A breed is an integral, numerous (not less than several thousand breeding animals of the parent herd), a qualitatively unique group of animals created by purposeful human labor. All individuals of this group are distantly related to each other, since they come from a relatively small group of common ancestors. At the same time, they are not close relatives, which excludes the manifestation of inbreeding depression in offspring (degeneration, reduced viability and productive characteristics).
Representatives of the same breed have a common history of development and formation of desirable traits, have specific, approximately the same economically useful qualities, similar appearance and body structure. These monotonous characteristics are persistently inherited to offspring. Within the breed there must be lines and families.
Line are descendants of an outstanding male ancestor in terms of their productive characteristics, who have successfully inherited his best qualities. Thus, the breeding of most farm animals is carried out along the lines. There are usually at least 10 lines within a breed. They are called by the name and number of the ancestor of the line. For example, within the Holstein breed of cattle, there are a large number of lines, including Montvik Chieftain 95679, Siling Traijun Rokit 252803, Vis Beck Aydiala 0933122, Reflectshin Soveringa 0198998 and others.
Families are highly productive female descendants (daughters, granddaughters, etc.) of an outstanding female ancestor. Family breeding is widely practiced in pig production, but is less common than line breeding. Families are called by the nickname or number of the ancestor. There are about 20-30 families within the breed. For example, in Estonian bacon breed there are 14 lines and 28 families of pigs, among which the most common families are Lunde, Kaina, Mateakas.
Lines and families are like variations within a breed. They are an indicator of the genetic richness of the breed. What is their purpose? Different productive characteristics that are difficult to combine in one animal or in the entire group of animals (for example, milk yield and fat content of milk, endurance and speed, multiple pregnancy and large mass of newborns, etc.) are fixed in lines and families. Accounting for the origin of animals enables specialists to carry out further breeding work with the breed. The purpose of breeding along lines and creating lines is to preserve the high economically valuable indicators of a unique individual in its offspring and thereby turn these qualities from individual into group ones, to fix and replicate the desired property.
Spawn is a large part of a breed that has been bred for a long time in isolation, in specific climatic conditions and has adapted well to them. Offspring are usually called by the geographical name of the area or settlement where these animals are bred. For example, in the Karabakh breed of sheep, the Karadolakh offspring is highly valued, represented by more massive animals, the live weight of which can reach 75 kg. The Black-and-White breed of cows includes three main offspring: Central, Ural and Siberian. In the breed of Russian goats, Yaroslavl and Gorky offspring are distinguished.
Cross is the offspring obtained from parents who belong to different lines. (And sometimes to different breeds, as, for example, in broiler poultry farming.) Typically, such animals combine the valuable characteristics of both lines and are used as productive, for the production of marketable products. Sometimes in such offspring the effect of heterosis is manifested, and the cross outperforms both parental forms in its performance. In modern animal husbandry, interline crosses are widely practiced in poultry farming. Crosses can be simple – only two lines are involved in breeding, or they can be complex – when the descendants of two different lines are mated with representatives of the third. So, there are many crosses in the Leggorn breed. Some of them: “Yantar-1”, “Crystal-5”, “Start-1”, “B-121”, “Progress”.
Hybrid is an animal whose parents belong to the same genus, but to different species: hare and hare – cuff; jaguar and leopard – jagopard; donkey and mare – mule; stallion and donkeys – hinny; tigress and lion – liger; musky drake and domestic duck – mulard; one-humped camel and llama – kama.
Many hybrids have been obtained to date. Mostly they are created by people, but sometimes the author is nature itself. The hybrid animals of natural origin include kidas, a hybrid of sable and pine marten, which is found in their joint habitats. Kidas are slightly larger than their parents, with a longer tail, and have a yellow coloration of the front of the neck. There are such animals in the Urals and near the Pechora River.
Grolar is a hybrid between a brown bear and a polar bear. Offspring are born white, but as they grow older, they become yellow-brown or bluish-brown. Several times hybrids were born in Germany and at the London Zoo. In nature, they are sometimes found in Alaska and Kodiak Island.
Mezhnyak is a hybrid of black grouse and wood grouse. Similar in appearance to the species to which his mother belongs. Hybrid females are barely distinguishable from the parent species. The male mezhnyak is slightly larger than his parents and at the same time much more powerful, therefore he often wins over his rivals in the fight for females during the mating season. But the eggs laid by the hybrid male turn out to be unfertilized, so it is impossible to breed chicks from them.
For this reason, mezhnyaks are considered harmful individuals, because they interfere with the normal course of reproduction of birds of both species. Hunters and huntsmen know about this and, on occasion, try to exterminate the mezhnyaks. The hybrid is rare. It usually appears in places where both species live, and when, as a result of extermination by hunters, a situation of acute shortage of males of one of the species is created. In this case, females mate with males of a related species and produce hybrid offspring.
Honorik is a hybrid between a ferret and a European mink. Occasionally, these animals are found at the intersection of their habitats. Outwardly, the honorik resembles a ferret with thicker and harsher hair, like a mink.
Often the creation of a hybrid by man occurs by accident or as a scientific experiment, sometimes in the case of artificial insemination, as in the case of the creation of kama. The female llama was inseminated with the sperm of a one-humped camel and received a hybrid offspring, which was of no economic interest to humans.
But in some species, conception occurs naturally if they are kept together for a long time. So it turned out liger – a hybrid of a lion and a tigress. Ligers are noticeably larger than both parental species. Outwardly, they are more like lions with blurry tiger stripes. Males lack a mane. Ligers love to swim.
In the same way, in 1910, in Bombay (India), several hybrids of a leopard and a lioness appeared, called leopon. These animals look like a lion, on the head and neck they have a mane up to 20 cm long and a brush on the tail. At the same time, brown and black irregularly shaped spots of various sizes are placed all over their body. In size, leopons are larger than a leopard, but smaller than a lion.
A hybrid of a male zebra with a horse – zebroid and a zebra with a donkey – zebrul was also obtained by natural mating. The background suit of hybrids is inherited from a horse or a donkey, but stripes of different intensity are visible on it. Hybrids have a valuable property – they are not susceptible to diseases that the tsetse fly carries and are used as pack animals. But hybrids have an aggressive disposition inherited from zebras, are difficult to drive around and are inconvenient to maintain. Such animals have been known since very ancient times.
Sometimes human-made hybrids occupy entire ecological niches. This happened to the bison, which was first obtained from a male bison and a female bison in the Askania Nova Reserve in 1907. Later, in 1940, one male and four females of this hybrid were moved to the Caucasus, to the places where the Caucasian bison once lived, which until 1927 were completely exterminated by hunters. The hybrid successfully took root, acclimatized and multiplied, occupying the ecological niche of the Caucasian bison.
There are also hybrids that have a very practical purpose. Among them, bester is a hybrid of beluga and sterlet. It was first created in 1952 in the Saratov region. Artificial crossing of two different species of fish of the sturgeon family made it possible to combine in bester the rapid growth of the beluga and the early maturation of the sterlet. Representatives of this hybrid usually reach a weight of 30 kg, and their length exceeds 1.8 m. Some individuals can weigh up to 63 kg and grow up to 2.3 m! There are two types of hybrid: beluga and sturgeon bester. The sterlet bester is smaller. This fish is grown for meat and caviar.
Mulards were bred to combine economically valuable properties and eliminate undesirable characteristics of both original species in one organism. So, for example, musky ducks are very clean, do not make noise, build up mainly muscle mass, and not fat, but at the same time their females are small, shy, and the young grow relatively slowly and mature late. In addition, Muscovy ducks are not suitable for industrial poultry farming.
In contrast to musky ducks, ordinary ducks are early maturing, grow quickly, suitable for any technology of growing and breeding, but their meat is fatty, they are unclean and create a lot of noise. The hybrid obtained as a result of crossing the musky and ordinary duck is gaining weight well, and already at the age of 2-2.5 months reaches a live weight of 1.4-1.5 kg. Moulards are clean, calm, their meat is of high quality and low in adipose tissue.
The Mule was created by crossing a donkey and a mare to perform work in unacceptably difficult conditions for horses in difficult terrain. But later they began to be used everywhere, in parallel with horses. In size and body proportions, mules are approximately equal to horses, but have long ears, a lighter head, and a less hairy tail. Their feet and hooves are like donkeys, and the color is always inherited from the mare.
Mules are unpretentious to the quality of food and conditions of detention. At the same time, they live longer than horses, are less susceptible to horse diseases, are very hardy and are not inferior in traction to horses (18 – 20% of their weight). There are two types of mules: pack mules and draft mules. The pack ones are smaller than the draft ones. On average, mules weigh about 400 kg. All representatives of this hybrid are sterile. Only a few cases of offspring from female mules are known in the entire history of their existence. There are about ten million mules in the world.
Hainak or zo is a hybrid of a yak and a cow. These animals are kept as productive mainly in Nepal, Mongolia, Tibet. The hybrid combined the adaptability of the yak to harsh local conditions, the high fat content of its milk and the milk productivity of a domestic cow.
Almost all hybrids are not able to produce their own offspring and are dead ends in the reproductive sense. But some of them are fruitful. For example, bester, grolar, nar (a hybrid between one- and two-humped camels), bison and others can successfully breed. In some cases, the offspring of only one of the sexes is fertile, as in kidas: females can produce offspring, and males are sterile. In ligers, females are also in most cases fertile, while males are sterile. Fertile and female-meadows, female tiger lions (a hybrid of a tiger with a lioness).
Most hybrids are superior to their parents in many ways. So, for example, ligers grow much larger than both lions and tigers. Mules are superior in endurance to horses, and in strength to donkeys. Nar is more massive than both types of camels.
The qualitative characteristics of the hybrids are not the same and completely depend on which species was used as the paternal and which as the maternal form. So, mules have good immunity, unpretentiousness to the conditions of feeding and keeping, as well as excellent operational properties. The hinny, on the contrary, is small in size, more like a donkey and does not represent a great economic value. The tigrolev has a mane, is inferior in size to both the tiger and the lion, and the liger, on the contrary, surpasses its parents in weight.
A crossbreed is the offspring obtained from the mating of animals of the same species but different breeds. Do it for a specific purpose or by accident. Thus, new breeds are obtained. For example, the Brahma chicken breed was obtained from the mixing of two parent breeds: Cochinchin and Malay fighting, horses Brabancons were obtained from mating Flemish and Arden breeds. And many of the other well-known breeds are combinations of several others. But this will be the next article.