(1) The ejaculation volume of reserve boars is generally 150 ~ 200ml, and that of adult boars is 200 ~ 400ml. The total number of sperm injected each time is about 20-80 billion. The amount of semen varies with pig breed, age, time interval of semen collection, climate and nutritional level. (2) Semen with normal color and smell is gray to milky white, and the thicker the semen concentration, the deeper the milky white. Normal semen has a special fishy smell, but it is by no means smelly or foul. If the semen is slightly red or green in color and smells abnormal, it is mostly inflammation; If there are abnormal particles on the gauze that filters semen, it is also a sign of inflammation; When semen is yellowish, it may be mixed with urine. Very thin and slightly black semen is usually of poor quality. Abnormal semen should be discarded, and boars should be treated symptomatically according to abnormal semen, or sperm collection operation should be checked and improved. (3) Viability refers to the percentage of sperm moving linearly in semen to the total number of sperm. The level of sperm motility is related to the conception rate and litter size of mating sows. Sperm motility should be checked after each sperm collection and before insemination. The test method is to drop 1 drop of fresh semen or diluted semen on a glass slide preheated to 35 ~ 37℃, and cover it with a cover glass, subject to the fact that the semen overflows the cover glass without flowing out and there is no air bubble in the middle. Put it under a microscope of 200 ~ 400 times. Each sample observed 3 ~ 5 visual fields and averaged them. If the semen is taken out at the preservation temperature, it should be heated to 35 ~ 37℃ before the vitality check, and then examined under a microscope after 2 minutes. Microscopy should be kept at a constant temperature, and should not be exposed to strong light or other adverse stimuli, so as not to affect the accuracy of judgment.
Under the microscope, there are three kinds of sperm movements: linear movement, in-situ swing and rotary movement, among which the sperm with linear movement has the strongest vitality and fertilization ability; Sperm swaying in situ is close to death; Sperm in rotational movement, often caused by cold shock or uneven permeability after dilution, may return to normal movement. Generally, the evaluation of sperm motility is based on the "ten-level system", that is, if 90% of sperm in a field of vision are moving forward, the score is 0.9, and so on. If the activity is lower than 0.6, it should not be used.
In practical work, fresh semen, semen dilution and insemination should be checked for vitality. (4) Density is the concentration of sperm, which refers to the number of sperm contained in 1 ml semen. It is another important index to understand semen quality. According to sperm motility and density, the dilution multiple of semen can be determined. The methods for determining sperm density mainly include visual inspection, blood cell count and sperm densitometer, among which blood cell count is the most commonly used.
visual observation
Combined with the observation of sperm motility, under the microscope, the area occupied by sperm is dense, otherwise it is sparse, and the area between dense and sparse is medium. "Diluted" semen can also be used for insemination, but it cannot be diluted. This method can only be a rough estimate of sperm density, which is greatly influenced by the subjective experience of the examiner and has a large error. This evaluation method is usually not used. Blood cell counting method is done with human blood cell counting board under microscope. Because the determination of pig semen quantity does not need too high precision, here is a relatively simple method.
Suck 0. 1ml of semen to be tested with a micropipette or1ml syringe, and put it into 10ml of water, and the semen will be diluted 100 times.
Slowly add the diluted semen into the calculation chamber along the gap between the counting plate and the edge of the cover (no bubbles can appear). Under the low-power microscope, we found 25 middle square calculation rooms with an area of 1mm2, then turned to the high-power microscope, found four corners of the middle square, and counted the sperm in these five middle squares. Each middle square consists of 16 small squares, and the sperm pressed on the edge of the middle square is not counted, and the left one is not counted, and vice versa. Press the counter for each sperm count. Calculate sperm density according to the following formula:
Sperm density = sperm number (the sum of sperm numbers in five squares) ×0.5 (1 100 million/ml) Sperm densitometer method Now there are special instruments with high degree of automation. By combining a spectrophotometer with a computer processor and a printer, the sperm density can be quickly measured by adding 1 drop of semen to the spectrophotometer.