What it is:
TSH is a blood test that looks at the signal between the brain and the thyroid to help evaluate thyroid function.
Why it is beneficial to breeders:
Helps identify thyroid imbalance that may not show on T4 alone
Useful for dogs with unexplained weight, energy, or coat changes
Supports evaluation of fertility and reproductive health
Adds clarity when thyroid results are borderline or confusing
When breeders should use it:
When T4 results are low or borderline
If breeding animals have ongoing coat, weight, or energy changes
When fertility or cycle regularity is a concern
As part of a more complete thyroid evaluation
 
To summarize:
TSH: A blood test that helps evaluate thyroid function by measuring how the brain signals the thyroid.