Carriere, P. D., DesCoteaux, L. and Bigras-Poulin, M. (2000) “Choosing the right cutoff level of milk progesterone to determine pregnancy status of dairy cows on day 21 post-breeding”, The Bovine Practitioner, 34(2), pp. 81–86. doi: 10.21423/bovine-vol34no2p81-86.