Abstract
A mature adult female African forest buffalo (Syncerus caffer nanus) of unknown age was presented with recurrent signs of hoof overgrowth, persistent anestrus, obesity, dull hair coat, and decreased activity. Complete blood counts (CBC) and serum biochemistry values were unremarkable. Decreased concentrations of triiodothyronine (T3) and total thyroxine (TT4) were noted when compared to domestic cattle and a healthy African forest buffalo. Treatment with oral levothyroxine (84 mg PO mixed with pellets every 24 h; Thyro-L, Vet-A-Mix, Shenandoah, IA, USA) increased blood concentrations of T3 and TT4, and improvements in clinical signs were noted including weight loss, hair re-growth, and reproductive cycling. The animal responded to treatment for 6 mo until its death during an anesthetic procedure.
To our knowledge, this is the first reported case of spontaneous hypothyroidism in a bovid. The animal responded to dietary administration of levothyroxine with increased thyroid hormone concentrations, and improved clinical demeanor and body condition. Anecdotally, rumen enzymes are thought to inactivate this hormone, and the traditional methods of administration in domestic cattle, parenteral or rectal, are difficult in a nondomesticated bovid. The findings of this case report suggest that future cases of bovid hypothyroidism may respond to oral supplementation of levothyroxine above the normal dose ranges for monogastric animals. Hypothyroidism should be considered as a differential diagnosis for any individual with obesity, dull hair coat, persistent anestrous, and overgrown hooves. Diagnosis and treatment may be relatively straightforward.
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