Companion Animal Breeding and Welfare Flashcards
Domestication
.
• Domesticationistheprocessofadapting(wildplantsand)animalsfor
human use and has a biological and cultural component.
• Biological–parentanimalsbecomereproductivelyisolatedfromthewild population and form a smaller group which will inbreed and undergo genetic drift.
• Over successive generations, this domestic “species” will multiply and be changed genetically by natural selection in the human environment.
• Cultural–domesticationbeginswhentheanimalistakenintothesocial structure of the human community and becomes, for the first time, “owned”.
• Over time, these tamed animals, through the combined effects of artificial and natural selection, breed further and further from their wild counterparts and develop into the domesticated animal.
• Thelatestphaseofthisculturalprocessiswhentheindividualownershipof the animal is enforced with a head collar and saddle, collar and lead or fenced, contained areas or fields, and like any other object the domesticated species can be bought, sold or exchanged at will.
Many suggest that a key factor in domestication is suppression of the animal’s “perceptual world”.
• A high degree of perception and quick reactions to stress are required for survival in the wild, whereas the opposite characteristics of docility, lack of fear and tolerance of stress are required for domestication.
• Unconscious and conscious selection for lowered perception would have begun with the earliest domesticated animals.
History of the Dog
Dog - Distinct breeds of dog seem to have appeared about 3000-4000 years ago.
• The greyhound type seems to be one of the most ancient of the foundation breeds, common in ancient Egypt alongside those kept as hunting and guard dogs.
• By the Roman period, most of the main breed types of dogs that exist today were well defined – hunting, guard, lap and sheepdog types were common.
• The Romans were aware of the principles of selective breeding and the benefits of early training.
History of the cat
Many have believed that it was the ancient Egyptians that domesticated the cat about 3600 years ago, however archaeological evidence from Cyprus demonstrates a cat buried with a human that is 9500 years old.
• Recent research suggests that cats were attracted to farming communities due to the mice and rats present feeding on the farmed crops.
• They provided a service to the farmers, keeping down the rodent population and so were allowed to stay, effectively domesticating themselves.
Attitude to animals in Middle Ages and Renaissance.
- The great era for the proliferation of dog breeds in Europe was the Middle Ages, from the 13th to the 15th centuries.
- The aristocracy use different breeds of dog for different types of hunting which increased their status and power and so developed wolfhounds, boarhounds, otterhounds and sighthounds.
- Pet–keeping was only acceptable amongst the clergy and the aristocracy.
- Anthropocentrism dominated the thinking during this time and animals were held responsible for their actions and so could be tried and sentenced.
Attitude to animals in 16th and 17th Centuries.
• Superstition and fear of satanic powers created a lot of mistrust in many animals including the dog but, in particular, the cat.
• Cats eyes with their vertical slits gives them a resemblance to snakes and this connection with a “serpent” and evil (Bible - the serpent in the Garden of Eden) meant that cats have often been associated with evil and the occult.
• The Witch Trials between 1566 and 1684 put some animals, especially cats, “in league with the devil” and they were often burned at the stake alongside “witches”.
“It was permitted for a witch to take her Cattes body nine times”.
(Beware the Cat, 1560).
Attitude to animals in 18th Century.
• Change in attitudes led to greater sympathy for
animals.
• A burgeoning interest in science.
• Vivisection came under attack.
• A lessening of the power of the Church.
• Jeremy Bentham (1748 – 1832) coined the phrase,
“ The question is not, can they reason? Nor, can they talk? But, can they suffer? Why should the law refuse its protection to any sensitive being”.
Attitude to animals in the 19th Century.
• 19th Century English Law viewed animals
as the property of human owners.
• But whilst human superiority was reinforced, more humane attitudes towards animals developed and animal welfare became of interest.
• The first official dog show was held in 1859.
• The first modern cat show in the UK was held in 1871 and the ‘The Standard of Points of Excellence and Beauty’ were developed for the breeds that existed at the time.
Attitude to animals in in the • 20th Century.
• Two world wars and an intervening economic recession slowed the pace of
the animal welfare movement.
• The 60s and 70s saw a major revival of interest in animal welfare and animal rights and involved the publication of certain very influential books.
• “Animal Liberation” – Peter Singer.
• “The Case for Animal Rights” – Tom Regan • “Victims of Science” – Richard Ryder.
The History of Selective Breeding of Companion Animals.
- The huge variation within companion animal species of atypical (compared to wild) size, colour, behaviour etc is a result of purposive selection by humans attempting to achieve a particular goal.
- The ‘creation’ of new strains is brought about by actively discarding animals from the breeding population that do not meet the “standard” and accelerating the breeding of those that do.
- This is, essentially, the same process of evolution that occurs in nature, however instead of the driver being “fitness” and “survivability” it is usually based on active selection for the way an animal looks and for particular traits that suit us.
- “Survival of the fittest” is not relevant to domestic species and many breeds of companion animal perpetuate although would not survive in the wild environment.
- Whilst there continues to be selection for utility, e.g. guide dogs, most selection criteria is based on either sporting value or aesthetics
- The welfare consequences of selective breeding will depend upon whether the selection is for a change that may be beneficial or harmful or perpetuates a phenotype with beneficial or harmful traits.
- We commonly think about selective breeding practices causing problems in dogs, but a range of companion species can be affected.
Breeding Programmes.
- Whether we are breeding beef cattle in order to produce more meat or a dog to have longer ears the principles behind breeding programmes are the same.
- A breeding programme is aimed at defined breeding objectives for the production of a next generation of animals.
- This involves –
- Recordingselectedtraits,
- Theselectionofpotentialparents,
- Establishingamatingprogrammefortheselected parents.
Breeding Strategies.
• (Methods used for selection and genetic modification.)
• There are three key methods utilised to produce new types –
1. Selection for characteristics within a breed, subspecies or species.
2. Cross-breeding to combine traits from two or more breeds.
3. Capturing mutations as and when they arise to spread the trait.
Selection for characteristics.
Breeders may focus on one trait (size, colour,
temperament).
• The approach would be to pair individuals that show an exaggerated form of the trait, e.g. a dense white appearance in certain breeds of cat.
• This method can impact on welfare if –
• The change to the characteristic has a direct effect, e.g.
white coat and ear tip squamous cell carcinoma in cats.
• If selecting for the trait concentrates harmful genes linked to the gene that regulates the trait.
• Often the focus is on multiple traits –
• Tandem selection - focusing on one character at a time and only moving on to address the next after progress with the
first.
• Parallel selection - a variety of characters are selected for simultaneously.
• Charactersmaybescorednumericallyandweightedaccordingtotheirrelativeimportancetothebreeder, e.g. in the Shar Pei exaggerated skin folds may be considered to be more important than tail length.
• Individualsarethenselectedforbreedingonthebasisoftheirtotalweightedscores.
• Welfare can be affected because focussing on aesthetic traits leaves little selection pressure for health traits.
Cross-breeding to combine traits from different breeds or strains.
- Cross-breeding is used with the aim of combining characteristics, that are believed to be desirable, from two or more existing breeds, for example –
- Dogs – Recent interest in crossing pedigree breeds, e.g. Cockapoos, Labradoodle.
- Horses - Arabs have been cross-bred with many other breeds with the aim of gaining some of their respected characteristics.
- Exotics - Gopher snakes x cornsnakes for appearance or behavioural traits.
Breeding to capture traits or new mutations.
- Following selection for animals that show the trait or combinations of traits desired by the breeder, efforts may then be made to ‘fix’ the relevant genes in the descendent population so that all in future will breed true for these characters.
- Fixing mutations generally requires a degree of inbreeding (the mating of related individuals).
Techniques involved include –
• Sibling-mating - mating together of full brothers and sisters.
• Parent-offspring mating or backcrossing - mating the offspring with its parent.
• Half-sibling matings.
• However, as noted above, there is a risk that, in selecting for particular desired features in this way, potentially harmful genes may be concentrated in the population.
• The detrimental effects of inbreeding have been known for many years and were studied and discussed by Darwin in the mid 1800s.
Consequences of selective breeding techniques.
- Hybridisation, back-crossing and inbreeding may all occur at times under natural conditions and may have played parts in the adaptation of populations to their environments.
- They do not necessarily always have harmful effects, indeed they can be beneficial under some circumstances.
- However, as mentioned above, their welfare consequences may often be more likely to be adverse than beneficial.
