Data on management practices used with automated milk feeders (AMF) are needed to identify factors associated with calf health in these systems. The objectives of this observational, longitudinal, cross-sectional study were to estimate the prevalence of calf diarrhea (CD) and bovine respiratory disease (BRD), and to identify factors associated with prevalence of these diseases at the pen level on dairy farms feeding milk to group-housed calves with AMF. Seventeen dairy farms with AMF in Ontario, Canada, were visited 4 times, seasonally, over 1 yr. The clinical health of all calves (n = 1,488) in pens (n = 35) with AMF was scored to identify the number of calves with CD and BRD. Data on calf, feeder, and pen management practices were analyzed using generalized linear mixed regression models for each disease. Overall calf-level prevalence of CD and BRD were 23 and 17%, respectively. Median (interquartile range, IQR) within-pen prevalence of CD and BRD were 17% (7 to 37%) and 11% (0 to 28%), respectively. Median age (IQR) for diarrheic calves was 25 d (16 to 42 d), and for calves with BRD was 43 d (29 to 60 d). Factors associated with lower within-pen prevalence of CD were the administration of vitamin E and selenium at birth [odds ratio (OR) = 0.56; 95% confidence interval (CI): 0.32 to 0.99], feeding of probiotics (OR = 0.44, 95% CI: 0.22 to 0.93), and adding fresh bedding every 2 to 3 d (OR = 0.43; 95% CI: 0.24 to 0.76) compared with every 7 or more days. In contrast, sharing air with older cattle (>9 mo old) was associated with increased within-pen prevalence of CD (OR = 4.54, 95% CI: 1.88 to 10.52). Additionally, total bacteria counts ≥100,000 cfu/mL in milk samples taken from the AMF mixing jar were associated with increased within-pen prevalence of CD during the summer visit (OR = 3.34; 95% CI: 1.31 to 8.54). Increased total solids in milk or milk replacer (OR = 0.48, 95% CI: 0.27 to 0.85) and feeding whole milk versus milk replacer (OR = 0.29, 95% CI: 0.11 to 0.75) were associated with lower within-pen prevalence of BRD. Factors associated with greater within-pen prevalence of BRD were sharing air with weaned cattle up to 8 mo old (OR = 3.21, 95% CI: 1.26 to 8.16), and greater depth of the wet bedding pack. The use of maternity pens for reasons other than just calving was associated with increased prevalence of both CD and BRD (OR = 1.85, 95% CI: 1.03 to 3.33; OR = 2.61, 95% CI: 1.21 to 5.58, respectively). These results suggest that isolation from older animals and frequent cleaning of the feeder and pen may help to reduce disease prevalence in group-housed calves fed with an AMF.
Bibliographical noteFunding Information:
This research was funded by Dairy Farmers of Canada (Ottawa, ON, Canada) as part of the Dairy Research Cluster 2 program. The first author also thanks the Administrative Department of Science, Technology and Innovation–Colciencias (Bogota, Cundinamarca, Colombia) for the PhD scholarship granted. The authors also thank the students who volunteered during data collection stages: Heidi Eccles, Mohamed Ibrahim, Amanda Armstrong, Allison Moorman, Sophia Marin, Danielle Fawcett, Melissa Speirs, Tanya Wilson (University of Guelph, Guelph, ON, Canada); Jose A. Bran (Universidade Federal de Santa Catarina, Florianópolis, Brazil); Ramiro Rearte (Universidad de La Plata, La Plata, Argentina); and Rolnei R. Daros (University of British Columbia, Vancouver, BC, Canada). Special thanks go to William Sears (statistical consultant, University of Guelph, Guelph, ON, Canada) for his patience and guidance with SAS; and to Matt Jorgensen (University of Minnesota, St. Paul, MN) for sharing his knowledge and experience with farms with automated milk feeders in the US Midwest, and to the participating dairy producers, their families, and their staff for allowing us to go into their farms and for all their involvement, help, and time during the year the study lasted.
- automated feeding
- dairy calf
- group housing