Triplex doppler ultrasonography to describe the uterine arteries during diestrus and progesterone profile in pregnant and non-pregnant bitches of different sizes.

Hemodynamics of uterine vascularization is modified throughout pregnancy to meet the increasing demand of the growing fetuses and triplex doppler ultrasonography is widely used in human medicine to study the uterine arteries and assess the fetal and placental conditions. The aim of our study was to confirm this observation in the bitch, to evaluate differences between bitches of different sizes and to study abnormal pregnancies. Forty-four bitches were monitored during the estrous period to determine ovulation and every 10 days from ovulation to 50 days post-ovulation: the resistivity (RI) and pulsatility (PI) indexes of the right uterine artery were measured as well as usual assessment of fetal development and follow up of the luteal function. Thirty-three out of forty-four bitches were pregnant, including 6 abnormal pregnancies (resorption of more than 10% of the embryos). We also divided them in four weight categories: 8 were small (<10 kg), 13 medium (10-25 kg), 13 large (>25-40 kg) and 10 were giant breeds (>40 kg). We observed that RI and PI decreased over time and were significantly lower for pregnant bitches compared to non-pregnant ones from 30 days post-ovulation. In contrast, RI and PI did not significantly vary with the size of the bitches and we could not determine a significant impact of abnormal pregnancies either. In conclusion, we found no significant difference related to the size of bitches in the RI and PI. The only significant difference between pregnant and non-pregnant bitches was observed from 30 days post-ovulation.

Fertility in Adult Bitches Previously Treated with a 4.7 mg Subcutaneous Deslorelin Implant.

The absence of fertility problems in male dogs after a single treatment with deslorelin acetate (Suprelorin(®)) is well acknowledged. However, reports on the application of deslorelin in the bitch and information concerning fertility after implant treatment are still limited. In this retrospective study, data concerning induced and spontaneous oestruses of 39 bitches from 17 breeds, treated with deslorelin acetate implants (4.7 mg Suprelorin(®), Virbac, France), were retrieved to assess post-treatment fertility (ovulation rate, pregnancy rate and litter size). Animals were grouped according to treatment characteristics: group 1 (Gr1) - females submitted to oestrus induction, showing natural oestruses afterwards (n = 19); group 2 (Gr2) - females re-implanted with 4.7 mg deslorelin acetate to re-induce oestrus, showing subsequent spontaneous post-implant oestruses (n = 7); and group 3 (Gr3) - females submitted to a 4.7 mg deslorelin acetate implant for oestrus suppression, evaluated at subsequent spontaneous post-implant oestruses (n = 13). Comparison of fertility traits between induced and post-treatment spontaneous oestruses in Gr1 and Gr2 (short treatments), or between spontaneous oestruses after long-treatment schedules (Gr 3) revealed a slightly better performance in spontaneous cycles compared with induced cycles: ovulation rate post-treatment was 97.1%, 94.1% and 94.4% and the pregnancy rate post-treatment was 91.2%, 88.9% and 84.6% for groups 1, 2 and 3, respectively. Nevertheless, fertility in induced and post-treatment oestruses was considered normal. Moreover, the individual litter size did not differ within groups between induced and spontaneous cycles. From these findings, we concluded that treatment with 4.7 mg deslorelin implants did not compromise the bitches' fertility in subsequent oestruses.

Suppression of fertility in adult dogs.

Unfortunately, the overpopulation of dogs is still a problem in the majority of countries and even though surgical methods of sterilization, the most traditional and commonly used technique, have been intensively performed, the impact on the dog population is negligible. The neutering of companion animals as ovariohysterectomy (spaying) or orchidectomy (castration) has its limitations because of the cost, the need of a surgical environment and the risk of surgical and/or anaesthetical complications (ACCD 2009). In fact, surgical castration has been banished in some northern European countries and has limited acceptance in other countries. In a survey performed in Sao Paulo, Brazil, 56.5% of the owners of adopted shelter dogs were against the surgical procedure for different reasons (Soto et al. 2005). Currently, the options for contraception, defined as suppression of fertility are based on hormonal treatment. The treatments can be divided into analogues of gonadotropin releasing hormone (GnRH), progestins and androgens. Other possibilities of contraception are via the immunological system with vaccinations against GnRH, the luteinizing hormone (LH) receptor and the zona pellucida proteins. Finally, there is also the intra-epididymal or intratesticular injection of sclerosing substances in dogs. Mechanical devices to disrupt fertility are not used anymore due to the side effects. Suppression of fertility in adult dogs will be reviewed in order of use and possible impact on the dog population.

Results of GnRH agonist implants in oestrous induction and oestrous suppression in bitches and queens.

Over the last 10-15 years, long-acting GnRH agonists have become widely available. In the field of small animal reproduction, most recent studies have focused on the use of two compounds developed under the form of subcutaneous implants: azagly-nafarelin and deslorelin. Only the latter has been commercially available for use in male dogs, first in Australia and New Zealand, then in several countries of the European Union since 2008. Although officially marketed for male dogs, this compound has also been studied in bitches and more recently in queens. Some published papers or recent presentations at congresses--still unpublished--have focused on the use of GnRH agonists implants in females.