Crossbreeding

Crossbreeding: Full Explanation with Myths & Truths

Crossbreeding is a process which encompasses a significant amount of debate and discussion within the domain of cattle business around the world. Crossbreeding is a process that is of significant interest to the beef producers and there are some myths and truths that are associated with the phenomenon of crossbreeding which is being undertaken on a wide scale in the modern cattle industry around the world. Now our experts from Assignment Help UK will tell you about the benefits of crossbreeding.

Crossbreeding has benefits: Truth

            It can be said that crossbreeding has several benefits such as a process known as heterosis. Heterosis can be defined as a phenomenon where a progeny of several varieties of a species or crosses between various species of cattle demonstrate increased biomass, developmental speed, and rate of fertility as compared to both the parents. The other major advantage crossbreeding is the element of breed complementarity. According to historical pieces of evidence, heterosis or hybrid vigor can be considered to be a positive result generating from the act of crossbreeding cattle as a crossbred animal has superiority in comparison with the average of its parents that are straight-bred. An enhancement in the weaning weight of cattle is one of the positive outcomes of crossbreeding.

In recent times, discussions on crossbreeding have included the references to breed complementarity which is the process of considering two diverse breeds and pairing them to complement the major and the core traits of each of the breeds. The main objective of crossbreeding is to emphasize each other’s strengths and weaknesses concerning the different breeds of cattle. The purpose of cross-breeding two animals is to develop upon the strengths of each of the animals. For instance, if there is a lack of muscling in one breed, then it can be overcome by the strong muscling feature in another breed. In other words, crossbreeding is all about developing a breed of cattle where the strong features of one breed complement the weak features of the other breed for achieving the final objective of producing a healthy breed of cattle.

It is interesting to know that there is significant popularity of inbreeding by some of the cattle breeders around the world, like in North America, where there is a high level of popularity of inbreeding among the breeds of cattle that are purebred. Inbreeding is successfully managed with the help of various mating programs. However, today a large number of dairy producers are getting more inclined towards crossbreeding due to some of the negative outcomes of inbreeding such as a reduction in fat, milk and protein production, greater counts of somatic cell, and increase in the cases of dystocia or difficulty in the birth of calves and instances of stillbirths. Crossbreeding counters all these problems by contributing towards reducing birth weights of calves, enhancement in the levels of fat and protein, making it possible for the older facilities to accommodate the moderate-sized cattle, and lowering inbreeding by using purebred sires for undertaking to crossbreed on the herd of cattle.

Crossbreeding
Crossbreeding

Crossbreeding is responsible for a significant increase in calf birth weight: Myth

It is often alleged that crossbreeding in cattle results in a significant increase in the birth weight of calves. According to a research conducted by the Meat Animal Research Centre or MARC, on over 25000 breeding or calves for some of the most reputed beef breeds and their crosses in the US, the effects of heterosis on the birth weight, weaning weight and yearling weight has been analyzed between several breeds like British with British; Continental with British and Continental with Continental. It was found in the study that the average enhancement in the birth weight of the calves was around 1-1.5 pounds as a result of heterosis. Therefore, crossbreeding does not increase the birth weight of calves by a significant volume as often believed to be.

We know that crossbreeding increases weight of calves in respect of the first-generation crossbreds. The weights of the calves that are born through crossbreeding are found to be more than the purebred calves. The birth weight of calves is generally not much of a concern for the cattle breeders. It is during situations where the calves are very large and the cows are having difficulty in calving or it is during those situations where the calves are born very small in size or weak in health that the cattle breeders become concerned about the birth weight of the calves. So, the birth weight of calves born through crossbreeding will be more than those born through pure breeds. However, the notion that the increase in the weight of the calves due to crossbreeding is detrimental to the future of the calves is a myth because the increase in weight is not something that is of too much concern. The weight only increases by a little margin that does not cause any harm to the future of the cattle.

The greater the genetic distance of the parental breeds, the more is the amount of heterosis: Truth

It is evident from several research studies that the more divergent the parental breeds of cattle are, the greater will be the heterosis. So, a beef producer will be able to see more heterosis that will lead to a more healthy calf that will result from the mating of two extremely divergent parents. The process of heterosis occurs from the combinations of various alleles that are considered as forms of a gene. These are gained from the breeds of the parents that enhances the heterozygosity at several places in the genome and it contributes to the recovery of the individuals from depression generating out of inbreeding. For example, crosses of cattle from British breeds such as Hereford and Angus might result in a relatively lesser degree of heterosis as compared to a cross between British and Continental breeds. Furthermore, a cross between a Bos taurus and Bos indicus will result in more heterosis as compared to crosses belonging to the breeds of Bos taurus.

We now know that the British breeds of cattle are more closely related to one another as compared to the Continental European breeds. It is interesting to learn that these breeds have diverged from one another around 100-200 years ago. Based on currently available data it is determined that Bos Taurus breed has diverged from Bos indicus breed around 80,000 to 1, 00,000 years ago and due to this, the two groups have become genetically distant. The genetic distance of the parents in the cattle is often considered to be an important factor for many of the cattle breeders because they want to ensure that the health of the calves that are born are in good condition and at the same time the birth weight of the calves are expected. Heterosis is desired in crossbreeding because it results in much healthier calves that are born from the parents. So, it is desirable by the dairy farmers that there is a bigger genetic distance between the parental breeds of cattle so that the amount of heterosis is more that leads to the birth of healthier cattle. Now our experts from My Assignment Help will tell you about the heterosis.

Heterosis is present only in the first generation of crossbreeding: Myth

There is a notion that heterosis exists only in the case of the first generation of crossbreeding. It is found that when there is mating between two straight -bred animals that are of diverse breeds, at the time of the first cross there will be heterosis. But the mating of an F1 with two F1 crosses where F1 cattle happened to be the offspring from the initial cross along with similar breed composition will create 50% heterosis in the process of mating. Furthermore, when there is the mating of two crossbred cattle there is a tendency of retention of some of the heterosis. But, the volume of heterosis that will be retained will be diverse for diverse crossbreeding systems that depend on the system and also the number of breeds that are involved. Hence, heterosis is not present only in the first generation of crossbreeding.

There are positive effects of the individual genes from the several breeds that are used in crossbreeding. It is found that the dairy crossbreeding producers receive an enhanced performance due to the occurrence of heterosis. In genetics, heterosis is also referred to as hybrid vigor. It is found that even after the first generation of crossbreeding, heterosis leads to an increased gain which is more than the average of the genetic level of the two-parent breeds of cattle. The bonus that is gained from heterosis encompasses around 5% for production and 10% for health, survival, fertility, and mortality. So, the effect of heterosis is evident even after the first generation of crossbreeding. Therefore, the dairy farmers should not believe in myths which say that heterosis can only be observed in the first generation of crossbreeding.

Crossbreeding helps to eliminate the several concerns of the dairy farmers related to inbreeding. If the breeds that are to be used in crossbreeding chosen effectively then, the impacts of heterosis are found to be opposite to the impacts of inbreeding depression. Heterosis leads to you an extra advantage on the parent breed advantage and can be considered to be highly valuable for various traits like health, vitality, disease resistance and fertility. Effective crossbreeding is undertaken through mating two of the superior breeds of cattle. To take the effects of heterosis to the next generation the breeds must be able to effectively complement each other and independently they must have substantial selection base for continuing the unique breeding goals.

Cross between unrelated lines in a breed causes heterosis: Myth

Heterosis does not occur when mating is conducted within breeds. It happens only at the time when there is the mating of cattle from two or more breeds. For instance, when there is a cross between Hereford x Hereford then there will not be any heterosis. Research studies indicate that heterosis occurs when there is the crossing of a British cattle with a Continental cattle or with a Bos indicus cattle. Hybrids are found to be more heterogeneous as compared to their parents. A reduction in the number of heterozygotes leads to a situation where there is an increase in the number of homozygotes. The mutants which are most recessive happen to be deleterious. Hence the inbred lines are caused to be weakened due to possessing an increment in the number of homozygous recessive genes. Hybrids are stronger because the recessive genes from each of the parents are usually hidden by the dominant genes from the other. The hybrids become even more heterozygous as compared to their parents and this is increased even more when there is a greater divergence in the parents. The contrast appears to be the most at the time when the parents happen to be highly homozygous inbred lines. In the case of species that are closely related, an enhancement in the growth or stature of the hybrids is accompanied most of the times by problems of fertility such as sterility in the hybrids. In respect of the interspecific crosses where the parents of the cattle are secured from the wild and non-inbred populations, the complementation process of deleterious recessive alleles cannot be held responsible for creating heterosis or hybrid vigor. We can say that there is a lack of effective understanding of the concept of hybrid vigor for heterosis regarding the interspecific hybrids. However, it is agreed that the reciprocal crosses that are made between species which are closely related results heterosis or hybrid vigor in one direction only but not in the case of the reciprocal cross. Developing nations frequently depend on crossbreeding to improve the exhibition of animal populaces, for the most part since they have not had the option to actualize appropriate hereditary appraisal and direct rearing projects in locally accessible breeds. For more information, you can also check with Instant Assignment Help.