Control of ovulation after prostaglandin treatment by means of ultrasonography and effect of the time of ovulation on conception rate in dairy cows

Attila Répási, Zoltán Szelényi, Jeno Reiczigel, Árpád Bajcsy, András Horváth, Ottó Szenci

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Primiparous and multiparous lactating crossbred dairy cows (after Day 40 postpartum) with a mature corpus luteum (CL) (diameter of ≥ 17 mm determined by ultrasonography) and having a follicle with a diameter of ≥ 10 mm were treated with natural prostaglandin F (n = 80). Those from the cows that showed oestrus within 5 days after treatment were inseminated (Group 1: n = 39). Other group of cows showing oestrus without treatment (Group 2: n = 41) were inseminated and served as controls. The ovaries of each cow were scanned by transrectal ultrasonography from the day of detected oestrus (Day-1) until ovulation, to measure the changes in the areas of the CL and the largest follicle and to determine the occurrence of ovulation. Although no significant differences were found between the treated and untreated cows in terms of a reduction in the area of the corpora lutea and of an increase in the area of the dominant follicles, the mean area of these follicles in Group 2 was somewhat greater than in Group 1. The highest conception rate was achieved if AI was performed at the same day as ovulation occurred in both groups (conception rate in treated group was: 62.5%, in untreated group: 66.6%, respectively) between Day 0 to Day 0. In Group 1, 54.5% conception rate has been achieved if ovulation occurred between Day 0 to Day 1, or 50% between Day 1 to Day 2 after AI, and 53.3% and 44.4% in Group 2, respectively. The conception rate for cows that ovulated before AI in Group 2 was 25%. No ovulation occurred in 7 cows until Day 2 after AI and none of them became pregnant. The overall conception rate was approximately 50% in both groups, but when the cows had ovulated too early or too late relative to the time of AI, the conception rate was significantly lower, thus determination of the optimal time for AI is of great practical importance in dairy herds.

Original languageEnglish
Pages (from-to)74-83
Number of pages10
JournalActa veterinaria Hungarica
Issue number1
Publication statusPublished - Mar 1 2014



  • Prostaglandin Fα
  • conception rate
  • dairy cow
  • time of ovulation
  • ultrasonography

ASJC Scopus subject areas

  • veterinary(all)

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