ADSA-SAD Undergraduate Competition: Undergraduate Original Research

A study evaluating the effects of metaphylaxis antibiotics and milk replacer additives on the health and development of Holstein bull calves (n = 52; mean body weight = 42.28 kg + 3 kg; starting age < 3 d) was conducted. The calves were placed into a completely random 3 × 4 factorial design with each group receiving either tilmicosin phosphate (TIL), ceftiofur crystalline free acid (CEF), or saline solution (CON) injected subcutaneously into the neck area. For the duration of the study, the calves also received a commercial milk replacer powder (22% crude protein / 20% crude fat) fed at 1.1% BW. Within metaphylaxis treatment, calves were randomly assigned to receive either; 1) 4 g/d for 7 d and then 2 g/d for 14 d of an egg-based probiotic (PR); 2) 2 g/d of 96% betaine (BE); 3) both PR and BE (BP); or 4) no additives . The calves were housed in individual fiberglass hutches with commercial calf starter and water provided ad libitum. The body weight of each calf was recorded twice weekly in addition to daily recordings of fecal scores (1 = firm to 4 = watery) for 54 d. Medical treatments provided to each calf for scours, respiratory distress, or febrile events were recorded daily. The cumulative response of these incidences were analyzed and used as an index of morbidity. None of the additive effects were significant for any of the measured variables. The use of metaphylaxis did not significantly affect the average daily gain (P > 0.60) as the average daily gain was ~0.45 kg. However, when examining fecal scores, CEF and TIL significantly reduced teh average fecal score over the control ((1.85 vs. 1.97 vs. 2.20 respectively) (P < 0.01)). The incidences of fever nor respiratory issues (P > 0.20) were influenced dramatically by metaphylaxis. Overall, the average daily treatment for fever was only 0.66 events and 0.39 events for respiratory distress. Metaphylaxis did not influence the occurrence of scours (fecal score > 2) (P > 0.87). Other than fecal score, these results indicate the use of metaphylaxis did not enhance productivity or reduce morbidity of Holstein neonatal bull calves.