The Relationship of Altered Thyroid Activity to Various Reproductive Phenomena in Gilts

Abstract

SUMMARY Three groups of fifteen Palouse gilts each were used to test the effects of altered thyroid activity on ovulation and fertilization rates and embryonic mortality in swine. Two groups received 0·15% thiouracil and 0·0123% thyroprotein, respectively, in a basal ration, and the third served as controls. All gilts were assigned to treatment sets at first oestrus and were bred to fertile boars at second oestrus. One-third of the gilts in each group were slaughtered 12–24 hr after the end of second oestrus, one-third slaughtered 25 days post coitum and the remainder allowed to farrow. An analysis of variance revealed no significant differences between groups for: ovulation rate, fertilization rate, embryonic mortality during the first 25 days of gestation, number of normal embryos at 25 days post coitum, or number of pigs born alive. A significant increase in the duration of gestation was found for thiouracil-treated females. Pigs born to thyroproteinsupplemented mothers were significantly heavier at birth than pigs born to thiouracil-treated mothers. Under the conditions of this experiment, X2 analysis indicated that thiouracil produced a highly significant embryonic mortality during gestation from the 25th day of pregnancy until farrowing. Thyroprotein treatment tended to lower embryonic mortality during the same period.

Solvent-extracted rapeseed oil meal as a protein source for pigs and rats /

“…conceived on first service after they reached the required breeding age; oestrus periods had been noted in these groups of the total ration and gestation gains were normal. Lucas et al (1958) noted that thiouracil-fed pigs had longer than normal gestation periods;…”

“…The mustard oil of the rapeseed oil meal has no effect on breeding sows, but it is advisable to guard against digestive disturbances by supplying powdered charcoal". Lucas et al (1958) Kennedy and Purves (1941) fed whole rapeseed as 457. of the total ration and reported a delay in development of the ovaries of immature female rats to the extent that the animals would not become pregnant until the age of 5 to 7 months rather than the normal 2 to 3 months. Jones e_t al.…”

Uterine enzyme changes in thyroidectomized rats at parturition

“…Maternal hypothyroidism during pregnancy has been shown to cause prolonged gestation (Lucas, Brunsted & Fowler, 1958), reduced litter size and fetal weight (Parrot, Johnston & Durbin, 1960;Stempak, 1962), fetal résorption and retarded fetal growth (Chu, 1944). The role of thyroid hormones for fetal growth and differentiation remains unclear (Kohler, Wojnorowich & Emhke, 1974) although they are believed to be indispensable for the successful outcome of pregnancy (Krohn & White, 1950;Bakshi, 1978).…”

Conception rate, milk production and endocrine responses of lactating Holstein cows to subtropical climates in Hawaii and Mexico

“…I thyroid damage and also found ro damage to fertility. Lucas, Brunstad and Fowler (1958) reported that feeding 0.15 % thiouracil (a goitrogen) to gilts did not affect ovulation rate, fertili zation rate, embryonic mortality during the first 25 days of gestation, or the number of pigs bom alive, but gestation was lengthened significantly.…”