Reproduction Nutrition Development, formerly Annales de Biologie Animale Biochimie Biophysique

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.

Background: Surgical sterilization is the most effective method of contraception for dogs. It also prevents pyometra and reduces the risk of mammary tumour development. However, this procedure also has negative effects, such as urinary incontinence. Steroid hormone deprivation following gonadectomy could also affect canine vaginal mucosa conditions and the microbial community colonizing the vaginal tract. This hypothesis was tested by comparing the vaginal cytology and microbial community of two groups of bitches, including 11 in anoestrus and 10 sterilized bitches (post-pubertal sterilization in the last 4 years). Bacteria were identified through metataxonomic analysis, amplifying the V3-V4 regions of16S rRNAgene, and culturing methods.Results: Vaginal mucosa cytology was suggestive of dystrophic conditions in sterilized bitches, whereas a typical anoestrus pattern with parabasal and intermediate cells was appreciable in anoestrous animals. Metataxonomic analysis revealed large inter-individual variability.Salmonella,MycoplasmaandStaphylococcuswere present in moderate quantities in almost all the samples in both groups. Mollicutes (class level) and Tenericutes (phylum level) were commonly present in moderate quantities in anoestrus samples, whereas these microbes were present at high levels in a single sample from the sterilized group.Based on culturing, a higher number of different species were isolated from the anoestrous bitches, andMycoplasma caniswas exclusively identified in an anoestrous bitch.Staphylococcusspp.was the most frequently isolated genus in both groups, followed byStreptococcusspp., and, among gram-negative bacteria,Escherichiaspp.andHaemophilusspp.A comparison of the numbers of the most frequently isolated genera of bacteria from vaginal cultures of bitches revealed thatPasteurellaandProteuswere the most frequently identified in sterilized animals based on metataxonomic analysis (p-value = 0.0497 and 0.0382, respectively), whereasStreptococcuswas significantly and most frequently isolated from anoestrous bitches using culture methods (pvalue = 0.0436).Conclusions: In this preliminary investigation, no global patterns of the vaginal bacteria community were noted that characterized the condition of the bitches; however, cytology suggested local modifications. Sterilization after puberty caused minimal alterations in the vaginal microbial community of bitches within 4 years after surgery.