Dr. Khalid Mohammed Karam Semen evaluation Lecture 4 Biotechnology Dr. Khalid Mohammed Karam

Semen evaluation Once semen has been collected it is maintained at a temperature of 30–35°C until it has been evaluated and is ready for further processing. An initial assessment of the quality of the semen can be made immediately after collection. If it appears fairly clear the concentration of spermatozoa will be unacceptably low. If the semen is not of reasonably uniform consistency or contains pus the presence of infection is indicated.

Gross examination 1- Volume : There are differences in semen volume among farm animals. The normal volume can be less than one ml as in ram and buck or hundreds of ml’s as in stallion. Generally, semen volume changes according to age, size, general or specific health and frequency of collection. Pre- collection false amount (teasing) is effective in increasing ejaculate volume.

2- color and consistency Depend on the sperm concentration and extraneous bodies. In general, the species with lower sperm concentration have lighter semen. It can be greyish white as in the stallion, to milky whitish as in the bull, buffalo and camel, to white creamy as in the ram and buck. The consistency should be fairly uniform. watery semen refers to chronic epididymitis Viscous semen refers to catarrhal inflammation of accessory glands. Presence of pus refers to seminal vesculitis

3- Evaluation of hygienic quality Any abnormal color, odor, or foreign materials such as hair, faecal particles, bedding and dirt indicates poor hygienic quality. The presence of blood or pus flakes may indicate affections in the reproductive tract. Yellow color may indicate preputial fluid or urine contamination in animals rather than bull and ram. All contaminated semen should be discarded.

4- pH Fresh semen has an alkaline shift for stallion, camel(7.2 - 7.8), While its acidic shift for the buffalo, ram, buck and bull(6.4- 6.8)

Microscopic examination 1- sperm motility It’s the most important individual quality test, since fertility is highly correlated with the number of motile sperm inseminated. Its important for passage of sperm through the cervix (in natural service) and utero tubal junction. It facilitates penetration of zona pellucida of the ovum during fertilization.

Mass motility Mass motility or wave motion of sperm is clearly demonstrated in the species with high sperm concentration, such as sheep, goat, cattle and buffalo. Mass sperm movement can be seen by eyes sometimes. It is generally poor in the stallion, camel and boar semen. A drop of fresh undiluted semen is placed on a warm slide (without cover slide). The intensity of swirling motion is studied under low power microscope (X10).

The mass motility can be graded from 0-5 in raw semen as follows Grade Descripition 0 immotile 1 stationary or weak rotatory movements 2 very slow wave movement 3 slow wave movement 4 rapid wave movements 5 extremely vigorous wave movements

Individual motility * A subjective evaluation of motility using raw semen for thin semen or extended by good quality extenders for thick semen so that the individual sperm can be seen. *sperm motility is extremely susceptible to environmental conditions such as excessive cold or heat. * only sperms that have forward or progressive movements are counted, but sperm with backward, vibrating or circling movements are not included. The abnormal sperm motility is correlated with male infertility.

Abnormal sperm motility is associated with : 1- aging 2- tail abnormality 3- cold shock 4- hypotonic diluter 5- contamination with water

Procedure A drop of fresh diluted semen is placed on a warm slide and covered with warm coverslip. The individual motility is examined with high power heated microscope stage (38’C). Several procedures have been developed for objective evaluation of sperm motility such as: Time lapse photomicrography Frame by frame playback videomicrography Spectrophotometry Computerized analysis

Parameters of individual motility include 1- percentage of motile sperm (normally 70-90%) 2-longevity of sperm motility in raw semen at room temperature. 3-longeviy of sperm motility in extended semen at room temperature. 4- longevity of sperm motility in extended semen at 4 C.

Sperm concentration General considerations: Accurate determination of the number of sperm per unit volume of semen is important for monitoring semen extension in the AI lab. It is also necessary for monitoring the reproductive capacity of the sire over a period of time.

Expressed as the number of sperm per ml ejaculate. The average of sperm concentrations(million/ml) 1000/bull, 700/buffalo, 2500/ram, 200/stallion,200/camel. The conc. Varies with sexual development, age of the male, feeding, general and reproductive health, size of testes and season Fertility of male may be affected when sperm conc. Is below 50% of the normal level

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