Hay - Composition

Composition

Commonly used plants for hay include mixtures of grasses such as ryegrass (Lolium species), timothy, brome, fescue, Bermuda grass, orchard grass, and other species, depending on region. Hay may also include legumes, such as alfalfa (lucerne) and clovers (red, white and subterranean). Other pasture forbs are also sometimes a part of the mix, though other than legumes, which ideally are cut pre-bloom, forbs are not necessarily desired. Certain forbs are toxic to some animals.

Oat, barley, and wheat plant materials are occasionally cut green and made into hay for animal fodder; however they are more usually used in the form of straw, a harvest byproduct where the stems and dead leaves are baled after the grain has been harvested and threshed. Straw is used mainly for animal bedding. Although straw is also used as fodder, particularly as a source of dietary fiber, it has lower nutritional value than hay.

It is the leaf and seed material in the hay that determines its quality. Farmers try to harvest hay at the point when the seed heads are not quite ripe and the leaf is at its maximum when the grass is mowed in the field. The cut material is allowed to dry so that the bulk of the moisture is removed but the leafy material is still robust enough to be picked up from the ground by machinery and processed into storage in bales, stacks or pits.

Hay is very sensitive to weather conditions, particularly when it is harvested. In drought conditions, both seed and leaf production are stunted, making hay that has a high ratio of dry coarse stems that have very low nutritional values. If the weather is too wet, the cut hay may spoil in the field before it can be baled. The hay may also develop rot and mold after being baled, creating the potential for toxins to form in the feed, which could make the animals sick. It also has to be stored in a manner to prevent it from getting wet. Mold and spoilage reduce nutritional value and may cause illness in animals.

The successful harvest of maximum yields of high-quality hay is entirely dependent on the coincident occurrence of optimum crop, field, and weather conditions. When this occurs, there may be a period of intense activity on the hay farm while harvest proceeds until weather conditions become unfavourable.