Toxicosis was induced in pregnant heifers by feeding 25,000 mg/head/day of FireMaster BP-6, a commercial blend of polybrominated biphenyls (PBB). The PBB feeding decreased dry matter intake approximately 50% by 4 days exposure. Emaciated animals became anorexic a few days prior to death at 33 to 66 days. Weight losses of heifers averaged 80 kg. Other clinical signs observed were dehydration, diarrhea, excessive salivation and lacrimation, fetal death, abortion, and general depression as evidenced by depressed heart and respiratory rates. Clinical signs were apparent after 10 days exposure and progressively intensified along with loss of condition until death. Clinicopathologic changes included significantly increased serum glutamic-oxaloacetic transaminase and decreased serum calcium by 30 days exposure. Lactate dehydrogenase, urea nitrogen, and bilirubin were elevated, and serum albumin decreased by 36 to 40 days. Principal urine changes were decreased speciflc gravity and moderate proteinuria. Pregnant heifers fed 0.25 or 250 mg/head/day for 60 days and nonpregnant heifers fed 250 mg/head/day for 180 days displayed neither clinical signs nor clinicopathologic changes indicating adverse effects from PBB exposure. Post-exposure, all heifers exposed to PBB for 60 days calved normally with zero calf mortality and were successfully rebred. Milk production was not different from control animals. Birth weights of calves from dams exposed to 250 mg PBB/head/day were significantly greater than calves of dams exposed to 0 mg or 0.25 mg/head/day. PBB exposure of dams produced no detrimental effects on calves as indicated by clinical signs, clinicopathologic changes, or performance.
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org. . The National Institute of Environmental Health Sciences (NIEHS) and Brogan & Partners are collaborating with JSTOR to digitize, preserve and extend access to Environmental Health Perspectives. Toxicosis was induced in pregnant Holstein heifers by feeding FireMaster BP-6 (polybrominated biphenyls) in daily oral doses of 25 g/head/day for 33-60 days. The individual heifers were dosed until each became moribund (days 33, 36, 39, 40, 41, or 66), at which time they were necropsied. Gross findings included dehydration, subcutaneous emphysema and hemorrhage, atrophy of the thymus, fetal death with concomitant necrosis of cotyledons, thickened wall of the gallbladder, inspissated bile, edema of abomasal folds, mucoid enteritis, linear hemorrhage and edema of the rectal mucosa, and secondary pneumonia. The livers were enlarged approximately 40%o. Kidneys were approximately double the normal size and were pale tan to grey in color. The perirenal lymph nodes were enlarged and edematous. Microscopic changes were the most marked in the kidneys, gallbladder and eyelid. Extreme dilatation of collecting ducts and convoluted tubules with epithelial degenerative changes of cloudy swelling, hydropic degeneration and separation from the basement membrane were principal changes in the kidney. Hyperkeratosis with accumulations of keratin in hair follicles of the epidermis and squamous metaplasia with keratin cysts in the tarsal glands were characteristic findings in sections of eyelids. Moderate to marked hyperplasia and cystic dilatation of the mucous glands in the lamina propria were common changes in the gallbladder. Foci of fatty degeneration and glycogen depletion were observed in liver sections. Necropsy of heifers immediately after 60 days exposure to 0.25 and 250 mg/head/day of PBB showed no gross or histopathological signs indicating toxicosis. Following parturition, at approximately 220 days after the PBB doses, heifers from the 0.25 and 250 mg/head/day groups and their calves were necropsied and displayed no signs of toxicosis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.