Utjecaj β-karotena i vitamina A na aktivnost jajnika mliječnih krava s kroničnim funkcionalnim sterilitetom.

The aim of this study was to determine the influence of supplemented β-carotene and vitamin A on the ovarian activity during the periovulatory period in dairy cows with chronic fertility impairment. A total of 46 non pregnant Holstein cows with fertility impairment, at the age of 5-7 years, were selected for this study. The animals in three experimental groups were supplemented wit h either a combination of β-carotene and vitamin A, β-carotene only or vitamin A only. Non supplemented animals served as controls. All animals included in the survey were gynecologically examined; the estrus was synchronized and inseminated. Initial blood levels of β-carotene as well as the levels at the time of insemination and in the luteal phase as well as the ovarian structures during ovulation and formation of corpus luteum and P4 and conception rate, were monitored. Significant increases in follicular size as well as luteal tissue growth were found in animals supplemented with β-carotene and vitamin A combination and vitamin A only. Positive correlation between the serum concentrations of β-carotene at insemination and at day 7 of the luteal phase and the concentrations of progesterone and the conception rate, lead to a conclusion that periovulatory β-carotene and and vitamin A supplementation could improve follicular growth and development of the corpora lutea in cows with fertility impairement.Cilj ovog istraživanja bio je utvrditi utjecaj dodanog β-karotena i vitamina A na ovarijalnu aktivnost tijekom periovulatornog razdoblja u mliječnih krava s kroničnim funkcionalnim sterilitetom. Za ovo istraživanje odabrano je 46 negravidnih krava holštajnske pasmine s funkcionalnim sterilitetom, u dobi od 5 do 7 godina. Životinje su podijeljene u tri pokusne skupine, s kombinacijom β-karotena i vitamina A, samo β-karotena i samo vitamina A. Kontrolna skupina bile su krave bez dopunske terapije. Svim životinjama na početku istraživanja izvršen je ginekološki pregled, sinkronizacija estrusa i umjetno osjemenjivanje. Mjerena je početna razina β-karotena u krvi, razina u vrijeme oplodnje i tijekom luteinske faze, zatim corpus luteum i razina P4, kao i postotak koncepcije. Značajan porast folikula kao i luteinskog tkiva zabilježen je kod životinja kojima smo dali kombinaciju β-karotena i vitamina A i samo vitamin A. Pozitivna korelacija između serumske koncentracije β-karotena tijekom oplodnje i 7. dana u luteinskoj fazi i koncentracije progesterona i stope oplodnje, upućuje na zaključak da periovulatorno davanje β-karotena i vitamina A može poboljšati folikularni rast i razvitak žutog tijela u krava s funkcionalnim sterilitetom