Evaluation of On-Farm Milk Progesterone Tests to Determine Nonpregnant Cows and to Prevent Insemination Errors

Abstract

The effect of using the on-farm milk progesterone test for early detection of nonpregnancy and for prevention of insemination errors was evaluated using modeling and simulation. The test was evaluated assuming low and high accuracies of progesterone measurement. For early detection of nonpregnancy, three testing schemes (one test on d 21 after service; two tests on d 21 and 23; three tests on d 19, 21, and 23) were compared against a control. Using the test extended the calving to first service interval by 3 d, resulted in 4 fewer d open, decreased the replacement rate from 20.4 to 18.4%, and increased the net return per cow per year by $13.00. Neither the accuracy of the test nor the testing scheme significantly affected the results. The use of the test to prevent insemination errors was evaluated for two error rates of estrus detection, 15 and 30%. Using the test resulted in .16 fewer services per conception, 3 additional d open, and $6.00 less in net return per cow per year. An interaction between using the test and the prevailing rate of errors in detection of estrus was found; the effect of the test was greater in herds with high prevalence of detection errors but was still unprofitable under the assumed costs and returns. © 1989, American Dairy Science Association. All rights reserved.