By Harry Brook
Every spring there is a strong temptation for livestock producers: getting the cattle out onto pasture as soon as possible. However, putting cattle on grass before it is ready will limit the grazing you can get out of it for the entire season and even longer. The why of this is dependent on the way grass grows.
Different grass species have different growth habits and different stages where they are best grazed. Timothy, a very popular grass, is really a poor pasture grass. It puts out three small leaves on the stem, then goes to head and seed production. Meadow bromegrass, on the other hand, is a lot different. It will stay vegetative for most of the summer, putting out 23 to 27 leaves before the seed head emerges. This provides far more grazing for the entire grazing season. There are also differences in spring growth between tame and native grass species. If you have to graze pastures early, tame pasture will be ready at least two weeks before native range.
To begin growth or to regrow after cutting or grazing, grasses must take energy out of the roots and move it into the shoots. This causes the root mass to shrink. If you don’t give the grass time to renew the energy in the roots, you end up with a situation where the vast majority of the grass roots are concentrated in the top two to four inches of soil. There they are short of nutrients and susceptible to dry conditions and I have often heard producers call the pasture “rootbound”. One solution for this condition is rest, but most graziers cannot afford to leave a pasture ungrazed for a couple of years. Another tool that can be used is using fertilizer to stimulate growth. It still requires moisture to get down into the root zone and you still have to allow the plants to grow at least six inches high prior to grazing.
Some other strategies to be used to provide early pasture include having forage kept over from last fall or grazing aftermath left from the previous year. This can work but there will be need for high quality supplements to be fed as well. Aftermath may be useful to fill up the cows but it will be low in feed value and protein. This can be a real problem if the cows have calves or are ready to calve, as milking cows requires a high level of feed quality.
Using a winter cereal seeded last fall can provide early season grazing. However, you still need to let the plant grow to the third or fourth leaf before putting the cows out. Also, after going through winter, the fall rye or winter wheat will attempt to head out early. Crested wheatgrass can be used as early season grazing, as it is one of the earliest grasses to start growing in the spring and survives spring grazing. Annual cereals can be grazed in a pinch but then you sacrifice grain production for the grazing. In annual crops, once the growing point is above the soil surface and is grazed, any regrowth has to come from the base of the plant and regrowth is slow, if at all. Another approach, though not recommended, is to set aside an early spring pasture as sacrifice. The cattle may not get much out of it but it should then be left ungrazed until the fall.
Once summer comes, you can get the most from your tame pastures by using a rest-rotation. The goal here is to take enough early on, to keep the plants vegetative but not too much so they can have energy to regrow. A rotational system allows for some flexibility as to when to use the forage. In wet years, you can also choose to hay any excess production.
Grass and hay production should be treated like any annual crop. Know the nature of the plants growing there and use them as they are best suited to meet your grazing needs. Working with the biology of the crop will benefit you and your livestock in the long run.
See below for some excellent videos on pasture management.