Inbreeding does not create undesirable recessive genes, but it does tend to bring to light these unfavorable genetics. This leads to a decline in average phenotypic performance called inbreeding depression. This phenomenon is well documented in all the major livestock species.
The most obvious effects of inbreeding are poorer reproductive efficiency including higher mortality rates, lower growth rates and a higher frequency of hereditary abnormalities. This has been shown by numerous studies with cattle, horses, sheep, swine and laboratory animals.
What are the do's and don'ts of breeding a bull to his daughter, mother, granddaughter, or sister? Mating any of the above would result in a high level of inbreeding. Generally speaking, inbreeding of this nature should be avoided.
I've been asked by several breeders if it is "OK to breed two half-siblings" (usually, a bull and a cow that share the same sire). The short answer is that there is nothing "wrong" with breeding any two animals of any degree of relatedness, as long as one realizes the potential risks and benefits of the mating.
The advantage of inbreeding in cattle are: - It guides in developing a pure line in any animal. - It can concentrate on the genes of a superior ancestor. - It can fix the desired type relatively quickly.
Can you breed registered cattle father to daughter, mother to son, and brother to sister? Mating of beef cattle that are close relatives (brother-sister, sire-daughter, son-dam) produces high levels of inbreeding. Inbreeding generally is detrimental to long-term reproductive performance and growth.
You can have father-daughter matings in beef cattle, but it is not recommended. This type of breeding practice is called inbreeding or close breeding. Again, this breeding practice is rarely practiced today, although it was common in the foundation animals of most breeds.
Inbreeding means mating father to daughter, mother to son, and brother to sister. Line breeding involves mating more-distantly related animals, although there is a conventional wisdom that says line breeding is whatever works and inbreeding is whatever doesn't.
If a cow gives birth to male and female twins, the female calf will never be able to breed. If it's two males, no problem. If it's two females, no problem. But if she gives birth to a male and a female, the female calf is infertile.
The mating couple.
Usually a bull will mate with a cow once, but it's not uncommon if it's done several times, especially if she has garnered the attention of more than one.
Bulls exhibit first sexual interest about three weeks prior to puberty and attain mating ability about 6 weeks after puberty. Although bulls that have reached puberty can breed, reproductive capacity increases as the bull continues to mature.
To achieve the ideal calving distribution, the guidelines for the length of mating are: maximum 60 days for bulls run with cows. minimum 45 days for bulls run with cows (if bulls are not run with the cows for long enough, the calving percentage is decreased).
Studies have confirmed an increase in several genetic disorders due to inbreeding such as blindness, hearing loss, neonatal diabetes, limb malformations, disorders of sex development, schizophrenia and several others.
Inbreeding increases the risk of recessive gene disorders
Inbreeding also increases the risk of disorders caused by recessive genes. These disorders can lead to calf abnormalities, miscarriages and stillbirths.
Some species don't bother, and don't seem to suffer, but mice, sand lizards and some shorebirds certainly do. For example, Black-legged kittiwake chicks are much more likely to die if their parents are closely related to each other, but this doesn't happen often because females try to select unrelated males.
The highest level of inbreeding by far (> 80%) is for the Norwegian Lundehund.
The most common parent-offspring mating is the breeding of a bull to his own daughters. This often happens in small "single bull" herds and occurs more rapidly than most people realize. When replacement heifers are kept from within the herd, close inbreeding will occur when a bull is used for three or more years.
The good news is: It is possible to leave bulls with the cows year-round and still maintain a calving season of three months or less.
You can avoid inbreeding if you utilize several breeding groups – if you know the parents of the cows. This is impossible, however, if cattle are bred on summer range where all cattle are pastured together. “At home, you can create separate breeding groups,” says Thomson.
Certain breeds, such as Simmental, Charolais, and Holstein, and also large heifers are more likely to produce twins. On the downside, cows that deliver twins have twice as many problems as cows that only deliver a single calf.
Inbreeding can lead to 'inbreeding depression': a reduction in available traits for offspring, making the population less genetically diverse and thus less able to adapt to their environments.
Individuals are expected to avoid mating with relatives as inbreeding can reduce offspring fitness, a phenomenon known as inbreeding depression. This has led to the widespread assumption that selection will favour individuals that avoid mating with relatives.
Conclusion. Inbreeding is a double-edged sword. On the one hand a certain amount of inbreeding can fix and improve type to produce excellent quality animals. On the other hand, excessive inbreeding can limit the gene pool so that the breed loses vigor.