Cs. Randhawa et Ss. Randhawa, Epidemiology and diagnosis of subclinical iodine deficiency in crossbred cattle of Punjab, AUST VET J, 79(5), 2001, pp. 349-351
Objective To determine the prevalence of iodine deficiency in crossbred cow
s (taurus x indicus) of Punjab and to assess the diagnostic value of the pl
asma concentrations of thyroid hormones, total cholesterol and free fatty a
cids in iodine deficiency. The efficacy of ethiodised oil, as a long-term s
upplement of iodine, was also evaluated.
Procedures Base-line survey of iodine status was conducted by measuring pla
sma inorganic iodine (PII) concentration in 48 crossbred cows from 31 dairy
units. Concentrations of plasma triiodothyronine (T-3), thyroxine (T-4), t
otal cholesterol and free fatty acids were compared between iodine deficien
t and normal cows. Circulating T-4 and T-3 concentrations were also determi
ned before and after injection of ethiodised oil in cows with low PII level
s.
Results The mean prevalence of iodine deficiency was 35.9% and showed consi
derable geographical variation from 0 to 86% within Punjab. Cardinal clinic
al signs of iodine deficiency were absent and basal plasma T3 and T4 concen
trations and their ratio did not differ between deficient and control cows.
Activity of circulating T4 and T4:T3 ratio increased in response to ethiod
ised oil injection and persisted beyond 70 days after injection.
Conclusion Asymptomatic iodine deficiency is prevalent in crossbred cows of
Punjab and response to iodine supplementation is the most reliable index o
f thyroid dysfunction associated with iodine deprivation. The results of th
is study also support the view that injection of 1 mL of 78% ethiodised oil
can prevent iodine deficiency for more than 70 days.