D. Gerber

Epididymal sperm from the African buffalo (Syncerus caffer) can be frozen successfully with AndroMed® and with Triladyl™ but the addition of bovine seminal plasma is detrimental

Numerous diseases are carried and can be transmitted from the African buffalo (Syncerus caffer) to livestock. Buffaloes free of specific diseases (BFSD) are thus in demand amongst game farmers. Current BFSD derive from a small genetic pool and hence there is a special interest in bringing new genetic material into such herds. In this study epididymal sperm from 16 mature African buffalo bulls was frozen with Triladyl and AndroMed extender (Minitüb, Tiefenbach, Germany) with and without addition of bovine seminal plasma. Post-thaw motility, longevity and acrosomal integrity were compared. In all but one animal, post-thaw motility was higher, although not always significant, if sperm was frozen with Triladyl than with AndroMed. Seminal plasma was detrimental to the post-thaw motility. Neither semen extender nor seminal plasma had an influence on post-thaw acrosomal integrity. It can be concluded that bovine seminal plasma at a concentration of 10% is detrimental rather than beneficial for the post-thaw motility of African buffalo sperm. Even though being inferior AndroMed does, however, have the advantage that it is a defined semen extender and therefore clearly has a lower risk of contamination.

Abortifacient and endocrine effects of metergoline in beagle bitches during the second half of gestation

The purpose of this study was to investigate the abortifacient effects of high doses of metergoline when administered to pregnant beagle bitches during the second half of gestation and to define the endocrine effects of this treatment as represented by plasma progesterone and estradiol concentrations. Previously, metergoline had been shown to be incompletely luteolytic and induced abortion in only one of eight pregnant bitches when 0.4-0.5 mg/kg were administered twice daily for 5 days from Days 18 to 20 of diestrus. Nine pregnancies in six beagle bitches were used for the present study. Three bitches were treated in each of two consecutive pregnant cycles. Metergoline was administered at a dose of 0.6 mg/kg per os twice daily, starting on Day 28 after the cytological onset of diestrus. Abortion was induced in eight of the nine treated pregnancies and started after 3-23 days of treatment (mean 12.5 days, S.D. 6.4 days). The abortions were completed within 0.5-8 days (mean 2.2 days, S.D. 2.7 days). There were no side effects associated with metergoline treatment and none of the abortions was associated with complications that required intervention. In the single bitch that did not abort, an ovarian granulosa cell tumor was discovered when the single fetus had to be removed surgically at term. Plasma progesterone concentrations declined after the start of metergoline administration in all pregnancies but levels below 4.8 nmol/l were required for successful abortions. Plasma estradiol concentrations showed a tendency to decline and fluctuate concurrently with the plasma progesterone levels. However, suppression of plasma estradiol concentrations by metergoline was not as complete as the suppression of progesterone and did not seem a prerequisite for abortion. The hormone profiles and treatment period required for abortion tended to be similar for both cycles of the three bitches that were treated during two consecutive pregnancies. This suggests a bitch effect on the factors that determine the efficacy of metergoline to induce abortion. The large variation and length of the treatment period that was required until abortion commenced was probably related to the relatively early start of treatment compared to other studies. The results of this investigation suggest that, similar to other prolactin suppressing ergot derivatives, metergoline causes complete luteolysis and can be used to reliably induce abortion only during the last 3 weeks of gestation.

Ex vivo influence of carbetocin on equine myometrial muscles and comparison with oxytocin

To determine the intercyclic effect of oxytocin and carbetocin on equine myometrial tissue, the effect of the drugs was evaluated through pharmacokinetic and pharmacodynamic studies. The complete pharmacokinetic profile for oxytocin was unknown and had to be established. To do so, 25 IU of oxytocin were administered intravenously to six cycling mares and blood samples were collected before and 2, 4, 8, and 15 min after administration. The half-life of oxytocin was determined to be 5.89 min, the clearance rate 11.67 L/min, mean residence time (MRT) 7.78 min. The effective plasma concentration was estimated to be 0.25 ng/mL. This was similar to the concentration achieved for the organ bath study where the concentration that produced 50% of the maximum effect (EC(50)) was calculated at 0.45 ng/mL. To determine the intercyclic effect of oxytocin and carbetocin uterine myometrial samples were collected from slaughtered mares in estrus, diestrus, and anestrus. The samples were mounted in organ baths and exposed to four ascending, cumulative doses of oxytocin and carbetocin. Area under the curve and amplitude, maximum response (E(max)), and concentration that produced 50% of the maximum effect were studied for each agonist and statistically evaluated. The effect of oxytocin on equine myometrial tissue was higher during diestrus, and surprisingly anestrus, than during estrus, whereas the effect of carbetocin was the same independent of the stage of estrous cycle. A significant difference was found for estrous and anestrous samples when oxytocin was used but not when carbetocin was used.

Ultrasound-guided injection of contrast medium into the crus penis for diagnosis of erection failure in bulls.

The objectives of this study were to demonstrate the ability to cannulate the crurae of the bulls penis under ultrasound guidance, to demonstrate contrast medium injected by this route in the distal penis, and to confirm the technique to be safe and repeatable. Five adult bulls with normal serving ability were used, one being subjected to the procedure twice. The procedure was performed with the bulls under general anesthesia and in lateral recumbency. A spinal needle was passed through the skin and into the crus penis under ultrasound guidance and two syringes containing an iodine-based contrast medium were connected to it. Stimulation using an electro-ejaculator with a rectal probe was initiated, and when the penis started developing an erection, 50-100 ml of contrast medium was injected. Lateral and ventro-dorsal radiographs were taken of the extended penis during, and at intervals after, injection. After a rest period of 5 min, clearance of the contrast medium was confinned and the procedure was repeated on the other crus penis. Each case therefore, contained two attempts. Successful cannulation of the crus penis was confirmed by observing indentation of its fibrous wall by the needle, free flow of blood, lack of resistance to the injection of air, which could be seen in the crus, and fluctuation of resistance to injection in synchrony with the pulsation of the electroejaculator. Contrast medium was demonstrated in the mid or distal portion of the penis in all six cases, or on 9 of the 12 attempts. Attainment of penile erection, a larger volume of contrast medium, and the order of cannulation all enhanced flow of contrast medium to the distal portion of the penis, with the first crus giving better results. On one occasion the needle worked out of the crus penis during stimulation, resulting in injection of contrast medium into the corpus spongiosum penis. All bulls recovered uneventfully and returned to normal serving ability. It is concluded that ultrasound-guided cannulation of the crus penis is a safe and successful method for the injection of contrast medium for contrast studies of the penis, and is less invasive than the surgical method.

Hypercalcaemic multicentric lymphoma in a dog presenting as clitoromegaly

Clitoromegaly is a clinical manifestation of various local and systemic conditions in all species. The external genitalia are a very rare site of primary or metastatic lymphoma in canines, with only one previously-reported case in a dog and only sparse reports in the medical literature. Lymphoma is also very rare in dogs less than four years of age. This account reports on a T-cell multicentric lymphoma in a 16-month-old Basset hound presented primarily for clitoromegaly. The patient survived for 68 days with cyclophosphamide-vincristine-prednisolone therapy. The causes of clitoromegaly in all species, including humans, are tabulated with references.

21 Effects of heterologous semen plasma and semen extenders on progressive motility of frozen-thawed ram sperm.

Frozen-thawed ram semen crosses the cervix poorly, necessitating laparoscopic insemination. Acceptable fertility can be achieved with frozen-thawed ram semen deposited at the external cervical opening if ram semen plasma (SP) is added (McPhie et al. 2000 14th ICAR 2, 78 abst). Homologous SP improves the fertility of frozen-thawed sperm of boars and dogs. Heterologous SP may have effects as well; the addition of bovine SP increased the ability of buffalo sperm (Syncerus caffer) to fertilize bovine oocytes in vitro (de Haas et al. 2003 Theriogenology 59, 392). The aim of the current study was to compare the effects of SP of rams (SPR), bulls (SPB), and dogs (SPD), protein-free TALP, Triladyl (Minitub, Tiefenbach, Germany), and skim milk upon longevity and percentage of progressively motile frozen-thawed ram sperm. Three ejaculates from each of six rams (2 Dorpers, 2 Dohne merinos, and 2 merinos), aged 2–4 years, were extended in Triladyl, pooled and frozen as a single batch per ram at 200 × 106/mL in 0.25-mL straws. SPR was obtained from the same rams and SPB from 5 bulls by centrifugation, while the post-sperm fractions were collected from 5 dogs (SPD). Within a species, the SP from different donors was pooled and frozen in aliquots at -18°C. The 108 straws (6 rams, 6 diluents, 3 replicates) were thawed in random order. Once thawed, a straw was emptied into a tube with 0.85 mL of the appropriate fluid at 37°C and kept for 6 h. Percentage of progressively motile sperm was estimated at ×200 magnification immediately and 2, 4 and 6 h after thawing. One person thawed the semen and prepared motility specimens, while another performed all motility evaluations. Data were evaluated by means of repeated-measures ANOVA, with rams as subjects and time and fluid as fixed effects. Non-significant interactions were removed from the model. Means were compared by means of Bonferronis test (P < 0.05). The model included ram, time, fluid, and ram × fluid, and time × fluid interactions, which were all significant (P < 0.01). Mean motility decreased from each time to the next and were 39.0% (0 h), 26.0% (2 h), 19.6% (4 h) and 12.6% (6 h), SEM 1.38%, n = 108. Mean motility was higher for skim milk (39.9%) than for all other fluids except Triladyl (27.7%), which was better than SPB (13.0%), whereas TALP (20.5%) and SPR (21.9%) were similar to Triladyl and SPB (n = 72, SEM 2.85%). The interactions (ram × fluid or time × fluid) were mainly due to SPD, SPR, Triladyl, and TALP, while milk resulted in the best and SPB in the lowest motility. This study shows that heat-treated skim milk maintains progressive motility of frozen-thawed ram sperm better than the SP of various species and protein-free TALP. In contrast to SPR, skim milk is known to result in poor fertility of frozen-thawed ram semen after cervical insemination. It would thus appear that maintenance of progressive motility in vitro may be a poor indicator of fertility after cervical insemination.