AKA..Brown stomach worm
Host: Bovine *MODEL FOR CATTLE NEMATODES*
Adults: Slender, reddish-brown, 1cm, spicules in males and vulva in females
Eggs: Delicate, 85um L, thin shelled, outer surface of shell smooth, containing a morula
LC: Direct, egg w/L1 under optimal conditions develops in fecal pat to L3 in 2 wk, (moist) migrate on to herbage, L3 ingested during grazing, may arrest.
Path: growth & leaving cause pathogenesis, reduction in function of gastric gland mass, distended gastric gland, thickened hyperplastic gastric mucosa, "moroccan leather", edematous abomasal folds, necrosis, hypoalbuminemai, submandibular edema, inappetance, wieght loss, diarrhea, leakage of endogenous protein into the gi.
CS: Type 1 Summer ostertagiosis - calves during 1st grazing season July to September, high morbidity; Type 2 Winter ostertagiosis - yealings in late winter or spring, hypoalbuminemia; profuse watery diarrhea, anorexia, weight loss 20%, poor coats, hindquarters soiled with feces common to both
Dx: clinical signs, seasonality, grazing history, fecal egg counts - type 1 (slow accumulation), type 2 negative due to arrested development, plasma pepsinogen levels, necropsy
Tx: Type1 - anthelmintics, moved to pasture not grazed by cattle; Type2 - anthelmintics for all forms, alternate grazing field; anthelminthic resistance to fenbendazole and morantel