Eliminating Pasture Parasite Larvae

Eliminating Pasture Parasite Larvae

David Sparks Ph.D.
David Sparks Ph.D.
Producers tend to focus on worms in their capital budgets but it is the worms on your pasture that should really be the concern. Especially the L3 larva phase. Initially the only larvae on the grass are those that have over wintered in the soil. Without a host, these larvae will begin starving to death once the temperature and their metabolism start to increase. This takes place before calves start grazing. I has cows eat the larvae, the parasite lifecycle continues. The cows load the pasture with new eggs. These eggs hatch and the larvae build up on the pasture throughout the summer. These are the larvae that eventually infect the calves. De- worming cows results in fewer eggs being deposited on the pasture for a period of time depending on the de-wormer. The problem with conventional de-wormers is that they only last a short time. Even if cows were dewormed in the spring, the de-wormer has worn off by the time parasite larvae reach their heaviest concentration Midsummer which is also about the time when calves start grazing. When you do a spring treatment with cows using Long Range, the cows act like a filter for the pasture. This is because few overwintering juveniles that have been ingested become adults. That means fewer eggs are shed onto the pasture to infect calves or to overwinter to infect cows and calves next season. You will see the benefits in two calf crops... This year's and texts.
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