However, a positive linear treatment effect for FCM and ECM and a quadratic treatment effect for milk yield were observed in the present study with a 7.5% (F4) and 4.4% (F8) milk yield increase compared with POS. In the present study, a positive linear and a quadratic treatment effect were observed for lactose yield (kg/d). Sulzberger et al. (2017) reported a negative linear treatment effect on milk yield and a negative linear trend for lactose yield as adsorbent concentration increased in the diet. In the current study, the positive linear trend for ECM could be responsible for the increased lactose yield in adsorbent-treated cows. Additionally, in the current study, a positive quadratic treatment effect was observed for protein yield (kg/d).