The physiological effects of feeding a fatty acid blend to calves including health, fecal consistency, milk intake, and growth were evaluated. A total of 262 calves were enrolled from 7 different farms across southwestern Ontario and 1 farm in western New York. At birth, calves were weighed and assigned to either a control or fatty acid (FA) group. After colostrum feeding, FA calves received 1.2 g of a fatty acid blend diluted with 9.6 g of skim milk powder into whole milk or milk replacer per feeding (2 times/d) until wk 8 of life. Control calves received 10.8 g of skim milk powder in whole milk or milk replacer per feeding (2 times/d). Study technicians visited farms weekly to collect health scores and BW data on 1- to 8-wk-old calves. Blood samples were collected from each calf at wk 1, 5, and 8. The mean of the total fecal scores over the 8-wk study period was reduced (P < 0.001) in FA compared with control calves. In addition, more calves were given a fecal score ≥2 (loose/watery diarrhea) over the 8-wk study period in the control compared with the FA group (P = 0.002). The incidence of treatment for diarrhea in the control group was 32%, compared with 23% in the FA group (P = 0.195). There was no effect of treatment on ADG (P = 0.83). In conclusion, FA improved fecal consistency, but there was no significant effect on the incidence of diarrhea or growth.