An analysis of ovarian dysfunction in high yielding dairy cows after calving based on progesterone profiles

448 post partum progesterone profiles of 335 high-yielding dairy cows of 6 well managed dairy herds were analysed to monitor ovarian function and dysfunction in the immediate post partum period. Progesterone was measured in milkfat by RIA, and profiles were set up based on twice weekly milk sampling, starting from ten days after calving until confirmation of a new pregnancy by rectal palpation. Attention was focused on the immediate post partum period from 10 days after calving until first insemination (preservice period). First progesterone rise indicative for the presence of active luteal tissue, occurred at an average of 37 days (n=435; stdev=26) after calving, illustrating that the first ovulation after calving appears at approximately day 32. The 448 examined profiles could be classified as follows: I. Normal profile: 239 (53.5%); II. Delayed cyclicity: 91 (20.5%); III. Cessation of cyclicity: 15 (3%); IV. Prolonged luteal phase: 89 (20%); V. Short luteal phase: 3 (0.5%) and VI. Irregular profiles: 11 (2.5%). Results show that almost half of the modern high-yielding dairy cows suffer from ovarian dysfunction in the preservice post partum period. Most important disorders are delayed cyclicity or anovulation and prolonged luteal phase, which together account for almost 90% of the abnormalities.