Tanzer Bozkurt

Effect of Exogenous GnRH at the Time of Artificial Insemination on Reproductive Performance of Awassi Ewes Synchronized with Progestagen–PMSG–PGF2α Combination

This study was carried out to investigate the efficacy of PGF(2alpha) for oestrus synchronization (ES) in Awassi ewes to which were administered the progestagen-PMSG combination, and to evaluate the effect of the exogenous GnRH administration immediately after the artificial insemination (AI) on their pregnancy rate and lambing performance during the breeding season. The ewes (n = 33) were treated with an intravaginal sponge impregnated with 30 mg fluorogestane acetate for 12 days and were injected with 500 IU PMSG at the time of removal of the sponge. The ewes were then divided into three equal groups of 11 ewes each. One millilitre of physiological saline (0.9% NaCl; placebo) was administered to each ewe in Group 1 at the time of second AI. Approximately 4 microg GnRH (busereline) was injected to each ewe in Group 2 immediately after second AI. A total of 150 microg PGF(2alpha) (cloprostenole) was injected at the time of sponge removal on day 12 and 4 microg GnRH immediately after the second AI was also treated to each ewe in Group 3. Intracervical AI with diluted fresh semen was performed twice at 12 and 24 h following the onset of oestrus. The injection-oestrus onset and injection-oestrus-end interval in Group 3 was significantly (p < 0.001) shorter than both Groups 1 and 2. Although the pregnancy rates of Groups 2 and 3 (81.8%; 9/11) were numerically higher than of Group 1 (63.6%; 7/11), the difference among the groups was statistically insignificant. The multiple birth rate of Group 3 was found higher than Groups 1 and 2. However, the number of single lambs of Group 1 was also higher than Groups 2 and 3 (p < 0.05). Despite the litter sizes of Groups 2 (1.27; 14/11) and 3 (1.55; 17/11) being numerically higher than Group 1 (0.73; 8/11), the differences among all the groups were statistically insignificant. In conclusion, the administration of PGF(2alpha) at the time of removal of the sponge shortens the injection oestrus-onset and oestrus-end interval in Awassi ewes treated with progestagen-PMSG. Additionally, exogenous GnRH treatment immediately after the AI increases the multiple birth rate of Awassi ewes synchronized with progestagen-PMSG-PGF(2alpha) combination.

The effect of vitamin E treatment during preovulatory period on reproductive performance of goats following estrous synchronization using intravaginal sponges

The objectives of this study were to investigate whether the use of intravaginal sponge for estrous synchronization of goats causes oxidative stress, and to examine the effect of administering vitamin E during preovulatory period on reproductive performance of estrous synchronized goats. Estrus was synchronized in 36 non-lactating adult does using intravaginal sponges containing 30 mg of fluorogestane acetate (FGA) for 14 days. All females received 500 IU of eCG at the sponge withdrawal. The goats were allocated at random to two groups balanced for breed, age and body weight. Treatment group (n=18) received 200mg of vitamin E i.m. at the time of sponge removal and again at the time of second artificial insemination. The other 18 goats (control) were administered 1 ml of physiological saline instead of vitamin E on each of these two occasions. All does in estrus was intracervically inseminated at 12 and 24h after the onset of estrus. Blood samples were collected every 72h during the experimental period for evaluation of malondialdehyde (MDA) and vitamin E concentrations. Serum MDA level increased and vitamin E concentration decreased during the period of vaginal sponge application. Following the sponge removal, MDA level declined rapidly to below basal level in the treatment group but remained high in the control group. Conversely, vitamin E concentration increased in the treatment group after the sponge withdrawal and remained at a low level in the control group. No statistically significant differences (P>0.05) were observed between groups in terms of estrous response, conception rate, gestation length or kidding rate. However, the number of multiple births (70.0% versus 50.0%) and prolificacy rate (2.40+/-0.37 versus 1.63+/-0.26 kids per kidding) were significantly higher (P<0.05) for the treatment group than those of the control group. The results indicate that the use of intravaginal sponges for estrous synchronization of goats causes an increase in level of oxidative stress. However, the vitamin E treatment during preovulatory period can prevent the overproduction of reactive oxygen species (ROS), and it may improve the multiple birth rates and the number of kids born in estrous synchronized goats.

Effects of acetylsalicylic acid and metamizol on hyaluronidase activity and sperm characteristics in rams

The effects of acetylsalicylic acid and metamizol on hyaluronidase activity of semen and sperm characteristics in rams were investigated. Acetylsalicylic acid and metamizol at the doses of 75 and 50 mg/kg were administered to the rams, respectively and then semen samples were taken at 1, 2, 4, 24, 48, 96, 120 and 144 h. The hyaluronidase activities of semen in rams treated with acetylsalicylic acid and metamizol were determined to increase significantly (P<0.001) when compared with control groups at all times. Additionally, the spermatozoa motilities in both groups were measured to increase significantly (P<0.05) when compared with control group. Furthermore, there were significant (P<0.01, <0.05) decreases in the sperm concentrations and semen volumes of rams treated with acetylsalicylic acid and metamizol at all times, respectively. In conclusion, although the use of acetylsalicylic acid and metamizol cause an increase in the hyaluronidase activities and spermatozoa motilities, these drugs decrease the sperm concentrations and semen volumes along 6 days. For these reason, the use of these drugs in breeding rams during ramming season is not suitable.