Original scientific paper
THE LEVELS OF THE CONCENTRATION OF THIROXINE IN THE SERUM OF LACTATING COWS DURING THE SEXUAL CYCLE
Boris Angelov
; Viša zemjodelska škola, Bitola, Makedonija
Abstract
By using the RIA method the total quantity of thiroxine (T4) i the blood serum of lactating cows of east-Friesian breed, in various seasons, during a three year period was investigated. During all staqes of estral cycle (0 day of estrus, 4-7 day of metestrus, 12-14
day of diestrus and 18-20 day of proestrus) the blood samples were taken. Test-kits of Yugoslavian production, for use in human medicine were applied, without previous valorization and adaption to use in veterinary practice. The basic statistical elaboration of the data (F test) showed that the total T4 in younger cows wak at a higher level as compared to elder ones, (from the first to the, fourth lactation, the TT4 concentration decreased). The established average level of X =52,580 ± 1,798 nmol/l coincides with the physiology values revealed by various authors for this kind, category, and breed os animals. By laboratory research of 238 samples of blood serum, significant differences were established between foliculin and luteal phases (higher level in estrus and protestrus) in warmer seasons. These differences are not significant in cooler seasons. These data are in contradiction with the data of other groups and are not in agreement with the tendencies established by average values for all the groups tested. (x=54,683 nmol/L; X=52,344 nmol/L; x=50,754 nmol/L; X = 52,586 nmol/l for estrus, metestrus, diestrus and proestrus respectively.
Keywords
Hrčak ID:
162250
URI
Publication date:
20.9.1991.
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