[Levels of luteinizing hormone in sheep of various breeds]

Determined were the LH values in the course of the sexual cycle which ranged within limits of 1 ng ml-1, with a peak of 60 to 250 ng ml-1 on the day of oestrus. By leaving the lambs with their mothers, the normal cycle is stopped, conclusive differences in the rest levels of LH were found out in the Finnish sheep breed, in Romanov sheep, and in the mutton Merino breed. After ovariectomy there occurred an increase of LH in sheep of the Tsigai breed to 6 ng ml-1 and in sheep of the mutton Merino breed to 18 to 22 ng ml-1.