Dairy Production Systems
In the U.S., milk comes from breeds of cattle genetically selected for milk production. At one time in the U.S., cattle were selected simultaneously for beef and milk production. This is still the case in many parts of the world. The common dairy breeds in the U.S. today have been selected almost exclusively for milk production for many generations.
Black and white Holstein cows make up over 90% of the U.S. dairy herd. Some Holsteins are red and white, but, aside from color, indistinguishable from black and white Holsteins. The U.S. Holstein is well known around the world for her ability to produce large volumes of milk, butterfat and protein. She is a very profitable cow for farmers when large amounts of feed with high levels of grain are available. The U.S. Holstein is relatively new to North America, with the first imports of registered Holsteins arriving in the 1880s. However, the breed has dominated production in the U.S. since the end of World War II, and advances in artificial insemination have increased her popularity in breeding programs around the world largely owing to her advantage in production over all other breeds.
The Jersey is the second most popular cow in the U.S. and makes up about 7% of the U.S. dairy herd. She is known for her smaller size (1000 lbs. for a mature Jersey cow versus 1500 lbs. for a mature Holstein cow), higher percentages of fat and protein in her milk, early maturity, and efficiency of milk production. Payment by milk processors to dairy producers based on the content of butterfat and protein in milk has increased the popularity of the Jersey, especially in markets where milk is manufactured into cheese. Other dairy breeds make up only around 2% of the dairy cattle population. These include:
- Ayrshires - moderately large cows that are red and white to mahogany and white and are known for producing milk that is quite rich in butterfat and for the conformation of their udders;
- Brown Swiss - large brown cattle that are known for their docile manner, high milk protein to milk fat ratio, sound feet and legs, and purported resistance to heat stress in hot and humid regions;
- Guernseys - red and white to mostly red and are somewhat larger than Jerseys and are known for the yellow color of the butterfat in their milk, which is rich in Beta-Carotene; and
- Milking Shorthorns - a rugged breed of cattle that are red and white to mostly red, mostly white, or roan (speckled) and are known for milk that is well suited for cheese production and for their grazing ability.
More information about the breeds of dairy cattle.
A few other dairy breeds have become popular more recently. Dutch Belted, Danish Jersey, Normandy, Montbeliarde, Danish Red, British Friesian, and Norwegian Red have gained notoriety for their purported superiority under grazing management (pasture production systems). Many of these breeds have been developed in countries where grazing is widely practiced. Nevertheless, many U.S. dairy producers have good success grazing Holsteins and other traditional U.S. breeds of dairy cattle.
Until recently, very little crossbreeding was practiced in the U.S. Crossbreeding, which refers to mating cows to bulls of a different breed, is gaining in popularity for several reasons. Much of the genetic improvement in Holsteins has been for milk production alone, while other breeds have been selected for other traits like fertility, moderate size, disease resistance, and strength. Thus, crossbreeding allows the breeds to compliment each other's strengths. There is also some level of hybrid vigor expected in the progeny; that is, first generation crosses may be better than the average of the parents.
Grazing versus Intensive Dairy Production Systems
the United States, most milk is produced by cows raised in intensive production
systems. These include tie
stall barns, free
stall barns, and open
lots. The more intensively managed systems feed cows rations that
are relatively high in concentrates
and stored forages. Other cows are raised in pasture-based systems, which
are the primary production system in several dairy producing countries
in the world, such as New Zealand. Pasture-based systems often strive
to optimize rather than maximize milk production while paying careful
attention to controlling input costs. Some producers use a combination
of the two systems, which is appealing in that it reduces costs, but still
allows the feeding of concentrate to improve milk production levels.