Managing your Pastures Better
During the warm months of the year enormous numbers of larvae can build up on your pasture. Your pastures are the primary source of the round worm larvae for your goats. Parasite larvae can live for long periods of time on your pastures. You can’t eliminate completely parasites in the pasture.
The magnitude of pasture contamination is affected mainly by
- Stocking rate (number of animals per grazing area). The higher/lower the stocking rate, the more/less feces are deposited on the grazing area, thus more/fewer eggs.
- Genetics of your herd - Some goats have more problems with worms than others and will produce more eggs in the pasture.
- Age of the animals – More eggs are also passed from young vs older animals.
- Season of the year and if parasites in the stomach are in arrested development or not. Most worms have a definite seasonality, so during their season, more eggs are produced and passed.
Pasture management is done by the following:
- Reduce the number of animals in your pastures (see overcrowding)
- Change the browse in your pastures
- Burn the pasture
- Rest your pastures from grazing
- Rotate the animals in the pastures
- Wait to turn your herd into a pasture until after the morning dew is gone which forces the larvae to the ground.
- Dry lot your animals at critical times and feed hay instead of going to a pasture.
Change the Browse
Goats are browsers. Goats love to browse and prefer shrubs and forages to grass. That means goats can be found sampling plants at all levels. Round worm and similar parasites will be found on grass. The larvae normally only travel 2-4 inches up a blade of grass. The higher your animals are grazing above the ground, the less likely they will ingest the larvae. Allowing goats to browse on other vegetation at higher levels will reduce the goat’s exposure to these worms. Incorporate browse plant species when possible..
There is growing evidence in work from New Zealand and Europe that grazing or feeding of plants containing condensed tannins (CT) can reduce the fecal egg count, larvae development in feces, and adult worm numbers in the stomach and small intestine.
Researchers are exploring the use of plants to control round worms with medicinal plants having anthelmintic properties. Forages, such as clover, vetches, chicory, and Sericea lespedeza, contain condensed tannins. Condensed tannins can reduce the number of stomach worms and egg production. Some of the forages that may have anti-parasitic effects include Birdsfoot Trefoil, Chicory, Sericea Lezpedeza.
- Sericea Lespedeza - Preliminary test with sericea lespedeza, a CT-containing perennial warm-season legume, have shown positive effects of reduced fecal egg counts in grazing goats and goats in confinement when the forage was fed as hay. Some studies have indicated feeding sericea lespedeza hay to goats can reduce fecal eggs counts by 80 percent and create a higher packed cell volume. We have planted some Sericea Lespedeza this year to see how it will do. It seems to be a very slow starting legume. We are hoping the growth dramatically improves next year so we will feel more comfortable allowing our herd to graze it.. Sericea Lespedeza, when fully developed, is a tall legume and that keeps the goats away from the ground while browsing.
- Chicory – In a study in Scotland, lambs reared on chicory without strategically used dewormers had lower faecal egg counts than their grass/clover grazing counterparts, and grew at similar rates as lambs reared on grass/clover in the presence of strategically used dewormers. The study indicated short and long term grazing on chicory has the potential to reduce worm burdens.
- Hay Grazer - Planting a Hay Grazer forage (sorghum x sudan hybred forage). This is a forage that grows tall. It can have a tall stem with big wide leaves higher up the stem. The goats only like the leaves therefore they will eat the leaves that are not near the ground and avoid the living site of the larvae. We planted some of this as a trial in one pasture this year. The goats ate the leaves and left the stem at least 4-5 inches tall. After they had eaten most of the leaves from the forage, we moved them to another pasture. In no time at all, the hay grazer shot up several feet tall again thus allowing our goats to come back and graze the higher forage again. The major focus on planting this is it keeps the goats away from the ground level where the parasite larvae are living.
Rotate the pastures
Rotating your animals to different pastures may help reduce the number of larvae available to them. The longer you can wait before grazing your herd in a pasture again, the better the chance that some of the larvae have died thus reducing the number of larvae that your goats may ingest to start their life cycle again.
As long as your goats are on the pasture, they are continuing to drop their pellets with millions of parasite eggs just waiting to hatch. The longer a pasture is resting from goats on it, the more larvae die and no new eggs are being dropped for future hatching. However, the main reason many breeders use pasture rotation is not for parasite control but to provide the most nutritious forage for growth and development. If grazed correctly, most forages reach the next most nutritious stage in about 30 days, so many rotation schemes have the animals returning to pastures at around 30 day intervals. Unfortunately, this 30 day interval is also about the same time necessary to ensure that the previous worm parasite contamination has now been converted into the highest level of contamination for the next grazing group.
Thus, 30 day rotation schemes may actually lead to increased worm parasite problems. In fact, heavy exposure over a short period of time can lead to disastrous clinical disease and losses. Rotation schemes of 2-3 months have been shown to have some effect on reducing pasture contamination in tropical and subtropical environments but in more temperate environments, contamination can extend out to 8-12 months depending on the conditions. For the most part, it is impractical to leave pastures ungrazed for such extended period of time.
Rotational grazing generally does not help to control internal parasites unless pasture rest periods are long enough (> 70 days). In fact, management intensive grazing (short duration, high intensity grazing) may exacerbate parasite problems in goats because the goats are grazing low to the ground right where the larvae are living..
A Clean or Safe Pasture
- A clean or safe pasture is one in which sheep or goats have not grazed for 6 to 12 months
- A tilled or burned pasture helps reduce the larvae count in it and certainly can make it safer
- If other animals like cattle or horse have grazed a pasture, they have consumed some of the larvae. The larvae are not harmful to them
- If a pasture has had hay removed from it, that will also reduce the height of the grass and allow more heat and sunlight to impact the larvae
- When possible, use the pasture for hay cutting after grazing. This will help to break the worm life cycle and prevent re-infestation. Direct sunlight during the summer months or during freezes in the winter will also help decrease the population of larvae that remain in the soil.
- When possible, alternate the pasture with a short cycle crop, such as culture alfalfa. This management practice will help to break the worm's life cycle, and decrease larvae population in the pasture and prevent re-infestation.
- The effect of mowing, if any, is not large. The proven effect of mowing early in the grazing season on pastures has resulted that farmers and extension workers think that a mown pasture is safe. Unfortunately, the preliminary data presented in studies demonstrate that this is not necessarily true for goat pastures that have been contaminated earlier in the grazing season.. Most goat farmers in the study indicated that they had mown in between grazing periods. Nevertheless, problems occurred on some farms applying mowing in 2002 Thus, the study concluded that they have to convince farmers that they should not only rely on mowing as a measure to get clean pastures.