Canine-specific tail-in, head-out sperm agglutination.

An interesting pattern of tail-in, head-out sperm agglutination was identified in a Brucella canis seronegative subfertile dog. Centrifuged seminal plasma from this dog could induce a similar pattern of agglutination in six other dogs, but not in ejaculates from a single stallion and two rams. The agglutination pattern was short-lived and appeared to depend on motility of spermatozoa, although intensity of agglutination may have been affected by concentration of agglutinating factor.

Curtailing parturition observation and performing preparturient cesarean section in bitches.

Properly planned elective cesarean section (CS) in bitches is considered safe and justified for some breeds. Therefore, planning a scheduled (fixed date and time) preparturient CS in bitches belonging to a subpopulation where a CS is unavoidable, seems justified. The first day of cytological diestrus (D0) was used to predict the date of parturition. The aims of this study were to (1) compare the mortality of puppies delivered by preparturient CS to those delivered by parturient CS, (2) determine the extent to which a preparturient CS (performed at 08:00 on D57, while the cervix is closed) would shorten gestation, (3) compare the level of progesterone at the time of preparturient CS to that at the time of parturient CS, (4) compare the change in hematocrit before and after CS for parturient- and preparturient CSs. Out of 99 gestations for which D0 was known and a preparturient CS planned, the CS was performed at the scheduled time in 61%, before the scheduled time because cervical dilatation had started in 32% and before the scheduled time in 7% because the bitches had started showing signs of impending parturition, although their cervices were still closed. This study showed high neonatal survival ratios and good Apgar scores after preparturient CS with 99% of puppies delivered by preparturient CS born alive and 98.8% surviving to 2 h. Performing preparturient CSs shortened gestation by four to 52 h. Progesterone level was significantly higher at the time of preparturient CSs than at the time of parturient CSs. Further studies are required to determine whether preparturient CSs on D57 are routinely safe in all breeds, does not affect long term survival of the puppies and to timeously identify bitches in which parturition starts prior to the date and time for the scheduled elective preparturient CS.

Is the biparietal diameter of fetuses in late gestation too variable to predict readiness for cesarean section in dogs?

Correct assessment of readiness for cesarean section is essential for timing elective cesarean section during late pregnancy in the bitch. In humans, biparietal diameter is sufficiently precise and accurate and used in a clinical setting daily. The objectives of this study were to determine whether fetal biparietal diameter in late gestation in the dog could be used to predict readiness for cesarean section by having reached a minimum cut-off value and to correlate the biparietal diameter to birth weight. The biparietal diameter of 208 puppies in 34 litters from 31 English bulldog bitches and 660 puppies in 78 litters from 70 Boerboel bitches were measured immediately after delivery by cesarean section, performed at full term, using digital calipers. At the same time the birth weight of the same 208 English bulldog puppies and 494 of the same Boerboel puppies in 59 litters from 54 bitches was measured by means of an electronic scale. With a cesarean section, all the puppies in a litter are delivered simultaneously and readiness for cesarean section must be determined for a litter. The minimum, median and maximum biparietal diameter varied from 21.1 to 47.8, 32.9 to 50.0 and 34.2-58.2 mm, respectively, among English bulldog litters and from 18.4 to 48.7, 35.5 to 49.7 and 39.8-54.3 mm among Boerboel litters. This large variation suggests that biparietal diameter is too variable within and among litters to be useful as a means of determining readiness for cesarean section.

The precision of predicting the time of onset of parturition in the bitch using the level of progesterone in plasma during the preparturient period.

Precise prediction of the time of onset of parturition in the bitch is of clinical importance. Many parturition management cases in clinical practice are presented in the last two weeks of pregnancy without a reliable estimate of the parturition date. The aim of this study was to assess the value of a single progesterone level in the blood plasma from a preparturient bitch to predict the time of onset of parturition. The temporal relationship between the decrease in the plasma progesterone levels and the time of cervical dilatation (TCD)-which correlates to the onset of stage 1 of parturition-was evaluated in 25 bitches in the preparturient period. Among bitches destined to reach TCD within 12 h there is a 2% probability of having a plasma progesterone level of 15.8 nmoL/L or above and a 6% probability of having a level of 8.7 nmoL/L or above. Conversely, if the level is below 8.7 nmoL/L there is a 99% probability of reaching TCD within 48 h and if the level is below 3.18 nmoL/L there is a 100% probability of reaching TCD within 24 h. These results allow the veterinary obstetrician to make prompt decisions in the management of parturition.

Estimated impact of multiple conceptuses per follicle on fecundity in the bitch.

Multiple conceptuses from one follicle due to multi-ovular follicles or monozygotic twins inflate the ratio between the numbers of conceptuses and corpora lutea and possibly the effect ascribed to experimental treatment. The aim of this study was to estimate the impact of multiple conceptuses per follicle on fecundity in the bitch. The numbers of conceptuses and corpora lutea of 105 bitches originated from 7 published experimental studies and of 132 from ovariohysterectomies done in a private practice and a welfare organisation. Ninety five bitches, producing 597 conceptuses, had at least as many conceptuses as corpora lutea; 83 had as many, 10 had one more and 2 had 2 more. Bootstrap resampling on these 95 bitches let us to conclude that 12.6% of bitches are expected to produce more oocytes that are each capable of yielding a conceptus than the number of follicles that ovulate and that 2.35% of conceptuses are expected to be in excess of the number of follicles that ovulate. Applying the results of the current study to 2 earlier studies showed that multiple conceptuses from one follicle may, at maximum, have increased the effect ascribed to prostatic fluid by 0.022 and 0.024 conceptuses per corpus luteum, which is minor in relation to the magnitude of the ascribed effects of 0.34 and 0.22 conceptuses per corpus luteum. The number of conceptuses relative to the number of corpora lutea provides a valid and precise measurement of fertility in the bitch.

Puppy survival and vigor associated with the use of low dose medetomidine premedication, propofol induction and maintenance of anesthesia using sevoflurane gas-inhalation for cesarean section in the bitch.

The safety of an anesthetic protocol consisting of medetomidine hydrochloride (7 µg/kg iv) as premedicant, propofol, (1-2 mg/kg iv) as induction agent and sevoflurane, at 2% in oxygen for maintenance of anesthesia was studied in 292 cesarean sections (CSs) and 2232 puppies delivered. Medetomidine effects were reversed using atipamezole hydrochloride at 50 µg/puppy sc immediately following delivery and in the bitch iv immediately following surgery. The protocol's safety for puppies was expressed using survival immediately, 2 h and 7 d after delivery, and Apgar scores (measurement starting 15 min after delivery of the last puppy). The maternal survival rate was established immediately, 2 h and 7 d after cesarean section (CS). The CSs included 148 on Boerboel, 84 on English bulldog and 60 on other purebred bitches, which resulted in 1378, 541 and 313 puppies, respectively. Boerboel, English bulldog and other purebred bitches yielded 97.39%, 96.67% and 91.69% live puppies at delivery, 95.43%, 88.35% and 89.78% alive by 2 h and 89.19%, 79.11% and 84.03% alive by 7 d. Sixteen (1.16%), 32 (5.59%) and 4 (1.28%) malformed Boerboel, English bulldog and other purebred puppies were euthanized. Thirty five, 18 and 26, Boerboel, English bulldog and other purebred puppies were stillborn respectively, of which 12, 9 and 15, respectively had been discovered dead upon ultrasound examination immediately before CS. After correction for fetuses found dead on ultrasound examination and malformed euthanized puppies, 98.21%, 95.60% and 94.30% of Boerboel, English bulldog and other purebred puppies survived until 2 h and 91.78%, 87.17% and 88.26% until 7 d. Two-hour survival rates are negatively correlated to the proportion of puppies in a litter with scores of 8 or below (r = 0.14, P = 0.01, n = 292 litters) and tends to be positively correlated to the lowest Apgar score in a litter (r = 0.11, P = 0.05, n = 292 litters). This study shows that medetomidine hydrochloride in the protocol used is a safe premedicant in bitches prior to cesarean section and is associated with good puppy vigor as well as 2 h and 7 d puppy survival rates. The use of medetomidine as premedicant permitted use of less than half the dose of propofol usually required as induction agent.

The precision of peri-oestrous predictors of the date of onset of parturition in the bitch.

Precise prediction of the date of onset of parturition in the bitch is clinically important. The study compared the precision with which four peri-oestrous predictors predict the date of onset of parturition. The predictors evaluated in 24 bitches were: the date of the first or only day of the LH surge, the date on which the concentration of progesterone in the blood plasma first exceeded 6 nmol/L, the date on which the concentration of progesterone in the blood plasma first exceeded 16 nmol/L and the date of onset of cytological dioestrus. Among the 24 bitches, the date of onset of cytological dioestrus predicted the date of onset of parturition with greater precision than the other three predictors. Following the evaluation of another 218 intervals between the onset of cytological dioestrus and the date of onset of parturition, it was shown that the onset of cytological dioestrus predicted the date of onset parturition with a precision of ±1 d, ± 2 d and ±3 d in 88%, 99% and 100% of the 242 pregnancies. This study concludes that the first day of cytological dioestrus is a useful predictor of the date of onset of parturition.

Hematocrit changes in healthy periparturient bitches that underwent elective cesarean section.

Hematocrits were measured before each of 406 cesarean sections performed on 324 bitches at term and again after crystalloid fluid therapy administered at 35 mL/kg over 1½-2 hours starting from induction. The mean hematocrit was 44.2% (95% confidence interval [CI] 43.8%-44.6%) before cesarean section and 37.8% (95% CI 37.3%-38.2%) after cesarean section and fluid therapy, with a mean decrease of 6.4% points (95% CI 6.1%-6.7%) over all 406 cesarean sections. These results provide the clinician with clear guidelines of the normal expected ranges of hematocrits in bitches before and after cesarean section. Results of this study show that bitches have hematocrits at term that are at the lower end of the normal reference ranges for nonpregnant dogs and that there is no true anemia of pregnancy. It is therefore suggested that if late term bitches present with anemia, other causes besides pregnancy should be considered.

Efficacy of vaccination at 4 and 6 weeks in the control of canine parvovirus.

Seroconversion after early vaccination at four weeks against canine parvovirus (CPV) using a high antigen titre vaccine was evaluated in 121 puppies from three breeds of dogs housed in kennels representative of the private practitioner's environment. The trial included 52 German shepherd pups, 25 Rottweiler pups and 44 Boerboel pups. From each group 11, 4, and 18 puppies acted as control dogs, respectively. Depending on the different groups, puppies were vaccinated at 4, 6, 9 and 12 weeks. The experimental group differed from the control group in that they received the high titre vaccine at 4 weeks of age, whereas the control group was not vaccinated at 4 weeks. Blood was collected from all pups prior to vaccination to measure maternally derived colostral antibody. The results indicated that vaccination at 4 weeks of age in pups with high maternally derived antibody levels, results in seroconversion rates that may lead to a reduction in the window of susceptibility with respect to CPV infection. The implications of the findings with respect to dogs in heavily contaminated environments are discussed.

Surgical uterine drainage and lavage as treatment for canine pyometra.

Pyometra is a common post-oestral syndrome in bitches. Classical treatment consists of either ovariohystorectomy or medical intervention. Surgical uterine drainage and lavage via direct trans-cervical catheterisation using a 5% povidone-iodine in saline solution was performed successfully in 8 bitches with pyometra. All bitches conceived and whelped without complications subsequent to this treatment. It is concluded that this method offers an effective alternative treatment for canine pyometra with shorter recovery times as well as good clinical recovery and pregnancy rates in bitches destined for further breeding.

Luteal and follicular count in bitches: assessment by means of magnetic resonance imaging.

This study was done to determine whether preovulatory follicles or corpora lutea (physiological structures, PS) can be counted in the ovaries of bitches by means of magnetic resonance imaging (MRI). In Experiment 1, the ovaries from 15 German shepherd bitches (five in the follicular phase, one in the periovulatory period, five during the first 38 days of diestrus and four between Day 48 of diestrus and full-term gestation) were embedded in gelatin to form three phantoms with 10 ovaries each. Each phantom was exposed to MRI, using a 1mm slice thickness, a 1mm slice interval, a voxel size of 1mm cubic and a variety of pulse sequences, whereafter the ovaries were dissected and the numbers of follicles, corpora lutea and cysts counted. T2-weighted images were superior to T1-weighted images. Each of three operators counted the numbers of PS and cysts on T2-weighted images obtained in the coronal, transverse and sagital planes of each ovary, which, for the 30 ovaries, provided 270 operator by ovary by plane estimations and 90 operator by ovary estimations for each type of structure. Images of cysts were hyperintense, those of early corpora lutea and follicles similar and moderate and those of late corpora lutea hypo-intense and not clearly discernable from ovarian stroma. Estimations of PS were too low in 68%, correct in 12% and too high in 20% of estimations (n=270). Estimations of PS were correct in three operator by ovary combinations, out by 1 in 22 and out by more than 1 in 65. No operator estimated PS correctly in any bitch. In Experiment 2 MRI was done on three deeply sedated bitches in the periovulatory phase in an attempt to obtain images of the ovaries in order to count the follicles. The acquisition time of 5-7 min rendered images of poor quality from live bitches and none of their ovaries could be seen. MRI is not suitable for counting follicles or corpora lutea in the ovaries of bitches.

First isolation of Campylobacter jejuni from the vaginal discharge of three bitches after abortion in South Africa.

Campylobacter jejuni was isolated in pure culture from the vaginal discharge from three German Shepherd bitches after late-pregnancy abortions. The main clinical sign occurring in the bitches was a profuse and odourless haemorrhagic vaginal discharge.

Coccidial infection in German shepherd dog pups in a breeding unit.

A commercial dog breeding unit experienced problems with acute diarrhoea, often haemorrhagic, in young German Shepherd Dog litters. No aetiologic diagnosis had been made. In order to determine whether coccidial infections were implicated, a survey was conducted to ascertain shedding of oocysts by dams, acquisition of coccidial infection by neonatal pups and to determine whether bouts of diarrhoea were associated with peak oocyst production. Oocysts of Isospora canis and I. burrowsi/I. ohioenis were recovered from 26.0% of faecal specimens from bitches and from 51.7% of similar specimens from litters. No association between shedding of oocysts by bitches and their litters could be demonstrated, nor was there consistent association between bouts of diarrhoea and peaks of oocyst shedding.

Plastic explosive poisoning in dogs.

A dog suspected of having ingested minute quantities of plastic explosive type 4 (PE4 containing cyclonite) was presented with congested mucous membranes, a fever, an increased pulse rate, hyperventilation, hypersensitivity and mild convulsions. Experimental poisoning of a dog confirmed the neurotoxic properties of PE4 and proved to be fatal at 14 mg kg-1 within 18 h after ingestion. The clinical signs and post mortem findings closely resembled strychnine poisoning in dogs.