Normal feline reproduction: The queen

The vaginal microbiota of healthy female cats

The vaginal microbiota of the queen (i.e., female cat) has never been described using culture independent methods. The objectives of the present research were to describe the vaginal microbiota of healthy domestic shorthair queens using both 16S rRNA sequencing and culture, and to assess the effects of age, living environment, and reproductive season on its composition. Thirty queens undergoing elective ovariectomy were included in the study. The vaginal samples were collected just before surgery, from animals under general anaesthesia. Two consecutive mini-swabs were introduced in the queens' vaginal tract. A preliminary study with 10 healthy queens aimed to negate sampling order's effect. Two consecutive samples for sequencing (5 queens, 10 swabs) and culture (5 queens, 10 swabs) were collected, confirming a match (100 % in culture, Bray-Curtis P = 0.96 in sequencing). The experiment included 20 queens that were prospectively grouped based on age (prepubertal N = 10, adult N = 10), living environment (indoor N = 10, outdoor N = 10), and time of the year, whether during the reproductive season (N = 10) or during seasonal anoestrous (N = 10). Bacteria were identified through metataxonomic analysis, amplifying the V1-V2 regions of 16S rRNA gene, and through standard culture followed by MALDI-TOF MS. The feline vaginal microbiota is dominated by Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteria. Escherichia-Shigella, Streptococcus, and Pasteurella were the most abundant genera. Although culture underestimated bacterial richness and diversity compared to sequencing, Escherichia and Streptococcus were the most isolated bacteria. No bacterial growth was observed in 15 % of samples (N = 3/20), whereas growth of one or two bacterial species was observed in 64.7 % (N = 11/17) and 35.3 % (N = 6/17) of cases, respectively. No differences in terms of alpha (Kruskal-Wallis rank sum test P = 0.65) and beta diversity (Bray-Curtis, Unweighted and Weighted UniFrac analyses P > 0.5) were observed. Although a difference in alpha diversity based on phylogenetic tree (P = 0.02) was detected between indoor and outdoor queens. In conclusion, mixed and monoculture of Escherichia coli, Streptococcus canis, Staphylococcus felis, and Enterococcus spp. are normal findings within the cat vagina. Age and reproductive season do not influence the feline vaginal microbiota, whereas further research is needed to elucidate the role of the living environment.

Scientific and technical assistance on welfare aspects related to housing and health of cats and dogs in commercial breeding establishments

This Scientific Report addresses a mandate from the European Commission according to Article 31 of Regulation (EC) No 178/2002 on the welfare of cats and dogs in commercial breeding establishments kept for sport, hunting and companion purposes. The aim was to scrutinise recent recommendations made by the EU Platform on Animal Welfare Voluntary Initiative on measures to assist the preparation of policy options for the legal framework of commercial breeding of cats and dogs. Specifically, the main question addressed was if there is scientific evidence to support the measures for protection of cats and dogs in commercial breeding related to housing, health considerations and painful procedures. Three judgements were carried out based on scientific literature reviews and, where possible a review of national regulations. The first judgement addressed housing and included: type of accommodation, outdoor access, exercise, social behaviour, housing temperature and light requirements. The second judgement addressed health and included: age at first and last breeding, and breeding frequency. Judgement 3 addressed painful procedures (mutilations or convenience surgeries) and included: ear cropping, tail docking and vocal cord resections in dogs and declawing in cats. For each of these judgements, considerations were provided indicating where scientific literature is available to support recommendations on providing or avoiding specific housing, health or painful surgical interventions. Areas where evidence is lacking are indicated.

Estrogen and progesterone receptors and antioxidant enzymes are expressed differently in the uterus of domestic cats during the estrous cycle

Sex steroids and antioxidant enzymes are important in female sexual development and adequate modulation of the estrous cycle, pregnancy, and fetal development. Therefore, modifications in its signaling or expression in the genital system are associated with reproductive dysfunctions. However, the spatial-temporal expression profile of receptors for sex steroids and antioxidant enzymes in the uterus of domestic cats throughout the estrous cycle needs to be studied. Cats in proestrus/estrus (N = 6), diestrus, (N = 7), and anestrus (N = 6) were used to evaluate the uterine expression of estrogen alpha (ERα), progesterone (PR), and androgen (AR) receptors and of the antioxidant enzymes superoxide dismutase 1 (SOD1), catalase and glutathione peroxidase 1 (GPX1) by immunohistochemistry and qPCR. The uterus of cats in diestrus showed lower protein and mRNA expression of ERα and PR compared to proestrus/estrus and anestrus, mainly in the luminal and glandular epithelium and myometrium, different from catalase and SOD1, which showed higher expression in diestrus in relation to other phases of the cycle. GPX1, on the other hand, showed lower uterine gene expression in diestrus compared to proestrus/estrus and anestrus. No significant differences in AR expression were observed. In conclusion, ERα and PR sex steroid receptors and antioxidant enzymes are expressed differently in the uterus of domestic cats during the estrous cycle.

Anti-Müllerian hormone in queens: Serum concentrations and total ovarian follicle population

The objectives of this study were: a) To report anti-Müllerian hormone (AMH) serum concentrations in neonatal, pre and postpubertal female cats. b) To establish the relationship between serum AMH with either age and estrous cycle c) To correlate the total number of different ovarian follicle types with AMH in adult queens. A single blood sample was collected from 10 neonates (including 5 male), 15 prepubertal and 48 postpubertal female cats to measure AMH. Eight, 10, and 18 of this latter group were in follicular (FP), luteal phase (LP), and anestrus (AN), respectively. The total number of each follicle type was histologically counted using the Gougeon and Chainy (1987) formula in a subgroup of 10 adult queens. Overall AMH mean of these the female cats was 6.31 ± 0.54 ng/mL. The neonatal females had lower AMH serum concentrations than their male littermates (2.56 ± 0.49 vs. >23 ng/mL; P < 0.01). Concentrations were also higher in prepubertal than in neonatal and postpubertal cats (11.79 ± 1.36 vs. 2.56 ± 0.49 vs. 4.87 ± 0.38 ng/mL; P < 0.01). Queens below 12 mo of age had the highest AMH levels (10.41 ± 1.16; P < 0.01). Age was inversely correlated with AMH (r = -0.5; P < 0.01). Animals in FP had lower AMH concentrations than AN females (2.51 ± 0.33 vs. 5.46 ± 0.76 ng/mL; P < 0.05). No difference in the total number of each follicle type were found between either ovary (P > 0.05). A high correlation was only found between small antral follicles and AMH concentrations (r = 0.85; P < 0.01). It was concluded, that AMH can provide an indirect, reliable marker for the assessment of ovarian follicle size and functionality. Age as well as pubertal state should be considered when evaluating AMH concentrations in this species.

Infertility In Queens: Clinical approach, experiences and challenges

CLINICAL CHALLENGES

It is not easy for a veterinarian to determine the cause of infertility in a queen. The simplest method is to start by investigating the most common causes and then progress by successive elimination to the less common causes. For example, mating problems are commonly responsible for reproductive failure, and owners should be particularly vigilant in checking that the mating is progressing satisfactorily. Frequently, a veterinarian may have to determine, among other things, if there is a uterine or hormonal disorder or if an infectious pathology may be involved. In the case of a queen that is not cycling, it is important to differentiate a lack of onset of puberty in a young queen from a lack of cyclicity in an adult queen.

AIM

This review sets out a practical, step-by-step approach that veterinarians can follow, starting with the most common causes of infertility in queens and moving towards more rare or specific causes.

EQUIPMENT AND TECHNICAL SKILLS

Simple techniques such as vaginal smears are essential to determine if a queen that is ready to be mated is in full oestrus, if a queen is cycling or not and to diagnose inflammation of the genital tract. Veterinarians should be familiar with the peculiarities of the swabbing technique in cats, as well as the interpretation of feline vaginal cytology. Progesterone assays are useful on many occasions in the diagnosis pathway. A laboratory capable of performing karyotypes should ideally be available. Finally, it is important to be able to perform an ultrasound examination of the ovaries and uterus in a queen.

EVIDENCE BASE

Although it appears that infertility is a problem among purebred queens, there is a lack of knowledge in this area and too few published studies. Some causes of feline infertility remain poorly investigated.