The influence of the obstetrical condition on canine neonatal pulmonary functional competence

Canine pulmonary clearance during feto-neonatal transition according to the type of delivery

The success of immediate adaptation to extrauterine life depends on appropriate lung function, however, elective cesarean section can increase the risk of respiratory distress as a result of reduced pulmonary fluid absorption. This study aimed to evaluate the influence of birth mode on pulmonary clearance and respiratory performance of canine neonates in the transition period. For this purpose, 37 neonates were selected according to the obstetric condition: Vaginal Eutocia (n = 17) and Elective C-section (n = 20). Neonates were evaluated for neonatal vitality score, as well as evaluation of heart and respiratory rates, body temperature and body weight, venous hemogasometric evaluation, blood lactate and glucose, pulse oximetry and radiographic evaluation during the first 24 h of life. Additionally, amniotic fluid electrolyte composition of each puppy was evaluated. There was no influence of the type of delivery on electrolyte composition of canine amniotic fluid and neonatal pulmonary liquid content, analyzed by thoracic X-Rays. On the other hand, elective cesarean section delayed pulmonary adaptation, resulting in hypoxemia and less efficient compensatory response to acid-base imbalance and thermoregulation. In conclusion, elective c-section does not delay pulmonary clearance, whilst alters pulmonary adaptation by less efficient gas exchange and lower oxygenation, hindering the compensatory response to acid-base imbalance during the fetal-neonatal transition in dogs.

Canine Amniotic Fluid at Birth Holds Information about Neonatal Antibody Titres against Core Vaccine Viruses

There is a growing interest in the composition of amniotic fluid (AF) in both humans and animals. In addition to its nutritional and protective functions for the foetus, current knowledge demonstrates that AF also serves advanced diagnostic, prognostic, and therapeutic roles. Newborn dogs have an underdeveloped immune system, making them highly susceptible to dangerous pathogens such as canine parvovirus (CPV-2), canine infectious hepatitis virus (CAdV-1), and canine distemper virus (CDV), thus exposing them to a high risk of mortality in the first weeks of life. Immunoglobulins G (IgGs) represent the only antibody isotype capable of crossing the placenta in a small amount and have been detected also in canine AF. The primary aim of this study was to investigate the reliability of AF collected at birth as a marker of passive immunity in canine species. For this purpose, total and specific IgGs against CPV-2, CAdV-1, and CDV were investigated and quantified in both maternal plasma and AF collected at the time of caesarean section. The vaccination status of the bitches was also taken into consideration. Since the immune system can be influenced by gestational age, with preterm infants having immature innate and adaptive immunity, IgG concentrations were correlated with amniotic lecithin, sphingomyelin, cortisol, surfactant protein A, and pentraxin 3 levels. In a previous study from our group on foetal maturity these molecules were measured in the same samples. Finally, correlations between their amniotic content and neonatal outcomes were investigated. This study demonstrates that AF analysis at birth can provide valuable insights into neonatal immunity in puppies, offering a non-invasive method to detect potential early health risks, for improved puppy care and management.

Maternal and neonatal cortisol and catecholamines throughout vaginal eutocia and C-section in dogs

Increased fetal cortisol is associated with catecholamine release, a primary factor for neonatal adaptive responses. However, relationship between canine peripartum cortisol and catecholamine is unknown. We aimed to compare serum adrenaline, noradrenaline and cortisol during peripartum in bitches and neonates of distinct obstetric conditions and to assess amniotic fluid cortisol concentration. Twenty females and maximum of three puppies per litter were allocated into Vaginal Eutocia (10 females; 17 neonates) and Elective C-section (10 females; 20 neonates) groups. Amniotic fluid was collected at delivery for cortisol concentration. Maternal and neonatal blood were collected prepartum, intrapartum, postpartum and 1h postpartum, and at birth, 30 and 60min, 12hs and 24hs, respectively, for cortisol, adrenaline and noradrenaline assessment. C-section determined higher noradrenaline throughout delivery and cortisol concentration from intrapartum through 1h postpartum, compared to vaginal birth. C-section maternal cortisol showed progressive increase from intrapartum onwards, while neonatal cortisol remained unchanged. No difference of maternal cortisol concentration occurred along whelping, whereas a significant decrease was verified for vaginal delivery puppies from birth until the 12hs. Puppies delivered vaginally had higher cortisol concentration at birth and 30min, compared to c-section puppies. There was a higher concentration of amniotic fluid cortisol in vaginal eutocia. In conclusion, c-section induces higher maternal stress during and after surgery, whilst vaginal delivery is a more neonatal physiologically stressful condition, contributing to better adaptation during transition.

Canine amniotic fluid at birth: From a discarded sample to a potential diagnostic of neonatal maturity

The definition of new reliable markers for neonatal maturity evaluation is crucial in canine clinical practice. Concerns about the safety of amniotic sampling in pregnant dogs have prevented its collection for diagnostic purposes. Moreover, amniotic fluid had been considered waste material until the latest studies reported amniocentesis as a reliable and safe procedure, even in the canine species. In our study, amniotic fluid (n = 63) collected at birth from ten dogs undergoing elective Caesarean sections at term was analysed to discover new potential indices of canine neonatal maturity. Based on gestational age, mothers and puppies were divided into two groups: the early group (≤65 days from luteinizing hormone (LH) surge, n = 5) and the late group (>65 days from LH surge, n = 5). Amniotic parameters of the lightest and heaviest puppy in individual/each litter, with a birth weight difference of at least 20% among littermates, were also compared. In particular, the content of lecithin, sphingomyelin, surfactant protein A (SP-A), cortisol, and pentraxin 3 (PTX3) in amniotic fluid, which is considered predictive of foetal development in humans, were investigated. Maternal serum SP-A and cortisol were also measured simultaneously. All amniotic parameters were detectable in canine amniotic fluid. Interestingly, the concentrations of different amniotic parameters correlated with each other. Lecithin was positively correlated with sphingomyelin (p < 0.0001), maternal SP-A (p < 0.0005), and the ratio of amniotic and maternal cortisol (p < 0.004). Amniotic SP-A was inversely correlated to maternal SP-A (p < 0.05), lecithin (p < 0.005), and lecithin-sphingomyelin ratio (p < 0.05). A positive correlation was also recorded between amniotic and maternal cortisol (p < 0.008). Considering that all puppies were born alive and mature, these data could provide a potential range of expected amniotic values in full-term new-born dogs. Furthermore, since gestational age was positively correlated with both maternal and amniotic cortisol (p < 0.0001) and amniotic PTX3 (p < 0.05), amniotic fluid seems to be an attractive, innovative, and minimally invasive matrix with potential diagnostic and prognostic utility for the investigation of canine maturity.

Effect of delivery management on first-week neonatal outcome: How to improve it in Great Danes

A different incidence of neonatal complications has been reported in several species according to the duration of the various labour stages and the type of delivery. Trauma associated with dystocia may result in the release of neonatal catecholamines and cortisol that negatively affect neonatal metabolism, thus survival. Aim of the present study was to assess how the first-week neonatal outcome is affected by a different management of parturition. Clinical records of 46 Great Dane litters from 8 different kennels were evaluated retrospectively. Data were grouped in 3 categories: vaginal delivery (VD), emergency C-section (ES), planned C-section (PS). The risk of stillbirth, early neonatal mortality and perinatal mortality was calculated at puppy and at litter level in each group. Data were statistically compared by the ANOVA and Chi-Square test (p < 0.05). Seventy-eight puppies were naturally delivered (VD), 120 experienced dystocia at birth that required emergency C-section (ES) and 105 came from planned C-section (PS). No statistical difference in neonatal bodyweight and litter size was observed among groups. In PS, both stillbirth and neonatal mortality resulted significantly lower than in VD and ES, resulting in the lowest observed perinatal mortality. The number of litters with stillbirth was significantly higher in ES than VD and PS. The number of litters with neonatal mortality resulted significantly lower in PS than VD and ES. The overall perinatal mortality in VD resulted statistically influenced from both stillbirth and neonatal mortality, while it resulted strongly affected by the high stillbirth in ES. No difference was observed for PS perinatal mortality. Present results, reporting a high incidence of dystocia as well as high perinatal and neonatal mortality, lead us to evaluate the opportunity to plan an elective C-section in Great Dane bitches, in order to minimize perinatal mortality.

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.

Elastographic and echotextural characteristics of foetal lungs and liver during the final 5 days of intrauterine development in dogs

Objective was to evaluate the echotexture and characteristics during terminal development of canine foetal respiratory and hepatic systems through elastographic examinations. Fifteen pregnant bitches were evaluated by ultrasonography twice daily, from the 53rd gestational day until whelping, and images obtained from 120 to 0 h before parturition were analysed. Images of foetal lungs and liver were recorded and then used for computer-assisted analyses to determine quantitative attributes. Acoustic Radiation Force Impulse (ARFI) elastographic of internal organs were classified as 'soft' (white areas) or 'hard' (dark areas) and quantitative analyses determined the mean shear wave velocities (SWV) of foetal lungs and liver. After delivery, canine neonates were clinically evaluated, and their health status was monitored weekly until 60 days post-partum. Sonographic parameters over time were compared by ANOVA and Pearson's correlations were used to determine associations between SWVs and echotextural variables. Foetal lungs and liver had a homogeneous echotexture and pulmonary parenchyma appeared hyperechoic when compared with that of the liver. Mean numerical pixel values (NPVs) of lungs decreased from 120 to 24 h and subsequently increased until parturition (P = 0.04). Lungs and liver mean (± SD) SWVs (0.98 ± 0.12 and 0.84 ± 0.11 m/s, respectively) didn't vary (P >  0.05) over time. Fluctuations in pulmonary NPVs indicated there was a pattern corresponding to structural and functional changes that occur during the terminal stage of pre-natal canine development and hence can be a useful diagnostic tool in veterinary. Foetal lung and liver SWVs were relatively consistent and there was no detectable changes during the pre-partum period for this variable or in echotexture.

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.

Estimation of fetal lung development using quantitative analysis of ultrasonographic images in normal canine pregnancy

We investigated the quantitative analysis of sonographic images to predict fetal lung maturity of the canine foetus in normal pregnancy. Twelve bitches were recruited in the present study. Serial ultrasonographic exams were performed at three pre-determined time periods corresponding to the pseudoglandular (40-48 days of pregnancy), canalicular (49-56 days of pregnancy) and saccular phase (57-63 days of pregnancy) of lung development. Mean grey level (MGL) and the standard deviation of the histogram (SDH) of fetal lung and liver sonographic images were measured with dedicated software. The lung-to-liver ratio (LLR) for both parameters was also calculated. Measurements were taken on the two caudal-most foetuses and then averaged. SDH did not show any statistically significant difference between the three time periods in the lungs or in the liver. MGL measured in the lungs significantly increased in the first period and reached a plateau during the last two periods. Liver echogenicity was constant during the first two periods and significantly increased during the last week of gestation. The LLR of MGL significantly decreased during the last week of pregnancy. The LLR was a very good test to detect fetal lung maturity (area under the receiver operator curve (AUROC) = 0.875); using a cut-off value of LLR < 1.541, sensitivity was 83.33% and specificity was 83.33%, positive likelihood ratio = 5. LLR of MGL is an accurate test to estimate lung development in normal canine pregnancies.