Contraceptive effect of a gonadotropin-releasing hormone vaccine on captive male brown bears (Ursus arctos).

Fertility control has traditionally been applied in zoos to control captive populations, and reversible contraception is important. However, contraceptive methods for male bears have not been reported. We aimed to establish a reversible contraceptive for male brown bears by investigating the effects of a gonadotropin-releasing hormone (GnRH) vaccine (Improvac®) that was developed for the immune castration of pigs. We vaccinated six bears with two sequential doses of 400 (n = 2) or 600 µg Improvac® (n = 4) with a 1-month interval during the pre-breeding season (February to April). We compared the reproductive parameters (testosterone levels and semen parameters) of the six vaccinated and four non-vaccinated (control) bears once during the breeding season (May or June). To investigate whether the reproductive performance could be restored in the following year of contraception, we also compared the reproductive parameters once during the breeding season in two bears between the year with GnRH vaccination and the following year without vaccination. Vaccination treatments suppressed reproductive parameters in 5 bears, although vaccination with 400 µg of Improvac® was not effective in one bear. Testosterone levels and the rate of progressive sperm motility were significantly lower, and total sperm count and testis size tended to be lower in vaccinated bears, compared with the controls. Blood biochemical findings and direct observations after Improvac® vaccination did not reveal side effects. Moreover, testosterone levels and spermatogenic scores of two bears were restored in the following year. We confirmed that the Improvac® vaccine elicited a reversible contraceptive effect in male brown bears.

Durable contraception in the female domestic cat using viral-vectored delivery of a feline anti-Müllerian hormone transgene.

Eighty percent of the estimated 600 million domestic cats in the world are free-roaming. These cats typically experience suboptimal welfare and inflict high levels of predation on wildlife. Additionally, euthanasia of healthy animals in overpopulated shelters raises ethical considerations. While surgical sterilization is the mainstay of pet population control, there is a need for efficient, safe, and cost-effective permanent contraception alternatives. Herein, we report evidence that a single intramuscular treatment with an adeno-associated viral vector delivering an anti-Müllerian hormone transgene produces long-term contraception in the domestic cat. Treated females are followed for over two years, during which transgene expression, anti-transgene antibodies, and reproductive hormones are monitored. Mating behavior and reproductive success are measured during two mating studies. Here we show that ectopic expression of anti-Müllerian hormone does not impair sex steroids nor estrous cycling, but prevents breeding-induced ovulation, resulting in safe and durable contraception in the female domestic cat.

Reversible control of reproduction in tom cats: medical options for manipulating libido and fertility.

BACKGROUND: There has been a growing interest in alternatives to surgery for controlling reproduction in tom cats, and the resultant medical options add to a practitioner's toolbox when handling these cases in clinical practice. It is important, however, that when suggesting these drugs, veterinarians have a good understanding of their mode of action, and their correct use and dosage. CLINICAL RELEVANCE: Breeders increasingly wish to be able to switch on/off the reproductive ability of their tom cats in a controlled manner. In addition, in small animal medicine, there has been concern from some academics, and a growing number of pet cat owners, about potential long-term effects of surgical sterilisation. Further, for some cats surgical castration may not be possible due to health conditions that mean anaesthesia is unsafe. In all of these scenarios, medical alternatives to surgery can prove useful. EQUIPMENT AND TECHNICAL SKILLS: No special equipment or technical skills are required. A good knowledge of the medical alternatives to surgical sterilisation for controlling reproduction in a tom, and making sure the patient is a suitable candidate, are, however, important for ensuring the cat's health during and after treatment and the owner's satisfaction. AUDIENCE: This review is aimed principally (but not exclusively) at veterinary practitioners working with cat breeders who seek a temporary arrest in their tom cat's reproduction. It may also help practitioners with clients who would like an alternative to surgery or with cats where anaesthesia for surgical castration is not possible. EVIDENCE BASE: Advances in reproductive feline medicine have resulted in improved knowledge of medical contraception. This review draws on scientific evidence-based papers that report on the mode of action, length of efficacy and potential side effects of different methods of medical contraception, as well as the authors' own clinical experience.

Reversible Control of Reproduction In Queens: Mastering the use of reproductive drugs to manipulate cyclicity.

BACKGROUND: The literature is full of papers reporting side effects of progestogens in cats; however, they are, in fact, safe drugs, as discussed in this article. Gonadotropin-releasing hormone (GnRH) agonists and melatonin are additionally a practical solution for controlling cyclicity in queens, but they also have some contraindications and need to be used carefully. CLINICAL RELEVANCE: Mastering the use of reproductive drugs allows feline practitioners to handle many more clinical situations than can be solved using surgery. It is not necessary to be a specialist in reproduction to be able to halt cyclicity in a valuable breeding queen using hormones. EQUIPMENT AND TECHNICAL SKILLS: A sound knowledge of appropriate dosages and criteria for patient selection for all reproductive drugs currently used in feline reproduction is the best guarantee of owner satisfaction and of ensuring the queen's health. Availability of a serum progesterone assay, either in-house or via an external laboratory, is also important, in order to confirm a queen is at an appropriate stage of the reproductive cycle for treatment. AUDIENCE: This article is aimed principally (but not exclusively) at veterinarians working with cat breeders and whose clientele is increasingly interested in alternative methods of controlling reproduction in pet queens. Surgery is no longer the only choice, and practitioners who manage to keep abreast of new developments will be able to address clients' needs in a modern, professional way. EVIDENCE BASE: This review draws on a vast body of scientific evidence-based literature. Previously, personal (and sometimes misinformed) opinions, such as the proposed dangerous side effects of progestogens, have been perpetuated in the scientific literature. The papers cited in this review have therefore been carefully scrutinised to distinguish reliable information based on controlled studies from non-evidence-based information.

Surgical contraception of free-ranging female capybaras: Description and comparison of open and minimally invasive techniques.

OBJECTIVE: To develop, describe, and evaluate 2 surgical techniques for contraception of free-ranging female capybaras. STUDY DESIGN: Prospective study. ANIMALS: Cadaveric (n = 3) and free-ranging female capybaras (n = 21). METHODS: Preliminary studies of surgical anatomy were performed on 3 capybara cadavers. Two different techniques for partial salpingectomy were evaluated in free-ranging female capybaras: bilateral minilaparotomy (LTG; n = 11) or bilateral laparoscopy (LCG; n = 10). Data concerning body weight, tubal ligation time, total surgical time, incision size, and intraoperative and postoperative complications were analyzed, as well as the clinical status and incisional healing 1 week postoperatively. RESULTS: Body weight (P = .214), ligation time of the left uterine tube (P = .901), and total surgical time (P = .473) were similar between the experimental groups. The ligation time of the right uterine tube was shorter in the LCG group (P = .0463). In the LTG, no differences were observed between the sides regarding the incision size (P = .478). No major intraoperative or postoperative complications occurred in either group. One LCG procedure had to be converted to LTG due to technical issues. All skin incisions healed without complication. CONCLUSION: Both procedures showed similar and satisfactory outcomes. CLINICAL SIGNIFICANCE: The proposed techniques may be a suitable alternative to conventional laparotomy for contraception of female capybaras, especially under field conditions.

Laparoscopic salpingectomy in Papio hamadryas for birth control in captivity.

OBJECTIVE: To evaluate the feasibility of laparoscopic salpingectomy in baboons (Papio hamadryas). We hypothesized that laparoscopic salpingectomy could be performed in baboon species within a reasonable amount of surgical time, with minor complications occurring at low rates. STUDY DESIGN: Case series and technique description. ANIMALS: Sixteen baboons (n = 16). METHODS: The surgical procedures were performed using the 3-port technique, with 5 mm instruments and a telescope placed at the umbilical and hypogastric regions. A salpinx dissection was performed, using a radiofrequency bipolar vessel sealing device, from the fimbriae to the uterine attachments. We evaluated the surgical duration, learning curve, and intraoperative and early postoperative complications. RESULTS: Ten adult and 6 subadult baboons with a mean weight of 9.32 kg, a range of 4-14.2 kg, and a standard deviation (SD) of 3.09 kg were included in the study. The total duration of surgery was 28.75 min (range, 16-50 min; SD, 9.60 min). The installation phase was completed in a mean time of 7.68 min (range, 3-15 min; SD, 3.43 min), and the time to complete the salpingectomy of both salpinges was 9.68 min (range, 4-20 min; SD, 3.97 min). No complications were observed in the postoperative period. CONCLUSION: Laparoscopic salpingectomy in Papio hamadryas was feasible, with an acceptable surgical time, low invasiveness, and only minor technical perioperative complications. CLINICAL SIGNIFICANCE: Laparoscopic salpingectomy could be a viable and safe therapeutic option in nonhuman primate birth-control programs.

Effects of GnRH agonists on testosterone and testosterone-stimulated parameters for contraception and aggression reduction in male lion-tailed Macaques (Macaca silenus).

Managing social groups in zoos requires controlling reproduction in individuals that do not have a current breeding recommendation, while simultaneously maintaining social harmony and animal well-being. Contraceptives, such as gonadotropin releasing-hormone (GnRH) agonists, that suppress testosterone production, offer a potential solution. They achieve infertility by interrupting spermatogenesis and may ameliorate androgen-induced aggression. This study investigated the effects of two GnRH agonists, histrelin and deslorelin, on testosterone, testis size, body weight and sperm production in male lion-tailed macaques, along with subjective observations of aggressive behavior. Five trials at three institutions with 14 males demonstrated that 100 mg histrelin or 9 to 12 mg of deslorelin could at least temporarily reduce testosterone, but a lower 6 mg dose was ineffective. However, ability of deslorelin to produce azoospermia varied among males, even at the highest dose. In general, a higher dose was needed (1) to achieve than to maintain suppression of any measured parameter and (2) to suppress sperm production than testosterone concentration. Testosterone production was also more likely than sperm production to recover, suggesting possible damage to seminiferous tubules but not to Leydig cells. Aggressive behavior was reduced in all but the group receiving the lowest dose. This allowed social groups to be maintained for many years despite recovery of testosterone in some males, suggesting that new social roles had been learned and become independent of androgen influence.

[GnRH agonist implants in small animal practice - what do we know 13 years following EU registration?] / GnRH-Agonisten in der Kleintierpraxis ­ Was wissen wir 13 Jahre nach der EU-Zulassung?

The availability of GnRH agonist implants offers the possibility of a reversible, temporary downregulation of endocrine and germinative testicular function in male dogs and hobs. This review provides an overview of the registered indication, the induction of temporary infertility in healthy, intact, sexually mature male dogs (4.7 and 9.4 mg deslorelin) and hobs (9.4 mg deslorelin) as well as various off-label indications. Off-label use requires strict indications, informed consent from the owner and a lack of licensed medication (safe and optimum effect). Off-label indications in the male dog include sexual-hormone dependant (disturbing) behavior, benign prostatic hyperplasia, small adenomas of the hepatoid glands and alopecia X. Successful use of deslorelin implants for estrus suppression in jils, but also for the treatment of hyperadrenocorticism in ferrets in general have been described. Similarly, hormonal castration can be induced in tomcats and queens. The variable time to onset of effect and its duration (extremely variable in some animals) represent a challenge for breeders. No (sufficient) contraceptive activity was identified in male rabbits and male guinea pigs; however, treatment did successfully suppress the estrus cycle in female individuals of these species, as well as reproductive activity in male and female rats. Regarding the use in birds and reptiles, significant species-specific differences exist with regard to efficacy, time until onset of effect and duration of downregulation. In birds, the implant is efficient to fully suppress egg laying in chicken, Japanese quail and psittacids. In doves, egg laying is only significantly reduced. Successful treatment of reproduction-associated (unwanted) behaviour patterns (feather picking, aggression) has also been described. In some male birds, namely zebrafinch and Japanese quail, the deslorelin implant is suitable to reduce testosterone levels. Successful treatment of hormone-dependent tumours (Sertoli-cell tumorus) in budgerigars has been described as well as the modulation of specific behavior in turkeys and an efficacy in facilitating their keeping (i. e. reduction of aggression). In reptiles, only the successful use of deslorelin in iguana has been demonstrated to date.

Contraceptive implants used by cat breeders in France: a study of 140 purebred cats.

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.

Phage constructs targeting gonadotropin-releasing hormone for fertility control: evaluation in cats.

OBJECTIVES: Phage-gonadotropin-releasing hormone (GnRH) constructs with potential contraceptive properties were generated in our previous study via selection from a phage display library using neutralizing GnRH antibodies as selection targets. In mice, these constructs invoked the production of antibodies against GnRH and suppressed serum testosterone. The goal of this study was to evaluate this vaccine against GnRH for its potential to suppress reproductive characteristics in cats. METHODS: Sexually mature male cats were injected with a phage-GnRH vaccine using the following treatment groups: (1) single phage-GnRH vaccine with adjuvant; (2) phage-GnRH vaccine without adjuvant and half-dose booster 1 month later; or (3) phage-GnRH vaccine with adjuvant and two half-dose boosters with adjuvant 3 and 6 months later. Anti-GnRH antibodies and serum testosterone, testicular volume and sperm characteristics were evaluated monthly for 7-9 months. RESULTS: All cats developed anti-GnRH antibodies following immunization. Serum antibody titers increased significantly after booster immunizations. In group 3, serum testosterone was suppressed 8 months after primary immunization. Total testicular volume decreased in group 1 by 24-42% and in group 3 by 15-36% at 7 months after immunization, indicating potential gonadal atrophy. Vacuolation of epididymides was observed histologically. Although all cats produced sperm at the conclusion of the study, normal morphology was decreased as much as 38%. Phage alone produced no local or systemic reactions. Immunization of phage with AdjuVac produced unacceptable injection site reactions. CONCLUSIONS AND RELEVANCE: Our phage-based vaccine against GnRH demonstrated a potential for fertility impairment in cats. Future research is required to optimize vaccine regimens and identify animal age groups most responsive to the vaccine. If permanent contraception (highly desirable in feral and shelter cats) cannot be achieved, the vaccine has a potential use in zoo animals or pets where multiple administrations are more practical and/or reversible infertility is desirable.

Comparative analysis of the reproductive activity of Leporinus piau (Characiformes: Anostomidae) in lentic and lotic environments

In this study, we determined the main reproductive parameters of piau gordura, Leporinus piau, in two sections of the São Francisco River basin. Between May 2015 and April 2016, a total of 573 specimens were captured from a lentic environment (section 1), the Três Marias Reservoir (TMR), and a lotic environment (section 2), downstream of the TMR at the confluence of the São Francisco River (SFR) with the Abaeté River. Analysis of reproductive activity showed that L. piau from both sections reproduced, but females and males from section 1 exhibited higher total length, body weight, Fulton condition factor, and gonadosomatic index values, as compared to section 2. Sexual dimorphism was evident in the species, with females being larger than males. Moreover, males reached first gonadal maturation at a smaller size than females. The peak maturation/mature stage was observed in November/April for females and males in section 1 and in November/December in section 2, coinciding with high temperatures and precipitation in the region. In both sections of the river, L. piau exhibited the typical characteristics of partial spawning, with a prolonged spawning period, and preferential reproduction in lentic environments.(AU)

Neste estudo, determinamos os principais parâmetros reprodutivos do piau gordura, Leporinus piau, em duas seções da bacia do rio São Francisco. Entre maio de 2015 e abril de 2016, um total de 573 espécimes foram capturados de um ambiente lêntico (seção 1), o reservatório de Três Marias (RTM), e um ambiente lótico (seção 2), à jusante da RTM na confluência do rio São Francisco (RSF) com o rio Abaeté. A análise da atividade reprodutiva mostrou que L. piau se reproduz nas duas seções, mas fêmeas e machos da seção 1 apresentaram maiores valores de comprimento total, peso corporal, fator de condição de Fulton e índice gonadossomático em comparação com a seção 2. O dimorfismo sexual foi evidente na espécie com as fêmeas sendo maiores do que os machos. Além disso, os machos atingiram a primeira maturação gonadal em tamanho menor do que as fêmeas. O pico do estágio de maturação/maduro foi observado em novembro/abril para fêmeas e machos na seção 1 e em novembro/dezembro na seção 2, coincidindo com altas temperaturas e precipitação na região. Em ambas as seções do rio, L. piau apresentou características típicas de desova parcelada com período de desova prolongada e reproduz preferencialmente em ambientes lênticos.(AU)

Retrospective characterization of reproductive tract lesions in relation to age, parity, and contraception in captive suidae and tayassuidae.

Reproductive management in zoos requires contraception or physical separation of sexes to ensure captive population viability, but information is sparse on the effects of parity, age, and contraceptive use on lifetime reproductive health in captive Suidae and Tayassuidae species. This retrospective study evaluated reproductive tissues and histories from babirusa (Babyrousa babyrussa), red river hog (Potamochoerus porcus), Visayan warty pig (Sus cebifrons), common warthog (Phacochoerus africanus), Vietnamese pot-bellied pig (Sus scrofa domesticus), domestic cross pig (Sus scrofa), Sunda island pig (Sus celebensis timoriensis), Eurasian boar (Sus scrofa), Bornean bearded pig (Sus barbatus), Ossabaw island hog (Sus scrofa domesticus), Guinea hog (Sus scrofa domesticus), Chacoan peccary (Catagonus wagneri), and collared peccary (Pecari tajacu). Age, parity, litter size, time-since-last-parturition, contraception exposure and type, and lesion prevalence were recorded. Reported chemical contraceptives used in females included porcine zona pellucida vaccine, progestins, GnRH analogues (deslorelin and leuprolide). Average litter size was significantly different between species (p < 0.0001) with the common warthog having the largest average litter size (3.5 ±â€¯0.2 offspring/litter). There was a trend for age to be positively correlated with leiomyoma/sarcomas (r = 0.6135; p = 0.0789). Progestins (medroxyprogesterone acetate, megestrol acetate, depomedroxyprogesterone acetate) were positively correlated (r = 0.8946; p = 0.0161) and GnRH analogues (deslorelin, leuprolide; subcutaneous) were negatively correlated with ovarian cysts (r = 0.9743; p = 0.0010). Across all species, there was a trend for age to be negatively correlated with folliculogenesis (r = -0.6528; p = 0.0566) and parturition gap length to be negatively correlated with follicular cysts (r = -0.8944; p = 0.1). Common warthog, babirusa, and Vietnamese pot-bellied pigs had the greatest diversity of uterine lesions and the highest prevalence of reproductive tract lesions of all species evaluated. Four of the 27 males (14.5%) in the dataset had testicular tumors. All males had prominent testicular interstitial cell populations, which appears to be within normal limits for these species. These data suggest prolonged gaps between pregnancies, age, and contraception are risk factors for reproductive tract lesions in Suidae.

Contraception within an elasmobranch captive breeding programme: a case report on the eagle ray Aetobatus ocellatus using gonadotrophin-releasing hormone (GnRH) agonist deslorelin (Suprelorin).

This study describes the first case of contraception within a captive elasmobranch breeding programme where an implant of Suprelorin, containing a long-acting gonadotrophin-releasing hormone (GnRH) analogue Deslorelin, was implanted in an eagle ray Aetobatus ocellatus, which successfully halted breeding.

Manipulation of the oestrous cycle of the bitch-what works for now.

Manipulation of the oestrous cycle of the bitch is a common request of pet owners for different reasons. On one side, clients may be interested in temporally preventing oestrus until the bitch has finished the performance career, or to manage the kennel in the presence of a stud dog and to avoid undesirable breeding. Additionally, clients with no interest to use their animal for breeding, may, for ethical reasons, prefer to avoid elective surgery such as ovariectomy, to control reproduction. On the other side, clients may want to induce oestrus to better control the time of birth, to use a male with limited availability during a specific time, or to reduce the duration of the interoestrous interval in bitches with a long oestrous cycle (>8 months). Both these options for oestrous manipulation are based on hormonal treatments. For oestrous prevention, synthetic progesterone has been used since the 1960s. Induction of oestrus has been established with reliable results using dopamine agonists in the late 1980s and more recently using GnRH agonists. This review is focusing on the current and recently available treatments to manipulate the oestrous cycle in the bitch.

Fertility control for managing free-roaming feral cattle in Hong Kong.

Human-wildlife conflicts are increasing worldwide. For instance, growing numbers of free-roaming feral cattle in Hong Kong are causing traffic accidents and damaging crops. Public antipathy towards lethal methods to manage wildlife has promoted research into alternative options, such as fertility control. The aims of this study were to assess the potential side effects and effectiveness of the injectable immunocontraceptive vaccine GonaCon on free-roaming feral cattle in Hong Kong. Sixty female cattle were captured and randomly assigned to treatment or control groups. Treatment animals were administered one dose of GonaCon, followed by a booster dose 3-6 months later. Control animals were administered an equivalent dose of a saline solution. The side effects of GonaCon were assessed by monitoring injection site, body condition and body weight at vaccination, at the booster stage and one year after initial vaccination. At the same times, blood samples were collected to quantify antibodies to the vaccine and to assess pregnancy status. GonaCon did not affect the body weight or body condition of cattle and had no adverse side effects such as injection site reactions, limping or abnormal behaviour. GonaCon did not appear to interrupt ongoing pregnancies but reduced fertility significantly: the proportion of pregnant animals in the GonaCon-treated group decreased from 76% at initial vaccination to 6% one year after vaccination, compared to 67% and 57% respectively in the control group. There was no difference between antibody titres at the booster stage or one year post vaccination, suggesting the booster dose maintained antibody levels. This study confirmed that GonaCon is safe and effective in inducing infertility in feral cattle, with a booster dose critical for maintaining infertility.

Hybrid model intermediate between a laboratory and field study: A humane paradigm shift in feline research.

OBJECTIVES: Non-surgical contraceptives are under development to provide accessible, affordable and humane alternatives for the management of free-roaming cat populations. The objective of this project was to develop a research approach for promising non-surgical contraceptives using outbred cats in a simulated free-roaming setting, meeting high standards for both animal welfare and scientific rigor. METHODS: A facility, specially constructed with indoor and outdoor living areas, was approved and regulated as both an animal shelter and a United States Department of Agriculture research facility. Thirty female and five male cats, healthy but at high risk of euthanasia, were recruited from animal shelters and private homes. Guided by a detailed protocol, cats were housed in this facility for up to 18 months after acclimatization. Cats were administered the study product or a placebo, and then entered into a breeding trial. Cats were adopted at the end of the study. A range of methods was used to provide enrichment and balance a natural environment with the need for detailed daily monitoring. RESULTS: Primary study results related to contraceptive safety and efficacy are published separately. Achieving a research model that is an intermediate step between a laboratory and an uncontained free-roaming cat colony was complex. Significant learnings shared in this current publication span: the selection of cats; acclimatization to a simulated colony environment; cat behavioral training during the study and in preparation for adoption; disease management; contract staff and volunteer support; and cat behavior throughout a breeding study. CONCLUSIONS AND RELEVANCE: This model inspires continued movement away from the paradigm of breeding cats for research and instead sources existing cats at risk for euthanasia. The housing and management of the cats elevates research animals' quality of life and provides positive post-study outcomes. While not appropriate for every feline research scenario, this hybrid model (between a laboratory and field study) proved to be a practical, humane and reliable scenario for research requiring a simulated real-world environment.

Postponement of canine puberty by neonatal administration of a long term release GnRH superagonist.

The objective of this study was to assess the efficiency and clinical safety of postnatal administration of a GnRH agonist on canine puberty postponement. Sexual steroids and histological gonadal changes were also described. Twenty-four littermate puppies were randomly assigned to: Deslorelin acetate 18.8 mg sc (DESLO; n = 12) or Placebo: sc (PLACE; n = 12) postnatally. The dogs were clinically and endocrinologically followed up until puberty when they were gonadectomized and their gonads histomorphometrically studied. Deslorelin postponed the age of puberty (72.7 ±â€¯4.8 vs. 35.8 ±â€¯1.9 weeks; P < 0.01) in these dogs. At the time of this submission, 3 DESLO dogs (108 weeks old) remain non-pubertal. All dogs concluded growing at a similar age (29.75 ±â€¯2.44 vs. 29.25 ±â€¯0.90 weeks; P > 0.1) independently of their group and pubertal status. None of the females had side effects while the 2 non pubertal DESLO males presented bilateral cryptorchydism. All the bitches ovulated at puberty (P > 0.1) and the 2 DESLO that were mated became pregnant. Deslorelin postponed basal serum sexual steroids up to puberty in both genders (P < 0.01). The histomorphometrical study of the testes revealed that the tubular diameter (P < 0.05), germinal epithelium height and composition (P < 0.01) were decreased in DESLO group. Ovarian structures did not differ between treatments (P > 0.05). It was concluded that postnatal deslorelin decreased sexual steroids reversibly postponing puberty in both genders without side effects in bitches and causing 2/6 of cryptorchydism and impairment of testicular histomorphometry in male dogs.

Gonadotrophin-Releasing Hormone Agonists and Other Contraceptive Medications in Exotic Companion Animals.

The use of a gonadotrophin-releasing hormone agonist slow-release implant (GnRH A-SRI) has become increasingly popular as an alternative for surgical contraception in many species. Although these implants have proven to be very effective in some species (eg, ferrets, rats, chicken, psittacines, and iguanas), they have been found less effective in other species (eg, male guinea pigs and rabbits, veiled chameleons, slider turtles, and leopard geckos). This review provides an overview of the available literature on the effects of GnRH A-SRIs in companion exotic animals.

Wildlife population control ­ reproductive physiology under the influence of contraceptive methods in mammalian wildlife, with emphasis on immunocontraception: the best choice? A literature review / Controle da população em animais selvagens ­ fisiologia reprodutiva sob a influência de métodos anticoncepcionais em animais mamíferos, com ênfase na imunocontracepção: a melhor escolha? Uma revisão da literatura

Human-wildlife conflicts, a growing and sad reality worldwide, makes population control of wildlife and feral animals one of the biggest challenges in wildlife management, especially due to the rapidly expanding human population, and consequently the ever-diminishing natural habitats of animals. Human activities and the destruction of nature forcing wildlife to move inevitably into urban and agricultural areas, causing "conflicts", such as the risk of zoonosis and traffic accidents, as well as damage to crops in the search for food, whose losses reach millions of dollars. For decades, science has been engaged in extensive efforts to develop methods of "humane" population control methods, and many techniques are being employed in order to control wildlife population. In this article, we present an overview of applied contraceptive methods with simplified graphic demonstrations of their interactions with reproductive physiology, furthermore relating pro and contra of utilized antifertility agents. These are being compared to a set of desired characteristics for free-ranging wildlife for in-field applications, with emphasis on reversible immunocontraception ­ concluding, therefore, the reasons why this concept is becoming the most appropriate and promising for free-ranging wildlife.(AU)

Os conflitos Humanos-Animais Selvagens são uma realidade crescente e triste no mundo inteiro, tornando o controle populacional da fauna silvestre e animais ferais o maior desafio, principalmente diante do crescimento da população humana e, consequentemente, da diminuição dos habitats naturais dos animais. As atividades humanas e a destruição da natureza, forçam os animais de vida livre a se dirigirem para áreas urbanas e agrícolas, inevitavelmente, causando conflitos, como o risco de zoonoses, acidentes de trânsito, bem como danos às plantações, quando em busca de alimentos, cujo prejuízo chega a milhões de dólares. Durante décadas, a ciência esteve empenhada em esforços extensivos para desenvolver métodos de controle populacional "humano"; e muitas técnicas foram utilizadas, a fim de se realizar um controle populacional destes animais silvestres. Neste artigo será apresentada uma visão geral dos métodos anticoncepcionais aplicados, com demonstrações gráficas simplificadas de suas interações com a fisiologia reprodutiva, bem como relacionando os prós e os contras dos agentes antifertilidade empregados; também serão comparados com um conjunto de características desejadas para as aplicações em fauna a campo, com ênfase em imunocontracepção reversível, concluindo assim, com as razões do porque este conceito torna-se o mais apropriado e promissor para animais silvestres de vida livre.(AU)

Vectored gene delivery for lifetime animal contraception: Overview and hurdles to implementation.

There is a need for permanent, non-surgical methods of contraception for many animal species. Here we discuss the hypothesis that transgene-mediated expression of fertility inhibiting molecules such as monoclonal antibodies, ligands for cell surface receptors, receptor decoys, or small RNAs can provide such a method, which we term vectored contraception. We outline the technologies involved, progress made, and discuss challenges to implementation.