Apr 20, 2012
Grazing Management Part 2
Management Intensive Rotational Grazing, otherwise known as MIRG, is a BIG part of Prescribed Grazing Management. It’s a system of grazing in which ruminant and non-ruminant herds are regularly and systematically moved to fresh pasture with the intent to maximize the quality and quantity of forage growth. MIRG can be used with cattle, sheep, goats, pigs, chickens, 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 end 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.
Animal Health Risks
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. As a side note, Sorry if your eating breakfast while reading this blog. Just though some of you might be interested in knowing exactly what causes bloat. 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. ESPECIALLY THIS TIME OF THE SEASON, if they’ve only been getting dry hay all winter! For this reason, It is important to make sure that your cattle are given plenty of free-choice hay while on lush green spring pastures, this will help limit the potential for your cattle to gorge themselves when turned onto new paddocks.
Animal Health Benefits and Animal Welfare.
Herd health benefits will obviously increase when any animal has access to open space, sunlight and fresh air. Freedom of movement within a paddock results in increased physical fitness, which limits the potential for injuries and abrasion often suffered when cattle (specifically Dairy), are never allowed to leave their "free-stall" while in lactation, Sometimes for up to a year and a half!! Allowing your cattle access to the outdoors (even if only for a few hours between milkings or overnight), reduces the potential of exposure to high levels of harmful microorganisms like those that can cause mastitis and milk fever. Outdoor activity also helps cattle keep their hooves naturally maintained, allowing your hoof trimmer more time at your neighbors and potentially cutting your vet bills almost in half too. The only drawback for most dairy producers is the initial loss of milk pounds per animal. But the over-all increase in herd health and decreased medical bill’s offsets the loss of production.
* Although milk yields are often lower in MIRG systems, net farm income per cow is often greater as compared to confinement operations. Additionally, a transition to management intensive rotational grazing is associated with low start-up and maintenance costs.
The main costs associated with transitioning to management intensive rotational grazing are purchasing fencing, fencers, and water supply materials. If a pasture was continuously grazed in the past, than you probably already have half if not most of what you need in the way of fencing and a fencer/charger. Cost savings to Ranchers/Farmers can also be recognized when one considers that many of the costs associated with livestock operations are transmitted to the cattle. For example, your cattle actively harvest their own sources of food for the portion of the year when grazing is possible.
In the North/East, we have our BEEFALO cattle on pasture year-round, but there are only "green forages" available for consumption April – November. This translates into lower costs for feed production and harvesting, which are fuel & time intensive endeavors. MIRG systems rely on the cattle to produce fertilizer sources by way of their manure. There is also no need for collection, storage, transportation, and application of this manure. Additionally, external fertilizer use such as N. P & K, contributes to other costs such as labor to apply it, purchasing costs, and the time to do it! It has been demonstrated that management intensive rotational grazing systems also result in time savings because the majority of work which might otherwise require human labor is transmitted to the herd.