Okan Atay

Umbilical artery doppler sonography in Saanen goat fetuses during singleton and multiple pregnancies.

The objective of this study was to evaluate the blood flow from the umbilical artery (UA) in healthy pregnant goats. Doppler sonography examinations were performed every two weeks in Saanen goats with a singleton (n = 5) or multiple (n = 4) pregnancy from 40 to 145 days of gestation. Fetal heart rates (FHR), pulsatility index (PI), and resistance index (RI) were recorded from the mid-cord site of the free-floating umbilical cord. FHR decreased gradually as the pregnancy progressed and significantly decreased during the last two examinations of all fetuses (P < 0.05). The mean PI level was dramatically different (P < 0.05) until 85 days of gestation, after which it reached a plateau level until parturition. Similar to PI, RI decreased by 85 days of gestation (P < 0.05), and decreased again by 130s gestation. No reverse or absent end-diastolic flow were observed in fetuses during any examinations. When comparing singleton and multiple pregnancies, there were no significant differences in UA pulsatility or resistance in fetuses seen. The middle of the second trimester was observed to be a threshold stage for indices in the pattern of caprine pregnancy. In conclusion, this work provides additional values that might be useful when evaluating singleton and multiple pregnancies, and may be evaluated in further studies regarding fetal monitoring.

The effects of immunological castration against GnRH with recombinant OL protein (Ovalbumin-LHRH-7) on carcass and meat quality characteristics, histological appearance of testes and pituitary gland in Kıvırcık male lambs.

The aims of the study were to investigate the effects of immunization against GnRH using OL protein (Ovalbumin-LHRH-7) on feedlot performance, carcass, meat quality and some reproductive traits in Kıvırcık ram lambs. Ram lambs in the immunization (I, n=7) group were immunized against GnRH using OL protein and boosted 2 weeks later. Control (C, n=7) group was not treated. The animals were kept at pasture for 6 weeks after the first immunization, subjected to a 70 day fattening program, and then slaughtered. Growth performance, various carcass and meat quality characteristics were not affected from the immunization. GnRH immunization induced GnRH antibody production, suppressed testosterone production and testicular growth (P<0.01). Testicular structure was negatively affected from the immunization, but not pituitary. These results suggest that immunization against GnRH with OL could be an alternative castration technique in ram lambs without negatively affecting carcass and meat quality characteristics.

GnRH or eCG treatment fails to restore reproductive function in GnRH immunized ewes

This study was designed to evaluate the potential of using eCG or GnRH in restoring reproductive functions in GnRH immunized ewes. Thirty-three multiparous Kivircik ewes were randomly assigned into either control group (n=11) or immunization group (n=22). Ewes were immunized against GnRH by injecting with a cocktail of ovalbumin-LHRH-7 (ovalbumin-GnRH-7) and thioredoxin-LHRH-7 (thioredoxin-GnRH-7) fusion proteins generated by recombinant DNA technology in April. 500 IU eCG or 0.008 mg GnRH analogue was used to induce ovulations. Serum GnRH antibodies were present in animals of the immunized group beginning the second week after the first immunization and maintained throughout the study (14 months). Immunization caused anestrus in immunized ewes. eCG or GnRH analogue administration given after 14 days progestagen (20 mg fluorogestone acetate, FGA) treatment during breeding season (mid July) did not induce ovulation in these ewes. Two more attempts with single or multiple eCG injections failed to induce ovulation in this group as well. It appears that the gonadotropin stimulation was not of adequate time since neither eCG nor GnRH administration was able to restore reproductive function in immunized animals. The immunization effect lasted more than a year. These results suggest that GnRH immunization exerts its effect via the hypothalamo-pituitary axis and that more than such stimulation is required to overcome the reproductive suppression.

The effects of supplemental vitamin E on reproductive development of prepubertal Karya male lambs.

The objective of this study was to determine the effect of dietary vitamin E supplementation on testicular and behavioural development, and histological appearance of testes in Karya male lambs. Thirteen lambs weaned at 2.5 months of age were used in the experiment. Experiment was carried out over a period of 70 days and all lambs were fed ad libitum on concentrate and 100 g/day clover hay per lamb. In addition, the experimental group (n=6) received a supplement of 45 mg/day vitamin E (dl-α-tocopherol acetate) per lamb. Testicular measurements and blood testosterone concentrations were recorded every second week. Behavioural tests were carried out four times per animal at three days intervals during the last 12 days of the experiment. After slaughtering, testicular tissue samples of all animals were collected and evaluated for the histological appearances. Except for mount attempts (P<0.05), sexual behaviour and testicular growth characteristics of the lambs were similar. The mounting parameters, testosterone concentrations and testes and epididymides weights were similar between the two groups. However, the mean of mounting weight was found lower (P<0.05) with Vitamin E lambs compared to control (28.78±3.48 vs. 33.98±3.64 kg, respectively). The area of seminiferous tubules was statistically different (P<0.001) between the two groups. However, there were no significant differences between the two groups for most of the reproductive characters. These findings suggest that supplementation of Vitamin E during early prepubertal age of Karya male lambs does not have considerable effects on the reproductive characteristics.

The possibilities of using individual birth weights as weaning criteria in dairy goat farming

The aim of the study was to evaluate the possibilities of using individual birth weight of kids as weaning criteria in Saanen and Alpine goats under intensive conditions. A total of 24 does and their 40 kids were divided to weaning groups when the kids reached three (X3) or four times (X4) of their individual birth weights. The experiment design was a 2×2 factorial design with two weaning stages (X3 vs X4) and two breeds (S: Saanen and A: Alpine). The averages of weaning age of the SX3, AX3, SX4 and AX4 kids were determined as 42.75, 42.21, 53.15 and 65.81 days, respectively. The weaning groups and the interaction between weaning and breed had significant effects (P<0.001 and P<0.05, respectively) on weaning age of the kids. The average daily weight gain before weaning was different in weaning groups (P<0.001). On the contrary, the growth performances of the kids until breeding age were not different between groups. The milk yield characteristics of dams in groups were not different. The results indicated...