Thyroid hormone levels in cow maternal and fetal sera during last trimester of pregnancy.

Thyroid hormone levels were studied in 51 paired pregnant cow and fetal calf serum samples (fetal age 7-9 months). Thyroxine and rT3 levels were substantially higher and those of T3 distinctly lower in calf fetuses as compared to respective mothers. An increase of T3 has been detected in calf sera at the fetal age 8 to 8.5 months. These results suggest some prenatal maturation of thyroxine metabolism in the calf.

[Lecithin and sphingomyelin in amniotic fluid in late pregnancy in dairy cows]. / Lecithin a sfingomyelin v amniové tekutine vysokobrezích dojnic.

Phospholipides were isolated from 26 amniotic fluids of highly pregnant dairy cows and the lecithin : sphingomyelin ratio (the L/S index) was determined; this ratio ranged from 1.9 to 12.0 (mean = 6.5; n = 20), and in other cases only lecithin was clearly detected (n = 6). During the studied period of 249 to 277 days of pregnancy, no significant correlation was found, by the method used, between the age of the foetus and the L/S index in the amniotic fluid. The modifications of the methods in which the concentrations of different phospholipids are used for the determination of the maturity of foetal lungs, are discussed, together with the possibility of using and interpreting the L/S index in cattle.

[The levels of various mineral substances in the blood plasma of bovine fetuses and their mothers in the third trimester of pregnancy]. / Hladiny nekterých minerálních látek v krevní plazmé bovinních fétu a jejich matek ve tretím trimestru.

The levels of total calcium, inorganic phosphorus, magnesium, sodium, potassium, and chlorides in the blood plasma, and the osmolality of the plasma, were determined in bovine foetuses (n = 20) and the dams (n = 20) in the third trimester of gravidity. The cows of the Bohemian Spotted breed were 2.5 to 7 years old. The foetuses were taken from the uterus by the Caesarean section with local anaesthesia. The foetuses were of both sexes (nfemale = 12, n male = 8). Only the level of total calcium and inorganic phosphorus in the blood plasma was much higher in the foetuses than in the dams and this difference was highly significant. The levels of other minerals showed no statistically significant differences in the two categories of animals tested. The osmolality of the blood plasma of the foetuses was almost the same as in the cows. The higher calcaemia and phosphoraemia of the foetuses ensues from the function of osteotrophic minerals in the process of quick growth and ossification in the third trimester of intrauterine life. The closeness of the levels of sodium, potassium and chlorides as well as the very similar osmolality of the blood plasma in the foetuses and the dams prove the "stability" of the dynamic balance of these parameters between the foetus and the dam in the internal environment of the womb.