The Milking Shorthorn or Dairy Shorthorn are were not strictly synonomous. The Milking Shorthorn is used t describe the modern day breed in America whereas the Dairy Shorthorn is a description that applies to the breed within the UK. The American Milking Shorthorn was founded upon pure bred Dairy Shorthorn stock but crossbreeding has taken place. Crossbreeding, referred to as introgression was tried as an experimental scheme in the UK in 1969. Crossbreeding was limited to begin with but the practice gathered pace and the more polite description of "blending" was used to describe the crossbreeding that took place involving at least eight or ten red breeds of cattle. The Dairy Shorthorn breed was compromised by this widespread practice of crossbreeding involving genetics from many other breeds and in 2012, the Rare Breeds Survival Trust stepped in and recognised the tiny percentage of pure bred animals that had escaped the systematic programme of crossbreeding and the remaining animals (barely more than 100 in number) were referred to as "original population"to Dairy Shorthorns. The RBST has a survival programme in place and great efforts are being made to avoid the extinction of the original population Dairy Shorthorn.
The breed is known as Milking Shorthorn in the United States, Canada, and New Zealand, and as Dairy Shorthorn in the United Kingdom, Ireland, Australia and South Africa. The Illawarra cattle breed of Australia is partially descended from Milking Shorthorn genetics. The Swedish Red and Norwegian Red breeds also have some ancestry based in Shorthorn genetics.
Milking Shorthorns are an average-sized breed, with mature cows averaging 140 cm (55 in) tall at the tailhead, and weighing 640 to 680 kg (1,410 to 1,500 lb). They are red, red with white markings, white, or roan. Red and white coat colour genes in purebred Milking Shorthorns are co-dominant, resulting in the roan coloration and unique color patterns seen in the breed. Average milk production for the breed is about 7,000 kg (15,000 lb) in an annual lactation of 305 days, with 3.8% butterfat and 3.3% protein.
Milking/Dairy Shorthorn cattle are also known for high levels of fertility, grazing efficiency, and ease of management that result in the breed being high suitable for low-input dairy operations in various production environments. Milking Shorthorns are known for their durability, longevity, and ease of calving as well as their versatility in a number of production environments.
The breed was established in the 18th century in Northeastern England, in the Valley of the Tees River bordering the counties of Durham, Northumberland and York. Bates and Booth established a "dairy-type" strain of Shorthorns on their farms in the region, and that strain has remained until this day.
Dairy Shorthorn cattle, known at one time as Durhams, were among the first cattle to be imported into Australia.
One of the first official demonstrations of the production ability of Milking Shorthorns was made at the World's Exposition in Chicago in 1893 where two of the leading cows of the test were Kitty Clay 3rd and Kitty Clay 4th, the latter standing third in net profit over all breeds. These sister cows became the foundation for the Clay cow family of Milking Shorthorns, developed at Glenside Farm, Granville Center, Pennsylvania.
The first dairy cows imported into New Zealand were Shorthorns, when in 1814, they were shipped from New South Wales. Shorthorns were used as draught animals in bullock teams, were good milkers and provided good meat. Shorthorn herds were established by the early 1840s, and for a long time Shorthorns were New Zealand’s most popular cattle breed.
The breed has served as part of the foundation for other red dairy breeds, including Swedish Red cattle, Angeln cattle and Illawarra cattle in Australia (with some Ayrshire ancestry). The Ayrshire cattle breed was originally formed from dairy-type Shorthorn cattle in Scotland.
The Milking Shorthorn breed has largely embraced a form of genetic expansion in populations around the world, in an effort to continue genetic improvement while avoiding the inbreeding concerns that can arise in a small population. As a result, the breed has seen dramatic improvement in both production and dairy conformation in the past 30 years while retaining a breed identity. Genetic expansion programs vary by population, but all populations have incorporated some level of outside genetics. Red Holstein genetics have been used in all populations to some degree. In Canada, selected Swedish Red genetics have been entered into the herdbook at 75% purity, while these genetics have 50% purity standing in the United States. Illawarra genetics from Australia are also largely incorporated by all Shorthorn herdbooks as 100%, minus any non-Illawarra/Shorthorn genetics (i.e. Red Holstein). As a result, the Milking Shorthorn breed in Canada has the lowest average inbreeding percentage of any dairy breed, despite having a relatively small population size.
While these genetic expansion programs have been embraced, national breed associations have been instrumental in ensuring that the breed works to retain the characteristics that make it an efficient alternative in the dairy industry. Some national breed associations have been active in either approving sires for use or directly selling semen on a range of sires of varying purity percentages. All countries have different herd book mechanisms for tracking the percentage of purity of each registered animal but some are more rigorous than others. The breed has largely ensured that breeders are able to follow whatever breeding program suits their needs, resulting in both herds of "blended" Shorthorns with many animals at less than 50% purity, as well as herds in several countries were most animals are purebred.
There are small groups of Milking/Dairy Shorthorns that have not incorporated outside genetics and remain true to the conformation and production levels of Shorthorns from the earlier part of the 20th century. The Dairy Shorthorn population in Australia, as well as the Native Milking Shorthorns of the United States are examples of such groups. In some countries, these animals may be known as Dual Purpose Shorthorns, as they tend to have higher fleshing capabilities than traditional dairy cattle.
The Milking/Dairy Shorthorn breed has seen population growth in several countries in the past decade after many years of population decline. The Canadian Milking Shorthorn Society had their highest registration and membership totals in over 25 years in 2012. All major populations have seen an increase in interest in Milking Shorthorns by dairy producers, artificial insemination organizations, and crossbreeders.
The Milking/Dairy Shorthorn breed was initially founded on the Coates Herd Book, widely thought to be the first pedigree herd book for cattle in the world. This herdbook includes both beef and dairy animals but the herdbook is divided between the two sections. Herdbooks in Canada and the United States were also combined until formation of independent breed societies in these countries.
The American Milking Shorthorn Society is the largest Milking Shorthorn population, registering in excess of 3000 animals per year. They are closely followed by the Shorthorn Society of Great Britain and Ireland. New Zealand, Canada, Ireland, Australia and South Africa have registered populations of Milking/Dairy Shorthorns. The Illawarra Cattle Society of Australia has the largest population of Milking Shorthorn-type cattle.