Effect of feeding frequency and route of administration on abomasal luminal pH in dairy calves fed milk replacer

The aim of this study was to determine the effect of feeding frequency and route of administration on abomasal luminal pH in suckling calves. Six male dairy calves with cannulae in the abomasal body were administered the following six treatments in a randomized crossover design: 24 h fasting, suckling of a high-quality milk replacer (all-milk protein; 12% of body weight [BW]/d) at 12-h (2x), 8-h (3x), 6-h (4x), and 3-h (8x) intervals, and ruminal intubation of milk replacer (12% of body weight/day) at a 12-h (2x) interval. Abomasal luminal pH was measured every second for 24 h with miniature glass pH electrodes. Least squares mean 24-h fasting abomasal luminal pH was 1.73, whereas mean 24-h pH after suckling and intubation of milk replacer every 12 h were higher at 3.44 and 3.17, respectively. Increasing the frequency of milk replacer suckling to 3x, 4x, and 8x increased mean 24-h abomasal luminal pH; however, there was no difference in mean 24-h pH between 3x (3.69), 4x (3.64), and 8x (3.67) suckling. The percentage of the 24-h recording period that abomasal luminal pH was > 3.0 was 0, 49, 53, 61, 61, and 71% for fasting, 2x intubation of milk replacer, and 2x, 3x, 4x, and 8x suckling of milk replacer, respectively. Increasing the frequency of milk replacer suckling may be efficacious in the prophylaxis of abomasal ulceration in milk-fed calves.