Prevalence of cesarean sections in swiss Bernese Mountain Dogs (2001-2020) and identification of risk factors

BACKGROUND

Dystocia is an important limiting factor in animal breeding due to its cost, stress for the mother and risk of death for the neonates. Assessment of incidence and characteristics of dystocia and the inherent risk of Cesarean section are of major importance. The aim of the present study was to evaluate the reproductive performance of Bernese Mountain Dogs in Switzerland, with a particular focus on the prevalence of Cesarean sections due to dystocia, and identification of possible risk factors.

RESULTS

The investigated population included 401 bitches, 207 sires, and 1127 litters. Litter size was significantly influenced by age and parity of the dam. Incidence of Cesarean section was 30.4%, with 2.0% of procedures being elective. History of previous Cesarean section, age of the dam, and a small litter size significantly influenced the risk for Cesarean section. The stillbirth rate was 12.0%, and the number of stillborn pups was significantly higher for litters delivered by Cesarean sections after birth of the first pup. The inbreeding coefficient had a low to non-significant impact on all reproductive parameters (e.g., litter size, number of stillborn pups).

CONCLUSION

The sample of Bernese Mountain Dogs of our study had an increased prevalence of Cesarean sections compared to the literature, and advanced age of the dam, litter size and prior Cesarean sections in the dam's reproductive history was identified as significantly influencing factors. In order to improve pups' survival rate, elective Cesarean section may be indicated in bitches that have had a previous Cesarean-section/s, are of advanced age, and/or have a small litter.

Risk factors for neonatal mortality prior to hospital discharge in brachycephalic and nonbrachycephalic dogs undergoing cesarean section

OBJECTIVES

To compare neonatal survival to discharge rates between brachycephalic and nonbrachycephalic dogs undergoing cesarean section (c-section) and identify risk factors for neonatal mortality.

STUDY DESIGN

Retrospective study.

ANIMALS OR SAMPLE POPULATION

A total of 480 puppies from 90 bitches undergoing 106 c-sections.

METHODS

Medical records of c-sections performed between January 2012 and September 2021 were reviewed. Data collected included brachycephalic versus nonbrachycephalic breed, elective versus emergency c-section, litter size (c-section and total [including those born prior to and via c-section]), and neonatal survival to discharge. A generalized linear mixed model (univariable and multivariable) was performed to evaluate variables versus neonatal survival.

RESULTS

Overall neonatal survival to discharge was 93.1% (447/480); survival was similar between brachycephalic and nonbrachycephalic breeds (p = .221, 202/213 [94.8%] brachycephalic survival, 245/267 [91.8%] nonbrachycephalic survival). Puppies delivered via elective c-section were more likely to survive compared to emergency c-section (p < .001, 238/240 [99.2%] elective survival, 209/240 [87.1%] emergency survival). Puppies delivered in larger c-section litters were more likely to survive (p < .004) compared to smaller litters. Total litter size had no effect on survival.

CONCLUSION

Brachycephalism had no effect on neonatal survival. Puppies delivered via elective c-section were more likely to survive compared to puppies delivered via emergency c-section.

CLINICAL SIGNIFICANCE

Outcomes following c-section are similar between brachycephalic and nonbrachycephalic breeds. While it is preferable to encourage selective breeding for bitches that are able to whelp naturally, elective c-section should be considered in bitches at high risk for dystocia to maximize neonatal survival.

Incidence and concomitant factors of cesarean sections in the bitch: A questionnaire study

Dystocia in the canine species is a common problem, and elective cesarean sections (C-sections) have become more frequent in breeds that are at risk. The aim of this study was to evaluate the incidence of C-section and contributing factors and to compare data on elective and emergency C-sections (e.g., regarding stillbirth). Using a questionnaire, a total of 423 bitches of 80 breeds and their 899 litters were included. The mean number of litters per bitch was 2.1 ± 1.1 litters. The overall rate of stillbirth was 6.7%. Of all litters, 194 were born via C-sections (21.6%), of which 35 were declared as elective and 159 as emergency due to dystocia. Significantly more C-sections were performed in either small litters (1-2 pups) or large litters (&gt;12 pups) (p &lt; 0.001). Bitches that have had prior C-sections had a 4-fold increase in the risk of successive C-sections (RR = 4.54 (95%CI 2.56–7.70; p &lt; 0.001). Furthermore, primiparous bitches of advanced age had a significantly higher incidence of emergency C-sections (p = 0.004). Stillbirth was significantly higher in emergency C-sections compared with that in elective C-sections (p = 0.003). Also, timing of intervention had a significant impact on stillbirth in emergency C-sections (p = 0.025). Within a breed-specific evaluation, significant differences were observed between breeds regarding incidence of C-section and stillbirth. Lesser-known breeds were represented in the population, and the results showed that the Norwich Terrier had the highest (51.6%) and the Gordon Setter had the lowest (4.8%) incidence of C-section (p &lt; 0.001). The inclusion and evaluation of lesser-known breeds regarding incidence of C-section is of importance as it shows that certain breeds without phenotypical traits such as brachycephaly may also have an increased incidence of emergency C-section and stillbirth. We further conclude that more importance may be given to the age at first parturition concerning the occurrence of dystocia and the decision making regarding possible elective C-sections.

Domestication of the Emblematic White Cheese-Making Fungus Penicillium camemberti and Its Diversification into Two Varieties

Domestication involves recent adaptation under strong human selection and rapid diversification and therefore constitutes a good model for studies of these processes. We studied the domestication of the emblematic white mold Penicillium camemberti, used for the maturation of soft cheeses, such as Camembert and Brie, about which surprisingly little was known, despite its economic and cultural importance. Whole-genome-based analyses of genetic relationships and diversity revealed that an ancient domestication event led to the emergence of the gray-green P. biforme mold used in cheese making, by divergence from the blue-green wild P. fuscoglaucum fungus. Another much more recent domestication event led to the generation of the P. camemberti clonal lineage as a sister group to P. biforme. Penicillium biforme displayed signs of phenotypic adaptation to cheese making relative to P. fuscoglaucum, in terms of whiter color, faster growth on cheese medium under cave conditions, lower amounts of toxin production, and greater ability to prevent the growth of other fungi. The P. camemberti lineage displayed even stronger signs of domestication for all these phenotypic features. We also identified two differentiated P. camemberti varieties, apparently associated with different kinds of cheeses and with contrasted phenotypic features in terms of color, growth, toxin production, and competitive ability. We have thus identified footprints of domestication in these fungi, with genetic differentiation between cheese and wild populations, bottlenecks, and specific phenotypic traits beneficial for cheese making. This study has not only fundamental implications for our understanding of domestication but can also have important effects on cheese making.

Dystocia after Unwanted Mating as One of the Risk Factors in Non-Spayed Bitches-A Retrospective Study

Simple Summary

This is an article presenting the clinical data on the incidence of difficult labour in dogs being mated without owners’ intentions (accidental mating, unplanned breeding). Despite the widespread availability of spaying and its safety, unplanned and unwanted pregnancies in dogs are still a frequent concern. Unfortunately, in 8.3% (76/914) of cases, they result in difficult labour and deadly complications for the dam and her litter. Better owners’ education about the importance of neutering their pets and understanding of the benefits of early spaying by animal shelter managements and by breeders selling pets might improve the situation in the future. On the other hand, in such cases, it seems to be justified to advise the termination of pregnancy through spaying or the use of abortifacient drugs, despite the ethical concerns, because waiting for natural delivery could cause unnecessary suffering both to the bitch and her unborn puppies.

Abstract

This article presents a retrospective study on dystocia cases in bitches that were unintentionally mated and carried an unwanted pregnancy in the last 39 years. The evaluated medical records include 76 cases of difficult labour, which is 8.3% of 914 dystocia cases recorded during the period. Of these bitches, 38.2% (29/76) were 8 years, and 18.4% (14/76) were younger than 12 months. In 67/76 cases (88.2%), conservative (pharmacological and manual) obstetrical assistance proved to be unsuccessful, and caesarian section (CS) had to be performed, in contrast to the remaining recorded cases of dystocia (in which the pregnancy was intended and expected) when CS was performed significantly less often, in 71.5% (599/838) of cases. In unplanned pregnancies, 46.6% (110/236) of delivered pups were dead compared to only 26.4% (864/3273) dead pups in planned pregnancies. p value < 0.05 was considered significant. Despite the widespread availability of the spaying procedure nowadays and its safety, unplanned and unwanted pregnancies in dogs are still a concern in clinical practice. However, throughout the years investigated here, we observed an apparent decrease in the occurrence of dystocia after unintended mating, with much less recorded cases from year 2004 (71 vs. 5). Most probably, this is due to the increasing popularity of surgical castration in both females and males, and rising societal awareness of its importance, giving hope that some improvement in the welfare of dogs has already been achieved.

Towards scheduled pre-parturient caesarean sections in bitches

Elective caesarean section (CS) is the safest means of delivering the litter in bitches in specific situations. Timeously performing elective pre-parturient CSs at a fixed time would be convenient and prevent emergency CSs and foetal demise. This review proposes a method of performing elective pre-parturient CSs which is safe for both the bitch and puppies. Brachycephaly, small litters and large litters, preceding litter delivered by CS and trial of labour after a preceding CS are identified as factors increasing the need for CS whereas emergency CS is identified as factor increasing foetal demise. The first day of cytological dioestrus more precisely predicts the day of onset of spontaneous parturition than the first day of the LH surge or the dates during oestrus on which progesterone (P4) first exceeds 6 nM or 16 nM. Foetal biparietal diameter at the time of onset of spontaneous parturition varies too much to accurately predict readiness for CS. During the last few days of gestation, P4 with cut-off concentrations at 15.8, 8.7 and 3.18 nM, but not plasma cortisol concentrations, hold promise as predictors of onset of parturition and when to perform pre-parturient CSs. A protocol associating medetomidine hydrochloride as premedicant with propofol as induction agent and sevoflurane as maintenance is safe for scheduled CS and yields good maternal and puppy survival rates at delivery, 2 hr and 7 days after CSs. Clinicians have to pay attention to the haematocrit of bitches at the time of cervical dilatation which is at the lower end of the normal reference ranges for non-pregnant dogs and to the decline in haematocrit during CS (as a proxy for blood loss) which is approximately 7% for both parturient (open cervix) and pre-parturient (closed cervix) CSs. Pre-parturient CSs can be scheduled and performed 57 days after onset of cytological dioestrus with puppy survival rates of 99%. Collectively, these studies provide a protocol to safely perform elective CSs in a large proportion of the obstetric population at a convenient time of the day but more research is required with larger numbers to establish whether this practice is routinely safe and safe in all breeds.

Congenital lung displacement in an English bulldog puppy

The English bulldog is notoriously predisposed to a number of disease conditions, including congenital defects, likely due to extreme genetic selection which has reduced genetic variability within this breed. The present report describes, for the first time, the main clinical and pathological features of congenital lung displacement in an English bulldog puppy. The defect involved the entire left lung, which was normally developed but rotated and shifted to the right hemithorax. The pathogenesis of congenital anomalies is largely unknown. characterisation of the genetic bases of these malformations is crucial for a reform of the breeding selection which is also aimed at correcting phenotypic abnormalities with a strong impact on individual health.

Factors influencing English Bulldog bitch fertility after surgical uterine deposition of fresh semen

The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P₄) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500 × 10⁶) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (P < 0.05) in bitches with >23 kg than bitches with <23 kg (83.9 vs 63.8%). Whelping rate was greater (P < 0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (P < 0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4 mL or >4 mL of semen). Litter size was larger (P < 0.05) in bitches >23 kg than lighter animals (3.72 ± 1.79 and 2.30 ± 1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P₄ concentration and infusion of oxytocin in the uterus at AI (P > 0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4 mL semen volume maximize whelping rates in this breed of dogs.

Canine dystocia in 50 UK first-opinion emergency care veterinary practices: clinical management and outcomes

Canine dystocia is a relatively common veterinary presentation. First opinion emergency care clinical data from 50 Vets Now clinics across the UK were used to explore dystocia management and outcomes in bitches. Caesarean section (CS) was performed on 341/701 (48.6 per cent (95 per cent CI 44.9 to 52.4)) of dystocia cases. The bulldog (OR 7.60, 95 per cent CI 1.51 to 38.26, P=0.014), Border terrier (OR 4.89, 95 per cent CI 0.92 to 25.97, P=0.063) and golden retriever (OR 4.07, 95 per cent CI 0.97 to 17.07, P=0.055) had the highest odds of CS among dystocic bitches compared with crossbreds. Brachycephalic dystocic bitches had 1.54 (95 per cent CI 1.05 to 2.28, P=0.028) times the odds of CS compared with non-brachycephalics. Oxytocin was administered to 380/701 (54.2 per cent) and calcium gluconate was administered to 82/701 (11.7 per cent) of dystocic bitches. 12 of 701 dystocia cases (1.7 per cent) died during emergency care. These results can help veterinary surgeons to provide better evidence on the risks to owners who may be contemplating breeding from their bitches. In addition, the results on the management and clinical trajectory of dystocia can facilitate clinical benchmarking and encourage clinical audit within primary care veterinary practice.

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.

Comparison of 3 anesthetic protocols for the elective cesarean-section in the dog: Effects on the bitch and the newborn puppies

This study assessed the influence of 3 different anesthetic protocols based on the quality of anesthesia induction and maintenance in four dog breeds (French Bulldog, n = 13; Yorkshire terrier, n = 12; Chihuahua, n = 10; Bull Terrier, n = 10) subjected to cesarean section. Neonatal mortality, birth defects and newborn viability were assessed. All females were pre-medicated with morphine (IM), and then were assigned to three different anesthetic protocols: group P (n = 17), anesthesia was induced with propofol (IV) and then also maintained with propofol until the complete delivery of puppies and then anesthesia was maintained afterwards with sevoflurane; group PS (n = 14), anesthesia was induced with IV propofol, and maintenance of the anesthesic plan was performed with sevoflurane; group PES (n = 14) the females were induced by propofol and an epidural anesthesia was then performed, anesthesia was then maintained with propofol until the complete extraction of all puppies and then anesthesia was maintained afterwards with sevoflurane. Throughout the surgery, group PES required a lower concentration of sevoflurane (p < 0.05), and extra doses of propofol or fentanyl during inhalatory anesthesia were not required. Mean values of heart rate (p < 0.01) were higher in females from groups P and PS. Mean values of blood pressure values were lower (p < 0.01) in group PES as compared with the other two groups. Birth defects were detected in 3.1% (5/162) of the neonates, with a significantly higher incidence (p < 0.05) in French bulldog puppies. Neonatal viability was assessed using a modified Apgar score model; Apgar score was defined immediately after delivery (Apgar0) and a second score was assessed 60 min after delivery (Apgar60). Apgar0 scores were significantly different between the groups, showing neonates of group PES the highest values (p < 0.05). In Apgar60, more than 94% of puppies were already classified as normal viability neonates (7-10 score) and no differences were observed between groups. This study confirmed that females of group PES showed a higher quality of anesthesia during surgery and a vitality of puppies immediately after delivery. Regardless of the anesthetic protocol used, French bulldog females and puppies required more clinical care than other breeds.

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.

Cortisol fetal fluid concentrations in term pregnancy of small-sized purebred dogs and its preliminary relation to first 24 hours survival of newborns

Along the perinatal period, in mammals, cortisol (C) plays a pivotal role in the final intrauterine fetal maturation and in the early neonatal adaptation. Because of the scarce knowledge about canine perinatology, the present study was aimed to assess the C concentrations in amniotic and allantoic fluids collected, without invasiveness, from small-sized, purebred newborn puppies born by elective cesarean section, at term of pregnancy. Possible correlations between fetal fluid C concentrations and maternal parity, litter size, birth weight, Apgar score, were evaluated. In addition, the possible effect of fetal fluid C concentrations on newborn survival at 24 hours of age, and the effect of the litter or the newborn gender on fetal fluid C concentrations were also assessed. The results, obtained from 50 born alive, normal-weight puppies, without gross physical malformation, showed that C concentration was higher in allantoic than in amniotic fluid (P < 0.01), even if a strong positive correlation between the two fluids C concentration was found (P < 0.0001; R = 0.83). Neither amniotic nor allantoic C concentrations were correlated to maternal parity, litter size, birth weight, and Apgar score. Interestingly, higher amniotic (P < 0.05), but not allantoic, C concentrations were found in puppies not surviving at 24 hours after birth. Therefore, it could be suggested that this parameter may be useful for the recognition, at birth, of puppies needing special surveillance during the first day of age. A significant (P < 0.001) effect of the litter in both amniotic and allantoic C concentrations was found. In conclusion, the present results showed that in small-sized purebred puppies, born at term by elective cesarean section, the exact fetal, maternal, or placental source contributing to fetal fluid C concentrations remains to be clarified. From a clinical perspective, however, the evaluation of amniotic C concentration at birth seems useful for the detection of puppies that need special surveillance during the first 24 hours of age, and should be coupled to the early newborn evaluation by Apgar score. However, the small total number of newborns, and especially of the dead puppies enrolled in the present study, suggests that further, more-focused investigations on a large number of subjects are needed before the method could be considered for application in the clinical practices.

The challenges of pedigree dog health: approaches to combating inherited disease

The issue of inherited disorders and poor health in pedigree dogs has been widely discussed in recent years. With the advent of genome-wide sequencing technologies and the increasing development of new diagnostic DNA disease tests, the full extent and prevalence of inherited disorders in pedigree dogs is now being realized. In this review we discuss the challenges facing pedigree dog breeds: the common pitfalls and problems associated with combating single gene mediated disorders, phenotypic selection on complex disorders, and ways of managing genetic diversity. Breeding strategies incorporating screening schemes have been shown to be successful in significantly reducing the prevalence of an inherited disorder and improving the overall health in certain breeds. However, with 215 breeds officially recognized by the Kennel Club in the United Kingdom and 396 inherited disorders currently identified, many breeds have reached the point at which successfully breeding away from susceptible individuals at a population-wide scale will require new genomic selection strategies in combination with currently available breeding schemes. Whilst DNA-based tests identifying disease causing mutation(s) remain the most informative and effective approach for single gene disorder disease management, they must be used along with current screening schemes, genomic selection, and pedigree information in breeding programs in the effort to maintain genetic diversity while also significantly reducing the number of inherited disorders in pedigree dogs.

Neonatal viability evaluation by Apgar score in puppies delivered by cesarean section in two brachycephalic breeds (English and French bulldog)

This study tried to define neonatal viability after cesarean section in brachycephalic breeds and the efficacy of an adapted Apgar test to assess newborn survival. Data from 44 cesarean sections and 302 puppies were included. Before surgery (59-61 days after ovulation), an ultrasound evaluation defined the fetal biparietal diameter (BPD). Immediately after the uterine delivery, the pups were evaluated to detect birth defects and then, a modified Apgar score (range: 0-10) was used to define neonatal health at 5min (Apgar 1) and 60min (Apgar 2) after neonatal delivery; puppies were classified into three categories: critical neonates (score: 0-3), moderate viability neonates (score: 4-6) and normal viability neonates (score: 7-10). Mean (±SEM) value of BPD was 30.8±0.1mm and 28.9±0.1mm in English and French Bull-Dog fetus, respectively. The incidence of spontaneous neonatal mortality (4.98%, 14/281) and birth defects (6.95%) were not influenced by the sex; however, congenital anomalies and neonatal mortality were higher (p<0.01) in those litters with a greater number of neonates. In Apgar 1, the percentage of critical neonates, moderate viability neonates and normal viability neonates were 20.5%, 46.3% and 33.1% respectively; sixty minutes after birth, the critical neonates only represented 10.3% of the total puppies. Almost all neonates (238/239) showing moderate or normal viability at Apgar 1, survived for the first 24h after birth. The results of the study showed a direct relationship (p<0.01) between the Apgar score and neonatal viability. Therefore, the routine performance of the Apgar score would appear to be essential in the assessment of the status of brachycephalic breed puppies.