Effectiveness of superovulation in heifers

The aim of the study was to estimate the effectiveness of superovualtion in heifers. Using multiple analysis statistically, examinations were carried out on 238 superovulated heifers, 11-56 months of age, of the angus, black-white x holstein, hereford, charolaise, limousine and piemontese breeds. The mean number of corpus luteum (NCL), total ova and embryos (TOE), total embryos (TE), menryos suitable for transfer (TRE) were respectively 7.52, 5.3, 4.05 and 3.08. Heifers superovulated with Foltropin-V had more TRE than those receiving Ovagen or Stimufol (3.49 to 2.89 and 3.19; p < 0,05). The higher number of collections the higher NCL (p < 0.01), TOE (p < 0.001), TE (p < 0.00005, TRE (p < 0.001) and DEG (p < 0.01). An important influence on superovulation results was the herd of origin of the cows. More NCL was ascertained in summer (p < 0.05), nevertheless In atumn a higher number of degenerated embryos was noted. The breed of heifers only had an influence on the number of corpus luteum. Heifers of the limousine and black-white x hf breed had more corpus luteum than piemontese. The higher the share of the blood of holstein-fresian breed was in the blood of black-white heifers the higher was the number of embryos (p < 0.001), embryos suitable for transfer (p < 0.001) and degenarated embryos (p < 0.001). There was no effect of the age of the heifers or bulls on effectiveness of superovulation, the number of embryos and embryos suitable for transfer, however bulls had a marginal influence on the proportion of TRE/TE (p < 0.06).