Risk factors for calf mortality on farms using automated feeders in the Midwest USA

Abstract Text:

Use of automated calf feeding systems is increasing across the USA, yet information regarding health and mortality outcomes is limited. The objective of this study was to investigate the association of various farm management practices, housing, and environmental factors with mortality in preweaned dairy calves.  Twenty-three Midwestern dairy farms were included in this mortality analysis. Farms were visited approximately every 60 days for 18 months. Housing and environmental factors were measured at the time of each visit. Management practices were collected using a questionnaire and mortality events were gathered from producer-kept records. Relationships between categorical factors of interest and mortality rate were calculated using the mixed procedure of SAS. Pearson’s correlation was used for continuous variables. Average mortality of calves on farms using automated feeders was 3.85±3.70%/yr and 57% of farms (13/23) reported mortality rates below 3%/yr. The maximum recorded mortality rate was 13.41%/yr and the minimum was 0.24%/yr. Farm average serum total protein concentration of calves < 5 days old was negatively associated with farm annual mortality rate (R= -0.50, P=0.02; mean sTP=5.4g/dL ±0.74). Farms that disinfect the navels of newborn calves had a lower (P=0.03) mortality rate (mean±SE, 2.97±0.80%; 78% of farms) than farms that do not disinfect (7.32±1.59%; 22% of farms). Farms that use the drinking speed of calves as an alarm had a lower (P<0.001) annual mortality rate (2.37±0.83%; 74% of farms) than those that do not (6.57±1.13%; 36% of farms). Farms that disinfect the calf pens between groups had a lower (P=0.04) annual mortality rate (2.55±0.94; 59% of farms) than those that do not disinfect (5.78± 2.55%, 41% of farms). Trends were detected in the correlations between mortality rate and bacteria counts (standard plate count) of milk collected from the feeder hose (R=0.37, P=0.08; median=435,000 cfu/mL, IQR=3,764,375 cfu/mL), size of the dairy (number of calves on site; R= -0.41, P=0.08; mean=82.18 ±84.26 calves) and age difference in calf groups (R=0.41, P=0.06; mean=3.07±2.03 wk). Basic calf-care practices remain vital to ensuring calf survival in automated feeding systems. These data indicate that farms using automated feeders are able to achieve a very low rate of death loss in preweaned calves, but a high variability in mortality among farms indicates continued room for improvement in calf death losses.

Keywords:

Automated calf feeding, mortality, management