Relationships among bedding materials, bedding bacteria counts, udder hygiene, milk quality, and udder health in US dairy herds

Abstract

Bedding is an important source of teat end exposure to environmental mastitis pathogens. To better control environmental mastitis, we need an improved understanding of the relationships among bedding selection and management, bedding bacteria counts (BBC), and udder health (UH). The objectives of this crosssectional observational study were (1) to describe BBC, bedding characteristics, udder hygiene scores, bulk tank milk (BTM) quality, and UH in US dairy herds using 1 of 4 bedding materials; (2) describe the relationship between BBC and herd measures of UH; and (3) identify benchmarks for monitoring bedding hygiene. Local dairy veterinarians and university researchers enrolled and sampled 168 herds from 17 states. Herds were on a Dairy Herd Improvement Association (DHIA) testing program and used 1 of 4 bedding types for lactating cows: new sand, reclaimed sand, manure solids (MNS), or organic non-manure materials. Each herd was sampled twice (winter and summer) in 2016. Samples and data collected included unused and used bedding, BTM samples, udder hygiene scores, DHIA test data, and descriptions of facilities and herd management practices. Bedding was cultured to determine the total bacteria count and counts of Bacillus spp., coliforms, Klebsiella spp., non-coliform gram-negative organisms, streptococci or streptococci-like organisms (SSLO), and Staphylococcus spp. Bedding dry matter, organic matter, and pH were also measured. Bulk tank milk samples were cultured to determine counts of coliforms, NAS, SSLO, Staphylococcus aureus, and Mycoplasma spp. Udder health measures included DHIA test-day average linear score (LS); the proportion of cows with an intramammary infection (IMI), where infection was defined as LS ≥4.0; the proportion of cows with a new IMI, where new IMI was defined as LS changing from <4.0 to ≥4.0 in the last 2 tests; the proportion of cows with a chronic infection, where chronic was defined as LS ≥4.0 on the last 2 tests; and the cumulative incidence of clinical mastitis in the 30-d period preceding sample collection. Although much variation existed within and among bedding types, mixed linear regression showed the use of MNS bedding to be generally associated with higher BBC, dirtier udders, increased coliform and SSLO counts in BTM, and poorer UH measures compared with organic non-manure materials, reclaimed sand, or new sand bedding materials. While controlling for important farm traits and management practices, mixed linear regression showed that increased counts of coliforms, Klebsiella spp., SSLO, and Staphylococcus spp. in both unused and used bedding were associated with poorer values for 1 or more herd-level measures of UH. Achievable benchmarks identified for counts of coliforms (unused: ≤500 cfu/cm 3 ; used: ≤10,000 cfu/ cm 3), Klebsiella spp. (0 cfu/cm 3 for unused and used), Staphylococcus spp. (0 cfu/cm 3 for unused and used), and SSLO (unused: 0 cfu/cm 3 ; used: ≤500,000 cfu/ cm 3) can be used to monitor bedding hygiene in most bedding materials, with minor variations suggested...

Bacterial Load of the Teat Apex Skin and Associated Factors at Herd Level

“…Therefore, Krömker et al [ 40 ] published benchmarks for bacterial counts in unused bedding, indicating a reduced risk for cows to develop mastitis: For esculin-positive streptococci and coliforms: 10 4 cfu/g and for total bacteria counts: 10 6 cfu/g (sawdust) or 7 × 10 8 cfu/g (straw). In a recently published study, achievable benchmarks for used bedding were published: For streptococci-like organisms (SSLO): 5 × 10 5 cfu/cm 3 and for coliforms: 10 4 cfu/cm 3 [ 25 ]. Data from previous studies dealing with bacterial growth in bedding materials indicated a nonlinear relationship between time and bacterial counts but a maximum increase within 24 to 36 h of use following contamination of animals and feces [ 38 , 41 ].…”

“…Cow pats were avoided at sampling to achieve an undistorted bedding sample. The number of days since fresh bedding had been most recently added to the pen were recorded [25].…”

Cattle barn bedding from recycled manure: some veterinary, technological and economic aspects of application

“…Due to the high risk of bacterial load on animals, additional processing steps were included in the technology aimed at reducing the number of pathogens in the final product by increasing the temperature [27]. Further studies established that liquid-solid manure separation and thermal treatment of solids made the application of this technology possible in wetter and colder regions [11,[28][29][30]. Drying in a dryer drum 27.5 -27.5…”

Recycled manure solids as a bedding material: Udder health, cleanliness and integument alterations of dairy cows in mattress stalls

“…Besides this, the RMS research is generally done on commercial farms (e.g. Rowbotham and Ruegg 2015, Bradley et al 2018, Patel et al 2019 where experiments are not controlled and also other housing conditions and management practices may affect the outcome. Thus, the aim of our study was to compare RMS bedding to peat bedding in a controlled cross-over experiment in a freestall barn with mattress stalls.…”

“…Several studies and reports present no connection between used RMS bedding and increased somatic cell count (SCC) or mastitis incidence (Harrison et al 2008, Rowbotham and Ruegg 2016b, Bradley et al 2018). On the other hand, Rowbotham and Ruegg (2015) reported a higher degree of nonfunctioning mammary glands and discarded milk, and Patel et al (2019) reported poorer udder health indicators, on farms using RMS as a bedding material, which may indicate more challenges managing udder health on these farms. The review of Leach et al (2015) demonstrated no systematic connection between RMS bedding and a high SCC or incidence of clinical mastitis.…”