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Title: GASTROINTESTINAL NEMATODES ON A GRAZING DAIRY OPERATION: EFFECT OF PARASITECONTROL ON PRODUCTION AND PARASITE TRANSMISSION

Author
item Gasbarre, Louis
item STOUT, WILLIAM - COLD RIDGE FARMS
item LOHR, LARRY - COLD RIDGE FARMS
item GUERRERO, JORGE - COLD RIDGE FARMS

Submitted to: American Association of Veterinary Parasitologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/28/2001
Publication Date: 7/14/2001
Citation: GASBARRE, L.C., STOUT, W., LOHR, L., GUERRERO, J. GASTROINTESTINAL NEMATODES ON A GRAZING DAIRY OPERATION: EFFECT OF PARASITECONTROL ON PRODUCTION AND PARASITE TRANSMISSION. AMERICAN ASSOCIATION OF VETERINARY PARASITOLOGISTS PROCEEDINGS. pp.51, 2001.

Interpretive Summary:

Technical Abstract: Grass-based dairy systems employing rotational grazing are becoming increasingly popular with small dairy farm operations in the Northeastern US. An early adoptee of grazing noticed drops in productivity around his 6th season, and suspected that the drop in productivity was the result of nematodiasis. He subsequently began treating cattle using top dress morantel whenever milk production decreased, resulting in as many as 6 drug applications over the grazing season (approximately 1 May to 31 October). In 1995 we began to characterize parasite transmission patterns on the farm using tracer calves and fecal sampling of each grazing group. Results indicated that the pastures had substantial numbers of Ostertagia ostertagi and Cooperia oncophora, and lesser numbers of Nematodirus helvetianus. Each year transmission was initiated by large numbers of parasites that overwintered on the pastures, and there was no significant level of arrestment. In the 3rd year of the study we began to strategically treat for the parasites. Treatment programs involved 1 to 3 early season treatments with either fenbendazole or an avermectin, coupled with an avermectin treatment at housing for louse control. Using PA DHIA records comparison of milk production for the first 2 years of the study to the next 3 years, indicated a 2-6 lb/animal/day increase in milk production during the grazing season when strategic treatments were used. The early season treatment removed large numbers of Ostertagia and Cooperia from the pastures, but if treatments were applied too early in the year there were significant blooms of Nematodirus especially on pastures with young heifers.