Factors associated with dairy calf health in automated feeding systems in the Upper Midwest United States

Abstract

Automated calf feeding systems are becoming more common on US dairy farms. The objective of this study was to evaluate calf health in these systems and to identify risk factors associated with adverse health outcomes on farms in the Upper Midwest United States. Over an 18-mo period on bimonthly farm visits to 38 farms, calves (n = 10,179) were scored for attitude, ear, eye, and nasal health, as well as evidence of diarrhea (hide dirtiness score of perianal region, underside of the tail, and tailhead). For all health score categories, a score of 0 represented an apparently healthy animal. Rectal temperatures were taken in calves scoring a ≥2 in any category, and those with a temperature>39.4°C were categorized as having a fever (n = 550). Associations were determined between farm-level variables and health scores to identify risk factors for higher (worse) scores. All health outcomes were associated with season of measurement, with fall and winter seasons increasing the odds of a high health score or detected fever. High bacterial counts measured in the milk or milk replacer were associated with increased odds for higher attitude and ear scores, and higher odds for calves having a detected fever. Higher peak milk allowance (L/d) was associated with lower hide dirtiness score, whereas a longer period of time (d) to reach peak milk allowance was associated with increased odds of higher scores for attitude, ear, eye, and hide dirtiness, as well as fever. Higher fat content in milk was associated with increased odds of high eye score. Less space per calf (m/calf) was associated with higher ear and eye scores, whereas larger group sizes were associated with increased odds of higher nasal score and decreased odds of higher hide dirtiness score. Rectangular pen shape was associated with decreased odds of higher eye score. Absence of a positive pressure ventilation tube was associated with increased odds of having a calf detected with a fever. Based on these results, we hypothesize that these factors could be managed to improve health outcomes for dairy calves on automated feeding systems.

Associations between management practices and within-pen prevalence of calf diarrhea and respiratory disease on dairy farms using automated milk feeders

“…We found that milk with a high content of bacteria was significantly associated with an increased prevalence of CD, but only during the summer visit. Jorgensen et al (2017) found that calves drinking milk with TBC >100,000 cfu/mL had a higher risk of receiving an abnormal score for attitude, ear position, and eye secretion, and a higher risk of having fever; however, they did not find a seasonal visit interaction with bacterial counts in milk. We do not have a clear explanation for the seasonal visit effect found in the present study; however, we speculate that during summer, calves might have experienced heat stress, causing immune suppression and, thus, increased susceptibility to pathogens and lower performance.…”

“…Research focused on the health impacts of raising calves with AMF systems and management practices other than group size is scarce. In North America, an observational study across farms in the US Midwest is the only available published research on this topic (Jorgensen et al, 2017). In that study, researchers found associations between individual calf health scores (e.g., attitude, temperature, hind-end dirtiness score) and management practices regarding milk feeding plan, cleanliness of the AMF, and ventilation.…”

Effect of age of introduction to an automated milk feeder on calf learning and performance and labor requirements

“…Many dairy producers prefer to introduce calves to an AMF as soon as possible (Jorgensen et al, 2017;Medrano-Galarza et al, 2017a) without clear evidence Figure 3. Mean daily milk intake (±SE) across the 5 stages of the milk feeding period (from 1 to 60 d of age) for 60 calves introduced to a group with an automated milk feeder at 5 d of age (conventional introduction) and before 24 h of age (early introduction).…”

“…In the present study, we did not find an effect of group size on the latency to learn to use the AMF. The weekly mean group size of the introductory pens (group pens 1) was 7.3 calves, whereas in the majority of commercial farms in Canada use group sizes of 10 to 15 calves (Medrano-Galarza et al, 2017a) and in the Midwestern United States the average is 17 calves (Jorgensen et al, 2017). Large group size increases the level of competition (Jensen, 2004), with older calves pushing small ones out of the feeder stall (Hepola, 2003).…”

“…Although research (Svensson and Liberg, 2006;Jensen, 2007) suggests that later introduction (i.e., >2 wk of age) to the group pen may be preferable in terms of calf health and farm labor, recent data on commercial dairy farms in North America indicate that the median age of introduction to group pens with AMF is 5 d and ranges from <1 to 14 d (Jorgensen et al, 2017;Medrano-Galarza et al, 2017a; mean group size was 17 calves and ranged from 6 to 60). This may stem from producers seeking to minimize the labor required for manually feeding milk to calves when using AMF.…”