COST-BENEFIT EVALUATION OF ON-FARM MILK PROGESTERONE TESTING TO MONITOR RETURN TO CYCLICITY AND TO CLASSIFY OVARIAN CYSTS

The effect of using on-farm milk progesterone testing to monitor retur n to cyclicity after parturition and to classify correctly and to trea t cystic cows was evaluated using modeling and simulation. The test wa s evaluated assuming low and high accuracies of progesterone measureme nt, first breeding policy of 40 d, average estrus detection rate of 55 %, and an average fertility rate of 55%. Three testing schemes (starti ng milk progesterone testing on d 30, 40, or 50 after parturition) wer e compared against a control to evaluate the effect of monitoring retu rn to cyclicity on cows' reproductive and economic performance. For th is purpose, the use of the test was an economically justifiable manage ment intervention. Starting to test on d 30 after parturition was the most effective scheme, reducing days open by 18 d, replacement rate by 2.4%, and increasing net return per cow per year by $11. Starting to test on d 50 postpartum was not economically justifiable. Accuracy of the test, within the range used in this study, was unimportant. Testin g was most profitable in herds with low fertility and low efficiency o f estrus detection. The use of the test to classify follicular and lut eal cysts and to select the appropriate therapy was not economically j ustifiable because of the low proportion of cystic cows and the high v ariation in response to therapy.