Effect of thyroactive compounds on lactating sows

Abstract

REVIEW OF LITERATURE Galactopoietic Compounds Since the early 1930s the relationship of the thyroid gland to milk secretion has been extensively investigated especially in the cow, It was shown that thyroidectomy of the dairy cow caused a marked depression in milk yield which could be corrected by feeding dried thyroid gland (Graham, 1934a). This led to the observation that the feeding of dried thyroid tissue would also increase the secretion of milk of cows in the declining period of lactation. Continued work led to the discovery that a similar increase In milk secretion could be obtained when crystalline thyroxine was injected into lactating cows (Graham, 1934b). These early investigations led to further interest In the use of thyroactive materials for lactating cows (Turner, 1956). The development of a method to produce thyroactive compounds from protein (Ludwlg and Von Mutzenbecher, 1939) led to the development of a method for the iodlnation of casein under controlled conditions. This product, iodinated casein, known as thyroprotein or commercially as Protamone made pos sible the worldwide study of the action of the thyroid gland upon the lactation process (Turner, 1956). Chemical assays of unwashed thyroprotein extract show that it contains at least ten iodinated compounds, including 8 Although thyroxine is not secreted into the milk in detectable quantities, the level of iodine in milk can be in creased by a dietary source of iodine (Wright et. al., 1955; Lengemann and Swanson, 1957). Furthermore, it appears that as the season advances from late winter to early summer, in creased blood and milk levels occur in the metabolism of iodine by the dairy cow (Lengeman et al., 1957). Components of the milk solids may be affected by the feeding of a galactopoietic thyroactive compound but the re sults reported by different investigators are not in complete agreement. Niacin is reported to be significantly increased (Kemmerer et^ al., 1946; Booth et al., 1947). Carotene is re ported to be increased and Vitamin A decreased (Hibbs and Krauss, 1947). The status of ascorbic acid, riboflavin and thiamin is confused as investigators report different trends (Van Landingham et al., 1944; Kemmerer e_t al., 1946; Booth et al., 1947; Thompson and Kon, 1949). It is reported that there is no change in the content of milk albumin and globu lin (Booth et al», 1947) as well as an increase in their con tent (Archibald, 1945). The status of the milk fat falls into this same confused picture as some investigators report no change and others report a slight increase (Ralston ert al..

Saccharin in baby pig nutrition

“…However, under conditions of continuous feeding of low levels of soluble saccharin this taste reflex mechanism probably would not come to prevent possible death. Johnson (1958) The injection of soluble saccharin intrapsritonally also failed to increase the rate of removal of glucose from the blood system. This is also in agreement with the work of Jorgensen (1950) and Kun and Horvath (1947) Quinn for their interest and contributions to the project.…”