Objectives Deslorelin 4.7 mg and melatonin 18 mg subcutaneous implants were studied in purebred male and female cats, via questionnaires sent to French cat breeders, to assess breed, age, duration of the contraceptive effect, fertility after use, changes in behaviour and side effects. Methods Reproductive data were collected in 57 tom cats and 41 queens implanted with deslorelin 4.7 mg, and 42 queens implanted with melatonin 18 mg, for a total of 140 purebred cats, from 38 different catteries, representing 18 breeds. Results Using deslorelin (Suprelorin 4.7 mg; Virbac), sexual behaviour in males was inhibited for a mean ± SD of 13.4 ± 3.2 (range 8–21) months in 37/57 cats. Of these, 24/37 mated successfully and produced litters at a mean of 15.5 ± 3.6 (range 9–20) months. Inhibition lasted 11 ± 1.1 (range 9–12; n = 6), 13.2 ± 2.4 (range 12–18; n = 6) and 15 ± 3.5 (range 9–18; n = 6) months in Norwegian Forest Cat, Singapura and Ragdoll males, respectively. In 26/41 females implanted with deslorelin 4.7 mg, oestrus was inhibited for a mean of 16.0 ± 5.7 (8–38) months; 12/26 went on to produce a litter. Of the side effects specific to females: two presented persistent oestrus, leading to the removal of the implant; two developed lactation; one had fibroadenomatosis; and one was sterilised owing to cystic endometrial hyperplasia. Using melatonin (Melovine 18 mg; Ceva), 33/42 females had oestrus inhibited for a mean of 86 ± 50 (range 21–277) days after implantation with a peak return to oestrus in March, and 12/33 had a subsequent litter. No side effects were reported. Conclusions and relevance This study is the first to collect a large amount of field data, in 140 purebred male and female cats where a deslorelin 4.7 mg or a melatonin 18 mg implant was used. These field results may allow for more accurate clinical advice and open up new avenues of research.

Since most of dystocia end up in caesarean sections (C‐sections), the history of any problem during whelping is a good reason to plan in advance a further C‐section. Our aim was to confirm that on a large sample and over an extended period of time, mortality in puppies <2 weeks of age was low, born after a planned C‐section using aglepristone as a primer. Seventy‐four C‐sections on 59 different bitches were included. Bitches were monitored during oestrus to estimate the day of ovulation by progesterone assays; 60, 61 or 62 days after ovulation, foetal viability was checked by ultrasonography and progesterone plasma level was measured. None of the bitches was at term (progesterone plasma level >2 ng/ml). An injection of aglepristone was performed in late afternoon to block the effect of progesterone, mimicking its drop at the end of pregnancy. The C‐section was conducted the following morning. Twenty‐one breeds were represented most of which were bulldogs (26%, 21/74) and Great Danes (16%, 13/74). Four hundred and thirty‐five puppies were born. A total of 43/435 puppies died within the first 2 weeks (9.89%). None of the puppies showed any external signs of prematurity. The average number of deaths per litter relative to the date after ovulation was similar (0.5 pups per litter at day 60, 0.7 at day 61, 0.4 at day 62). This study shows that planned C‐section after an accurate determination of ovulation and using aglepristone as a primer is a safe procedure for bitches and their offspring. It may be offered to owners if a pregnant bitch is “at risk” of dystocia.

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Objectives Although lactation and suckling suppresses fertility in most mammals, some feline breeders have reported spontaneous oestrus during lactation, causing distress to kittens. This led the Official French Feline Pedigree Registry (Livre Officiel des Origines Félines – LOOF) to send a questionnaire to cat breeders requesting data on their last three litters. The aim of this study was to investigate the prevalence of lactational oestrus, its impact on litters and potential associations with litter size, age, parity, breed and seasonality. Methods Answers from 108 breeders were collected, providing data on 238 litters in 23 different breeds. Data were also collected on successive litters from multiparous queens (n = 20) and were analysed separately from the 195 independent births. Results Of the 195 independent births with complete data sets, 96 (49%) queens came into oestrus during lactation, 37 (38%) of which were associated with loss of maternal interest (n = 20), milk quality variation (n = 2), clotted milk (n = 3), reduced milk quantity (n = 13), which in kittens led to reduced weight (n = 6), diarrhoea (n = 9), vomiting (n = 4), nausea (n = 2) or death (n = 4), and bottle feeding (n = 2), early weaning (n = 4) or modified litter behaviour (n = 1). A significant association was found between small litter size (one or two kittens) and the onset of lactational oestrus ( P = 0.007) and between births occurring in February, March and April and lactational oestrus ( P = 0.005); there was no association with age or breed. Conclusions and relevance Breeders perceived a relationship in 38% of cases of lactational oestrus with maternal disinterest, clotted milk, reduced milk yield and in kittens, weight loss, vomiting, diarrhoea or even death. An association between small litter size and lactational oestrus was found, as well as with births occurring between February and April. Breeders presenting with at-risk females should be warned. Conservative and preventive measures such as contraceptive options are discussed as a possible therapy.

We evaluated the cell composition and function of canine pancreatic pseudoislets (PIs) produced from 42- to 55-day-old fetuses, 1- to 21-day-old pups, and an adult dog pancreas. After mild collagenase treatment, partially digested tissues were cultured for 2–3 weeks. PI production started on culture day 3, was marked for 6 to 9 days, and then stopped. PI production was greatest with the neonatal specimens, reaching about 12 million aggregates per litter (55-day-old fetus) or per pancreas (1-day-old pup). Cell composition at all stages was similar to that in adult pancreatic islets, with predominant β cells, scant α cells and, most importantly, presence of δ cells. Among pancreatic markers assessed by quantitative real-time PCR (qRT-PCR) mRNA assay, insulin showed the highest expression levels in PIs from newborn and adult pancreas, although these were more than 1000 times lower than in adult islets. Pdx1 mRNA expression was high in PIs from 55-day-old pancreases and was lower at later stages. Consistent with the qRT-PCR results, the insulin content was far lower than reported in adult dog pancreatic islets. However, insulin release by PIs from 1-day-old pups was demonstrated and was stimulated by a high-glucose medium. PIs were transplanted into euglycemic and diabetic SCID mice. In euglycemic animals, the transplant cell composition underwent maturation and transplants were still viable after 6 months. In diabetic mice, the PI transplants produced insulin and partially controlled the hyperglycemia. These data indicate that PIs can be produced ex vivo from canine fetal or postnatal pancreases. Although functional PIs can be obtained, the production yield is most likely insufficient to meet the requirements for diabetic dog transplantation without further innovation in cell culture amplification.