The answer depends on your current dairy farming system and the grazing situation your cows will move to. Some farmers use grazing as a supplement to a confinement housing and feeding system, and others move from confinement to a system that relies on pasture to the greatest extent possible.
Farmers who add some grazing to a confinement system need not see a drop in milk production provided the pastures are of high quality, pastures are rotationally grazed, and the total ration is adjusted to meet the cows' nutritional needs. In addition, cow health often improves when they have daily access to pasture.
Farmers who move from a confinement housing and feeding system to a full grazing system usually do experience a drop in milk production. However, the more important question is what happens to profitability. Several studies have shown that pasture-based systems have the potential to be more profitable than confinement systems of a similar herd size. However, there is wide variation in profitability among both types of farms. A transition to grazing should be carefully planned and evaluated both from a farming and a financial perspective because there are many factors to consider.
The amount of land available to graze, the type and quality of the pastures, the way pastures are managed, and the level of supplementary grain feeding all have a bearing on milk production and profitability. Like any plant, cool-season grasses will grow rapidly in the early spring and slow during midsummer when the plant begins its reproductive cycle. With adequate nutrients and moisture and good grazing management, leafy vegetative growth can be maintained throughout the growing season. Vegetative growth is highly nutritious and will support good levels of milk production. Rotational grazing is an important pasture management tool for high yields of productive pastures that will support good animal performance.
