Background:
Bull fertility diagnosis is very important as semen collected from a single bull is used to inseminate hundreds of cows. So far, no single in vitro techniques have been developed to assess bull fertility successfully. The cervical mucous sperm penetration test has been considered as one of the tests to assess bull fertility in vitro. However, the sperm penetration test results are not consistent with the field fertility assessment. This is due to failure in collecting proper cervical mucus of appropriate quality, as the quality of the mucus changes during different stages of estrus. Hence, synthetic media for sperm penetration was developed to assess semen quality. Technology Details:
Bull fertility determination is very important as semen collected from a single bull is used to inseminate hundreds of cows. Based on the in vitro assessment of sperm fertility, the results are extrapolated to predicting bull fertility. The semen from high fertile bulls can be used for inseminating cows through an artificial insemination program. The cervical mucus sperm penetration test has been considered as one of the tests to assess bull fertility in vitro. However, the sperm penetration test results are not consistent with field fertility assessment when performed with natural cervical mucus collected from the cervix of the cow. This is due to failure in collecting proper cervical mucus of appropriate quality, as the quality of the mucus changes during different stages of estrus. Generally, the cervical mucus is collected from cows in their estrus and stored at -80°C for 30 min followed by cold storage in liquid nitrogen at -196°C. Similar procedures are adopted for collecting the cervical mucus of buffaloes, wherein difficulties in collection of cervical mucus have been reported due to very little quantity of cervical mucus probably due to inherent breed character. Hence, synthetic media for sperm penetration was developed to assess semen quality. The synthetic media can be filled in the capillary tube and one end of the capillary tube has to be inserted in the semen samples perpendicularly. After incubation at a particular temperature for a predetermined time, the vanguard spermatozoa travel distance in the synthetic media was assessed under a microscope. The vanguard sperm travel distance was positively correlated to field pregnancy rate. This test can be used to select the neat semen samples for further freezing and in frozen semen samples to pass on to artificial insemination. This test can be applied to assess semen quality and bull fertility. This test can be used as a screening measure to process semen samples for freezing as well as for artificial insemination. By applying this technique, good quality semen samples can be produced and distributed to the field and the field fertility rate could be improved. Ultimately, farm productivity and the economy will be improved.