Association of the early stage of the subclinical form of atrophic rhinitis with hypothyroidism in growing pigs

Abstract

The concentrations of serum thyroid hormone (TH), thyroxine (T 4), triiodothyronine (T 3) and reverse tri-iodothyronine (rT 3), were measured in 4·5-5·5-month-old pigs, from randomly chosen herds with subclinical forms of atrophic rhinitis (AR) diagnosed by X-ray (rtg+) and in healthy (rtg−) controls. It was found that concentrations of TH were significantly lower in rtg+ pigs and that the decrease was related to all the hormones measured. In one herd 5–6 months old mean daily weight gain in AR-free pigs was 0·401 and in AR pigs 0·304 kg ( P < 0·001). In pigs 8–10 months old which already displayed clinical signs of AR and were rtg+, the TH levels were low, but not significantly different from that of the controls. The results obtained indicate that the early, subclinical AR is associated with an uncompensated form of hypothroidism.