Calcium, parathyroid hormone, oxytocin and pH profiles in the whelping bitch.

Despite the high prevalence of primary uterine inertia in whelping bitches, the underlying pathogenesis remains unclear. The objectives were to i) determine serum concentrations of total calcium, ionized calcium (iCa), parathyroid hormone (PTH), and blood pH in normally whelping bitches throughout the peri-parturient period; and ii) investigate relationships among iCa, PTH, and acid-base status, and the role that they and oxytocin may have in the underlying pathogenesis of canine uterine inertia. Bitches were randomly selected from a population of German Shepherd Dog bitches with a history of uncomplicated parturition (Group 1; n=10), and from a population of Labrador bitches with a clinical history of an increased incidence of uterine inertia and stillbirths (Group 2; n=20). Jugular blood samples were collected daily from -4 d to the onset of whelping (t=0 h), and then every 4h until the last pup was born. Overall, bitches from Group 2 had higher mean+/-SEM serum concentrations of PTH (4.72+/-2.45 pmol/L, P<0.001), lower iCa (1.31+/-0.08 pmol/L, P<0.05), and higher venous pH (7.41+/-0.03, P<0.005) than bitches from Group 1 (2.9+/-1.44 pmol/L, 1.38+/-0.06 mmol/L, and 7.33+/-0.02, respectively) during the periparturient period. However, there was no significant difference between Groups 1 and 2 for serum oxytocin concentrations during the periparturient period (45.5+/-40 and 65.5+/-82 pg/mL). We inferred that low iCa resulting from a rising pH and decreasing PTH during the periparturient period may have contributed to decreased uterine contractility and increased risk of stillbirths. Therefore, manipulating the cationic/anionic difference in diets of pregnant bitches, similar to the bovine model for hypocalcamia, may reduce the incidence of stillbirths in the bitch.

Influence of seminal plasma on fertility of fresh and frozen-thawed stallion epididymal spermatozoa.

The use of epididymal stallion spermatozoa for routine artificial insemination can secure easy future use of valuable genetics after unforeseen death or injury of a valuable stallion. The aims of this study were to (1) directly compare pregnancy rates for fresh and frozen-thawed stallion epididymal and ejaculated spermatozoa after conventional artificial insemination and (2) to investigate the effect of seminal plasma on the fertility of epididymal spermatozoa after insemination. Twenty-one mares were randomly assigned to three stallions. Mares were inseminated at five consecutive oestrous periods using fresh ejaculated spermatozoa (Fr-E, n=18), fresh epididymal spermatozoa that had been exposed to seminal plasma (Fr-SP+, n=12) or fresh epididymal spermatozoa that had never been exposed to seminal plasma (Fr-SP-, n=9), frozen-thawed ejaculated spermatozoa (Cr-E, n=18), frozen-thawed epididymal spermatozoa that had been exposed to seminal plasma prior to freezing (Cr-SP+, n=18) and frozen-thawed epididymal spermatozoa that had never been exposed to seminal plasma (Cr-SP-, n=15). Pregnancy examinations were performed 14 days after each ovulation. Pregnancy rates were 55.6% (Fr-E, 10/18), 75% (Fr-SP+, 9/12), 22.2% (Fr-SP-, 2/9), 38.9% (Cr-E, 7/18), 27.8% (Cr-SP+, 5/18) and 6.7% (Cr-SP-, 1/15). Overall pregnancy rates for fresh and frozen-thawed epididymal spermatozoa that had been exposed to seminal plasma were significantly better than for epididymal spermatozoa that had never been exposed to seminal plasma (P<0.05). We conclude that the exposure of stallion epididymal spermatozoa to seminal plasma improves pregnancy rates.

Technical note: A rapid enzyme-linked immunosorbent assay blood test for pregnancy in dairy and beef cattle.

The ruminant trophoblast produces pregnancy-associated glycoproteins (PAG) that can be detected in the blood of pregnant animals. The objective was to determine the accuracy of a rapid ELISA PAG-based test for the purpose of pregnancy detection in cattle. Blood was sampled from dairy cattle (539 Holstein cows, 173 Holstein heifers, 73 Guernsey cows, 22 Guernsey heifers, and 12 Jersey heifers) and crossbred beef cattle (145 cows and 46 heifers) that were >or=25 d after insemination (range = 25 to 45 d for dairy and 29 to 56 d for beef). Cattle were examined by ultrasonography for detection of pregnancy within 2 d of blood collection. Whole blood or plasma was incubated in a polystyrene tube coated with a monoclonal PAG antibody for 15 min. The tubes were then washed and subjected to sequential incubations with a biotinylated polyclonal PAG antibody (15 min, followed by wash), a horseradish peroxidase-streptavidin solution (15 min, followed by wash), and a peroxidase substrate. Tubes were visually assessed for color after 15 min (clear solution = PAG negative, not pregnant; blue solution = PAG positive, pregnant). Total assay time was approximately 90 min. The ultrasound examination was used as the standard for pregnancy diagnosis. The sensitivity (99.8 +/- 0.2%), specificity (91.7 +/- 1.4%), and negative predictive value (99.7 +/- 0.3%) for the PAG test used in dairy cattle were similar for different breeds and for cows and heifers. The positive predictive value for the test was greater in dairy heifers than in dairy cows (96.5 +/- 1.4% vs. 90.5 +/- 1.7%, respectively). In beef cattle, the sensitivity (100%), specificity (92.3 +/- 3.0%), positive predictive value (95.0 +/- 2.0%), and negative predictive value (100%) for the PAG test were similar for cows and heifers. The accuracy of the test was not different for dairy and beef cattle. In conclusion, the rapid ELISA pregnancy test based on PAG was highly sensitive and specific for pregnancy detection in dairy and beef cattle.

The use of deslorelin implants for the synchronization of estrous in diestrous bitches.

A novel approach to estrous induction in diestrous bitches is described. Twelve spontaneously cycling anestrous bitches served as controls. Thirteen anestrous and 15 diestrous bitches were induced to come into synchronous estrous using prostaglandin (diestrous bitches only) and deslorelin implants (Ovuplant). Implants contained either 2.1 or 1.05 mg deslorelin and were administered beneath the vestibular submucosa. All treated bitches came into estrous, regardless of implant size. Whereas all anestrous bitches ovulated, one of six diestrous bitches treated with the larger implant and three of nine treated with the smaller implant failed to ovulate. Induced bitches generally produced fewer corpora lutea than controls. Sixty-seven percent of control bitches became pregnant, with 0.63 fetuses per corpus luteum, whereas the pregnancy rate and fetuses per corpus luteum were 67 and 70% and 0.42 and 0.55 in the anestrous bitches induced with 1.05 and 2.1 mg deslorelin implants, respectively (not different from controls). Only 2 of 15 induced diestrous bitches conceived a detectable pregnancy, one of which was resorbed. In conclusion, although ovulatory estrous can be induced in bitches that had their most recent ovulation 40-100 days ago, these bitches are very unlikely to become pregnant during the induced estrous. The reason for the poor fertility in these diestrous bitches requires further study.

Failure of hCG to support luteal function in bitches after estrus induction using deslorelin implants.

Induction of estrus with deslorelin implants was followed by abortions in bitches that conceived during the induced estrus. Lowering the deslorelin dose and choosing a better implantation site prevented the abortions. This study investigated the hypothesis that induction of estrus with deslorelin is followed by reduced serum progesterone concentrations (SPC) during the ensuing diestrus. Assuming that reduced luteal function resulted from reduced LH secretion due to hypophyseal down-regulation of GnRH receptors, the effect of human chorionic gonadotropin (hCG) treatment on the SPC of diestrous bitches was also investigated. In Experiment 1, 10 spontaneously cycling bitches served as controls, whereas estrus was induced with deslorelin implants in 24 others. In Experiment 2, six diestrous bitches were treated with a single dose of hCG between Days 39 and 45 of diestrus. The SPC was lower in deslorelin-induced bitches from Days 35 to 56 of diestrus and hCG increased SPC during the first 24 h after treatment, followed by a dramatic decline thereafter. Although SPC recovered in pregnant bitches, it remained much lower (< or = 1 ng/mL) than in untreated, non-pregnant bitches. The suppression of progesterone secretion after hCG treatment suggested that decreased luteal activity in deslorelin-induced bitches may not be a simple consequence of down-regulation of hypophyseal GnRH receptors.

The first reported case of equine nocardioform placentitis in South Africa.

Since the late 1980s a distinct form of focally-extensive mucoid to mucopurulent uterine body chronic placentitis,caused by nocardioform organisms, hasbeen recognised in horses in the USA state of Kentucky and possibly in other areas. This disease has led to increasing numbers of foal losses from late abortions, still-births, prematurity, or early neonatal deaths. The foals are usually not infected, but may be small or emaciated. Modes of infection and transmission are as yet unknown. Nocardia spp. and related nocardioform bacteria as causes of equine infertility, endometritis and foal death are briefly reviewed. A case of near full-term abortion involving a Friesian mare in the Pretoria district of Gauteng Province in South Africa during February 2000, with the same placental lesion as described in the Kentucky cases, is presented. Nocardioform organisms were visualised on impression smears and histological sections of affected foetal membranes, and were also cultured. The organism has been identified at the Livestock Disease Diagnostic Center of the University of Kentucky as an Amycolatopsis sp. of the less-commonly diagnosed group of nocardioforms causing placentitis in the USA. The organism was cultured from the uterus of the mare 18 days post-foaling, but after a 2-week course of oral trimethoprim and sulphamethoxazole, based on antibiogram sensitivity testing, a uterine flush yielded no growth. A semen sample from the sire of the aborted foal did not yield any Gram-positive filamentous branching bacteria. The mare subsequently conceived to a single insemination.

Rectal prolapse associated with a healed pelvic fracture in a pregnant free-ranging African black rhinoceros (Diceros bicornis). Part 1: anaesthesia.

Anaesthesia was required in a heavily-pregnant, adult, free-ranging African black rhinoceros Diceros bicornis with a rectal prolapse for examination and possible treatment. The animal was immobilised with 4.5 mg etorphine and 60 mg azaperone. For continued observation, the immobilised animal was transported to a boma. Additional etorphine and azaperone were administered to keep the animal anaesthetised during treatment and transport. In addition, 15 mg nalorphine was administered during this time to improve ventilation and reduce muscle rigidity. Sixty hours later, in preparation for surgery, 2.5 mg etorphine and 40 mg azaperone were administered, followed by endotracheal intubation and halothane anaesthesia. During anaesthesia, a decrease in tidal volume was observed. Venous blood-gas analysis indicated a decrease in the oxygen partial pressure, and a mixed respiratory and metabolic acidosis. Cardiac arrest was preceded by an increase in heart rate and tidal volume after 80 min of inhalation anaesthesia.

Rectal prolapse associated with a healed pelvic fracture in a pregnant free-ranging African black rhinoceros (Diceros bicornis). Part 2: surgery and necropsy.

The oedematous and traumatised protruding section of the rectal tissue of an adult free-ranging female African black rhinoceros (Diceros bicornis) was surgically amputated. Immediately before completion of surgery, the rhinoceros died of anaesthetic-related cardiac arrest. At necropsy a deformed pelvis and sacrum associated with a healed fracture of the left ileal wing were noted. New bone formation in and around the left ventral sacral foramina may have resulted in neuropathy of particularly the 3rd and 4th left ventral sacral nerves, which (in the horse) supply the majority of the nerve fibres innervating the caudal rectum and anus. The cause of the injury is not known, although back injuries, presumably sustained during mating by bulls, have been recorded in white rhinoceros. An encounter with elephants could also have been responsible for the injury in this case.

Could treatment of pregnant mares prevent abortions due to equine piroplasmosis?

Treatment of pregnant mares to prevent abortions due to equine piroplasmosis is a novel idea practised empirically at some Thoroughbred studs in South Africa. This paper presents the results of an investigation to ascertain whether imidocarb dipropionate crosses the equine placenta. Three pregnant mares were injected intramuscularly with imidocarb and their foetuses were mechanically aborted at varying time intervals thereafter. Imidocarb was found in foetal blood at a level similar to that in the dam's blood, suggesting that imidocarb administered to the dam would be available for anti-parasitic activity in the foetal circulation. Uncertainty concerning the time of treatment to achieve the desired effect currently makes this a questionable exercise.

Failure of luteolysis leads to prolonged gestation in a bitch: a case report.

A healthy, 5-yr-old rough collie bitch exhibited prolonged gestation, characterized by intrauterine fetal death and plasma progesterone concentrations (PPC) above 6 nmol/L/d until Day 65 or 66 of cytologic diestrus, which then only dropped following treatment with dinoprost tromethamine. The bitch showed no signs of parturition prior to laparotomy and hysterotomy on Day 63, which revealed 5 corpora lutea (CL) on the left ovary and 1 on the right ovary; 5 full-term, dead conceptuses without obvious autolysis but with 4 of the 5 placentas detached; and a tightly closed cervix. All conceptuses were in the left uterine horn. Treatment with dinoprost tromethamine was initiated 1 d after hysterotomy and was continued for IO d (120 microg/kg twice daily for a total dose of 240 microg kg/d). The discharge of lochia through the cervix and lactation started 3 d after the onset of treatment. Plasma progesterone concentration was 14.4, 16.2 and 1.6 nmol/L/d on the day of hysterotomy and at 1 and 3 d after the onset of prostaglandin therapy, respectively. The reason for the failure of luteolysis to occur is not known.

Semen quality after thawing: correlation with fertility and fresh semen quality in dogs.

Fifty-four semen samples from five dogs were evaluated both, fresh and after thawing. Some of these semen samples were mixed with autologous prostatic fluid after thawing and used to inseminate each of nine bitches 4-7 times intravaginally. All bitches conceived and the mean number (+/- SD) of conceptuses, number of corpora lutea and ratio between conceptuses and corpora lutea (implantation rate) were 5.7 +/- 2.8, 9.4 +/- 1.1 and 0.63 +/- 0.34, respectively. The mean incidence of normal sperm morphology and progressively motile spermatozoa for all semen samples were 71.5 +/- 13.5% and 74.4 +/- 7.1%, respectively, in fresh semen and 52.0 +/- 18.5% and 53.4 +/- 12.6% in frozen-thawed semen. Extension rate was 1:3 for all semen samples and the mean sperm concentration after thawing was 12.08 +/- 6.66 x 10(7) ml-1. The only semen quality variables after thawing that were correlated with implantation rate were the number of spermatozoa inseminated on day-2 and number of progressively motile spermatozoa inseminated on day-2 (where day 0 is the day of onset of dioestrus as determined by cytology) (Spearman's rank correlation coefficient > 0.7, n = 9, P < 0.05). This study suggests that it is essential that frozen-thawed semen is inseminated on day-2 and that an insemination dose of 10-11 x 10(7) progressively motile frozen-thawed spermatozoa is adequate to achieve a mean implantation rate of 75% or higher. The incidence of either proximal or distal cytoplasmic droplets in fresh semen was negatively correlated with motility after thawing in three of five dogs (Spearman's rank correlation < -0.5, n = 6-17, P < 0.05). Neither the percentage spermatozoa with normal morphology in fresh semen nor the percentage progressively motile spermatozoa in fresh semen nor the concentration of spermatozoa after thawing were correlated with motility after thawing. Fresh semen quality, with the exception of the incidence of retained cytoplasmic droplets, has little value in predicting the progressive motility after thawing in frozen dog semen.

Sexual and in-contact transmission of asinine strain of equine arteritis virus among donkeys.

Two in a group of five naturally seropositive donkey stallions were found to shed equine arteritis virus (EAV) in their semen as demonstrated by virus isolation. Direct intramuscular inoculation of sonicated semen from one virus-shedding stallion (S3) caused clinical disease in two donkeys from which virus was recovered and in which seroconversion was detected. Sexual transmission was confirmed in two mares mated to S3 when after a febrile response during which EAV was isolated from huffy coats and nasal and ocular exudates, both mares were found to have seroconverted. In-contact transmission in a susceptible stallion was demonstrated after its exposure to a sexually infected mare. The 3' end of the asinine virus was amplified directly from donkey semen with EAV-specific primers, and its nucleotide sequence was found to be homologous to that of the prototype Bucyrus virus isolated from horses. These results indicate that EAV and its disease transmission are analogous in donkeys and horses.

Success with intravaginal insemination of frozen-thawed dog semen--a retrospective study.

This retrospective study reports on the fertility of bitches (n = 40) that were inseminated into the fornix vaginae with frozen-thawed sperm from 9 sperm donors. In most bitches, the inseminations were repeated daily although, in 5 bitches, 1-2 d were skipped between some inseminations. All semen had been frozen by the same method and all prostatic fluid had been frozen at -18 degrees C prior to use. Sixteen Beagle bitches (Group 1) were inseminated with frozen-thawed semen to which 3-5 ml prostatic fluid had been added post-thaw. Ten German Shepherds and 4 other bitches of similar size (Group 2) were inseminated after adding 6-10 ml prostatic fluid to the frozen-thawed semen. Ten different German Shepherd bitches (Group 3) were inseminated without using prostatic fluid. The volumes of individual insemination doses were 3.5-6 ml, 7-12 ml and 1-3 ml for Groups 1, 2 and 3 respectively. The number of progressively motile sperm per insemination varied from 9 x 10(6) to 300 x 10(6). Sixteen of 16, 13 of 14 and 6 of 10 bitches conceived in Groups 1, 2 and 3 respectively. Mean litter sizes were 4; 5.6 and 4 in Groups 1, 2 and 3 respectively. The pregnancy rate of Groups 1 and 2 combined was higher than that of Group 3 (P < 0.01). The mean number of foetuses per bitch bred was 5.2 (SD 3.2) for Group 2, which was higher than the 2.4 (SD 2.8) of Group 3 (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of addition of autologous prostatic fluid on the fertility of frozen-thawed dog semen after intravaginal insemination.

Vaginal insemination of frozen-thawed dog semen usually gives a highly unpredictable fertility rate with poor pregnancy rates in most bitches. This study was designed to establish whether litter size, pregnancy rate and conception rate could be improved by the addition of autologous prostatic fluid to the frozen-thawed semen before insemination. Twenty German shepherd bitches that were free of any clinical reproductive abnormality or suspect breeding history were used. The bitches were stratified according to their ages and randomly assigned within strata to treatment (group T, n = 10) or control groups (group C, n = 10). All bitches were inseminated daily with frozen-thawed semen for the duration of that stage of vaginoscopic oestrus during which the vaginal folds were shrunken and angular. Bitches in group T were inseminated with semen to which 7-10 ml of frozen-thawed sperm-free autologous prostatic fluid has been added immediately before insemination. No prostatic fluid was added to the semen used to inseminate the bitches in group C. Each inseminate contained 100 x 10(6) progressively motile spermatozoa after thawing. Semen was deposited in the vaginal fornix using a disposable plastic bovine artificial insemination pipette. For groups T and C the mean number of conceptuses per cycle (litter size), the mean ratio of conceptuses to corpora lutea (conception rate), and the pregnancy rate were 5.2 +/- 3.01 and 2.4 +/- 2.84, 0.577 +/- 0.35 and 0.23 +/- 0.27, and 100% and 60%, respectively. The addition of autologous prostatic fluid to frozen-thawed canine spermatozoa significantly improved the litter size (P = 0.023), the conception rate (P = 0.0127) and pregnancy rate in bitches (P = 0.043).(ABSTRACT TRUNCATED AT 250 WORDS)

Encephalitozoon infection in a still-born foal.

A stud Clydesdale foal was still-born near full term. Macroscopic examination revealed a normal placenta, pulmonary atelectasis and faint white mottling of the kidneys. Microscopically there was severe lymphoplasmacytic interstitial nephritis. Numerous organisms resembling Encephalitozoon cuniculi were present in the affected kidneys. The organisms occurred in the areas of inflammation as well as in the renal glomeruli and intracellular cysts in the renal tubular epithelial cells and exhibited Gram positive staining. Ultrastructurally the organisms possessed a polar vacuole and a spiral filament typical of Microsporidia. The organisms were not detected in sections of the other organs examined.

Acrosomal damage and progressive motility of stallion semen forzen by two methods in 0.5-milliliter straws.

Post centrifugation and postthaw progressive motility and postthaw acrosomal damage were used to evaluate two different freezing methods (A and B) on 11 ejaculates of one stallion and 6 of another. In Method A, extended semen was centrifuged in 50-ml centrifugation tubes in which 0.25 ml hyperosmotic, glucose-based medium were layered in the apex of the tubes to serve as a cushion. Spermatozoa were resuspended in freezing medium, packaged in 0.5-ml PVC straws and frozen at -60 degrees C/min. Method B differed only in that the hyperosmotic cushion was omitted during centrifugation. Straws were thawed at 75 degrees C for 6 sec and then transferred into a waterbath at 37 degrees C. The postcentrifugation and postthaw progressive motility and postthaw acrosomal damage were similar for Methods A and B. Method B, however, was found to be technically easier to carry out. It also offers less chance of error or contamination because only two diluents are admixed to the semen as opposed to the three diluents used in Method A. Method B is regarded as more practical and thus preferable to Method A.

Fertility of stallion semen frozen in 0.5-ml straws.

Semen of 2 pony stallions was frozen by 2 methods in 0.5 ml PVC straws. The fertility of the frozen-thawed semen was evaluated by inseminating 60 mares during 69 oestrous cycles. An overall single cycle pregnancy rate of 55% was achieved. Freezing method, stallion, insemination during steroid-synchronized oestrus or insemination only every 2nd day during oestrus did not significantly influence pregnancy rates. Pregnancy rates were significantly improved from a mean 44% to a mean 73% when the mean number of progressively motile spermatozoa per insemination was increased from 175 x 10(6) to 249 x 10(6). It is concluded that the simpler freezing technique will yield satisfactory pregnancy rates when semen with a post-thaw progressive motility of 30% is used for AI. Starting when ovulation is anticipated to occur within the next 48 h mares should be inseminated every 2nd day with at least 220 x 10(6) progressively motile spermatozoa per insemination until ovulation is confirmed.