THE GALACTOPOIETIC EFFECT OF IODINATED CASEIN: DOSE RESPONSE RELATIONSHIPS DURING PROLONGED TREATMENT

Abstract

1. In an experiment involving fifty-nine cows, the relative values were assessed of daily dosages of 15, 20 and 25 g. of iodinated casein incorporated in cattle cubes. Treatment was continued from 3 months after calving for 28 weeks, except on cows which went dry before this time. 2. The expected increase in milk yield lasted for 8 weeks, after which the response to the two lower doses quickly disappeared. The response to 25 g. of iodinated casein was maintained at a reduced level throughout the period of treatment. 3. The yield of butter fat reacted very similarly to milk yield. 4. There was no effect on the proportions of butter fat or of non-fatty solids in the milk. 5. Body weight was reduced by amounts proportional to the doses; this loss in weight gradually disappeared. After 12 weeks of treatment there were no significant differences between the groups. 6. There was no significant effect on the health of the cows or on their reproductive activity.