companion animal breeding and welfare

what is a tame wild animal?

accepted living alongside humans, dont carry out expected natural behaviour

what do animals need in order to be domesticated?

• polyphagic - cannot have specific diet (only one food overly = monophagic)

• relatively fast growth rate - reaching adulthood in a year

• likely to breed in captivity

• docility - calm animal

• unlikely to panic

• is animal social? does it have social hierarchy? - needs to be structured so we can step in as role

the huge variation within companion animal species of atypical (compared to wild) size, colour, behaviour etc is a result of what?

purposive selection

what is the process of ‘creating’ new strains of an individual animal is brought about by what?

actively discarding animals from the breeding population who do not meet the standard and accelerating the breeding of those that do meet the standards

what are disadvantages of selective breeding?

we as humans pick the characteristics we like/prefer without considering the need for a characteristic in an animal itself or the consequences should that characteristic be removed

if characteristic is removed there is the chance it will be gone forever, many mutations are down to chance

what is paedomorphism ?

the retention of juvenile traits into adulthood

what is a negative impact of paedomorphism?

can impact intraspecific communications

what is survival of the fittest?

in the wild environment, if not able to survive, they will not survive and are unlikely to pass on their genetics, unequal reproduction

how is survival of the fittest different in domestication and in the wild?

many domesticated breeds would be unable to survive in wild environment

some species see continued selection for utility , meat or sporting value

how can we evaluate objectives in a breeding programme?

• selection for characteristics within a breed, sub-species or species

• cross-breeding

• capturing mutations when they arise (not all mutations are negative)

how is species and sub species different?

generally geographically separated, could still viably mate

eg african elephant is species, forest african elephant is sub species

how is breed and sub species different?

subspecies are a separate part of the species, generally geographically separated by can still viably mate with other members of the species

breed and sub species are the same however breed is human done

when breeding we will pair individuals showing exaggerated forms of the trait, what negative impact can this have ?

welfare impacts if the characteristics has a direct effect on something

if selecting characteristics; concentrates harmful genes relating to them

what is tandem selection?

focus on one characteristic at a time

what is parallel selection?

variety of characteristics selected for simultaneously

how do we prioritize certain traits over others ?

when looking at more than one characteristics can be scored numerically and weighted according to their importance

when is animal welfare affected in terms of selective breeding?

when focus on aesthetic traits leaves little selection for health

why do we cross-breed?

used with the aim of combining characteristics that are believed to be desirable , from 2 or more existing breeds

what is hybridisation?

2 species produce offspring carrying traits from both species

• less common in the wild - unlikely to come into contact

• assumption that offspring are infertile, not always

following selection for animals that show the desired trait or combinations of traits by a breeder , efforts may be made to continue the relevant genes in the descendent population,

what is the aim of this?

how can this be achieved?

to result in all offspring in the future holding the trait

fixing mutations generally requires a degree of inbreeding , siblings mating , parent offspring mating (back-crossing), half siblings

as inbreeding increases so does the effect of inbreeding depression, what are the impacts of this ?

• loss of fertility

• reduced birth weights

• reduced litter size

• reduced neonate size

• increased risk of disease

some impacts do not impact directly on welfare (eg impaired fertility)

selective breeding can result in exaggerated morphology what are the problems of this ?

• communication affected (eg taillessness in cats)

• long hair needing constant management and behavioural challenges

• short hair leading to hypothermia/sunburn

• some colours link to health challenges

• decreased body size leads to smaller brain and smaller offspring

one of the most commonly known morphology challenges is brachycephalic, selecting for these face traits can lead to what health and welfare problems?

• skin folds

• laboured breeding, prolapsed soft palates

• ocular problems as a result of selection for particular eye and eyelid shapes

• syringomyelia in cavalier king charles spaniels

what is the founder effect?

loss of genetic variation which can be seen when a new population is established from a limited number of individuals , small group start a new population

what is a population bottleneck?

environmental effect reduces the size of a population and the new population is only built from those original survivors