Rotational grazing

In agriculture, Managed intensive rotational grazing (MIRG), also known as cell grazing, mob grazing and holistic managed planned grazing, describes a variety of closely related systems of forage use in which ruminant and non-ruminant herds and/or flocks are regularly and systematically moved to fresh rested areas with the intent to maximize the quality and quantity of forage growth.

One primary goal of MIRG is to have a vegetative cover over all grazed areas at all times, and to prevent the complete removal of all vegetation from the grazed areas ("bare dirt")

MIRG can be used with cattle, sheep, goats, pigs, chickens, turkeys, ducks and other animals. The herds graze one portion of pasture, or a paddock, while allowing the others to recover. The length of time a paddock is grazed will depend on the size of the herd and the size of the paddock. Resting grazed lands allows the vegetation to renew energy reserves, rebuild shoot systems, and deepen root systems, with the result being long-term maximum biomass production. MIRG is especially effective because grazers do better on the more tender younger plant stems. MIRG also leave parasites behind to die off minimizing or eliminating the need for de-wormers. Pasture systems alone can allow grazers to meet their energy requirements, and with the increased productivity of MIRG systems, the grazers obtain the majority of their nutritional needs without the supplemental feed sources that are required in continuous grazing systems.

One key element of this style of animal husbandry is that either each grazed area must contain all elements needed for the animals (water source, for instance) or the feed or water source must be moved each time the animals are moved. Having fixed feeding or watering stations defeats the rotational aspect, leading to degradation of the ground around the water supply or feed supply if additional feed is provided to the animals. Special care must be taken to ensure that high use areas do not become areas where mud, parasites or diseases are spread or communicated

Ruminal tympany, also known as bloat, is a common problem in grazing systems for ruminants, although not for pigs or poultry, that if left untreated can lead to animal death. This problem occurs when foam producing compounds in plants are digested by cows, causing foam to form in the rumen of the animal and ultimately prohibiting animals from expelling gas. The risk of bloat can be mitigated by seeding non-bloating legumes with the grasses. Animals are especially susceptible to bloat if they are moved to new pasture sources when they are particularly hungry. It is therefore important to ensure that the herd is eating enough at the end of a rotation when forage will be more scarce, limiting the potential for animals to gorge themselves when turned onto new paddocks.

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Wikipedia