Survey of management practices related to bovine respiratory disease in preweaned calves on California dairies

Abstract

In the spring of 2013, a survey of California (CA) dairies was performed to characterize management practices related to bovine respiratory disease in preweaned calves, compare these practices across geographic regions of the state, and determine the principal components that explain the variability in management between herds. The questionnaire consisted of 53 questions divided into 6 sections to assess management practices affecting dairy calves from precalving to weaning. The questionnaire was mailed to 1,523 grade A licensed dairies in CA and 224 responses (14.7%) were collected. Survey response rates were similar over the 3 defined regions of CA: northern CA, northern San Joaquin Valley, and the greater southern CA region. The mean size of respondent herds was 1,423 milking cows. Most dairies reported raising preweaned calves on-site (59.7%). In 93.3% of dairies, preweaned calves were raised in some form of individual housing. Nonsaleable milk was the most frequent liquid diet fed to preweaned heifers (75.2%). Several important differences were identified between calf-raising practices in CA and practices reported in recent nationwide studies, including herd sizes, housing practices, and sources of milk fed to heifers. The differences between the CA and nationwide studies may be explained by differences in herd size. Regional differences within CA were also identified. Compared with the 2 other regions, northern CA dairies were found to have smaller herds, less Holstein cattle, calves remained with dams for longer periods of time after calving, were more likely to be certified organic dairies, and raised their own calves more often. Principal component analysis was performed and identified 11 components composed of 28 variables (questions) that explained 66.5% of the variability in the data. The identified components and questions will contribute to developing a risk assessment tool for bovine respiratory disease in preweaned dairy calves.

Management factors associated with bovine respiratory disease in preweaned calves on California dairies: The BRD 100 study

“…Current knowledge based on numerous studies underscore colostrum management and vaccinations as important components of BRD prevention; however, the current study's dairies may have exhibited uniform colostrum and vaccination practices. The principal component analysis of a California survey on management practices related to bovine respiratory disease in preweaned dairy calves performed in 2013 identified calf housing as the component construct with the largest variation proportion (Love et al, 2016a). The component construct contained the variables hutch style, calf contact, flush used, and waste milk fed to heifers.…”

“…In 2013, managers of 1,523 California dairy herds were surveyed using 2 mail questionnaires followed by a reminder card after each mailing. The survey aimed to identify the variety of management practices known to be associated with the incidence of BRD in preweaned calves with the purpose of characterizing these practices, comparing them across geographic regions of the state, and determining the principal components that explain the variability in management between herds (Love et al, 2016a). Respondents to the survey were given the option of providing contact information if they were interested in participating in a follow-up study.…”

“…The 11 principal components identified in the 2013 survey formed the basis for the on-farm questionnaire (Love et al, 2016a). Briefly, the questionnaire collected information about demographics (location, herd size, and organic or conventional production), maternity pen management (density and individual or group pens), colostrum management (source, heat treatment, storage, quality, volume fed, and testing of calves for failure of transfer of passive immunity), calf management (housing, time of weaning, treatment of sick calves, criteria for treatment, and type and volume of milk fed), vaccinations (type, timing, and frequency of administration to adult cattle and calves), and dust abatement (whether perceived as a problem and type of abatement).…”

“…Milking herd size was categorized as <250 (R), 250-999, 1,000-3,999, and >4,000 milking cows. Regions were categorized based on differences in climate and types of dairies as northern California (NCA; R), the northern San Joaquin Valley (NSJV), and greater southern California (GSCA), where the southern San Joaquin Valley and southern California are combined into a single region due to low recruitment success for southern California dairies (Love et al, 2016a;Figure 2).…”

“…Our hypothesis was that BRD is associated with management practices related to risk factors for BRD, such as the amount of colostrum and milk fed, housing type, and vaccinations. The research described here is a further step in the development of a risk-assessment tool for BRD in preweaned calves on California dairies following the survey of management practices related to BRD in preweaned calves on California dairies (Love et al, 2016a).…”