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Thyroid hormone concentrations in young, healthy, pretraining greyhounds
R E Shiel1, S F Brennan, A J Omodo-Eluk
1School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
The Veterinary Record
|November 6, 2007
Summary
Young greyhounds exhibit significantly lower total thyroxine (T4) and free T4 levels than other breeds. These thyroid hormone measurements are unreliable for diagnosing hypothyroidism in greyhounds due to low assay detection limits.
Area of Science:
- Veterinary Medicine
- Endocrinology
- Canine Health
Background:
- Thyroid hormone levels in dogs vary by breed.
- Establishing breed-specific reference ranges is crucial for accurate diagnosis.
- Greyhounds may have unique physiological characteristics affecting thyroid function.
Purpose of the Study:
- To determine total thyroxine (T4) and free T4 concentrations in healthy young greyhounds.
- To compare these values with non-breed-specific reference ranges.
- To assess the suitability of T4 assays for diagnosing hypothyroidism in this breed.
Main Methods:
- Blood samples were collected from 46 healthy young greyhounds.
- Total thyroxine (T4), free T4, total tri-iodothyronine, and thyroid-stimulating hormone levels were measured.
- Results were compared against established non-breed-specific reference intervals.
Main Results:
- 91.3% of greyhounds had below-range total T4; 34.8% were below assay detection.
- 20.5% had below-range free T4; 13% were below assay detection.
- All dogs had normal total tri-iodothyronine and thyroid-stimulating hormone levels.
Conclusions:
- Young greyhounds possess inherently lower total and free T4 concentrations.
- Standard T4 assays are unreliable for diagnosing hypothyroidism in greyhounds.
- Breed-specific reference ranges are essential for accurate thyroid diagnostics in greyhounds.
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