Question: Which breed of dairy cattle originating in Holland produced the world-record breaking amount of semen for a bull in 2012?
Context: Estonian red cattle (Estonian: Eesti punane veis) are a dairy cattle breed from Estonia.  The color is red, but sometimes it varies from red-white to brown and rarely black.  Red cattle was developed by Angli, North Slesvigi and the Danish Red dairy cattle.  In the last century the biggest breeders were Middendorff and Sievers. World Dairy Expo is a five-day event showcasing dairy cattle and the newest technologies available to the dairy industry.  The show is held annually at the Alliant Energy Center in Madison, Wisconsin, United States.  Considered the largest and most important dairy cattle show in North America, it has been held in the first week of October since 1967. Holstein Friesians (often shortened to Holsteins in North America, while the term Friesians is often used in the UK) are a breed of dairy cattle originating from the Dutch provinces of North Holland and Friesland, and Schleswig-Holstein in Northern Germany and Jutland.  They are known as the world's highest-production dairy animals. Lineback Dairy Cattle is a dual breed of cattle, derived from the Holstein breed, and to whom the Randall cattle bear a strong resemblance.  While not a commonplace breed, they are found in small numbers as "productive pets" amid larger numbers of other dairy cattle breeds on dairy farms throughout North America. Mastitis in dairy cattle is the persistent, inflammatory reaction of the udder tissue.  Mastitis, a potentially fatal mammary gland infection, is the most common disease in dairy cattle in the United States.  It is also the most costly to the dairy industry.  Milk from cows suffering from mastitis has an increased somatic cell count. The Alderney was a breed of dairy cattle originating from the British Channel Island of Alderney, though no longer found on the island.  The pure breed is now extinct, though hybrids still exist. Toystory was a Holstein bull that has sired an estimated 500,000 offspring in more than 50 countries around the world.  He was owned by Genex Cooperative Inc and he was housed Shawano, Wisconsin.  In 2012 Toystory produced a world record-breaking 2 millionth unit of semen at eleven years of age and was the first Holstein bull in history to achieve this mark.  This surpassed the previous world record of 1.7 million units of semen set by a Dutch Bull named Sunny Boy.  Over his lifetime Toystory produced 2.4 million units of semen.  Toystory died on Thanksgiving day in 2014 at thirteen years of age.  "The death of TOYSTORY means the passing of the industry's most prolific sire," stated Keith Heikes, Genex Chief Operating Officer, "This bull was one of a kind for many reasons." A zebu ( , or ; "Bos primigenius indicus" or "Bos indicus" or "Bos taurus indicus"), sometimes known as indicine cattle or humped cattle, is a species or subspecies of domestic cattle originating in the Indian subcontinent.  Zebu are characterised by a fatty hump on their shoulders, a large dewlap, and sometimes drooping ears.  They are well adapted to withstanding high temperatures, and are farmed throughout the tropical countries, both as pure zebu and as hybrids with taurine cattle, the other main type of domestic cattle.  Zebu are used as draught oxen, dairy cattle, and beef cattle, as well as for byproducts such as hides and dung for fuel and manure.  In 1999, researchers at Texas A&M University successfully cloned a zebu. The Chinese Black Pied or Chinese Black and White is a Chinese breed of dairy cattle.  It derives from cross-breeding with local cows of black and white dairy cattle of various breeds imported since the 1870s from Canada, Germany, Japan, the Netherlands, the United Kingdom and the United States.  It is the most numerous dairy breed in China and is distributed throughout the country. Showing dairy cattle provides the dairy farmer a means of buying and selling their cows or heifers and selecting foundational cows for their dairy herd.  Shows can be social events in addition to serving as important business opportunities, and ages of those who show and attend cover a broad range.  Dairy shows are also an important tool in sparking the interest of young people to become involved in the dairy industry.  The six breeds of dairy cows that are shown are Ayrshire cattle, Brown Swiss cattle, Milking Shorthorn, Guernsey cattle, Holstein cattle and Jersey cattle.  In order to register for a show, payment and the registration for the cow or heifer must be submitted.  The registration would include the breed, birthdate, dam and sire of the animal.
Answer: Holstein Friesians