Effect of sodium cloprostenol and flunixin meglumine on luteolysis and the timing of birth in bitches

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.

Primary uterine inertia in four labrador bitches

Uterine inertia is a common cause of dystocia in the bitch and is designated as primary (i.e., uterine contractions fail to ever be initiated) or secondary (i.e., uterine contractions cease after a period of time but before labor is completed). The etiology of primary uterine inertia is not well understood. The accurate diagnosis of primary uterine inertia requires the use of tocodynamometry (uterine monitoring). Primary uterine inertia has been postulated to result from a failure of luteolysis resulting in persistently elevated progesterone concentrations. In this study, primary uterine inertia was diagnosed in a series of four bitches in which luteolysis was documented suggesting some other etiopathogenesis for primary uterine inertia.

Differentiation between pyometra and cystic endometrial hyperplasia/mucometra in bitches by prostaglandin F2alpha metabolite analysis

Bitches with pyometra are potential emergency cases which may be clinically difficult to differentiate from cases of cystic endometrial hyperplasia (CEH) in combination with mucometra. In the present study plasma prostaglandin F(2alpha), as measured by its main metabolite 15-keto-13,14-dihydro-PGF(2alpha) (PG-metabolite) concentrations, blood biochemical and hematological parameters were measured in 59 bitches with pyometra, 10 bitches with CEH and nine controls to determine if PG-metabolite could differentiate between the three uterine conditions. Bitches with pyometra had significantly higher plasma levels of PG-metabolite than bitches with CEH (P=0.002) and the controls (P=0.002). PG-metabolite analysis alone had a high sensitivity (98.3%) and a high specificity (80.0%) for the differentiation of pyometra versus CEH in bitches where fluid in the uterus was diagnosed. When a combination of PG-metabolite and percentage band neutrophils (PBN) was used for differentiation of the two diagnoses, a sensitivity of 100% and specificity of 90.0% was obtained. This means that the combination of PG-metabolite and PBN analysis allows for differentiation between cases of pyometra and CEH. If the PG-metabolite level in a bitch is >or=4,524 pmol l(-1), there is a 99% probability of the diagnosis pyometra versus CEH. Levels of PG-metabolite >or=3,054 pmol l(-1), >or=2,388 pmol l(-1) or>or=1,666 pmol l(-1) indicates a 95%, 90% or 80% probability of pyometra, respectively. At high PG-metabolite levels (above about 3,000 pmol l(-1)), PG-metabolite alone is enough for differentiation of pyometra versus CEH. The results of the present study showed that PG-metabolite analysis is valuable in the diagnosis and prediction of severity of uterine diseases.

Induction of parturition in the bitch with the progesterone-receptor blocker aglépristone

The triggering mechanism for parturition in the bitch remains unclear. Consequently, the development of drugs to successfully induce parturition in the dog has been difficult. The aim of this study was to evaluate the efficacy of the progesterone-receptor blocker aglépristone for the induction of parturition in beagle bitches. The course of parturition was therefore investigated in six parturitions induced by aglépristone and in six spontaneous parturitions. In addition, data were collected on pup survival and growth rates. Aglépristone was administered twice with a 9h interval on day 58 of pregnancy. If parturition did not proceed a standard intervention protocol was applied. Expulsion of the first pup occurred between 32 and 56 h after the first treatment with aglépristone, at which time the plasma progesterone concentration was still elevated. Accordingly, the gestation length of the bitches in the induced group (59.5+/-0.2 days) was significantly shorter than that of the spontaneously whelping bitches (62.2+/-0.5 days). The expulsion phase length, the inter-pup interval, the number of puppies born dead, and the number of clinical interventions needed during parturition did not significantly differ between the spontaneously whelping and the induced group. Pup survival and mean birth weights in the two groups did not differ significantly and aglépristone treatment had no significant influence on the growth rates. The results of this study show that aglépristone is an effective drug which can be used safely for the induction of parturition in the dog.

Investigations on the expression of cytokines in the canine corpus luteum in relation to dioestrus

Control of luteal regression in the dog is still poorly understood. Unlike other domestic animal species, luteolysis is not prevented by hysterectomy. Indications that PGF(2alpha) may act as an endogenous luteolytic agent have been found only in pregnant animals during the prepartal decline of progesterone. Evidence from several species indicates that the immune system plays an important role in corpus luteum (Cl) function, possibly by the release of cytokines from immigrant immune cells. Hence, in the present experiment we attempted to examine the expression of cytokines in the canine Cl during the course of dioestrus (formation and regression of the Cl), using RT-PCR. Groups of 4-5 bitches were ovario-hysterectomised on days 5, 15, 25, 35, 45 and 60-80 after ovulation. Canine-specific primers for IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, TNFalpha, IFNgamma and TGFbeta1 were used. Positive and negative controls were included in all tests. Adequate expression was confirmed by sequencing selective samples of positive PCR products. The expression of mRNA for IL-8, IL-10, IL-12, TNF-alpha and TGF-beta1 was detected in all samples at each stage of dioestrus, without any obvious variations indicating a likely modulatory function of these cytokines in differentiation, maintenance or regression of the canine Cl. All tests for the expression of mRNA for IL-4, IL-1beta and IL-2 were negative. More negative than positive results were obtained when testing for the expression of mRNA for IL-6 and IFN-gamma, leading to the conclusion that expression of these two cytokines is at a low level, and no conclusion can be drawn as to their involvement in control of Cl function.

Correlations among body temperature, plasma progesterone, cortisol and prostaglandin F2alpha of the periparturient bitch

The results of this study suggest that, besides the irrelevant role of body temperature measurement to predict the impending parturition in the bitch, progesterone and 15-ketodihydroprostaglandin F2alpha plasma level records could be more suitable to detect the approaching whelping in this species. More interesting was the statistically significant substantial increase in body temperature beginning 12 h after the onset of parturition. Therefore, if any significant increase in body temperature is recorded at the end of pregnancy without the beginning of the expulsion of fetuses, it could indicate problems at parturition. In this study, cortisol levels increased significantly at the time of delivery and remained high 12 h after the beginning of parturition, decreasing within 36 h after the onset of whelping. 15-ketodihydro-prostaglandin F2alpha levels increased significantly 24 h before parturition and again at the onset of whelping. Progesterone levels decreased significantly, starting 24 h before the onset of whelping and remained low after delivery.

The induction of parturition in the bitch using sodium cloprostenol

The objectives of this studies were to determine a continuous low-dose treatment regimen for the administration of sodium cloprostenol to the bitch that did not cause polydipsia, and whether this treatment would induce normal and timed parturition in bitches during late pregnancy. Non-pregnant greyhound bitches (n=18) received sodium cloprostenol subcutaneously, via a miniosmotic pump, at dose rates of 0.875 to 4.5 microg/kg/24 h, for 7 days (Days 0 to 7). Daily water intake was measured from Day -2 to Day 9. Polydipsia was observed in bitches treated with the higher dose rates but not in bitches treated with the lowest dose rate of 0.875 microg/kg/24 h. In the second experiment, pregnant greyhound bitches received sodium cloprostenol at dose rates of 1 (n=4), 2 (n=1) and 3 microg/kg/24 h (n=1), on Day 57 of pregnancy. Polydipsia was observed in bitches treated at the higher dose rates of 2 and 3 microg/kg/24 h, but not in the bitches treated at the lower dose rate of 1 microg/kg/24 h. These treatments resulted in the successful induction of parturition. Parturition was associated with a decrease in plasma progesterone concentrations, a reduction in body temperature, and an increase in plasma concentrations of 13,14-dihydro-15-keto prostaglandin F2alpha. The first puppy was born 37.7 +/- 2.9 h after the start of treatment (range 28 to 46 h). The duration of whelping was approximately 15.7 +/- 2.2 h (range 10 to 24 h). The litter size was 9.2 +/- 0.8 pups (range 6 to 12 pups), and the puppy survival rate was 6.0 +/- 0.8 per litter (range 4 to 9 pups). This study demonstrated that the administration of sodium cloprostenol in continuous low dose for 24 h is an effective treatment for the induction of parturition in bitches during late pregnancy. This treatment resulted in the birth of healthy pups, with minimal or no side effects to the bitch.