Canadian National Dairy Study: Herd-level milk quality

Abstract

The objective of this study was to estimate Canadian national milk quality parameters and estimate the bulk tank milk (BTM) prevalence of 4 mastitis pathogens, Staphylococcus aureus, Streptococcus agalactiae, Mycoplasma bovis, and Prototheca spp., on Canadian dairy farms. A questionnaire was sent to all Canadian dairy producers. Of the 1,062 producers who completed the questionnaire, 374 producers from across the country were visited and milking hygiene was assessed. Farm-level milk quality data for all Canadian dairy producers was collected from the provincial marketing boards and combined with the questionnaire and farm visit data. In addition, a BTM sample was collected either during the farm visit or by the marketing board in November of 2015 and was tested for 4 major mastitis pathogens using the PathoProof Mastitis Major 4 PCR Assay (Thermo Fisher Scientific Inc., Waltham, MA). Apparent herd-level prevalence was 46% for S. aureus, 6% for Prototheca spp., 0% for M. bovis, and 0% for Strep. agalactiae. Due to the low prevalence of M. bovis and Strep. agalactiae and a lack of significant factors associated with farms testing positive for Prototheca spp., an association analysis could only be carried out for Staph. aureus-positive farms. Factors associated with Staph. aureus-positive farms were not fore-stripping cows before milking (odds ratio = 1.87), milking with a pipeline system (odds ratio = 2.21), and stall bases made of a rubberized surface (mats and mattresses), whereas protective factors were using blanket dry cow therapy (odds ratio = 0.49) and applying a tag or visible mark on cows known to have chronic mastitis infections (odds ratio = 0.45). The Canadian national production-weighted geometric mean somatic cell count was determined to be 208,000 cells/mL. This is the first national dairy study conducted in Canada. Participating farms had higher milk yield; were more likely to have a loose housing system, parlor, or automated milking system; and had lower weighted mean BTM somatic cell count than the national level. Sampling larger farms with better milk quality means the apparent prevalence of the 4 mastitis pathogens likely underestimates the true levels.

Reproductive management practices on dairy farms: The Canadian National Dairy Study 2015

“…Selection bias was minimized as both DHIA and non-DHIA herds were invited to participate. A slight response bias may have occurred, due to a higher proportion of farms enrolled in milk recording and a lower proportion of tiestall respondents compared with the national averages; however, milk production and milk quality data analyzed from the same survey suggest no meaningful differences between respondents and nonrespondents (Belage et al, 2017;Bauman et al, 2018). We found a wide variety of estrus detection methods implemented across Canadian farms.…”

“…We noted many similarities between that study and the present, but we now shed light on management differences among regions, herd demographics, and respondent characteristics. Figure 1 demonstrates that the population in our study is fairly representative of the distribution of housing types in Canadian dairy herds (Bauman et al, 2018). Although regional differences were noted in response rates, the differences were small and the weighted estimates for reproductive practices differed only slightly from the crude proportions.…”

“…Comparable to the National Animal Health Monitoring System Dairy Study in 2014, the Canadian National Dairy Study (NDS) 2015 was designed to target all licensed Canadian producers and gather information on the health and management of dairy cattle (Bauman et al, 2016). Based on a large survey offered to all producers and follow-up visits to a subset of respondent herds, the NDS generated data on herd demographics, biosecurity, animal care and welfare, calf health (Renaud et al, 2017), reproductive management, and milk quality (Belage et al, 2017;Bauman et al, 2018). The objectives of our study were to characterize the use of various reproductive management practices on Canadian dairy farms and describe differences based on regional and demographic variables.…”

Training method for animal-based measures in dairy cattle welfare assessments

“…The methods have been previously validated (Domecq et al 1995;Chapinal et al, 2009;Gibbons et al, 2014) and adapted from the Canadian Code of Practice for the Care and Handling of Dairy Cattle (National Farm Animal Care Council, 2009) and from Gibbons et al (2012) and Vasseur et al (2013). The training workshop described in this manuscript was used to train assessors for the National Dairy Study 2015 (Bauman et al, 2018). The workshop was designed to train 14 assessors over a 3-d period for the 6 ABM: HI, LM in freestall and tiestall facilities, BCS, udder, flank, and leg CLN.…”

“…The 14 trainees were undergraduate university students (n = 3), veterinary students (n = 7), and veterinary technicians (n = 4) from the 5 Canadian Colleges of Veterinary Medicine and had a range of minimal or moderate to no previous training on evaluating these ABM. The purpose of the training was to standardize the welfare-scoring methodology to be used as one part of the comprehensive National Dairy Study (Bauman et al, 2018).…”