Reproductive health in domestic animals.

Introduction This review article is targeted at readers with knowledge of human reproductive health and it attempts to focus on reproductive differences between man and animals. It is not the authors’ intention to provide an extensive review of reproductive health of all animal species with the exception of man. The review ends with a list of suggested further reading for those readers interested in exploring this fascinating topic in greater detail. Instead, this review concentrates on production and companion animals. Production animals must generate their owner a profit, whilst companion animals are often considered to be cherished family members. The owner’s attitude to these two types of animal is thus quite different. Man has interfered with animal reproductive health since domestication started. Man wants animals to breed when ‘required’ and to stop procreating when the owner dictates. Man also wants to decide the genetic constitution of the offspring. In short, man wants to decide when mating takes place and between which particular animals. These requirements are taken to be a fundamental part of domestication. This interference in animal reproductive health concentrates on two main issues: breed when needed and stop breeding when not desired. The policy is utilised in two ways in the two main forms of domestication: production animals (e.g. cow, sheep, horse, camel, poultry, fish, dog) and companion animals (mainly dogs and cats, although horse, poultry and fish may be included in this category). The breeding policy is different for the two groups, as is the attitude towards the individual animals concerned. Many techniques used in human reproduction have been developed by veterinarians and vice versa, and the extensive exchange of knowledge has benefited both professions. However, it is rarely possible to extrapolate from one species to another without careful investigation. One must especially beware against taking a drug from the human clinic, adjusting the dose using a formula based on milligrams of drug per kilogram of weight, and expect a valid result when the drug is injected into an animal. Sometimes the effect may be the opposite of that expected in humans (e.g. morphine will make a cat hyperactive).