In 60 dairy cows with inactive ovaries, follicular cyst, luteal cyst, persistent corpus luteum and silent heat as diagnosed by rectal palpation, and those that had not resumed ovarian cycles until 60 days postpartum, progesterone concentrations for differential diagnosis of reproductive disorders were measured and were compared in matched plasma, skim milk and milk fat samples at 10 days interval.
The incidence rate of reproductive disorders were as follows; inactive ovaries 20(33.3%), silent heat 11(18.3%), follicular cyst 7(11.7%), luteal cyst 7(11.7%), persistent corpus luteum 7(11.7%), pyometra 4(6.7%), vaginitis 2(3.3%), cystic corpus luteum 1(1.7%), and endometritis 1(1.7%), respectively.
Cows having a progesterone concentration in plasma and skim milk < 1.0 ng/㎖, and in milk fat < 80.0 ng/㎖ were considered to have inactive ovaries or follicular cyst. Those with concentrations in plasma and skim milk ≥ 1.0 ng/㎖, and in milk fat > 80.0 ng/㎖ were regarded as the cases of luteal cyst or persistent corpus luteum. Progesterone concentrations in above cows did not differ significantly between the time of initial determination and the 10 days after initial determination. But progesterone concentrations in cows with silent heat did differ significantly between the time of initial determination and the 10 days after initial determination(P<0.05).
The accuracy of rectal palpation for making a differential diagnosis of ovarian dysfunction, as defined on basis of progesterone concentrations, were as follows; follicular cyst 55.6%, luteal cyst 50.0%, inactive ovaries 90.5% and persistent corpus luteum 60.0%, respectively.
It may be concluded that progesterone determinations at 7.0 days interval is practical as an aid to diagnosing ovarian dysfunction, particularly follicular cyst and luteal cyst.
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