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

Evidence-based practice in canine artificial insemination

A number of methods are currently used to predict the optimal date of insemination of the breeding bitch, particularly with the use of frozen-thawed canine semen which has a far shorter lifespan than fresh semen. Aside from confirming cytological oestrus, vaginal cytology is of no assistance in predicting the most fertile day(s) in a bitch; however, a neglected avenue of research suggests that vaginal cytology may be of great importance in confirming the days of optimal fertility retrospectively. Similarly, vaginoscopy provides clues as to the stage of a bitch's cycle but is inadequate as a sole determinant of her most fertile days. Nevertheless, vaginoscopy is useful to identify very late oestrus and the onset of dioestrus, as well as Stage I of labour (cervical dilatation). Due to variations in the rate at which circulating progesterone concentrations rise in individual bitches, the reliability of circulating progesterone concentrations for determining the optimal day(s) of insemination with frozen-thawed semen decreases as values rise. Moreover, progesterone assay results can vary widely due to extrinsic factors such as the time of blood sampling, sample storage conditions and the assay employed. Finally, this review investigates evidence surrounding various insemination routes and suggests that well-performed vaginal insemination, even with frozen-thawed semen, may be an acceptable approach for cases where transcervical insemination is impractical.

Assessment of Vcheck® analyzer for rapid progesterone concentration measurement including recommendations for achieving the optimal breeding time in bitches

Background and Aim

Serum progesterone concentration plays critical role in determining the optimal breeding time in bitches and diagnosing reproductive-related issues. This study aimed to conduct a comparative analysis of serum progesterone results obtained from commercial point-of-care immunological analyzers, namely, Vcheck®, with those obtained using chemiluminescent microparticle immunoassay (CMIA). Our overarching goal was to evaluate these analyzers' accuracy and establish standardized guidelines for optimal breeding timing.

Materials and Methods

Ninety-four serum samples from bitches were analyzed using the Vcheck® analyzer and compared with CMIA. Thorough documentation included the mean, standard deviation, 95% confidence interval (CI), and minimum and maximum values of serum progesterone concentrations. Furthermore, Pearson's correlation coefficient, Lin's concordance correlation coefficient, and the bias correction factor were meticulously recorded.

Results

The mean progesterone concentration measured using the Vcheck® analyzer was significantly lower than that measured using CMIA, with a mean difference of 1.26 ng/mL of serum. The Bias correction factor was 0.935, which was nearly 1.00, indicating that the line of best-fit was on the perfect line of agreement, providing insight into the measurement accuracy. Pearson's correlation coefficient, a measure of precision, was also close to 1 (0.939), confirming the reliability of the data. Furthermore, Lin's concordance correlation coefficient was 0.877, indicating a fair overall agreement between the Vcheck® and CMIA methods. These results support the validity of the Vcheck® analyzer's results. The present study was developed by aligning with established CMIA guidelines and adapting them using the range and 95% CI derived from each set of results, ensuring a standardized and rigorous approach.

Conclusion

The Vcheck® analyzer provides a rapid assessment of serum progesterone concentration in bitches, with results comparable to those measured using the CMIA technique. However, when considering the use of the Vcheck® analyzer, it is recommended that the results should be interpreted carefully and the interpretation guidelines should be followed. In conclusion, Vcheck® provides a reliable and convenient method for veterinarian practitioners to measure canine progesterone levels in a clinical/hospital setting.

[Induction and endocrine control of parturition in domestic mammals - Part 2 - Species-specific aspects and their relevance to the applicability of birth induction procedures]

The endocrine regulation of birth is based on an intensive exchange of signals between fetus, placenta and mother. Apart from sheep, our knowledge of the underlying processes is still very incomplete. However, current observations suggest substantial species differences. Of critical importance for the onset of the final steps of the signaling cascade leading to active labor is "prepartum progesterone withdrawal," which is based on luteolysis (e. g., cattle, goat, buffalo, camelids, pig) or a breakdown in placental progestogen production (sheep, horse), depending on the relevant progestogen source in late pregnancy. Knowledge of birth-associated regulatory processes allows species-specific regulatory mechanisms to be mimicked for drug-based induction of labor. Furthermore, species-independent mechanisms such as the inhibition of progesterone receptors are available. In addition to efficacy, other aspects such as tolerability for dams and offspring as well as drug regulations must be taken into account when selecting active ingredients under practical conditions.

Aldosterone-progesterone relationship in sexually intact Chihuahua bitches

BACKGROUND

Aldosterone represents an important target of heart failure therapy and may be a valuable indicator of the renin-angiotensin-aldosterone system activity. However, its assessment might be challenging because of the effect of individual factors. In a recent study, intact female dogs showed the highest value of urinary aldosterone-to-creatinine ratio (UAldo:C) compared to other sex categories. In humans and rodents, an influence of progesterone has been reported by several studies. To our knowledge, the relationship between aldosterone and progesterone has not yet been investigated in dogs. The aim of this prospective study was to investigate this relationship in sexually intact Chihuahua females, measuring both hormones twice in the same bitch, that is in anoestrus when progesterone concentrations are baseline and in dioestrus when they are high.

RESULTS

The study population consisted of 14 sexually intact Chihuahua bitches. Serum progesterone (34.06 (21.17-44.90) vs. 0.19 [0.13-0.38] ng/ml; P < 0.001) and urinary aldosterone (9886.98 ± 5735.22 vs. 5005.72 ± 2127.73 pg/ml; P = 0.01) were significantly higher in dioestrus compared to anoestrous. Urinary aldosterone-to-creatinine ratio was higher in dioestrus compared to anoestrus (4.16 [3.17-6.80] vs. 3.39 ± 1.64 µg/g), but it did not reach the statistical significance (P = 0.056). Serum progesterone showed a moderate positive correlation with urinary aldosterone (ρ = 0.638, P < 0.001) and UAldo:C (ρ = 0.516, P = 0.005).

CONCLUSIONS

The results of the present study suggest the existence of a progesterone-aldosterone relationship in canine species, indicating that sex and phase of reproductive cycle should be taken into account when interpreting aldosterone concentrations. Further studies are needed to confirm these results on a larger canine population and to identify the underlying mechanisms in this species.

Clinical use of the canine foetal kidney formula in dogs of different maternal sizes during the last ten days before parturition

Data concerning the use of the canine foetal kidney length (L) formula in the prediction of parturition timing are still lacking. In our study, we aimed to evaluate the accuracy of the L formula in predicting the parturition date during the last 10 days of pregnancy. Twenty-five clinically healthy pregnant bitches, aged 2-9 years and weighing 3.5-52.2 kg, were ultrasonographically monitored from -11 to 0 days before parturition (dbp). Kidney L was measured for the three most caudal foetuses, and the parturition day was estimated using the kidney formula, whose accuracy was calculated as the percentage of cases estimated (ranges of ± 1 or ± 2 days) on the actual parturition date. A K-proportions test was performed to identify differences in the accuracy among maternal sizes and the sex ratio of pups, and a two-proportions z-test was performed to identify differences between litter size classes (≤ 7 vs. > 7 pups) and time ranges (-11/-5 and -4/0 dbp). An accuracy of 35% within ± 2 days was found in the range of -11/-5 dbp and an accuracy of 30% within ± 2 days was found in the range of -4/0 dbp. The accuracy differed between small (53% ±1 day and 60% ±2 days) and large (10% within ± 1 and ± 2 days) bitches (P = 0.019 within ± 1 day, and P = 0.007 within ± 2 days). For small litter sizes, the accuracy was 38% within ± 1 day and 44% within ± 2 days, and for large litter sizes, it was 14% within ± 1 and ± 2 days. A threshold value was found between litter size classes within ± 2 days. The use of the L formula during the last ten days of pregnancy did not seem to warrant good accuracy in the prediction of parturition date. Further studies on different maternal sizes should be performed.

Use of a Point-of-Care Progesterone Assay to Predict Onset of Parturition in the Bitch

An assay of circulating progesterone (P4) is commonly used to estimate progress through late gestation in the bitch. Point-of-care assays provide rapid results, a major advantage over laboratory-based assays. This study aims to compare P4 levels determined by the Catalyst® Progesterone point-of-care assay with those determined by chemiluminescent immunoassay (CLIA) and to identify the expected distribution of Catalyst P4 levels at time intervals 3 days prior to the onset of parturition in pregnant bitches. Twenty-eight pregnant bitches carrying two or more fetuses were admitted to a specialist veterinary reproduction hospital 53 days after the onset of cytological diestrus or, when that date was not known, 57 days after the last mating. Vaginal speculum examinations were performed every 6 h until the onset of cervical dilatation (TCD). Serum samples were collected twice daily (08h00 and 18h00) until TCD. For most samples, fresh serum was assayed for P4 immediately using the Catalyst assay (CatP4), then frozen until assayed by CLIA (IMMULITE 2000; ImmP4). However, for some samples, CatP4 was not analyzed prior to freezing. For these data points (n = 33), CatP4 for fresh serum was estimated from CatP4 assayed on frozen-thawed serum, based on a comparison between CatP4 on fresh vs. frozen-thawed sera. In comparison to ImmP4, CatP4 levels up to and including 7 nmol/L appear to have a constant bias of −1.69 nmol/L (limits of agreement −4.91 to 1.52), while levels &gt;7 nmol/L appear to have a proportional bias of −17.9% (limits of agreement −68.6% to 32.7%). Bootstrapped percentiles of CatP4 results spanned 0.4–9 nmol/L within 12 h of TCD, 0.9–11 nmol/L 12–24 h from TCD, and 2.2–13.5 nmol/L 24–36 h from TCD. A CatP4 &gt;9 nmol/L indicates a bitch that is unlikely to reach TCD within 12 h. Bitches with CatP4s below 3.5 nmol/L are likely to reach TCD within 36 h and bitches with a CatP4 below 2.2 nmol/L are likely to reach TCD within 24 h. In conclusion, the Catalyst Progesterone assay provides rapid assessment of circulating P4 in the bitch, with clinical application in the monitoring of late term pregnant bitches.

The use of serum progesterone and prostaglandin F2α metabolite levels to predict onset of parturition in the bitch

The prediction of time to onset of parturition in a preparturient bitch is of great clinical value, particularly for bitches at high risk of dystocia and those lacking relevant clinical data from the time of breeding. In a previous study, four cut-offs for plasma progesterone levels, measured by radioimmunoassay, were shown to be useful for predicting the likelihood of a bitch entering stage one of parturition within defined time intervals. The first aim of the current study was to evaluate these cut-offs in a clinical setting, using serum progesterone samples drawn from preparturient bitches 12-hourly instead of 6-hourly and assessed using chemiluminescence immunoassay. Furthermore, the use of 13,14-dihydro-15-keto-prostaglandin F_2α, (PGFM), a metabolite of prostaglandin F_2α , in predicting the time to onset of parturition was evaluated. Forty bitches carrying two or more foetuses were admitted to a specialist veterinary reproduction hospital 53 d after the onset of cytological dioestrus when that date was known, or 57 d after the last mating. Vaginal speculum examinations were performed every 6 h until cervical dilatation was visualised (time of cervical dilatation; TCD). Serum samples were collected at 08h00 and 18h00 daily until TCD. All bitches underwent elective caesarean section at TCD. Results of this study show that approximately 5% and 10% of preparturient bitches will reach TCD within 12 h despite a serum progesterone level of at least 15.8 nmol/L and 8.7 nmol/L respectively. In addition, there is a 95% probability that a preparturient bitch will reach TCD within 48 h if her serum progesterone level is below 8.7 nmol/L, and a 91% probability of her reaching TCD within 24 h if her serum progesterone level is below 3.18 nmol/L. Around 90% of bitches that demonstrate a 20% increase in PGFM over a 12-hour period are likely to be within 36 h of TCD. These results provide useful benchmarks for the management of canine parturition.

Comparison of three progesterone quantification methods using blood samples drawn from bitches during the periovulatory phase

Background and Aim:

Measuring blood progesterone (P4) concentration has become an essential diagnostic tool in small animal reproductive medicine. Methods enabling precise and rapid on-site measurements are in high demand, especially for the optimization of breeding management in bitches. This study aimed to compare two commercial on-site methods (Speed™ P4, Virbac [M1] and mini VIDAS®, bioMérieux [M2]) and a well-established radioimmunoassay (RIA), which was used as a reference method.

Materials and Methods:

Comparative measurements were performed on 52 blood serum samples collected from 45 clinically healthy bitches of different breeds. The dogs had been presented to determine the estrus cycle stage and predict the time of ovulation. Each sample was divided into three aliquots. In aliquot 1, P4 was measured immediately applying M2. Aliquots 2 and 3 were stored at −20°C until analysis was performed using RIA and M1. The consistency of the three methods was investigated by pairwise linear regression analyses.

Results:

In RIA, the P4 concentrations ranged between 1.1 and 25.4 ng/mL. Regression analyses revealed highly significant (p<0.0001) positive correlations between the three methods applied (M1 vs. RIA: R=0.94; M2 vs. RIA: R=0.98; and M1 vs. M2: R=0.91).

Conclusion:

The results show that the two commercial on-site methods tested exhibit approximately equal, high consistency with the radioimmunological reference method and can, therefore, be used beneficially in a clinical setting. However, biological interpretation of data must be performed in a method-specific manner.

Canine parturition: what is known about the hormonal setting?

Parturition is a challenging physiological process with perfect timing dictated by the events leading to the end of pregnancy in the female, and by the maturation of the fetus(es). The process of parturition remains an intricate interaction of hormones in a fine-tuned timing that remains to be better elucidated in the dog. In the dog pregnancy is maintained by the progesterone production by the corpora lutea, in which some hormones play a luteotrophic action. At term of pregnancy, the pre-parturient luteolytic cascade is the most apparent event, characterized by a rapid decline in plasma progesterone concentrations and useful in predicting the onset of spontaneous parturition. In contrast, cortisol plasma concentrations measurement showed high variability and suggested to be related to the stress condition instead of the onset of parturition. Both prostaglandin F2α and E2 concur in the process of parturition in the dog. The measurement of oxytocin plasma concentrations, also very variable, is implicated in uterine contractions. The measurement of plasma oxytocin concentrations showed to be useful to distinguish between normal and disturbed parturition, allowing the prompt recognition of dystocia and the immediate obstetrical intervention. In contrast to other species, no significant roles of estrogens for the initiating of parturition were demonstrated. Relaxin, the main pregnancy hormonal marker in the dog, beside an endocrine action, is also supposed to play a paracrine/autocrine role at the utero-placental unit and to support the maintenance of high plasma progesterone concentrations through a luteotrophic action, concurring to the main action of prolactin. Although important information has been provided, some aspects in the understanding the hormonal interactions and action timing implications in the process of parturition in the dog remains to be better investigated and represent intriguing topic for basic knowledge and applied research.

Does Bacteria Colonization of Canine Newborns Start in the Uterus?

Simple Summary

A well-balanced microbial flora plays a fundamental role in puppies’ early development. Bacteria were thought to colonize newborns at birth, but some studies have challenged this hypothesis. A healthy fetus at term may already harbour bacteria and the uterus may also not be sterile. Time of initial microbiota development might be placed earlier in life. In this investigation we sampled uterus, amniotic fluid and meconium of healthy canine fetuses delivered through cesarean section (elective or emergency) and carried out bacteriological examinations. In contrast with the ‘sterile womb paradigm’, bacteria were isolated from all the sampled sites and materials, independently of the cesarean type. Further studies are necessary to confirm our results. We adopted traditional bacteria culture techniques, but molecular methods, which look for bacteria DNA, could also be performed to deepen the knowledge on this matter.

Abstract

The assumption that requires the uterus to be a sterile environment to sustain a successful pregnancy has been recently challenged in humans, and is still under debate. The aim of this study was to assess whether bacteria can be isolated from the pregnant uterus and from amniotic fluid and meconium of healthy canine fetuses at term, delivered through cesarean section. Fifteen dams of different breed, age and parity, undergoing either elective (n = 10) or emergency (n = 5) cesarean section after a healthy pregnancy, were included in the study. Swabs for bacterial culture were collected from the uterus, and from amniotic fluid and meconium. Bacteria were isolated from all the sampled sites and materials, irrespective of cesarean type. In most cases, different bacteria were isolated from the different sites. Acinetobacter spp., coagulase-negative Staphylococci and Bacillus spp. were frequently found while Pseudomonas aeruginosa, Micrococcus spp., Moraxella spp., Macrococcus spp., Glutamicibacter spp., Stenotrophomonas spp. and Psychrobacter spp. were only occasionally identified. Our data show that uterus and fetuses may not be sterile in healthy term canine pregnancies.

Evaluation of surface plasmon field-enhanced fluorescence spectroscopy for rapid measurement of progesterone concentration in bitches

OBJECTIVE

To compare progesterone (P4) concentrations measured with surface plasmon field-enhanced fluorescence spectroscopy (SPFS) and chemiluminescence immunoassay (CLIA) in serum and plasma samples of client-owned bitches of various ages and breeds and to determine reference ranges for P4 concentrations at various stages of the estrous cycle.

SAMPLES

102 serum samples and 104 plasma samples.

PROCEDURES

In experiment 1, 1 aliquot each of serum and plasma was analyzed for P4 concentration by use of SPFS incorporated in a veterinary-specific point-of-care immunologic analyzer and CLIA. In experiment 2, serum collected from bitches in various stages of the estrous cycle was analyzed for P4 concentration by use of SPFS to establish reference ranges for each stage.

RESULTS

In experiment 1, P4 concentrations measured by SPFS and CLIA were highly correlated (serum, r = 0.966; plasma, r = 0.968). In experiment 2, ranges of serum basal (proestrous) P4 concentrations (n = 114) and P4 concentrations at the estimated time of ovulation (76), during pregnancy or diestrus (107), and during the prepartum period (50) measured with SPFS were 0.42 to 1.46 ng/mL, 3.69 to 7.85 ng/mL, 11.73 to 28.24 ng/mL, and 1.54 to 3.22 ng/mL, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Because serum and plasma P4 concentrations measured with SPFS were highly correlated with those measured with CLIA and ranges of serum P4 concentrations measured with SPFS for each of phase of the estrous cycle were well-defined for the large sample size, veterinarians may be able to accurately use this veterinary-specific point-of-care immunologic analyzer with SPFS methodology to determine P4 concentrations of bitches in their daily practice.

Usefulness of Maternal and Fetal Parameters for the Prediction of Parturition Date in Dogs

An accurate parturition timing is of key importance for breeders and veterinarians in order to give professional assistance to parturition in dogs. However, pregnancy length calculated from the breeding date has a wide variability. Different parameters and formulas have been described and calculated, as well as their accuracy which is affected by various factors: stage of pregnancy, litter and maternal size. Therefore, the selection of the most appropriate parameter panel poses the challenge of weighing their influences and impact on the overall accuracy. The aim of this review is to analyze the parameters useful for parturition timing, especially their accuracy, and to propose the addition of fetal maturity and criteria for its evaluation to detect readiness for parturition. Parameters, as described in literature, are classified as: (i) maternal parameters, (ii) fetal parameters, (iii) ultrasonographic assessment of maternal and fetal heart rate and blood flow, (iv) parameters indicating fetal maturity. A focus on recently described parameters-such as fetal gastrointestinal motility and fetal lung development detected by quantitative ultrasound-is reported. Currently, the most accurate way to predict parturition day is represented by a prepartum progesterone drop, but the identification of a panel of ultrasonographic parameters combining their significance and their accuracy throughout pregnancy is still needed.

Effect of Delivery by Emergency or Elective Cesarean Section on Nitric Oxide Metabolites and Cortisol Amniotic Concentrations in at Term Normal Newborn Dogs: Preliminary Results

Simple Summary

The high perinatal mortality rates in dogs are partly attributable to stress at parturition, with the production of cortisol (C), and related to the type of delivery, that is elective or emergency cesarean sections (ELCS and EMCS). Nitric oxide metabolites (NOs) are also related to the type of parturition (ELCS or EMCS), because of the different emotional and physical stresses experienced by the bitch in these two scenarios. The study aimed to assess the concentrations of C and NOs in the amniotic fluid of puppies delivered by ELCS or EMCS. In the amniotic fluid of the 32 puppies delivered by ELCS, C, and NOs concentrations were significantly lower than those found in the amniotic fluid of the 22 puppies delivered by EMCS. Lower C concentrations were found at increasing newborn viability assessed by Apgar score. Higher amniotic NOs concentrations were associated to increasing mother’s parity, puppies’ birthweight, and time of labor within the EMCS group. Due to the possible concurrence of several compartments (maternal, maybe placental, and fetal) to the final amniotic fluid composition, the definition of the role played by the three compartments in the higher C and NOs concentrations found in amniotic fluids collected from puppies delivered by EMCS than ELCS needs further clarifications.

Abstract

The neonatal response to stress was reported to be related to the type of delivery, that is elective or emergency cesarean sections (ELCS and EMCS, respectively). Nitric oxide (NO) is also reported to be related to uterine inertia, and high levels of NO metabolites (NOs) are associated with physical and emotional stress. The study aimed to assess the concentrations of cortisol (C) and NOs in the amniotic fluid of puppies delivered by ELCS or EMCS. In total, 32 puppies were delivered by ELCS and 22 by EMCS. ANCOVA showed an effect of the ELCS vs. EMCS on both amniotic NOs (p < 0.001) and C (p < 0.001) concentrations. Lower amniotic C concentrations were found at increasing Apgar score (p < 0.001). Higher amniotic NOs concentrations were associated to increasing mother’s parity (p < 0.001), puppies’ birthweight (p < 0.001), and time of labor within the EMCS group (p < 0.05). A positive correlation between birthweight and amniotic NOs concentrations was also found (p < 0.05) in the EMCS group. Due to the possible concurrence of several compartments (maternal, maybe placental, and fetal) to the final amniotic fluid composition, the definition of the role played by the three compartments in the higher C and NOs concentrations found in amniotic fluids collected from puppies delivered by EMCS than ELCS needs further clarification.

Ultrasonographic analysis of fetal gastrointestinal motility during the peripartum period in the dog

The aim of this study was to investigate fetal gastrointestinal motility (FGM) of dogs using ultrasonic imaging and its association with vaginal and rectal temperature, serum progesterone concentrations and fetal heart rate. Pregnant bitches were examined after day 54 of gestation and there were determinations of vaginal and rectal temperature and serum progesterone concentrations. The fetal abdomen was evaluated for 30 s using longitudinal and transversal assessments, and FGM was scored as 0 (no peristalsis) or 1 (evident peristalsis). Number of fetuses with a 1 or 0 score were determined for each bitch (number and the percentage of fetuses with FGM). A total of 135 FGM measurements were recorded. There was FGM in 0/3, 0/6, 1/6 (16.7 %), 3/20 (15 %), 5/18 (27.3 %), 18/28 (64.3 %), 12/17 (70.6 %), 14/22 (63.6 %), 6/9 (66.7 %), 4/6 (66.7 %) fetuses from day -9 until 0 preceding parturition, respectively. In the last 5 days before parturition, 63.3 % of fetuses had FGM. Vaginal and rectal temperature were strongly and positively correlated (P < 0.001). Vaginal temperature was positively correlated with progesterone concentrations and fetal heart rate (P < 0.01), and there was a small negative correlation with FGM (r = -0.331, P < 0.05). Due to ease of data collection, the assessment of FGM is a valuable procedure for evaluation of fetal maturity in dogs. Vaginal and rectal temperatures are reliable variables to be assessed during the last week of pregnancy for estimating the time of parturition.

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.

Evaluation of serum C-reactive protein concentration as a marker of impending parturition and correlation with progesterone profile in peri-partum bitches

C-reactive protein (CRP) is one of the major acute phase proteins in dogs. It is produced by the liver and rapidly increases in response to an inflammatory stimulus. The aim of this study was to measure CRP concentrations around parturition and to verify whether this protein could be useful, together with progesterone (P), to detect the onset of parturition in bitches. The CRP and P concentrations were measured in 66 serum samples from 28 healthy pregnant bitches, collected between -5 and +2 days from parturition (day of parturition = day 0). The effect of 'days from parturition', parity, and litter size on P and CRP concentration was analyzed and the correlation between CRP and P values was calculated. The P and CRP values were affected by 'days from parturition'. While P decreased during the last days of pregnancy, CRP concentration was greater than the normal range (0-1.07 mg/dl) starting the parturition day with the increase starting on day -1. The CRP concentration profiles during the days around parturition have not been previously reported in dogs. The increase in CRP very near the time of parturition and the low magnitude of the increase do not allow for it to be useful in clinical practice to assess the onset of parturition in the bitch.

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.