Please, please don't be so hard on yourself. You have been doing the very best you could for Otis, and the difference in interpretation by the two vets may not be so great, really.
There are others on this board with much more familiarity with greyhound values than I, but take a look at the greyhound blood values pinned in "greyt information"; especially about thyroid values. Here is a quote;
"T4
Greyhound: .5-3.6 (mean 1.47+/- .63)
Other dogs: 1.52-3.60
These figures are from a University of Florida study of thyroid function in 221 greyhounds — 97 racers, 99 broods, and 25 studs — so it included both racers and “retired.†While greyhound thyroid levels are a whole chapter unto themselves, a good rule of thumb is that greyhound T4s run about half that of other breeds."
For thyroid values, greys are often misdiagnosed as hypothyroid. There is a special lab and a special vet with expertise in this area; my Polly was thought to be hypothyroid because of low values and her bald thighs, but the special lab said she was just fine for a greyhound, and I know that she is.
The WBC count seems to me to require a titre for tick borne disease -- and there is also a special lab for that. Your vet can draw the blood and send it off for you. I don't think the antibiotics will affect the results of the titres if done within a few days of beginning the antibiotic therapy.
Here are the special labs:
For TBD: we used Protatek Reference Laboratories,
Dr. Cynthia J. Holland
ProtaTek Reference Laboratory
574 East Alamo Street, Suite 90
Chandler, AZ 85225
Tel: (602) 545-8499 Fax: (602) 545-8409
and here is their web site: http://www.protatek.com/
I just think that the slowly rising WBC count suggests a TBD taking increasing hold ...
I have to look for the thyroid lab -- I think it was in Michigan --
Yes! http://animalhealth.msu.edu/
They are THE lab for tests and interpretation of greyhound thyroid values.
Feel better, sweet Oatie!