Intratesticular and intraepididymal injections to sterilize male cats: From calcium chloride to zinc gluconate and beyond

Male animal sterilization: history, current practices, and potential methods for replacing castration

Sterilization and castration have been synonyms for thousands of years. Making an animal sterile meant to render them incapable of producing offspring. Castration or the physical removal of the testes was discovered to be the most simple but reliable method for managing reproduction and sexual behavior in the male. Today, there continues to be global utilization of castration in domestic animals. More than six hundred million pigs are castrated every year, and surgical removal of testes in dogs and cats is a routine practice in veterinary medicine. However, modern biological research has extended the meaning of sterilization to include methods that spare testis removal and involve a variety of options, from chemical castration and immunocastration to various methods of vasectomy. This review begins with the history of sterilization, showing a direct link between its practice in man and animals. Then, it traces the evolution of concepts for inducing sterility, where research has overlapped with basic studies of reproductive hormones and the discovery of testicular toxicants, some of which serve as sterilizing agents in rodent pests. Finally, the most recent efforts to use the immune system and gene editing to block hormonal stimulation of testis function are discussed. As we respond to the crisis of animal overpopulation and strive for better animal welfare, these novel methods provide optimism for replacing surgical castration in some species.

Hypertonic Activity of Injection Solutions Can Cause Post-injection Complications (Review)

Introduction. A review of the scientific literature showed that the current standards for assessing the quality of drugs does not include an assessment of the osmotic activity of drug solutions and their local irritant effect on tissues at the sites of subcutaneous, intramuscular and intravenous injections. Therefore, currently injectable solutions considered to be of high quality may not have isotonic activity and high postinjection safety.

Text. A study of the concentration range of quality drug solutions ready for injection showed that the acceptable concentration value of the main ingredients is in the range of 0.01 to 76 %. Direct measurement with an osmometer of the osmotic activity of injection solutions, considered qualitative today, has shown that injection solutions can have hypotonic, isotonic and hypertonic activity and their osmotic activity can be in the range of 0 – 3900 mosmol/l water. Study of acidic activity of drug solutions showed that in accordance with pharmacopoeial requirements of drug quality modern quality drug solutions ready for injection can have acidic, neutral or alkaline activity. Solutions with hypertonic activity have been found to have a local irritant effect. Moreover, an increase in hypertonic activity of drug solutions increases their local irritant effect. It has been found that excessively high hypertonic activity of drug solutions may be the cause of the development of a local postinjection complication known as "Nicolaou syndrome", the cause of which has remained unknown for a long time. Nicolaou syndrome includes local pain syndrome, aseptic inflammation, necrosis, and abscess.

Conclusion. The authors conducted a literature review, the results of which led to conclusions and assumptions. Solutions containing drugs in concentrations greater than 10 % may have the highest hypertonic activity, which can cause excessive dehydrating, local irritating and cauterizing effects. Therefore, injections of such drugs are most dangerous with the development of post-injection necroses and abscesses. That is why timely dilution of concentrated drug solutions with water by 2–10 times increases injection safety. It is proposed to include the assessment of osmotic activity and local irritant effect of drug solutions in the standard of drug quality control.

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.

Fertility Control in Wildlife: Review of Current Status, Including Novel and Future Technologies

Wildlife conservation requires varying degrees of management of endangered species as well as management of their potential predators and competitors. Conservation also depends on ameliorating human-wildlife conflict, especially where there is a threat to the safety of people and of their pets and livestock. In addition, sustainability of wildlife populations can be affected by feral domestic animals or invasive species, that require removal or control. With the increasing concern for animal welfare, non-lethal methods of limiting population size and distribution, such as fertility control, are gaining favor. Breeding programs in zoos depend on highly effective and selective contraception to manage sustainable insurance populations. This review covers fertility control methods currently in use, those that have not lived up to past promises, and others that are under development and present hope for addressing remaining challenges.