Investigation of vitamin A and beta caroten in bull semen adn the results of fertility in cows inseminated with these semens

59 SUMMARY The current study was conducted to determine vitamin A and beta, carotene levels in seminal plasma of bulls, influence of exogenously administered vitamin A on spermatological parameters of semen and on fertility of cows inseminated artificiallywith these semen samples were assesed. Five Holstein bulls housed at Lalahan Animal Research Institute and 200 Holstein cows raised by the farmers in and around Elazığ were used in this study. Semen samples were taken with the help of an artificial vagina. Samples were taken twice a week and each time two consecutive ejaculates were taken. The first round of semen collection was continued for five vreeks. Afterwords, two doses of vitamin A (each consist of 4.000.000 I.U. of vitamin A) were administered to the bulls at 10 days interval. After 35 or 40 days from second injection the second round of semen collection was carried out. Initially all the semen samples wTere examined and the first ejaculates from each collection were frozen and stored untill usage for artificial insemination. The second ejaculates were centrifugeted and seminal plasma samples v/ere stored in deep freezer for determination of vitamin A and beta carotene levels. Laiciphos 456 was used as semen diluent. Fifty ml of egg yolk was added into this diluent. The volume of semen paiilett was 0.25 ml and each paillett contained 20 million active sperm. During the freezing., the paillettes were kept in the fume of liquid nitrogen for seven minutes in order to reduce the temparature of the samples from + 4 °C to - 140 °C. Afterwords the paillettes were stored in the liquid nitrogen. The thawing of the samples were carried out at + 3? °C in 20-30 seconds. Artificial inseminations ¥/ere performed by depositing the semen samples into the uterus as soon as the tip of the pistole passed the cervix.60 Vitamin A and beta carotene analysis of seminal plasmas were determined by High Performance Liquid Chromatography. Before vitamin A administration, avarage semen volume of bulls was 4.4 i 0.33 nü, avarage pH value was 6.40 ^ 0.03, total rate of abnormal sperm v/as 1 1.50 % and the most, frequently encountered anomaly was associeted with the tail and the rate of this anomaly was 10.32 %. Avarage sperm concentration was 0.96? ± 0.05 x lOtyml and avarage sperm motility was 70.40 %. The avarage motility of sperm after the freezing and thawing was 60 %. Following vitamin A administration the avarage semen volume was 4.4 ±- 0.16 ml and the avarage pH value was 6. İd i 0.03, total rate of abnormal sperm reduced to §.% £ and again tail associated anomalies were the most frequently encountered anomalies with 7.4 1 % rate. Again in the vitamin A administered bulls avarage sperm concentration was 1.1 15 ± 0.04 s 109 / ml and avarage sperm motility was 79.60 % and the avarage motility of sperm after the freezing and thawing was 64 %. Before the vitamin A administration the level of vitamin A in the seminal plasma of five bulls ranged from 4.35 i 0.25 ng/rnl to 5.14 i 0.16 ng/ml with the avarage level being 4.79 i 0. 13 ng/ml. After the vitamin A administration the level of vitamin A in the seminal plasma of five bulls ranged from 5.52 t 0.17 ng/ml to 7.46 1 0.46 ng/ml with the avarage level being 6.45 - 0.3 1 ng/rnl. Avarage conception rate in cows inseminated with semen collected from bulls before vitamin A administration was 62 % and avarage conception rate In cows insaminated with semen collected from bulls after vitamin A administration was 71 56. The difference between the sperm motility, abnormal sperm rates and the levels of vitamin A in seminal plasma of bulls before and after the vitamin A administration was found to be statistically significant (p< 0.0 1 ).61 A positive correlation between the sperm motility, concentration of sperm, vitamin A level in seminal plasma and fertility of bulls vms determined.