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Variations in the concentration of 17ß-oestradiol and testosterone levels in calves of different sex, age, breed and farm origin

Marko Samardžija ; Veterinarski fakultet Sveučilišta u Zagrebu, Hrvatska
Ines Gulić ; Hrvatska
Dražen Đuričić ; Veterinarska stanica Đurđevac, Hrvatska
Nina Kudumija ; Hrvatski veterinarski institut, Zagreb, Hrvatska
Miroslav Benić ; Hrvatski veterinarski institut, Zagreb, Hrvatska
Jelka Pleadin orcid id ; Hrvatski veterinarski institut, Zagreb, Hrvatska

Puni tekst: hrvatski pdf 558 Kb

str. 255-265

preuzimanja: 186



Physiological levels of the sex hormones 17β-oestradiol and testosterone vary based on animal species, age, sex, breed, rearing technology, nutrition, stress and environmental factors. These hormones are essential for growth and development, and for sexual maturity and reproductive function. Due to their anabolic effects, they have been used as growth promoters in intensive livestock production, applied in feed or as an implant. However, due to their toxic, mutagenic, teratogenic and cancerogenic effects in animals and humans, their use is now banned in food animal production. Today, the use of these natural hormones is permitted exclusively for therapeutic purposes in the treatment of reproductive and pregnancy disorders. Considering the constant development of new synthetic substances that might have anabolic effects and their possible misuse, it is necessary to perform regular controls during the fattening period to determine the physiological values of the levels of these hormones. Accordingly, the aim of this study was to investigate the physiological levels of the natural hormones 17β-oestradiol and testosterone in the blood of calves of different sex, age, breed and farm origin in the Republic of Croatia. For this purpose, 32 calves of both sexes (5 males and 27 females), aged 2-5 months, of different breeds and categories (13 calves of Simmental breed, 2 calves of meat breed and 17 calves of Holstein breed) were randomly selected from three farms for inclusion in this study. During general clinical examination by an authorized veterinarian, no visible clinical changes or conditions were observed that could influence the physiological levels of the investigated hormones. The average level of 17β-oestradiol was 28.83±10.95 ng/L. The concentration of testosterone was lower than the detection limit of the analytical method applied in 24 samples of calf plasma. In eight samples in which this hormone was detected, the average concentration was 126.7±167.5 ng/L, indicating wide variability in the levels of this hormone. A statistically significant difference was determined only for 17β-oestradiol, taking into account the composition of breeds tested (P<0.05). Considering that the established concentrations of the analysed hormones were consistent with the physiological concentrations recorded in the literature, any suspected illegal use of anabolic agents in the examined calves is excluded.

Ključne riječi

17β-oestradiol, testosterone, physiological levels

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Podaci na drugim jezicima: hrvatski

Posjeta: 511 *