Effect of colostrum supplementation administered at a behavior-based alert for calf diarrhea

The objective of this randomized clinical trial was to determine whether supplementing colostrum at the time of a behavior-based alert would reduce diarrhea severity and improve feeding behavior, activity, and growth in Holstein calves. Calves were trained to use an automated milk feeder (Foerster-Technik) at 3 d of age and offered milk replacer ad libitum until 4 wk, 9 L/d from 4 to 7 wk, and gradually weaned from 7 to 9 wk. Calf starter (20% CP) was offered ad libitum from 3 d of age via a separate automated feeder. A behavioral alert (≤60% rolling deviation in milk intake or drinking speed over 2 d) identified calves at risk for diarrhea between 3 to 21 d of age. A total of 179 calves were monitored; however, only 88 calves created an alert. Calves were randomly assigned to receive 1 L of bovine colostrum replacer (CR; 130 g/L, 14% IgG, 46% CP, 25% CF, 5.37 Mcal/kg) or 1 L of milk replacer (MR; 150 g/L, 26% CP, 18% CF, 4.53 Mcal/kg) once daily for 4 d by bottle. Fecal consistency was scored daily until 14 d post-alert; diarrhea was defined as loose feces for ≥ 2 d or watery feces for ≥ 1 d. Calves were enrolled at their first alert and remained in the analysis regardless of diarrhea status. Body weight was recorded at birth, at alert, and weekly thereafter, and activity was measured using accelerometers from 3 d of age. Mixed Poisson regression assessed diarrhea duration, and mixed logistic regression evaluated the odds of receiving supportive treatments administered by farm staff blinded to treatment assignment (non-steroidal anti-inflammatory drugs (NSAID) and additional milk supplementation). Mixed linear regression models with repeated measures evaluated milk intake, drinking speed, steps, growth, and the treatment × time interaction over 14 d and 6 wk post-alert. Calves triggered the alert at 10.3 ± 2.7 d of age and were diagnosed with diarrhea at 10.2 ± 2.6 d. Diarrhea duration did not differ between treatments (incidence rate ratio = 1.11; 95% CI: 0.86-1.43). However, CR calves had lower odds of receiving an NSAID (OR = 0.10; 95% CI: 0.02-0.45) and milk supplementation (OR = 0.26; 95% CI: 0.09-0.80) than MR calves 14 d post-alert. Over the 14 d post-alert, CR calves consumed more milk (9.3 ± 0.23 vs. 8.4 ± 0.21 L/d) and had faster drinking speeds (435 ± 11 vs. 399 ± 11 mL/min). A day × treatment interaction was observed for steps, with CR calves performing 180 ± 76 more steps/d from d 8-13. Over 6 wk, CR calves had greater starter intake (191; 95% CI: 142-246 vs. 153; 95% CI: 110-205 g/d), and a treatment × week interaction for body weight, resulting in a 2.0 ± 0.79 kg advantage from 2 to 6 wk post-alert. Short-term colostrum supplementation at the time of a behavior-based alert did not reduce diarrhea duration but reduced the need for additional treatments and improved feeding behavior, activity, and growth. These findings suggest that colostrum supplementation following a behavior-based alert may support recovery and longer-term performance in calves that developed diarrhea.