Causes of Overfeeding

Grains

• Grains, such as corn, barley and oats, are fed to farm animals as a supplement to a regular hay or grass feeding program. There are several reasons to feed grain to farm animals such as to provide nutrients that are missing in the forage feed, to produce faster weight gain, to increase milk production in lactating females and to provide energy in working animals. Grains are a high-energy feed, and should be fed with consideration to the animal's growth requirements, work expectations and/or reproductive needs. Excess energy is stored as fat in an animal.
  In times of drought or hay shortages, livestock owners often substitute an increase of corn feed. Because of the high protein and sugar content of corn, increasing the volume of feed corn often results in an increase of fat storage in livestock, resulting in overweight animals.

Hay

• At some point during the year, if not year 'round, livestock owners feed hay to the farm animals. There are many varieties and combinations of baled hay-alfalfa, grass, oat, wheat, rice, grain and combinations of the aforementioned. Each variety, or combination, provide different nutritional value to the animal being fed.
  Alfalfa hay usually contains a slightly higher level of digestible energy, vitamin A and calcium than straight grass hay. It is possible for alfalfa to contain twice the protein amount and three times the calcium level of a grass hay. Therefore, animals that require more protein and minerals, or have a high activity level, are fed alfalfa.
  Mature beef cattle, goats and sheep do fine on plain hay of any type, though lactating females need adequate protein. A good quality grass hay is adequate.
  Overfeeding any type hay to farm animals will cause more waste, and possibly less sanitary conditions, than obesity in the animal.

Pastures

• Only horses have a health risk when overfed on pasture feed. Besides the potential of excessive weight, a condition known as founder can occur. Founder results from an inflammation of the laminae in the hoof of a horse. Generally, only the front hooves are affected, but all four feet may get it in severe cases and it is painful to the horse. Allowed to graze continuously or for an extended time in a rich grass or alfalfa pasture, an overweight or fat horse may develop grass founder. Mild cases of founder are treatable, but extreme and prolonged cases can remain with horse the rest of its life.

Environmental Concerns

• Overfeeding of farm animals not only produces waste of feed, but also excess animal waste, both of which can have an impact on the environment. Wasted feed generally ends up on the ground, and with moist conditions, develop mold. If the ground is muddy, the wasted feed and mold becomes worked into the soil, changing the composition.
  Excessive animal waste happens when too much feed is given that an animal cannot process, and, thus, eliminates it. Animal waste, if not removed, harbors insects and vermin and an unhealthy and unsanitary environment for the animals and humans.
  Both wasted feed and animal waste that is located near any open water source, such as a stream, canal or pond, has the potential of contaminating the water. Therefore, great care should be taken to either not house farm animals near water sources or clean the animal area of excess feed and manure routinely, if the animals must be near the water source.

Overfeeding and Reproduction

• Overfeeding an animal that is intended for reproduction purposes can affect the ability to reproduce. Because of a probable hormonal imbalance, obese animals may have irregular cycles and are frequently sterile. During breeding time, overweight females may have a difficult time conceiving and/or carrying the fetus to birth. This applies to all breeds of farm animals--not just horses. Overweight farm animals also may experience difficulty in giving birth.