Influence of Iodine and Selenium Deficiency on Macro and Trace Element Content of Ewe's Milk (Blackhead Dairy Breed)

N. PETROVA, L. ANGELOW, D. TODOROVA and D. DOCHEVSKI

Institute of Animal Science, BG-2232 Kostinbrod, Bulgaria

Abstract

PETROVA, N., L. ANGELOW, D. TODOROVA and D. DOCHEVSKI, 1999. Influence of iodine and selenium deficiency on macro and trace element content of ewe's milk (Blackhead dairy breed). Bulg. J. Agric. Sci., 5: 907-910

A study was carried out to establish the effect of Se and I supplementation in feeding of Blackhead sheep breeds on milk production, trace (Se, I, Zn) and macro (Ca, Mg) elements concentration of milk during the first 56 days of lactation. Twenty ewes of Blackhead dairy breed, divided into two groups were fed according to ARC norms with different amounts of selenium and iodine during the experiment. The daily ration included 0.08 mg Se/kg DM and 0.10 mg I/kg DM. The control group received additionally 0.15 mg Se/day as NaHSeO3 and 0.20 mg I/day as KI. The milk samples were taken on the 7th, 14th, 28th, 42nd and 56th day.
The low levels of Se and I in the ration of Blackhead sheep led to 16,1% decrease of daily milk production during the first 56 days of lactation.
The amount of Se and I for all investigated period in Se-I deficiency group decreased twice (51%) and two third (67,8%) respectively.
The influence of Se-I deficiency on Zn, Ca and Mg content of the sheep milk was negative for Zn content from 28th to 56th days of investigated period, positively for Ca content at the beginning (7th 14th days), and at the end (56th day), and negative for Mg content for all investigated period (except 56th day).
The results demonstrated the necessity of correction in Se and I concentration in the ration for lactating Blackhead sheep.

Key words: sheep, milk, selenium-iodine deficiency, macro and trace element content