behavior depends to a varying degree on visual, olfactory, auditory and tactile cues. In all species visual and tactile cues are probably most important in the actual act of copulation but even in blind males may copulate if experienced.
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Height, width and color of the female, attitudes of acceptance, such as her stance as the male approaches, reaction of the female to pressure of the bulls head on her rump or back, pressure of the shoulder on the mare’s rump or biting of the skin of the mare’s rear parts by the stallion and by the boar’s snout lifting of the sow’s rear quarters, odour of the rear parts in horses and sheep and vocalization by the stallion and boar are all factors in the precopulatory and copulatory acts in domestic animals.
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Sex drive, libido or sexual desire of the male is largely determined genetically but that environmental influences play an important role in modifying it. It is well known that males differ widely in their ability to copulate frequently.
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The differences between animals were due to the reactivity of their tissues, such as the brain, rather than to the differences in the amount of hormone secreted or present in the body.
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Thus variations in endocrine function may be linked with changed reactivity in the target organs, especially the central nervous system, as well as with the hormone producing organ. Many of the complex components of copulatory behavior are determined by hormone action during various stages of development and may be persist after castration.
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It is extremely difficult to evaluate the libido and mounting ability of Brahman, Zebu or Santa Gerturdis bulls since these breeds copulate mainly at night and rapidly so the copulatory act can only rarely be observed.
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Innate virility is reflected in the number and frequency of copulations that occur in a period of time and these vary widely between males.
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Although sex drive, mating behavior or libido is largely genetic nature it is subject to great modification by many environmental or physical factors.
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Males with strong sex drive require more severe and prolonged environmental and physical insults to significantly affect their mating behavior than do males with weak sex drive.
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