Detection of oestrus and effect of androgenization of heifers
1998
Choma, J. | Maracek, I. | Lazar, L. (Ustav Experimentalnej Veterinarnej Mediciny, Kosice (Slovak Republic))
The level of oestrus detection in a herd of heifers was evaluated based upon the visual observation of the oestrus symptoms, radioimmunological determination of progesterone, repeated rectal palpation of ovaries, insemination success and early diagnosis of pregnancy. The mean values of progesterone in the blood serum on days 0, 6, 21, 28, 35 and 42 after artificial insemination were 0.86, 11.48, 25.54, 29.54, 27.70 and 32.15 nmol/l, respectively. Precision of the oestrus detection found by stockmen was 53.33, by zootechnicians 69.7 and veterinarians 100%. A ratio of correctly found oestrus of heifers to the real number of animals in oestrus was for all workers lower - 25.81, 37.09 and 79%, respectively. Administration of repeated doses of testosterone to females resulted in an increase in its levels in the serum and successfully induced male sexual behaviour. Histological examination of ovaries revealed separation of the granulous membrane of follicular cells from the theca interna cells at disappearing of the basal membrane. The multiplication of blood vessels in the theca interna and parenchyma of periodic corpus luteum, which was formed by dark or small lutein cells and only sporadically by light lutein cells, was observed. It is concluded that efficiency of finding animals in oestrus by workers in animal production was only 51.6% and female androgenization induced male sexual behaviour suitable to use for oestrus detection
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