title: Association of blood cholesterol with occurrence of fat necrosis in cows and tall fescue summer toxicosis in steers.
abstract: Factors associated with fat necrosis in cows and tall-fescue summer toxicosis in steers were studied. In the cow study, fescue pastures were fertilized, using 3 rates of N: high N (703 to 483 kg and 0 kg of N/ha/year from broiler litter in 1972 to 1974 and 1975, respectively), moderate N, and low N (224 and 74 kg of N/ha/yr from NH4NO3, 1972 to 1975, respectively). Bermuda grass pastures were fertilized at 2 rates of N: moderate N and low N (280 and 20 kg of N/ha/year from NH4NO3, 1972 to 1975, respectively). Fat necrosis developed only in cows grazing tall fescue, with an occurrence of 60%, 8%, and 3% for high-N, moderate-N, and low-N pastures, respectively. Cows grazing the high-N fescue, and to some extent those grazing the moderate-N fescue, had clinical signs of summer fescue toxicosis. Plasma cholesterol concentrations were lowest in cattle grazing the high-N fescue, averaging 114 mg/dl, followed by 134 and 127 mg/dl in cattle grazing the moderate-N and low-N fescue, respectively. In the steer grazing study, 24 paddocks of 0.49 ha each were seeded with tall-fescue lines G1-307 or G1-306 or with tall-fescue cultivars, KY-31 or Kenhy. All paddocks were fertilized with 170 kg of N/ha/year. Serum cholesterol concentrations were lower in steers grazing on G1-307 than in steers grazing on G1-306 or cultivars. Serum total lipids followed a similar trend, with a positive correlation (r = 0.49) between cholesterol and total lipids.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood* / Q000209:etiology; D002784:Cholesterol / Q000097:blood*; D005260:Female; D005308:Fertilizers; D008055:Lipids / Q000097:blood; D008297:Male; D009336:Necrosis; D009566:Nitrates; D009584:Nitrogen / Q000032:analysis; D010939:Plant Poisoning / Q000097:blood / Q000209:etiology / Q000662:veterinary*; D010947:Plants, Toxic / Q000032:analysis; D006109:Poaceae; D012621:Seasons
chemical_list: D005308:Fertilizers; D008055:Lipids; D009566:Nitrates; D002784:Cholesterol; D009584:Nitrogen; C006568:ammonium nitrate