Inbreeding in captive populations of animals also occurs, and is generally done intentionally for various reasons. Animals can become inbred as a result of selective breeding for desirable traits. Animals in captivity face different selection pressures in comparison to those in the wild, as they are provided with optimal environmental conditions and have the natural ability to choose a mate removed. Breeding solely within a single captive population of animals eliminates the addition of different alleles to the gene pool and reduces the genetic diversity of the population. This means that the probability of genetic material being more uniform is more common in a captive population and so inbreeding depression is more likely to occur.
Inbreeding is likely to occur on commercial farms as a by-product of selective breeding. As many of the animals will possess the alleles for the same desirable traits to maximise yield and profit, these animals will be bred and this can have a negative impact on animal welfare. For example, dairy cattle can be bred for maximum milk production, and even though this increases profit for a farmer, it has adverse effects on the cow, leaving it more susceptible to diseases such as mastitis and milk fever, and therefore reduces the cow’s ability to survive and reproduce. This has been recognised and the issue surrounding casual breeders has been discussed ‘High producing cows are increasingly difficult to breed and are subject to higher health costs than cows of lower genetic merit for production’ (Cassell, 2001). Despite the fact that this is not characterised as breeding between closely-related individuals, the effects of inbreeding remain visible due to the close genetic uniformity. On the other hand, closely-related individuals can be bred together in an attempt to initiate a desirable trait in a herd and whilst this may occasionally be successful, undesirable characteristics can become evident in the offspring produced, as the frequency of recessive alleles increases in the herd, with potential deleterious effects. The offspring with these characteristics can be removed through more selective breeding, however as only these individuals are being bred, without the addition of new alleles these offspring will continue to be produced, exhibiting the reduced biological fitness as a result of the animals used. Likewise to the aforementioned viper case, to counter inbreeding in commercial / production animals if symptoms of inbreeding depression are evident, a farmer can introduce an animal from a different bloodline to the existing animals in the herd. This is another example of outbreeding and results in the addition of new genetic material into the herd to prevent the unprofitability that occurs as a result of inbreeding depression, with the culling of deformed offspring prevented and a reduced cost of treating the animals that are more susceptible to diseases. Similarly to commercial animals, when inbreeding depression occurs in domestic animals it is generally as a result of selective breeding for desirable …show more content…
This increase in homozygosity is what causes the increased susceptibility to disease in many pedigree breeds. This is displayed through the bearded collie, which has an average inbreeding coefficient of 14.9%, higher than the equivalent of a grandparent and grandchild mating (12.5%). This level of inbreeding has resulted in the breed becoming more susceptible to Addison’s disease, an autoimmune disease that affects the adrenal glands, resulting in an adrenal insufficiency in the body. Although not
Inbreeding is likely to occur on commercial farms as a by-product of selective breeding. As many of the animals will possess the alleles for the same desirable traits to maximise yield and profit, these animals will be bred and this can have a negative impact on animal welfare. For example, dairy cattle can be bred for maximum milk production, and even though this increases profit for a farmer, it has adverse effects on the cow, leaving it more susceptible to diseases such as mastitis and milk fever, and therefore reduces the cow’s ability to survive and reproduce. This has been recognised and the issue surrounding casual breeders has been discussed ‘High producing cows are increasingly difficult to breed and are subject to higher health costs than cows of lower genetic merit for production’ (Cassell, 2001). Despite the fact that this is not characterised as breeding between closely-related individuals, the effects of inbreeding remain visible due to the close genetic uniformity. On the other hand, closely-related individuals can be bred together in an attempt to initiate a desirable trait in a herd and whilst this may occasionally be successful, undesirable characteristics can become evident in the offspring produced, as the frequency of recessive alleles increases in the herd, with potential deleterious effects. The offspring with these characteristics can be removed through more selective breeding, however as only these individuals are being bred, without the addition of new alleles these offspring will continue to be produced, exhibiting the reduced biological fitness as a result of the animals used. Likewise to the aforementioned viper case, to counter inbreeding in commercial / production animals if symptoms of inbreeding depression are evident, a farmer can introduce an animal from a different bloodline to the existing animals in the herd. This is another example of outbreeding and results in the addition of new genetic material into the herd to prevent the unprofitability that occurs as a result of inbreeding depression, with the culling of deformed offspring prevented and a reduced cost of treating the animals that are more susceptible to diseases. Similarly to commercial animals, when inbreeding depression occurs in domestic animals it is generally as a result of selective breeding for desirable …show more content…
This increase in homozygosity is what causes the increased susceptibility to disease in many pedigree breeds. This is displayed through the bearded collie, which has an average inbreeding coefficient of 14.9%, higher than the equivalent of a grandparent and grandchild mating (12.5%). This level of inbreeding has resulted in the breed becoming more susceptible to Addison’s disease, an autoimmune disease that affects the adrenal glands, resulting in an adrenal insufficiency in the body. Although not