The effects of natural exposure to high levels of zinc and cadmium in the immature pony as a function of age.
Abstract: To study the effects of environmental exposure to zinc and cadmium in immature foals, five pregnant ponies were raised within 2.9 km of the New Jersey Zinc Smelter in Palmerton, Pennsylvania. The mares and their foals were kept outdoors on timothy hay and orchard grass. The foals were examined daily for signs of illness and blood samples were taken monthly for estimation of serum zinc, copper, and ceruloplasmin levels. The foals were sacrificed at 2.5, 4.5, 8.5, 13.5, and 18.5 months of age. Necropsy revealed generalized osteochondrosis in joints of the limbs and cervical vertebrae, lymphoid hyperplasia, and eosinophilia. Two of the foals had developed mild lameness. The concentrations of zinc, cadmium, copper, lead, magnesium, and calcium were determined in liver, kidney cortex, and pancreas. The concentration of cadmium and zinc were the only elements that were greatly elevated in all three tissues as compared to control animals. The concentration of cadmium was directly correlated with age in the three tissues (e.g., 23.9 to 212.7 micrograms/g wet wt in kidney cortex), whereas zinc was significantly increased (range 132 to 954 micrograms/g wet wt in liver) but there was no correlation with age. It was concluded that the development of osteochondrosis is associated with increased exposure to zinc and possibly cadmium. The classical signs of cadmium toxicosis, such as renal damage and osteomalacia, were not observed.
Publication Date: 1986-08-01 PubMed ID: 3732202DOI: 10.1016/s0013-9351(86)80104-9Google Scholar: Lookup
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- Journal Article
- Research Support
- U.S. Gov't
- Non-P.H.S.
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research article studies the effects of environmental exposure to high levels of zinc and cadmium on young foals. The findings suggest that increased exposure to these metals may induce osteochondrosis—a joint condition—in foals, although classical signs of metal toxicosis were not observed.
Study Design and Experimentation
- The researchers conducted an experimental study on five pregnant ponies that were raised near a zinc smelter in Pennsylvania, subjecting them to naturally high levels of zinc and cadmium.
- The ponies and their foals were kept outdoors and fed on timothy hay and orchard grass.
- The health of the foals was monitored daily for signs of illness and blood samples were taken monthly to estimate levels of serum zinc, copper, and ceruloplasmin – an enzyme that carries copper in the blood.
- The foals were eventually euthanized at different stages ranging from 2.5 to 18.5 months, and a necropsy, or post-mortem examination, was performed on each.
Findings and Observations
- The necropsy findings included generalized osteochondrosis in the joints of the limbs and cervical vertebrae, lymphoid hyperplasia – an abnormal increase in the cells that constitute lymphoid tissue, and eosinophilia – which is a high number of eosinophils, a type of disease-fighting white blood cell.
- Mild lameness was observed in two of the foals.
- The concentration of zinc, cadmium, copper, lead, magnesium, and calcium in liver, kidney cortex, and pancreas tissues was determined. Elevated levels of cadmium and zinc were identified in all three tissues, compared to control animals.
- Levels of cadmium showed a correlation with age in all three tissues examined, whereas zinc levels were significantly increased, but did not correlate with age.
Conclusion
- The research suggests a relationship between the development of osteochondrosis in foals and increased exposure to zinc and possibly cadmium. This implies that young horses in environments with high zinc and cadmium levels may be at risk of joint conditions.
- However, the classic signs of cadmium toxicosis, such as kidney damage and a bone weakening condition called osteomalacia, were not observed in the subject animals.
Cite This Article
APA
Kowalczyk DF, Gunson DE, Shoop CR, Ramberg CF.
(1986).
The effects of natural exposure to high levels of zinc and cadmium in the immature pony as a function of age.
Environ Res, 40(2), 285-300.
https://doi.org/10.1016/s0013-9351(86)80104-9 Publication
Researcher Affiliations
MeSH Terms
- Aging
- Animals
- Cadmium Poisoning / physiopathology
- Environmental Exposure
- Female
- Horses
- Kidney / analysis
- Liver / analysis
- Male
- Maternal-Fetal Exchange
- Metallurgy
- Metals / blood
- Osteochondritis / chemically induced
- Pancreas / analysis
- Pregnancy
- Zinc / toxicity
Grant Funding
- S07-RR05464 / NCRR NIH HHS
Citations
This article has been cited 3 times.- Paßlack N, Mainzer B, Lahrssen-Wiederholt M, Schafft H, Palavinskas R, Breithaupt A, Neumann K, Zentek J. Concentrations of strontium, barium, cadmium, copper, zinc, manganese, chromium, antimony, selenium and lead in the equine liver and kidneys. Springerplus 2014;3:343.
- Mochizuki M, Mori M, Hondo R, Ueda F. A new index for evaluation of cadmium pollution in birds and mammals. Environ Monit Assess 2008 Feb;137(1-3):35-49.
- Sokoloff L. Acquired chondronecrosis. Ann Rheum Dis 1990 Apr;49(4):262-4.
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