ANIMAL HUSBANDRY

Animal husbandry is the dynamic set of relationships between humans and animals, in which qualities considered to be advantageous to humans are emphasized and further developed. The term can refer to the practice of selectively breeding and raising livestock to promote desirable traits in animals for utility, sport, pleasure, or research, but also refers to the efficient exploitation of a species in agriculture in a way that benefits all species involved in the relationship.

origin of breeding.
Animal husbandry has been practiced for thousands of years, since the first domestication of animals. Selective breeding for desired traits was first established as a scientific practice by Robert Bakewell during the British Agricultural Revolution in the 18th century. One of his most important breeding programs was with sheep. Using native stock, he was able to quickly select for large, yet fine-boned sheep, with long, lustrous wool. The Lincoln Longwool was improved by Bakewell and in turn the Lincoln was used to develop the subsequent breed, named the New (or Dishley) Leicester. It was hornless and had a square, meaty body with straight top lines. These sheep were exported widely and have contributed to numerous modern breeds.
Under his influence, English farmers began to breed cattle for use primarily as beef for consumption - (previously, cattle were first and foremost bred for pulling ploughs as oxen). Long-horned heifers were crossed with the Westmoreland bull to eventually create the Dishley Longhorn. Over the following decades, farm animals increased dramatically in size and quality. In 1700, the average weight of a bull sold for slaughter was 370 pounds (168 kg). By 1786, that weight had more than doubled to 840 pounds (381 kg).
Animal herding professions specialized in the 19th century to include the cowboys of the United States and Canada, charros and vaqueros of Mexico, gauchos and huasos of South America, and the farmers and stockmen of Australia.
In more modern times herds are tended on horses, all-terrain vehicles, motorbikes, four-wheel drive vehicles, and helicopters, depending on the terrain and livestock concerned. Today, herd managers often oversee thousands of animals and many staff. Farms, stations and ranches may employ breeders, herd health specialists, feeders, and milkers to help care for the animals. 
Breeding techniques
Techniques such as artificial insemination and embryo transfer are frequently used today, not only as methods to guarantee that females breed regularly but also to help improve herd genetics. This may be done by transplanting embryos from high-quality females into lower-quality surrogate mothers - freeing up the higher-quality mother to be reimpregnated. This practice vastly increases the number of offspring which may be produced by a small selection of the best quality parent animals. On the one hand, this improves the ability of the animals to convert feed to meat, milk, or fiber more efficiently, and improve the quality of the final product. On the other, it decreases genetic diversity, increasing the severity of disease outbreaks among other risks.

History in Europe

The semi-natural, unfertilized pastures formed by traditional agricultural methods in Europe, were managed and maintained by the grazing and mowing of livestock. Because the ecological impact of this land management strategy is similar to the impact of a natural disturbance, the agricultural system will share many beneficial characteristics with a natural habitat including the promotion of biodiversity. This strategy is declining in the European context due to the intensification of agriculture, and the mechanized chemical based methods that became popular during and following the industrial revolution.

Sustainability

In organic and biodynamic farming methods, animals play an important role in achieving closed or sustainable system by providing multiple functions to the agricultural system. In the Balinese context, for example, ducks are herded through rice paddies at particular stages of the growing season. The ducks eat insects and weeds that inhibit the growth of seedlings, and prevent the farmer from using herbicides or pesticides. Their droppings contribute nitrogen to the soil as a natural source of fertilizer, and the movement of their feet and bills in the water of the terrace ecosystem increases the oxygen content of the soil thus increasing nutrient availability.

Climate change
Due to the significant contribution of agriculture to the emissions of non-CO2 greenhouse gases methane and nitrous oxide, the relationship between humans and livestock is being analyzed for its potential to help mitigate climate change. Strategies for the mitigation include optimizing the use of gas produced from manure for energy production (biogas).