Preliminary Studies of Seminal Attributes and Semen Cryo-banking of Nepali Indigenous Lulu (Bos taurus) Bull under Ex-situ Conservation

Abstract

Indigenous animals are valuable genetic property of a country. The Nepali indigenous Lulu cattle breed is in endanger state. Cryopreservation is a simple and potent technology to preserve the gametes and could be used for genetic dissemination. Therefore, the study was conducted to evaluate the seminal attributes of fresh semen with a final goal of cryo-banking of Lulu (Bos taurus) semen. Two
Lulu bulls were used for the study. A total of 24 ejaculates, 12 ejaculates from each Lulu bull were evaluated for seminal attributes. The mean semen volume, color, mass activity, sperm motility, sperm viability, sperm concentration, abnormal acrosome, mid piece and tail and, abnormal head were 1.6 ± 0.8 ml, 2.8 ± 0.7 grade, 3.1 ± 0.6 grade, 67.5 ± 9.6%, 90.7 ± 4.0%, 977.7 ± 76.1 x 106
/ml, 10.1 ± 1.9 and 9.0 ± 1.4%, respectively. Further, 4 ejaculates (≥ 1.5 ml semen volume, ≥ 65% sperm motility
and ≥ 800 × 106/ml sperm concentration) from each Lulu bull were used for freezing. The mean motility and viability were 71.9 ± 5.3% and 87.9 ± 6.7% after 90 minutes of cooling. Similarly, mean motility and viability were 70.0 ± 4.6% and 87.1 ± 6.3% after 210 minutes of cooling. The motility and viability of post thawed semen were 51.3 ± 5.2% and 70.4 ± 6.3%. A total number of 174 doses
semen straw were cryo-banked. It was concluded that the semen volume, sperm motility and sperm concentration were comparatively lower compared with most of the bulls breed. The sperm viability and abnormal percentage was considered acceptable. Due to the acceptable post thawed sperm motility and viability recorded, cryopreservation of Lulu semen is hereby recommended so as to preserve
the Lulu breed. Although, the cryopreserved semen must be tested in fertility trials following artificial insemination.