Why We Move Our Cows Daily
Moving the cows, in Management Intensive Grazing (MIG), mimics the movement of large herds of bison moving across grasslands. Because a domesticated herd is not so big and our cattle feel safe, they do not stay very close together and completely graze one spot before moving on as a wild herd would.
In a large paddock, a herd of cattle spread out. Each cow will pick the best forages and eat them down to the ground. This allows less desirable forage species and undesired species to thrive as the cattle avoid eating them.
Additionally, when cattle are allowed to continuously graze a large paddock, they often find a tree or other favored spot where they lounge. They drop huge amounts of manure in their favored lounging spot. They also compact the soil from their continuous presence and the constant trampling kills all the forages in the spot.
We avoid these behaviors by using one strand of electrified poly-wire strung across a paddock to keep the cows in a smaller space and force them to eat a bit of everything.
Ideally, I get the cows moved when they have trampled 1/3 of the paddock, eaten 1/3, and left 1/3. The 1/3 ratios are important - and there's a lot of science and art that goes into getting it just right (I know, because I have overgrazed a paddock more than once!). Also, if a paddock is grazed with 8-10 inches of forage at the start, about 5-6 inches should to be left when they are done.
In the video, the cows were in a rather small space and I moved them to another somewhat small space. In this case, I'm working around Pecan trees that we just planted in the paddocks to provide shade in the future. So the small spaces are dictated by wire hung around where the trees are coming up from seed. Working with smaller spaces means moving the animals more frequently. In this case, they were only in that paddock for half a day and I expect they will need to be moved again by late afternoon.
Ideally, a daily move is what I'm looking for. Twice a day is, well, twice the work.
Some of our paddocks have too many trees to split them with poly-wire and the cows will spend several days to a week in those areas.
Trample 1/3 of the Paddock:
We want to trample 1/3 of the paddock for several reasons. First, all that material that is left lying on the ground feeds the soil microbiology. Along with the manure left behind, this fertilizes the paddock. Second, the trampled materials protect the soil, and it's microbiology, from high temperatures created when the sun beats down directly on the soil. It also protects the soil from taking a beating by heavy rains as the debris breaks the fall of water droplets and disperses them more slowly for better absorption.
Leave 1/3 of the Paddock and Graze Only to 5 or 6 inches:
This sounds like wasting grass right? Not true. Keeping the grass just a few inches taller allows that grass to recover faster, which in turn allows it to be grazed again even sooner. Taller grass also provides protection to the soil in the same ways that the trampled materials do. Taller grass is also very important here where we often have very dry summers - the tall grass shades the soil and retains more moisture. Obviously this is a huge benefit during a drought as it allows forages to survive without water.
Taller grasses have also been allowed to develop their roots more and this lets them pull water and other nutrients for themselves from deeper in the soil.
Short Grazing Time and Long Rest Periods:
Plants benefit from the reduced grazing time and a long rest period of at least 30 days. When cattle continuously graze a paddock, choosing only their favored forages to eat, the plants are not allowed to regrow. This weakens the root system, weakening the entire plant. The result is that the undesirable forages have the advantage and become stronger and more populous!
Short grazing time also reduces soil compaction created by the weight of cattle walking.
Long rest periods are also beneficial in reducing parasite loads. Parasites exit an animals body through their manure. Their life cycles are not very long and waiting to re-graze a paddock allows sufficient time to break the life cycle and reduce or eliminate parasites in livestock.