تعيين فراواني غلظت يد معدني در سرم و شير گاوهاي دامداري هاي صنعتي شهرستان گلپايگان

Iodine Deficiency in Golpayegan Dairy Herds

Iodine is an essential trace element for dairy cattle. Recent studies in Iran and Isfahan province show that endemic goitra is prevalent in many parts of Iran. In the winter and summer of 2000, 4 dairy herds from different farms in Golpayegan were selected randomly for iodine determination. According the number of dairy cattle in each farm, some dairy cattle, that were in a similar condition (age, milk yield,...) were selected randomly and the total plasma (or serum) iodine and iodine in the milk were assayed by the Sandell-Kolthoff reaction. In all herds (except one of them) the total plasma (or serum) iodine in winter (P<0.01) and in the summer (P<0.05) was lawer than the critical level in dairy cattle. There was also a significant effect of season on iodine level in plasma; the total plasma (or serum) iodine was lower in winter than in summer (P<0.05). The result of this study showed also that milk iodine level was not a good index for iodine status in dairy cattle; it was very variable because of teat dipping after every milking. This study indicated that inputs of commom iodine supplements were inadequate for dairy cattle diet in these farms.