OBJECTIVE To determine prevalence of anthelmintic resistance on sheep and goat farms in the southeastern United States. DESIGN Cross-sectional study. ANIMALS Sheep and goats from 46 farms in 8 southern states, Puerto Rico, and St Croix in the US Virgin Islands. PROCEDURES Parasite eggs were isolated from fecal samples, and susceptibility to benzimidazole, imidathiazole, and avermectin-mil...

The influence of dietary protein supply on the nutritional penalty associated with the acquisition phase of the immune response to gastrointestinal nematodes in lambs was investigated. Groups of lambs were offered either a low-protein diet (L; 62 g metabolizable protein (MP)/kg dry matter (DM)) or high-protein diet (H; 95 g MP/kg DM) while being either infected with the equivalent of 2.000 L3 T...

Objective: Determine the productive and immune response of Blackbelly lambs infectedwith gastrointestinal nematodes (GIN) fed with saccharin.Design/ methodology/ approach: A total 18 lambs, an initial live weight (LW) 13.9 + 3.2 kg, were randomly assigned to three different treatments (T): T1, anthelmintic treatment basal diet (CTah); T2, without (STah); T3, grazing (STPS). This experiment foll...

Clinical and subclinical intestinal parasitism is characterized by impaired production (Sykes & Coop, 1976; Steele, 1978) with poor growth rates in young animals and loss of body weight in older animals. Sheep also incur severe reductions in wool growth. A number of comprehensive reviews prepared over the last decade characterize and contrast the magnitude of such impairment across a range of i...

OBJECTIVE Develop a computer simulation model that uses daily meteorological data and farm management practices to predict populations of Trichostrongylus colubriformis, Haemonchus contortus and Teladorsagia (Ostertagia) circumcincta and the evolution of anthelmintic resistance within a sheep flock. Use the model to explore if increased refugia, provided by leaving some adult sheep untreated, w...