Calibration of the Progesterone Model to Literature Data. The progesterone model (Equation 1) predicts progesterone measured daily on Days 1 to 14 by Tsai and Wiltbank (1998), Mann et al. (2006), Clemente et al. (2009), and Forde et al. (2011) to good accuracy (R2 = 0.99). This indicates that the model provides good predictions of progesterone on days/ times where progesterone was not measured. This is demonstrated in Supplemental Figure S1 (https:// doi .org/ 10 .3168/ jds .2017 -14306) for the Clemente et al. (2009) progesterone dynamics and that 3 measurements of progesterone on Days 1, 7, and 14 can be used by the model (Equation [1]) to provide a good prediction of progesterone. We also found that the estimated model parameters for the Tsai and Wiltbank (1998), Mann et al. (2006), Clemente et al. (2009), and Forde et al. (2011) progesterone dynamics based on a subset of the progesterone data (Days 1, 7, and 14) are not significantly different than those based on the full progesterone data (Days 1–14). Our results with only 3 progesterone measurements on Days 1, 7, and 14 are consistent with our previous results with 4 progesterone measurements on Days 2, 5, 7, and 15 (Shorten et al., 2018).