Rotating animals to fresh paddocks not only allows for management of a farm’s grazing resources, but it also can help lessen nutrient overload from manure and reduce parasite pressure.
Parasites move in a continuous life cycle. Eggs are deposited in manure and through time, those eggs turn into infective larvae. The infected animals are moved to pasture, where they deposit infected manure, and the parasite is ingested and the cycle starts anew.
Parasites need cool and moist conditions to thrive. Eggs can hatch in as little as six days and larvae can last as long as 120 days. Egg development does not occur when temperatures are at or below freezing and eggs and larvae are killed when temperatures are hot and dry.
Most larvae will be found within the first 2 inches of plant growth from the base of the plant, so managing to ensure overgrazing does not occur will help decrease ingestion of parasites.
“Unfortunately, parasites can go dormant inside the host animal during unfavorable conditions, so while you may not think parasites are an issue during a drought, any change to favorable conditions can result in a rapid flush and quick development from egg to infective larvae,” warns Mary Keena, livestock environmental management specialist at NDSU’s Carrington Research Extension Center.
If rotation of animals from pasture to pasture isn’t possible, removing manure daily or weekly from the grazing area is another management strategy. Another method for breaking the parasite life cycle is to use multispecies grazing.
Parasites are host-species specific, so if an infestation occurs in sheep or goats, horses or cattle could rotate into that pasture and not be affected by those parasites. Different species also typically eat and select for different plants, which can help extend the forage supply.
Source : ndsu.edu