How it began
The Jersey was bred on the island of Jersey, the southernmost of the Channel Islands, from cattle brought over from the nearby Norman mainland. It was first recorded as a separate breed around 1700. A 2020 paper in Frontiers in Genetics reports that laws against importing livestock were enacted as early as 1763; a 1789 law forbade imports of foreign cattle. The Royal Jersey Agricultural and Horticultural Society was formed in 1833 and opened the Jersey Herd Book on March 3, 1866.
Before it existed
Before the ban, cattle moved freely between the islands, France and England. French cattle were being passed through Jersey to England free of tariff, which threatened the price of island animals. The 1789 law was meant to keep the island stock pure and to steady export prices. Before then, cows were sometimes given as dowry in marriages between Jersey and Guernsey families.
How it works
The breed was shaped by isolation and record keeping. No outside cattle could enter, and from 1866 every animal on the island was registered in the herd book, which works as a complete census from which ancestry can be traced. The cows are small, about 350 to 410 kilograms, in shades of brown from light tan to nearly black. The milk is high in butterfat, about 4.8 percent, and protein, with a yellowish tinge. The genetics paper states the breed gives more milk per unit of body weight than any other dairy breed.
How it spread
Jerseys were in high demand abroad. In 1860, 1,138 cows were exported through England. Exports to the United States began around 1850, and the American Jersey Cattle Club was formed in 1868. From 1873 to 1879, 7,330 head were shipped to England, America, Australia, France and New Zealand, and by 1910 more than 1,000 a year went to the United States alone. In Denmark, France, New Zealand and the United States the Jersey developed into independent national breeds.
What lasted
The island herd stayed genetically isolated for 219 years while its descendants adapted to climates and farming systems around the world. The breed tolerates heat well, calves easily and needs less feed for upkeep because of its low body weight. The genetics study credits Jersey cows with a longer productive life than other dairy breeds.
Where it stands today
Jersey cattle are found in at least 82 countries. In July 2008 the States of Jersey ended the import ban and allowed bull semen to be brought in, because island cows had fallen behind international Jerseys in productivity. According to the 2020 study, two of every three calves born on the island are now sired by international Jersey bulls.
