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Animal Science Department, University of Kentucky, Lexington 40546
ABSTRACT
Recent interest in ß-carotene has been stimulated by reports that reproductive performance in cattle was improved with dietary supplementation of ß-carotene even when the diet was supplemented with vitamin A. Vitamin A requirements for cattle are based on studies with ß-carotene as the vitamin A source and with studies with vitamin A in the ester or alcohol form. Most of the studies with cattle that demonstrate the need for vitamin A for optimum reproduction were when ß-carotene was the source of vitamin A. Recent German reports show an improvement in conception rate, intensity of estrus, and changes in luteinizing hormone patterns when cattle received ß-carotene supplementation of low carotene diets. These diets were supplemented with vitamin A. A similar study from Israel did not detect benefits of ß-carotene. The active form of vitamin A for reproduction in rats and other species has not been determined; however, vitamin A does meet the reproductive requirements. The ruminant animal does have differences in carotene metabolism from the rat. Before the role of ß-carotene for reproduction in cattle can be clarified, the specific function of carotene or the specific form of vitamin A for reproduction needs to be determined.
1 Invitational paper presented at the 76th Annual Meeting of the American Dairy Science Association, June 29, 1981.
2 This manuscript (81-5-201) is published with the approval of the Director of Kentucky Agricultural Experiment Station.
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