Evaluation of the early conception factor dip stick test in dairy cows between days 11 and 15 post-breeding

Abstract

A field study was conducted between February and November 1995 using 139 Holstein cows to determine the accuracy and the usefulness of the ECF Dip Stick Test performed between days 11 and 15 post-breeding. Results of the ECF tests were compared to pregnancy diagnosis after 25 days post-breeding using ultrasonography and transrectal palpation. The apparent conception rate of the study population based on transrectal palpation was 38%. The ECF test sensitivity, specificity, positive and negative predictive values were 81%, 26%, 40% and 69%, respectively. The Kappa value (0.06; 95%CI -0.19 to 0.30) demonstrated no agreement between the ECF test and the final pregnancy status of dairy cows. These results would indicate that the ECF test is not a good predictor of pregnancy because the proportion of false positive results was high at 46% (64/139). Furthermore, the accuracy of the test to detect open cows is not acceptable with the high proportion of false negative tests of 31% (10/32). This finding would indicate that 19% (10/53) of the cows diagnosed pregnant rectally were misdiagnosed as non-pregnant by the ECF test. Finally, many factors such as the incubation time, the personal assessment of the test reaction and the source of light can also affect the ECF test reading. Based on the current technology, the authors would not recommend the use of the ECF test to help dairy producers reduce non-productive days.