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1.	Dahlberg, Josef, et al. (author) Microbiota data from low biomass milk samples is markedly affected by laboratory and reagent contamination 2019 In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 14 Journal article (peer-reviewed)abstract Discoveries of bacterial communities in environments that previously have been described as sterile have in recent years radically challenged the view of these environments. In this study we aimed to use 16S rRNA sequencing to describe the composition and temporal stability of the bacterial microbiota in bovine milk from healthy udder quarters, an environment previously believed to be sterile. Sequencing of the 16S rRNA gene is a technique commonly used to describe bacterial composition and diversity in various environments. With the increased use of 16S rRNA gene sequencing, awareness of methodological pitfalls such as biases and contamination has increased although not in equal amount. Evaluation of the composition and temporal stability of the microbiota in 288 milk samples was largely hampered by background contamination, despite careful and aseptic sample processing. Sequencing of no template control samples, positive control samples, with defined levels of bacteria, and 288 milk samples with various levels of bacterial growth, revealed that the data was influenced by contaminating taxa, primarily Methylobacterium. We observed an increasing impact of contamination with decreasing microbial biomass where the contaminating taxa became dominant in samples with less than 10 4 bacterial cells per mL. By applying a contamination filtration on the sequence data, the amount of sequences was substantially reduced but only a minor impact on number of identified taxa and by culture known endogenous taxa was observed. This suggests that data filtration can be useful for identifying biologically relevant associations in milk microbiota data.
2.	Dahlberg, Josef, et al. (author) Microbiota data is strongly affected by contamination if milk samples have low microbial biomass 2018 Conference paper (other academic/artistic)
3.	Dahlberg, Josef, et al. (author) Microbiota of bovine milk, teat skin, and teat canal: Similarity and variation due to sampling technique and milk fraction 2020 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103, s. 7322-7330 Journal article (peer-reviewed)abstract The aim of this study was to evaluate the effect of sampling technique and milk fraction on bovine milk microbiota data and to compare the microbiota in milk to microbiota on the teat end and in the teat canal. Representative milk samples are highly important for assessment of bacteriological findings and microbiota in milk. Samples were obtained from 5 healthy lactating dairy cows at udder quarter level during 1 milking. Swab samples from the teat. end and teat canal, and milk samples collected using different techniques and in different milk fractions were included. Milk was collected by hand stripping and through a teat canal cannula before and after machine milking, through a trans-teat wall needle aspirate after milking, and from udder quarter composite milk. The microbiota of the samples was analyzed with sequencing of the V1-V3 region of the 16S rRNA gene. In addition, somatic cell counts and bacterial cultivability were analyzed in the milk samples. Microbiota data were analyzed using multivariate methods, and differences between samples were tested using analysis of similarity (ANOSIM). Differences between samples were further explored via individual studies of the 10 most abundant genera. The microbiota on the teat end, in the teat canal, and in udder quarter composite milk, collected using a milking machine, differed in composition from the microbiota in milk collected directly from the udder quarter. No differences in milk microbiota composition were detected between hand-stripped milk samples, milk samples taken through a teat canal cannula, or milk samples taken as a trans-teat wall needle aspirate before or after milking. We conclude that for aseptic milk samples collected directly from the lactating udder quarter, sampling technique or milk fraction has minor effect on the microbiota composition.
4.	Duse, Anna, et al. (author) Occurrence and Spread of Quinolone-Resistant Escherichia coli on Dairy Farms 2016 In: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 82, s. 3765-3773 Journal article (peer-reviewed)abstract Quinolone-resistant Escherichia coli (QREC) is common in feces from young calves, but the prevalence and genetic diversity of QREC in groups of cattle of other ages and the farm environment are unknown. The aims of the study were to obtain knowledge about the occurrence of QREC on dairy farms, the genetic diversity of QREC within and between farms, and how these relate to the number of purchased animals and geographic distances between farms. We analyzed the within-sample prevalence of QREC in individual fecal samples from preweaned dairy calves and postpartum cows and in environmental samples from 23 Swedish dairy farms. The genetic diversity of the QREC isolates on 10 of these farms was assessed. In general, QREC was more prevalent in the dairy farm environment and in postpartum cows if QREC was commonly found in calves than if QREC was rare in calves. In particular, we found more QREC organisms in feed and water troughs and in environments that may come into contact with young calves. Thus, the results suggest that QREC circulates between cattle and the farm environment and that calves are important for the maintenance of QREC. Some genotypes of QREC were widespread both within and between farms, indicating that QREC has spread within the farms and likely also between farms, possibly through purchased animals. Farms that had purchased many animals over the years had greater within-farm diversity than farms with more closed animal populations. Finally, animals on more closely located farms were more likely to share the same genotype than animals on farms located far apart.
5.	Duse, Anna, et al. (author) Risk factors for antimicrobial resistance in fecal Escherichia coli from preweaned dairy calves 2015 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 500-516 Journal article (peer-reviewed)abstract The primary objective of this study was to investigate calf and farm factors associated with antimicrobial-resistant Escherichia coli in the feces of preweaned dairy calves in Sweden. In particular, we investigated the effects of feeding calves colostrum and milk from cows treated with antimicrobials. The secondary objective was to describe the prevalence of resistant E. coli in feces of preweaned dairy calves in Sweden. Fecal samples from 3 calves, aged 7 to 28 d, from 243 farms were analyzed for the within-sample prevalence of E. coli resistant to nalidixic acid, streptomycin, and cefotaxime using selective agars supplemented with antimicrobials. In addition, resistance to 12 antimicrobials was tested in one randomly selected E. coli isolate per calf. Information was collected from the farmers via questionnaires regarding the use of colostrum and milk from cows treated with antimicrobials as calf feed and other uses of antimicrobials in the herd. Multivariable zero-inflated negative binomial and logistic regression models were used to assess the effect of various risk factors for shedding of resistant E. coli. Escherichia coli resistant to streptomycin, nalidixic acid, or cefotaxime were isolated from 90, 49, and 11% of the calves, respectively. Resistance to at least one antimicrobial was found in a random isolate of E. coli from 48% of the calves. Feeding colostrum from cows treated with antimicrobials at drying off did not affect the prevalence of resistant E. coli. In contrast, feeding milk from cows treated with antimicrobials during lactation resulted in significantly more nalidixic acid- and streptomycin-resistant E. coli than when such milk was discarded; no significant effect was seen for other resistance traits. Furthermore, an interaction was found between feeding milk from cows treated with antimicrobials and use of fluoroquinolones in cows. In general, the prevalence of resistance was lower for older calves and calves on small farms. Other factors that were associated with the shedding of resistant E. coli were administration of oral dihydrostreptomycin to calves, administration of systemic tetracycline and ceftiofur to cows and calves, housing of the calves, predominant breed of the herd, and geographic location of the farm. The presence of resistant E. coli in calves was clearly due to multiple factors, but minimizing the feeding of milk from cows treated with antimicrobials during lactation should lower the prevalence of resistant E. coli in the gastrointestinal tract of the calves.
6.	Duse, Anna, et al. (author) Risk factors for quinolone-resistant Escherichia coli in feces from preweaned dairy calves and postpartum dairy cows 2015 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 98, s. 6387-6398 Journal article (peer-reviewed)abstract Quinolone resistance may emerge in gut bacteria (e.g., in Escherichia coli) of animals. Such bacteria could cause infections in the animal itself or be transmitted to humans via the food chain. Quinolone resistance is also observed in fecal E. coli of healthy dairy cattle, but the prevalence varies between farms, not solely as a result of varying degree of fluoroquinolone exposure. The objective of this study was to identify risk factors for the fecal shedding of quinolone-resistant E. coli (QREC) from dairy calves and postpartum cows. Rectal swabs from 15 preweaned calves and 5 postpartum cows per farm were collected on 23 Swedish dairy farms to determine the prevalence of QREC. Risk factors for the shedding of QREC were investigated using multivariable statistical models. Quinolone-resistant E. coli were found on all but one farm. Factors associated with QREC shedding by calves were being younger than 18 d, being fed milk from cows treated with antimicrobials, recent use of fluoroquinolones in the herd, carriage of QREC by postpartum cows, and using the calving area never or rarely as a sick pen compared with often. Factors associated with QREC shedding by cows were calving in group pens or freestalls compared with single pens or tiestalls, purchasing cattle, sharing animal transports with other farmers, and poor farm hygiene. Proper biosecurity and improved hygiene, as well as minimizing fluoroquinolone exposure and waste milk feeding, may be important factors to reduce the burden of QREC on dairy farms.
7.	Persson Waller, Karin, et al. (author) Relationship between somatic cell count, polymorphonuclear leukocyte count and quality parameters in bovine bulk tank milk 2009 Conference paper (other academic/artistic)
8.	Persson Waller, Karin, et al. (author) Udder health in beef cows and its association with calf growth 2014 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 56 Journal article (peer-reviewed)abstract Conclusions: Subclinical mastitis and IMI, but not blind quarters, were common in beef cows, but the prevalence varied markedly between herds. Most IMI were caused by staphylococci and more than 95% of those were sensitive to penicillin. Cows with large funnel-shaped teats or pendulous udder after calving, and cows with blind quarters were at risk of having subclinical mastitis and/or IMI. Poor hygiene was also a risk factor for udder health problems. No significant associations were found between udder health and calf weaning weight. More studies on risk factors are warranted to improve advisory services on awareness and prevention of mastitis in beef cows.
9.	Persson, Ylva, et al. (author) Associations between Staphylococcus aureus intramammary infections and somatic cell counts in dairy goat herds 2015 In: Small Ruminant Research. - : Elsevier BV. - 0921-4488. ; 133, s. 62-66 Journal article (peer-reviewed)abstract Staphylococcus (S.) aureus is an important pathogen in cheese producing dairy goat farms. The aim of this study was to investigate whether somatic cell count (SCC) and PCR analysis of S. aureus in bulk tank milk (BTM), and/or SCC in udder half milk samples could indicate intramammary infection (IMI) with S. aureus. Milk samples (n = 1042) were collected from lactating udder halves of 521 lactating does from 16 herds in mid to late lactation. From the same herds 29 BTM samples were collected. Udder half samples were cultured on blood agar plates and the SCC was measured by California mastitis test (CMT) and DeLaval cell counter (DCC-SCC). Bulk tank milk samples were analysed by PCR for presence of S. aureus and by DCC-SCC. In 15% of the udder halves bacteria was found and of these 80% had CNS and 8% had S. aureus. Udder halves infected with S. aureus had significantly higher DCC-SCC and CMT than udder halves not infected (P<0.0001) and udder halves infected with CNS (P<0.01) and higher DCC-SCC than udder halves infected with other bacteria (P=0.0004). There was a significantly higher risk for a doe to have S. aureus IMI in at least one udder half if the CMT was high in one udder half and low in one udder half (P=0.04) compared to does with low CMT in both udder halves. Significant associations between BTMSCC, S. aureus positive BTM, or IMI with S. aureus could not be found. However, 6 out of 8 herds with S. aureus IMI were PCR positive for S. aureus at least once. A difference in CMT between milk from udder halves within a doe can be used as an indicator for S. aureus IMI at goat level. On udder half level, milk SCC, measured with DCC or CMT, can be used to detect S. aureus IMI. (C) 2015 Elsevier B.V. All rights reserved.
10.	Persson, Ylva, et al. (author) Intramammary infections and somatic cell counts in meat and pelt producing ewes with clinically healthy udders 2017 In: Small Ruminant Research. - : Elsevier BV. - 0921-4488. ; 156, s. 66-72 Journal article (peer-reviewed)abstract Mastitis in sheep is common and is important both from an economic and from a welfare point of view. It can be either clinical or subclinical, bacterial or, more seldom, lentiviral. There are no data on the national prevalence of subclinical mastitis (SCM) or intramammary infection (IMI), and causative pathogens, in ewes in Sweden.Diagnosis of SCM and/or IMI is based on inflammatory indicators, measured in milk and additional bacteriology. Somatic cell count (SCC) is the most widely used indicator of SCM and/or IMI and can be measured either directly or indirectly with e.g. California Mastitis Test (CMT). However, the use of SCC as an indicator for mastitis and/or IMI in ewes is not fully evaluated, especially not in meat- and pelt producing herds. The aim of this study was therefore to investigate the prevalence of IMI and bacterial panorama in ewes with clinically healthy udders, in meat- and pelt producing herds in Sweden. Moreover, we wanted to define a cut-off for SCC and CMT for detecting ewes with IMI that would be suitable for use under field conditions.Udder half milk samples (n = 2134) were collected at weaning and lambing from meat- and pelt producing ewes (n = 773), in 22 farms in Sweden. Only clinically healthy animals were included in the study. Milk samples were analysed for bacteriology and SCC and were given a CMT score.Intramammary infection was found in 30% of the ewes and in 14% of the udder half milk samples. No bacteria were found in 74% of the milk samples, and mixed flora was found in 12% of the samples. Among the 287 milk samples where IMI was identified, coagulase negative staphylococci (CoNS) were most prevalent (58%) followed by Staphylococcus (S.) aureus (9%) and Mannheimia (M.) haemolytica (6%). Among the 165 CoNS findings S. simulans was the most common (26%), followed by S. warren, S. equorum, S. xylosus, S. haemolyticus and S. chromogenes. A CMT score of >= 3 and a SCC of 500,000 cells/ml at weaning or CMT score 3 and a SCC of 400,000 cells/ml after lambing gave the highest possible Se at the same time as the highest possible Sp for identifying udder halves with IMI and may be used for screening for IMI in Swedish meet and pelt producing herds.To conclude, one third of Swedish meat- and pelt producing ewes without clinical signs in the udder had IMI M one or both udder halves at weaning and or after lambing, and CoNS was the most common bacterial finding. A high SCC 400,000-500,000 cells/nil) was associated with IMI and a difference in having a high (CMT 3-5) or low (CMT 1-2) between udder halves can be used as an indicator of IMI under field conditions.
11.	Wickström, Erik, et al. (author) Relationship between somatic cell count, polymorphonuclear leucocyte count and quality parameters in bovine bulk tank milk 2009 In: Journal of Dairy Research. - 0022-0299 .- 1469-7629. ; 76, s. 195-201 Journal article (peer-reviewed)abstract The somatic cell count (SCC) in bovine bulk tank milk is presently used as an indicator of raw milk quality, reflecting the udder health status of the herd. During mastitis, SCC increases, mostly owing to an influx of polymorphonuclear leucocytes (PMN) from blood into milk, with a concomitant change in milk composition. Bulk tank milk samples were categorized according to their SCC, as well as polymorphonuclear leucocyte count (PMNC), to study relationships between SCC, PMNC and various raw milk quality traits, i.e. contents of total protein, whey protein, casein, fat and lactose, casein number, proteolysis and rheological properties. The proportion of PMN, obtained by direct microscopy, was significantly higher in samples with high SCC compared with low SCC samples. SCC and PMNC were strongly correlated, yielding a correlation coefficient of 0.85. High SCC samples had lower lactose and casein contents, lower casein number and more proteolysis than low SCC samples. Samples with high PMNC had a lower casein number than low PMNC samples. Samples with high and low SCC or PMNC did not differ in respect to rheological properties. Our results do not indicate that PMNC is a better biomarker than SCC for raw bulk tank milk quality, as previously proposed.
12.	Aspán, Anna, et al. (author) Genotypic variation among Staphylococcus aureus isolates from cases of clinical mastitis in Swedish dairy cows 2010 In: Veterinary Journal. - : Elsevier BV. - 1090-0233 .- 1532-2971. ; 185, s. 188-192 Journal article (peer-reviewed)abstract The main aim of this study was to examine genotypic diversity of 82 Staphylococcus aureus isolates from cases of acute clinical mastitis in cattle using pulsed-field gel electrophoresis, and to investigate pulso-type differences between geographical regions of Sweden. The work also investigated haemolysis type (alpha, alpha beta), beta-lactamase production, and the association between S. aureus pulsotypes and breed, parity and presence of teat lesions. All isolates came from different farms.In total, 25 pulsotypes were found, but most only once or twice. The most common pulsotype accounted for 26% of the isolates and was found in all regions. The distribution of pulsotypes in the southern region of the country differed from the northern and middle regions. alpha beta- or alpha-Haemolysis was found in 66% and 34% of the isolates, respectively, and beta-lactamase production was found in 9% of the isolates. Variation in haemolysis type or beta-lactamase production was found within some pulsotypes. The results indicate that some pulsotypes have spread widely between herds within the country. (C) 2009 Elsevier Ltd. All rights reserved.
13.	Capurro, Aldo, et al. (author) Identification of potential sources of Staphylococcus aureus in herds with mastitis problems 2010 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 180-191 Journal article (peer-reviewed)abstract Staphylococcus aureus is a common udder pathogen of dairy cows that often causes herd problems. Various mastitis control programs have been used to combat the problem but have not always been efficient in preventing new Staph. aureus infections, indicating the presence of possible sources of infection other than those traditionally considered. Therefore, the aim of the study was to identify potential sources of infection relevant for Staph. aureus mastitis within 5 dairy herds with udder health problems caused by Staph. aureus. Samples were collected from milk of lactating cows, from body sites, and from the environment of lactating cows, dry cows, late pregnant heifers, young heifers 4 to 12 mo old, and heifer calves 0 to 3 mo old. Isolates of Staph. aureus were identified and compared using pulsed-field gel electrophoresis. Four to 7 unique Staph. aureus pulsotypes were found within each herd, with one strain predominating in milk in each herd. The milk pulsotypes were also frequently isolated in body samples, especially on hock skin, and in the immediate environment of lactating cows, and were sometimes found in other animal groups, especially in dry cows and heifer calves 0 to 3 mo old. The prevalence of Staph. aureus in milk and other types of samples varied markedly between herds. Staphylococcus aureus isolates with genotypes indistinguishable from those found in milk also dominated in extra-mammary sites within the dairy herds studied, and hock skin was identified as an important reservoir of Staph. aureus. The results contribute new knowledge necessary to improve strategies for udder health control in herds.
14.	Carlzén, Rikard, et al. (author) Experiences from herd outbreaks of Streptococcus agalactiae 2011 Conference paper (other academic/artistic)
15.	Cooray, Ruby, et al. (author) Haptoglobin comprises about 10% of granule protein extracted from bovine granulocytes isolated from healthy cattle 2007 In: Veterinary Immunology and Immunopathology. - : Elsevier BV. - 0165-2427 .- 1873-2534. ; 119:3-4, s. 310-315 Journal article (peer-reviewed)abstract Haptoglobin (Hp) is a plasma protein with haemoglobin binding capacity important in maintaining the iron homeostasis and in disease processes influenced by iron metabolism. In cattle Hp is one of the major acute phase proteins, and increases rapidly during infectious disease. At acute clinical mastitis in dairy cows the Hp concentration increases markedly both in blood and milk. Hepatocytes are considered to be the main origin of Hp, but expression of Hp mRNA has also been found in the mammary gland and leukocytes in healthy cattle. In the present study we show that bovine granulocytes, isolated from peripheral blood of healthy cattle, contain abundant amounts of Hp within the granules. As shown by two-dimensional gel electrophoresis (2-DE) in combination with matrix assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-ToF-MS) bovine granulocyte Hp consists of two sets of peptides ca. 20 kDa (a-chains) and ca. 40 kDa ((3-chains) with multiple iso-forms.
16.	Duse, Anna, et al. (author) Farming practices in Sweden related to feeding milk and colostrum from cows treated with antimicrobials to dairy calves 2013 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 55 Journal article (peer-reviewed)abstract Background: Milk produced by cows in receipt of antimicrobial therapy may contain antimicrobial residues. Such antimicrobial-containing waste milk must be withdrawn from human consumption and is therefore sometimes used as calf feed. Unfortunately, this approach might promote selection of antimicrobial resistant bacteria in the calves' intestinal microbiota. The objectives of this study were therefore to obtain an overview of waste milk feeding practices on Swedish dairy farms and to investigate if these practices were associated with certain farm characteristics. A representative group of 457 Swedish dairy farmers participated in a web-based survey with questions about the use of colostrum and milk from cows treated with antimicrobials at dry off or during lactation, respectively, as calf feed. Results: Colostrum (milk from the first milking after calving) and transition milk (milk from the second milking to the fourth day after calving) from cows treated with antimicrobials at dry off was fed to calves on 89% and 85% of the farms in the study, respectively. When antimicrobial therapy was given to cows during lactation, 56% of the farms fed milk that was produced during the course of treatment to calves, whereas milk that was produced during the subsequent withdrawal period was fed to calves on 79% of the farms. Surveyed farmers were less prone to feed such milk if the antimicrobial therapy was due to mastitis than other infections. In Sweden, a majority of antimicrobial treatments during lactation are systemic administration of benzylpenicillin and thus, the bulk of waste milk in Sweden is likely to contain residues of this drug. Feeding waste milk to calves was more common on non-organic farms, and on farms located in Southern Sweden, and was less common on farms with cows housed in cold free stalls barns. Conclusions: Waste milk that may contain antimicrobial residues is, at least occasionally, used as feed for calves on a majority of surveyed Swedish dairy farms. Future work should focus on the effect of waste milk feeding on the occurrence of antimicrobial resistant bacteria in the calves' intestinal microbiota.
17.	Ekman, Lisa, et al. (author) A shotgun metagenomic investigation of the microbiota of udder cleft dermatitis in comparison to healthy skin in dairy cows 2020 In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15 Journal article (peer-reviewed)abstract Udder cleft dermatitis (UCD) is a skin condition affecting the fore udder attachment of dairy cows. UCD may be defined as mild (eczematous skin changes) or severe (open wounds, large skin changes). Our aims were to compare the microbiota of mild and severe UCD lesions with the microbiota of healthy skin from the fore udder attachment of control cows, and to investigate whether mastitis-causing pathogens are present in UCD lesions. Samples were obtained from cows in six dairy herds. In total, 36 UCD samples categorized as mild (n = 17) or severe (n = 19) and 13 control samples were sequenced using a shotgun metagenomic approach and the reads were taxonomically classified based on their k-mer content. The Wilcoxon rank sum test was used to compare the abundance of different taxa between different sample types, as well as to compare the bacterial diversity between samples. A high proportion of bacteria was seen in all samples. Control samples had a higher proportion of archaeal reads, whereas most samples had low proportions of fungi, protozoa and viruses. The bacterial microbiota differed between controls and mild and severe UCD samples in both composition and diversity. Subgroups of UCD samples were visible, characterized by increased proportion of one or a few bacterial genera or species, e.g. Corynebacterium, Staphylococcus, Brevibacterium luteolum, Trueperella pyogenes and Fusobacterium necrophorum. Bifidobacterium spp. were more common in controls compared to UCD samples. The bacterial diversity was higher in controls compared to UCD samples. Bacteria commonly associated with mastitis were uncommon. In conclusion, a dysbiosis of the microbiota of mild and severe UCD samples was seen, characterized by decreased diversity and an increased proportion of certain bacteria. There was no evidence of a specific pathogen causing UCD or that UCD lesions are important reservoirs for mastitis-causing bacteria.
18.	Ekman, Lisa, et al. (author) Hock lesions in dairy cows in freestall herds: a cross-sectional study of prevalence and risk factors 2018 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 60 Journal article (peer-reviewed)abstract Background: Hock lesions (HL) in dairy cows are a common animal welfare problem in modern dairy production with freestall housing systems, but there are no large-scale studies addressing its epidemiology in Sweden. The aims of this cross-sectional study were to investigate the prevalence of HL of different severity in 100 Swedish freestall dairy herds, and to identify cow- and herd-related risk factors. Associations between HL and mastitis as well as culling were also investigated.Results: In total, 3217 cows from 99 herds were included in the statistical analyses. The overall cow prevalence of hair loss on the hock (mild HL) was 68% and the prevalence of ulceration or evident swelling of the hock, with or without hair loss, (severe HL) was 6%. The within-herd prevalence varied among herds, between 23 and 100% for mild HL, and between 0 and 32% for severe ones. Breed (higher risk for Swedish Holstein than for Swedish Red) and days in milk (higher risk at 181-305 days than at 0-90 days) were cow-related risk factors associated with both types of lesions, whereas higher parity and cleaner cows were associated only with increased risk of severe HL. A reduced risk for mild HL was seen in cows housed on mattresses compared to rubber mats, and in cows housed on peat compared to other bedding materials. Also, cows in herds with a high proportion of not yet inseminated heifers older than 17 months had a lower risk of mild HL than cows in herds with a low proportion. Risk for severe HL was lower when cubicles were of recommended width compared to under recommendation, for organic production compared to conventional, and when teat dip or no treatment after milking was used, compared to teat spray. For both mild and severe HL, herringbone milking parlors were associated with higher risk than tandem parlors. We found no significant associations between HL and mastitis or culling.Conclusions: The prevalence of HL is high in Swedish dairy herds, although most lesions are mild. Several cow- and herd-related risk factors were identified and the results can be used to improve recommendations for the prevention of HL in Swedish freestall dairy herds.
19.	Ekman, Lisa, et al. (author) Incidence of udder cleft dermatitis (UCD) in dairy cows and risk factors for transitions to UCD 2020 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103, s. 11736-11749 Journal article (peer-reviewed)abstract Udder cleft dermatitis (UCD) is a common skin condition in Swedish dairy cows, affecting the anterior parts of the udder. The main objective of this study was to investigate incidence rate and duration of UCD in a 1-yr longitudinal study. Other objectives were to investigate risk factors for transitions from being healthy to having mild or severe UCD, and from having mild UCD to having severe UCD, and associations between UCD and clinical mastitis, somatic cell count (SCC) and hock lesions. Seven herds were included in the study and visited 9 times each at 6-wk intervals. At the visits, mild and severe UCD lesions, hock lesions, udder conformation traits, and hygiene scores were registered for each cow milked in the milking parlor. Information on breed, parity, days in milk (DIM), results from test milkings (milk production, SCC, and urea level), and veterinary treatments was also obtained. A UCD case was defined as one or several consecutive observations of UCD. The incidence and duration of UCD were described. Mixed-effect logistic regression models were used to analyze associations between potential risk factors and transitions to any type of UCD. Separate risk factor analyses were performed for transitions to mild arid severe UCD. Associations with SCC, mastitis, and hock lesions were also analyzed with mixed-effect logistic regression models. The mean overall incidence of new UCD cases for all visits and herds was 0.5 cases per cow-year at risk. Risk factors associated with a higher risk of a transition to any type of UCD and mild UCD were breed (Swedish Red vs. Swedish Holstein), an indentation or fold at the fore udder attachment, and increasing DIM. In addition, a low milk urea level was associated with a lower risk of transition to any type of and mild UCD. Cows with previous mild UCD and high-yielding cows had increased risk for a transition to severe UCD. Cows that had an observed transition to severe UCD had an increased risk of veterinary-treated clinical mastitis within 6 wk after the UCD observation. No associations were found between UCD and SCC or hock lesions. The median observed duration of a UCD case was 12 wk, but most cases did not have an observed start or end during the study period. The observed duration of cases including severe UCD was longer than for cases involving only mild UCD. The high incidence and often long duration of UCD emphasize the need for preventive measures and treatment strategies.
20.	Ekman, Lisa, et al. (author) Mild and severe udder cleft dermatitis-Prevalence and risk factors in Swedish dairy herds 2018 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 101, s. 556-571 Journal article (peer-reviewed)abstract Udder cleft dermatitis (UCD) is an inflammatory skin condition affecting the anterior parts of the udder of dairy cows. The lesions may present as mild or severe skin lesions and have been associated with mastitis and digital dermatitis. The full etiology and pathogenesis are not understood and no large-scale studies have investigated prevalence and risk factors. Therefore, the main objectives of the study were to investigate the prevalence of mild and severe UCD in Swedish dairy herds and to identify risk factors associated with such lesions. We also wanted to investigate risk factors for all cases of UCD and to determine whether UCD increases the risk for mastitis and culling. A random sample of 100 freestall dairy herds were included in the study, and each herd was visited once. Cows were registered as having no, mild, or severe UCD. Additional cow and herd data were obtained via observations, interviews, and the Swedish Official Milk Recording Scheme. The data were analyzed using logistic regression models to identify risk factors for mild and severe UCD. In total, data from 3,479 cows in 99 herds were analyzed. The prevalence of mild and severe UCD was 19 and 9%, respectively. Lesions were found in 98 of 99 herds but the within-herd prevalence of mild (0-43%) and severe (0-33%) UCD varied notably between herds. Breed (Swedish Red compared with Swedish Holstein), certain udder conformation traits, and higher parity were risk factors associated with increased risk of UCD. In addition, cows with hock lesions and cows in herds with high incidence of culling due to hoof and leg diseases had a higher risk for mild UCD. More days in milk and high milk yield were cow-related risk factors associated with severe UCD. Three housing-related factors (shorter cubicles, mattress as cubicle base, and cubicles installed before 2001 compared with 2001-2005), a high incidence of veterinary-treated clinical mastitis and culling due to udder diseases, and a low incidence of culling of first-parity cows in early lactation were herd-related risk factors associated with increased risk for severe UCD. In addition, cows in herds with a high proportion of heifers older than 17 mo that were not inseminated were associated with lower risk of all UCD. Finally, UCD was not associated with the outcomes milk somatic cell count, veterinary-treated clinical mastitis, or culling in the multivariable analyses. The etiology of UCD is most likely multifactorial, involving udder conformation traits and other cow-related risk factors as well as herd-related risk factors. The high prevalence of severe UCD lesions in Swedish dairy cows emphasizes the need for preventive measures arid efficient treatments.
21.	Ekman, Lisa, et al. (author) Recovery from udder cleft dermatitis in dairy cows 2021 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 104, s. 3532-3546 Journal article (peer-reviewed)abstract Udder cleft dermatitis (UCD) is a common skin problem in dairy cows, localized at the fore udder attachment or between the udder halves. The main objectives of this study were to investigate spontaneous recovery from UCD in a longitudinal study and to investigate the treatment effect on UCD of a topical spray containing chelated copper and zinc in an additional treatment trial. Spontaneous recovery was investigated during a 1-yr longitudinal study in which 7 Swedish dairy herds were visited 9 times each, at 6-wk intervals. During the visits, all cows milked in the milking parlor were examined for mild and severe UCD, udder conformation traits, hygiene, and hock lesions. Additional cow and herd data were obtained from the Swedish official milk recording scheme. Recovery was defined as 2 consecutive observations of no UCD after a UCD case (1 or more consecutive observations of UCD). The recovery rate was calculated and factors associated with recovery were analyzed using discrete-time survival analysis. A treatment study was conducted in 4 of the herds after completion of the longitudinal study. Cows with UCD were allocated to treatment or a control group, and cows in the treatment group were treated once every day for 14 to 28 d. At follow-up visits on d 14, 28, and 56, all cows were scored for UCD. To investigate the effect of treatment, an ordered logistic regression model was used, with UCD score on d 56 (no, mild, or severe) as the outcome. Other potential explanatory variables were also included in the model. A total of 38% (126 of 329) of the cows in the longitudinal study made a spontaneous recovery from UCD. A long duration of UCD, severe lesions and higher parity reduced the chance of recovery. Among the recovered cows, 47% (59 of 126 cows) had a recurrent case of UCD after the recovery. In the treatment study, there was no difference in UCD score on d 56 between the treatment and control groups. Factors that affected the UCD score on d 56 were the duration of UCD before the treatment study started, UCD score on d 1 and udder conformation. Our findings emphasize the importance of further studies to identify effective treatment regimens as well as further studies to unravel the pathophysiology of UCD to improve the recommendations on how to prevent these lesions.
22.	Emanuelson, Ulf, et al. (author) Diagnostic test performance of somatic cell count, lactate dehydrogenase, and N-acetyl-beta-D-glucosaminidase for detecting dairy cows with intramammary infection 2016 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 99, s. 1440-1448 Journal article (peer-reviewed)abstract The main objective of this study was to investigate the diagnostic test performance of somatic cell count (SCC), lactate dehydrogenase (LDH), and N-acetyl-beta-D-glucosaminidase (NAGase), analyzed in composite test milking samples, for detecting dairy cows with or without intramammary infection (IMI). A second objective was to investigate whether an adjustment of these udder health indicators according to their associations with different influential factors (i.e., parity, days in milk, and season) improved their test performance. Moreover, we wanted to investigate whether test performance of SCC improved if SCC results from previous adjacent test milkings were included in the model. Such test milking data were not available for LDH or NAGase. In this cross-sectional study, quarter milk samples for bacteriological examination were taken from almost 1,000 cows from 25 dairy herds during 3 consecutive days: the day before test milking, the day of test milking, and the day after test milking. From each cow, a composite test milking sample was analyzed for milk composition, SCC, LDH, and NAGase. Among the cows sampled, 485 were IMI negative and 256 were IMI positive in one or more udder quarters according to the definitions used. The remaining cows had inconclusive IMI status. To assess the test performance of SCC, LDH, and NAGase to identify IMI-negative and IMI-positive cows, univariable generalized estimating equation models were used with the udder health indicator of interest as outcome and IMI status as explanatory variable. From these models, receiver-operator characteristic curves were created and the area under cure (AUC) was calculated. From each model, a cut-off was chosen for calculations of the sensitivity (Se), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) for each udder health indicator. The AUC was similar for the adjusted SCC (0.84), nonadjusted SCC (0.83) and geometric mean SCC (0.80-0.81), but much lower for LDH (0.66) and NAGase (0.62). The highest Se, Sp, PPV, NPV, and ACC were obtained using SCC. Adjustment of the udder health indicators for influential factors (e.g., parity) did not improve the test performance markedly, whereas adding information about SCC from previous adjacent test milkings improved the test performance of SCC slightly. In conclusion, of the udder health indicators investigated, SCC had the best overall ability to correctly identify IMI-negative and IMI-positive dairy cows.
23.	Emanuelson, Ulf, et al. (author) Management practices associated with udder health of first-parity dairy cows in early lactation 2009 In: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 88, s. 138-149 Journal article (peer-reviewed)abstract This study aimed at investigating associations between management routines including feeding, housing, and milking around calving, and udder health of first-parity cows in early lactation in Swedish large, high producing, low bulk-milk somatic cell count (SCC) dairy herds housed in free stalls. Seventy-two dairy herds participated and data concerning 1189 first-parity cows calving during the study period (October 2005-January 2006) was collected. Multivariable regression analysis were performed with three different outcomes; within-herd number of first-parity cows veterinary treated for clinical mastitis at days -10 to 60 after calving, within-herd number of first-parity cows with a SCC >= 200,000 cells/mL at first test-day, and SCC of first-parity cows at first test-day. Cow factors significantly associated with good udder health of first-parity cows (few cases of clinical mastitis and or low SCC) were being of the Swedish Red breed, having a high milk yield at first test-day, and a milk-urea >= 5 mmol/L at first test-day. Herd factors significantly associated with good udder health were having mattresses as flooring in the cubicles in the lactating cow housing, and to house the first-parity cows in tie stalls 1 month before calving. Cow factors significantly associated with poor udder health of first-parity cows were having a milk-urea <4 mmol/L at first test-day. Herd factors significantly associated with poor udder health of first-parity cows were feeding first-parity cows sugar-beet pulp or corn silage, and to give silage from a different batch to pregnant heifers than to lactating cows. Moreover, to have sawdust or shavings in the calving pen, to be moved from the calving pen >= 2 days after calving, to milk first-parity cows at the calving site instead of in the parlor, and to rinse, clean or disinfect milking units before a first-parity cow was milked were also significantly associated with poor udder health of first-parity cows. The results indicate that different control measures must be taken depending on the nature of the udder health problem. (c) 2008 Elsevier B.V. All rights reserved.
24.	Gidekull, Maria, et al. (author) alpha-Tocopherol and beta-carotene concentrations in feed, colostrum, cow and calf serum in Swedish dairy herds with high or low calf mortality 2018 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 60 Journal article (peer-reviewed)abstract Background: A study of herd-level risk factors for calf mortality in large Swedish dairy herds showed low serum concentrations of alpha-tocopherol and beta-carotene in 1-7 day old calves to be more common in high mortality herds. Therefore, we aimed to investigate if calf mortality risk at herd level is associated with concentrations of alpha-tocopherol and/or beta-carotene at individual level in feed, colostrum, cow and calf serum, while controlling for herd level covariates. Inclusion criteria were affiliation to the Swedish official milk recording scheme, herd size of >= 120 milking cows/year, calf mortality risk (day 1-90) of at least 6% (high mortality; HM) or less than 1% (low mortality; LM) and located within one of two regions in southern Sweden. This cross-sectional study was performed in 2010 in 19 -(n(HM) = 9; -n(LM) = 10) dairy herds. Questionnaires were used to collect information about feed and routines for colostrum feeding. Feed (n = 57), colostrum (n = 162), cow serum (n = 189) and calf serum samples (n = 187) were collected and analysed for alpha-tocopherol and beta-carotene. Other analyses e.g. total serum protein, fat content, and total solids in colostrum were also performed. Linear regression models with vitamin concentrations in feed, colostrum, cow and calf serum as outcome were performed.Results: Calves in HM herds had lower concentrations of alpha-tocopherol in serum than calves in LM herds, but the effect depended on total protein status in serum of the calf (P = 0.036). Calves from herds that fed transition milk for 3 days or more had higher alpha-tocopherol concentrations in serum than calves from herds feeding transition milk up to 2 days (P = 0.013). Fat percentage in colostrum was positively associated with alpha-tocopherol (P < 0.001) and beta-carotene concentrations in colostrum (P < 0.001). A diet containing >= 20% (in kg dry matter) maize silage of the total ration was negatively associated with beta-carotene concentration in cow serum (P = 0.001).Conclusions: High calf mortality risks were associated with lower concentrations of alpha-tocopherol in calf serum for calves with failure of passive transfer. Feeding transition milk longer was associated with higher concentrations of alpha-tocopherol in calf serum. In HM herds, evaluation of the calves' alpha-tocopherol status is recommended.
25.	Gidekull, Maria, et al. (author) Risk factors for calf mortality in large Swedish dairy herds 2011 In: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 99, s. 136-147 Journal article (peer-reviewed)abstract The aim of this study was to identify possible risk factors for 1-90 day calf mortality in large Swedish dairy herds. Sixty herds with a herd size of >= 160 cows were visited once between December 2005 and March 2006. Thirty herds were known to have low mortality (LM) and 30 were known high mortality herds (HM). Upon the visit, data about housing and management was collected from interviews with personnel responsible for the calves. The herd status regarding the calves' passive transfer (total protein), levels of alpha-tocopherol, beta-carotene and retinol, and excretion of faecal pathogens (Cryptosporidium spp., Escherichia coli F5, rota and corona virus) was evaluated based on targeted sampling of high risk calf groups; in each herd, blood and faecal samples were collected from calves 1-7 and 1-14 days old, respectively. Similarly, the herd status regarding clinical respiratory disease in calves and history of respiratory virus exposure was evaluated based on lung auscultations and blood samplings of calves 60-90 days old. The median calf mortality risk (in calves 1-90 days of age) among HM herds was 9% (Range: 6-24%) and among LM herds 1% (Range: 0-2%). LM and HM herds were compared using five logistic regression models, covering potential risk factors within different areas: "Disease susceptibility", "Factors affecting the gastrointestinal tract", "Factors related to transmission of infectious disease", "Hygiene" and "Labour management". The percentage of calves, 1-7 days old, with inadequate serum concentrations of alpha-tocopherol and beta-carotene were significantly higher in HM herds compared to LM herds and also associated with higher odds of being a HM herd (OR = 1.02; p = 0.023 and OR = 1.05; p = 0.0028, respectively). The variable "Average number of faecal pathogens in the sampled target group" was significantly associated with higher odds of being a HM herd (OR = 4.65: p = 0.015), with a higher average in HM herds. The percentage of calves with diarrhoea treated with antibiotics was significantly higher in HM herds and was associated with higher odds of being a HM herd (OR = 1.08; p = 0.021). The median age at death of calves in the age interval 1-90 days that died during a one-year period was significantly lower among HM herds (13 days) than in LM herds (24 days) (p = 0.0013) The results indicate that gastrointestinal disorders may be an important cause of calf mortality in large Swedish dairy herds. Furthermore, our study provides additional indications that fat soluble vitamins might play an important role for calf health. (C) 2010 Elsevier B.V. All rights reserved.
26.	Gidekull, Maria, et al. (author) Variations of serum levels of a-tocopherol and b-carotene in Swedish dairy herds with low and high calf mortality 2013 Other publication (other academic/artistic)
27.	Johansson, Birgitta, et al. (author) Effects of vitamin status and health in dairy cows fed without synthetic vitamins 2012 In: Landbauforschung Völkenrode. Sonderheft. - 0376-0723. ; , s. 394-397 Conference paper (peer-reviewed)abstract Synthetic vitamin supplementation is not consistent with organic production and it is important to investigate how dairy cows manage without synthetic vitamin supplementation. The study aimed to compare the performance of cows given no synthetic vitamins (NSV) with cows (control; C) fed synthetic vitamins according to Swedish recommendations. Swedish Holstein cows (n=28) fed a 100 % organic diet were studied during two lactations. Vitamin status in cow plasma and milk, milk yield and composition, health and fertility were measured. From each cow, five blood and five milk samples were collected during lactation. In first lactation, C cows tended to have a higher concentration of α-tocopherol and their β-carotene concentration was higher compared to NSV cows. The C cows tended to have fewer cases of mastitis than NSV cows in the second lactation. No differences were found in production and fertility. In conclusion, dairy cows need vitamin A and E supplement, at least around calving when the requirements are high.
28.	Johansson, Birgitta, et al. (author) Status of vitamins E and A and β-carotene and health in organic dairy cows fed a diet without synthetic vitamins 2014 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 97, s. 1682-1692 Journal article (peer-reviewed)abstract Synthetic vitamin supplementation is not consistent with organic production, so it is important to investigate whether dairy cows can maintain their health and production without synthetic vitamins being added to their diet. In basic dairy cow diets, provitamin A (beta-carotene) and vitamin E are mainly found in pasture and in grass and legume silages, but the concentrations are highly variable. This study compared the vitamin status and health of cows without synthetic vitamin supplementation (NSV group) with control cows (CON group) fed synthetic vitamins according to Swedish recommendations (600 IU of vitamin E and 80,000 IU of vitamin A per cow per day) to investigate whether dairy cows can fulfill their requirements of vitamins A and E without supplementation with synthetic vitamins. Vitamin concentrations in blood plasma and milk, health, fertility, milk yield, and milk composition were measured in Swedish Holstein cows (n = 28) during 2 complete lactations. All cows were fed a 100% organic diet containing grass-legume silage, cold-pressed rapeseed cake, peas, cereal grains, and minerals. Blood samples were collected from each cow 3 wk before expected calving, at calving, and 3 wk, 3 to 5 mo, and 7 to 9 mo after calving. Samples of colostrum were taken and milk samples were collected 4 d after calving and at the same time as the 3 blood samplings after calving. The only difference in vitamin status between groups was found in colostrum in yr 1, when CON cows tended to have a higher concentration of alpha-tocopherol, and their beta-Carotene concentration was higher compared with NSV cows. The NSV cows tended to have more cases of mastitis than CON cows in yr 2. Within the NSV group, fewer cows were healthy and more cases of mastitis were observed in yr 2 than in yr 1. The groups did not differ in production parameters. In conclusion, the vitamin status in blood and milk of the studied cows indicated that cows in organic dairy production can fulfill their requirements of vitamins A and E without any supplementation of synthetic vitamins, except at the time around calving, when the requirements are high. However, the impaired health of NSV cows in yr 2 may indicate a long-term negative health effect in cows fed no synthetic vitamins.
29.	Lindqvist, Hanna, et al. (author) Effects of RRR-alpha-tocopheryl acetate supplementation during the transition period on vitamin status in blood and milk of organic dairy cows during lactation 2011 In: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 142, s. 155-163 Journal article (peer-reviewed)abstract This study investigated effects of daily supplementation with RRR-alpha-tocopheryl acetate, during the transition period around calving, on concentrations of alpha-tocopherol in plasma and milk from prepartum to mid-late lactation of dairy cows. Retinol and beta-carotene contents also were measured. The study included 2 experiments, where all cows were fed 100% organic diets, with high proportions of grass-legume forage. The experimental design was a randomised complete block. In experiment 1, the basal diet contained 70 and 60 IU of RRR-alpha-tocopherol/kg DM (dry period and lactation, respectively) and was supplemented with 0 (C) or 2400 (E) IU of RRR-alpha-tocopheryl acetate from 3 weeks before to 3 weeks post calving (PC). In experiment 2, the basal diet contained 29 IU of RRR-alpha-tocopherol/kg DM plus 31 (dry) or 20 (lactating) IU of synthetic vitamin E/kg DM and was supplemented with 0 (C) or 2400 (E) IU of RRR-alpha-tocopheryl acetate from 3 weeks before to 3 weeks PC. Synthetic vitamins A and D also were supplemented in experiment 2. Blood samples were collected at 3 weeks before expected calving, at calving, at 3 weeks PC and between 5 and 7 months PC, while milk samples were collected from colostrum, at 4 days PC, at 3 weeks PC and between 5 and 7 months PC. In both experiments, E cows tended to have higher plasma concentrations of alpha-tocopherol at calving than C cows. At 3 weeks PC, concentrations in plasma were 34% and 22% higher in E cows than in C cows in experiment 1 and 2, respectively (P<0.05). The treatments resulted in similar vitamin concentrations in milk in experiment 1. In experiment 2, the basal diet was low in RRR-alpha-tocopherol, and E cows had 61%, 207% and 181% higher concentrations of alpha-tocopherol than C cows in the milk from colostrum, 4 days PC and 3 weeks PC, respectively (P<0.05). There were no differences between treatments in either plasma or milk later in lactation. High concentrations of alpha-tocopherol and beta-carotene in forage decreased the effect of the E treatment. However, as concentrations of alpha-tocopherol and beta-carotene in forage are difficult to predict vitamin supplementation is recommended, especially around calving. Retinol concentrations in plasma in experiment 1 were generally low (< 0.25 mg/l during the transition period), indicating that vitamin A supplementation also is necessary, especially during the transition period. (C) 2011 Elsevier B.V. All rights reserved.
30.	Lindqvist, Hanna, et al. (author) Effects of RRR-α-tocopheryl acetate supplementation during the transition period on vitamin status in blood and milk of organic dairy cows during lactation 2011 In: Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård. - 0347-9838. ; 277, s. 86-90 Conference paper (other academic/artistic)
31.	Lindqvist, Hanna, et al. (author) Tillskott av vitaminer – behövs det? 2012 Conference paper (peer-reviewed)
32.	Lundberg, Åsa, et al. (author) Associations between bacterial genotype and outcome of bovine clinical Staphylococcus aureus mastitis 2014 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 56 Journal article (peer-reviewed)abstract Background Staphylococcus aureusis an important cause of clinical mastitis in dairy cows worldwide. The cure rate after antimicrobial treatment of clinicalS. aureusmastitis is very variable due to both cow and bacterial factors. Studies have shown that bacterial genotype might affect short-term bacteriological and clinical cure, but the long-term outcome has been less studied. The objectives of this study were to investigate associations between bacterial genotype and long-term outcome of veterinary-treated clinical mastitis (VTCM) caused byS. aureusduring a follow-up period of 120 days and to study genotype variation among SwedishS. aureusisolates.S. aureusisolates from cases of VTCM were genotyped by pulsed-field gel electrophoresis. Long-term outcome measurements used were somatic cell count (SCC), additional diagnoses of VTCM, milk yield and culling. Isolates were classified into clusters (>80% similarity) and pulsotypes (100% similarity). Clusters and pulsotypes were grouped according to occurrence. Multivariable mixed-effect linear regression models including cow and bacterial factors with possible influence on SCC or milk yield were used to calculate differences in SCC or milk yield between groups. Additional outcome measures were calculated using a test of proportions. Results The isolates (n = 185) were divided into 18 clusters and 29 pulsotypes. Two pulsotypes were classified as common, and were found in 64% of the cases of VTCM. Remaining isolates were classified as less common or rare pulsotypes. The distribution was similar at cluster level. Outcome was calculated from follow-up data on 111 cows. Significantly lower SCC during the follow-up period was found in cows infected with common clusters compared to in cows infected with less common/rare clusters. The proportion of cows with SCC <200 000 cells/ml during the whole follow-up period was significantly higher in the group common clusters than in the group less common/rare clusters. Bacterial genotype did not influence the other outcome parameters. Conclusions In Sweden, twoS. aureuspulsotypes, identified in about 64% of clinicalS. aureuscases, were widespread. Cows infected with the common genotypes had significantly lower SCC during 120 days after treatment compared to cows infected with less common or rare genotypes. Conclusions In Sweden, two S. aureus pulsotypes, identified in about 64% of clinical S. aureus cases, were widespread. Cows infected with the common genotypes had significantly lower SCC during 120 days after treatment compared to cows infected with less common or rare genotypes.
33.	Lundberg, Åsa, et al. (author) Influence of bacterial genotype on outcome of clinical Staphylococcal aureus mastitis 2011 Conference paper (other academic/artistic)
34.	Lundberg, Åsa, et al. (author) Prevalence of bacterial genotypes and outcome of bovine clinical mastitis due to Streptococcus dysgalactiae and Streptococcus uberis 2014 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 56 Journal article (peer-reviewed)abstract Background: Streptococcus dysgalactiae and Streptococcus uberis are common causes of clinical mastitis (CM) in dairy cows. In the present study genotype variation of S. dysgalactiae and S. uberis was investigated, as well as the influence of bacterial species, or genotype within species, on the outcome of veterinary-treated CM (VTCM). Isolates of S. dysgalactiae (n = 132) and S. uberis (n = 97) were genotyped using pulsed-field gel electrophoresis. Identical banding patterns were called pulsotypes. Outcome measurements used were cow composite SCC, milk yield, additional registered VTCMs and culling rate during a four-month follow-up period. Results: In total, 71 S. dysgalactiae pulsotypes were identified. Nineteen of the pulsotypes were isolated from more than one herd; the remaining pulsotypes were only found once each in the material. All S. uberis isolates were of different pulsotypes. During the follow-up period, the SCC of S. dysgalactiae-cows was significantly lower than the SCC of S. uberis-cows (P <0.05). Median SCC of S. dysgalactiae-cows was 71 500 cells/ml and of S. uberis-cows 108 000 cells/ml. No other differences in outcome parameters could be identified between species or genotypes. Conclusions: Identical S. dysgalactiae genotypes were isolated from more than one herd, suggesting some spread of this pathogen between Swedish dairy herds. The genetic variation among S. uberis isolates was substantial, and we found no evidence of spread of this pathogen between herds. The milk SCC was lower during the follow-up period if S. dysgalactiae rather than S. uberis was isolated from the case, indicating differences in treatment response between bacterial species.
35.	Lundberg, Åsa, et al. (author) Udder infections with Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis at calving in dairy herds with suboptimal udder health 2016 In: Journal of Dairy Science. - : Elsevier. - 0022-0302 .- 1525-3198. ; 99:3, s. 2102-2117 Journal article (peer-reviewed)abstract Udder infections with Staphylococcus aureus, Streptococcus dysgalactiae, and Streptococcus uberis are common causes of bovine mastitis. To study these pathogens in early lactation, a 12-mo longitudinal, observational study was carried out in 13 herds with suboptimal udder health. The aims of the study were to investigate the occurrence of these pathogens and to identify if presence of the 3 pathogens, and of genotypes within the pathogens, differed with respect to herd, season, and parity. Quarter milk samples, collected at calving and 4 d in milk (DIM), were cultured for the 3 pathogens. Genotyping of staphylococcal and streptococcal isolates was performed using spa typing and pulsed-field gel electrophoresis, respectively. For each of the 3 pathogens, cows with an udder infection at calving or 4 DIM were allocated to 1 of 4 infection types: cleared (pathogen present only at calving), persistent (pathogen present in the same quarter at calving and 4 DIM), new (pathogen present only at 4 DIM), or cleared/new (pathogen present in 1 quarter at calving and in another quarter at 4 DIM). Associations between season or parity and overall occurrence of pathogens or infection types were determined using univariable mixed-effect logistic-regression models and the Fisher's exact test, respectively. The most commonly occurring pathogen was Staph. aureus, followed by Strep. dysgalactiae and Strep. uberis. Persistent infections were the most common infection type among Staph. aureus-infected cows, whereas cleared infections were the most common among Strep. dysgalactiae- and Strep. uberis-positive cows. The proportion of cows with persistent Staph. aureus infections and the proportion of cows having a Strep. uberis infection at calving or 4 DIM were higher in the multiparous cows than in primiparous cows. Infections with Strep. dysgalactiae were less common during the early housing season than during the late housing or pasture seasons, whereas persistent Strep. uberis infections were less common during the pasture season than during the late housing season. The relative occurrence of the 3 pathogens, infection types of each pathogen, and genotype diversity of each pathogen throughout the year or in different seasons and parities varied among the herds, indicating that underlying factors predisposing for udder infections at calving differ between herds. Genotyping of bacterial isolates gave important insight into how such infection patterns differed within and between herds. These findings emphasize the need to choose preventive strategies for each individual herd.
36.	Nyman, Ann, et al. (author) Associations of udder-health indicators with cow factors and with intramammary infection in dairy cows 2014 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 97, s. 5459-5473 Journal article (peer-reviewed)abstract The objective of this study was to investigate if and how cow factors and intramammary infection (IMI) are associated with 4 different udder-health indicators in dairy cows as a first step in investigating whether the diagnostic performance of these indicators can be improved. The investigated indicators were somatic cell count (SCC), lactate dehydrogenase (LDH), N-acetyl-beta-D-glucosaminidase (NAGase), and alkaline phosphatase (AP) measured in milk. In this cross-sectional study, approximately 1,000 cows from 25 dairy herds were sampled for bacteriology (quarter milk samples) during 3 consecutive days: the day before test milking, at the day of test milking, and at the day after test milking. The whole-udder test milking sample was analyzed for milk composition, SCC, LDH, NAGase, and AP. Cow data (parity, breed, milk yield, percentage of milk fat and protein, milk urea concentration, and days in milk from the sampled test milking) were collected from the Swedish milk-recording scheme. Of the sampled cows 485 were considered IMI negative and were used in multivariable mixed-effect linear regression models to investigate associations between cow factors and the udder-health indicators. A second modeling including all cows, both IMI negative and IMI positive (256 cows), was also performed. The results showed that all udder-health indicators were affected by cow factors but that different cow factors were associated with different indicators. Intramammary-infection status was significantly associated with all udder-health indicators except AP. Parity and milk urea concentration were the only cow factors associated with all indicators in all models. The significant cow factors explained 23% of the variation in SCC and >30% of the variation in LDH, NAGase, and AP in IMI-negative cows, showing that LDH, NAGase, and AP are more affected than SCC by cow factors. The IMI status explained 23% of the variation in SCC in the model with all cows but only 7% of the variation in LDH and 2% of the variation in NAGase, indicating that SCC has the best potential as a diagnostic tool in finding cows with IMI. However, further studies are needed to investigate whether the diagnostic properties of these udder-health indicators will improve with adjustment according to their associations with different cow factors when used as a diagnostic tool for finding cows with IMI.
37.	Persson Waller, Karin (author) Agglutination tests for identification of Staphylococcus aureus from cases of bovine mastitis 2011 Conference paper (other academic/artistic)
38.	Persson Waller, Karin (author) An improved method to culture Staphylococcus aureus from bovine milk 2010 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 1534-1538 Journal article (peer-reviewed)abstract Staphylococcus aureus is an important udder pathogen often associated with subclinical mastitis in dairy cows. Identification of Staph. aureus-positive udder quarters and cows is an important part of control programs to reduce spread of Staph. aureus within and between dairy herds. Therefore, accurate and easy-to-perform culturing methods of Staph. aureus in milk are needed. In the present study, 8 methods for isolation of Staph. aureus in bovine milk samples were investigated. The methods involved different culturing volumes, enrichment, incubation, and freezing processes as well as sedimentation and use of the Mastistrip cassette (SVA, Uppsala, Sweden). Three different sets of milk samples were collected, and 6, 5, and 4 methods were used in each subset of samples. Our results indicate an increased probability of detecting Staph. aureus in milk samples when a simple incubation step (37 degrees C for 18 h) without additives was included before culturing. Using this incubation method, the number of Staph. aureus-positive udder quarters and cows increased by 50 and 29%, respectively, compared with using the standard method of direct culturing of 10 mu L of milk. The improved method may be especially useful for detection of low concentrations of Staph. aureus in milk; for example, when screening herds for Staph. aureus.
39.	Persson Waller, Karin, et al. (author) CNS species and antimicrobial resistance in clinical and subclinical bovine mastitis 2011 In: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 152, s. 112-116 Journal article (peer-reviewed)abstract Coagulase-negative staphylococci (CNS) are often associated with bovine mastitis. Knowledge about the relative importance of specific CNS species in different types of mastitis, and differences in antimicrobial resistance among CNS species is, however, scarce. Therefore, the aims of this study were to compare prevalence and antimicrobial susceptibility of CNS species in clinical and subclinical mastitis using material from two national surveys. Overall, Staphylococcus chromogenes and Staphylococcus epidermidis were the most common CNS species found followed by Staphylococcus simulans and Staphylococcus haemolyticus. S. epidermidis was significantly more prevalent in subclinical than in clinical mastitis, and a similar trend was observed for Staphylococcus saprophyticus, while Staphylococcus hyicus was significantly more common in clinical mastitis. The prevalence of beta-lactamase producing isolates varied markedly between CNS species, and was significantly higher in S. epidermidis and S. haemolyticus (similar to 40%), than in S. simulans and S. chromogenes where none or a few of the isolates produced beta-lactamase. Resistance to more than one antimicrobial substance occurred in 9% and 7% of the clinical and subclinical isolates, respectively. In conclusion, the distribution of CNS species differed between clinical and subclinical mastitis indicating inter-species variation of pathogenicity and epidemiology. Overall, the prevalence of antimicrobial resistance was low, but some variation between CNS species was observed. (C) 2011 Elsevier B.V. All rights reserved.
40.	Persson Waller, Karin (author) Comparison of a commercialized phenotyping system, antimicrobial susceptibility testing, and tuf gene sequence-based genotyping for species-level identification of coagulase-negative staphylococci isolated from cases of bovine mastitis 2009 In: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 134, s. 327-333 Journal article (peer-reviewed)abstract In order to evaluate the usefulness of some phenotypic and genotypic methods for species identification of coagulase-negative staphylococci (CNS), isolates were obtained from bovine cases of clinical and sub-clinical mastitis from different geographical areas in Sweden. By using the Staph-Zym (TM) test, antimicrobial susceptibility testing, and sequencing of part of the CNS tuf gene and, when needed, part of the 16S rRNA gene we characterized 82 clinical isolates and 24 reference strains of 18 different species of staphylococci. The genotypic methods identified nine different species of CNS among the 82 milk isolates. A comparison with results obtained by tuf gene sequencing showed that Staph-Zym (TM) correctly identified CNS reference strains to species level more often than bovine milk CNS isolates (83% and 61%, respectively). In addition, tests supplementary to the Staph-Zym (TM) were frequently needed in both groups of isolates (50% of reference strains and 33% of milk isolates) to obtain an identification of the strain. It is notable that Staph-Zym (TM) judged two isolates as CNS, although they belonged to other species, could not give a species name in 11% of the bovine CNS isolates, and gave 28% of the isolates an incorrect species name. The present study indicates that the studied phenotypic methods are unreliable for identification of CNS from bovine intra-mammary infections. (C) 2008 Elsevier B.V. All rights reserved.
41.	Persson Waller, Karin, et al. (author) Incidence of mastitis and bacterial findings at clinical mastitis in Swedish primiparous cows-Influence of breed and stage of lactation 2009 In: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 134, s. 89-94 Journal article (peer-reviewed)abstract Mastitis is a common disease also among primiparous dairy cows. Identification of the extent and type of problem is important to initiate correct control measures. In Sweden, unique national production and disease databases are available. The main aim of the study was to investigate the occurrence of mastitis, measured by the annual incidence of veterinary-treated clinical mastitis (VTCM) and geometric mean of monthly milk somatic cell count (SCC) recordings in Swedish primiparous cows in relation to older cows during 2002-2006 with emphasis on breed differences. Other aims were to study differences between primiparous and older cows in the distribution of bacterial findings at clinical mastitis, and the occurrence of VTCM and bacterial findings in relation to stage of lactation using data from a Swedish field study performed 2002-2003. Descriptive statistics and univariable analyses were used in the investigations. During 2002-2006 approximately 10% of Swedish primiparous cows experienced VTCM each year, while the geometric mean SCC of Swedish primiparous cows was approximately 65,000 ml(-1). Both parameters were lower than in older cows. Primiparous cows of the Swedish Red (SR) breed had better udder health than cows of the Swedish Holstein (SH) breed. The overall distribution of udder pathogens was similar in primiparous and older cows. In primiparous cows, most VTCM occurred during the first week after calving, and Staphylococcus aureus and Streptococcus dysgalactiae were the most common udder pathogens during this period. Better control measures directed at these infections are warranted around calving to reduce the risk of mastitis in primiparous cows. (C) 2008 Elsevier B.V. All rights reserved.
42.	Persson Waller, Karin (author) Intramammary infections with different non-aureus staphylococci in dairy cows 2018 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 101, s. 1403-1418 Journal article (peer-reviewed)abstract Subclinical mastitis causes an increase in milk somatic cell count (SCC) and can lead to reduced milk production and early culling. In many countries, non-aureus staphylococci (NAS) is the most common bacterial finding in subclinical mastitis of dairy cows. New methodology makes it possible to identify NAS species, but knowledge about the epidemiology is limited. The objective of this project was to improve advisory services for mastitis control by investigating associations between NAS and SCC, milk production, and persistence of intramammary infections (IMI). Farmers who had sent milk samples to the Swedish National Veterinary Institute (Uppsala, Sweden) were asked to participate if NAS was identified in the samples. Participating farmers were asked to resample all udder quarters of the cow once within 1 mo. Regression models were used to investigate associations between NAS and cow factors, udder quarter California mastitis test and SCC, and persistence of IMI. Associations with cow composite milk yield and SCC were also investigated. In total, 671 cows from 201 herds were enrolled in the study, and 19 NAS species were identified, of which the 4 most common were Staphylococcus epidermidis, Staphylococcus simulans, Staphylococcus chromogenes, and Staphylococcus haemolyticus. Persistent IMI was more common in udder quarters with Staphylococcus hyicus and S. simulans and less common in those with Staphylococcus saprophyticus IMI. beta-Lactamase production by the different NAS species varied from 0 to 100%. There was a significant association between NAS species and California mastitis test and SCC of udder quarters, and this varied depending on parity. The cow composite milk SCC at the test milking before the initial sample was taken differed significantly with NAS species, but not at the subsequent test milking. Milk yield-at the test milking before or after the initial sample-did not differ significantly for NAS species. There were no significant associations between milk yield or SCC and persistent NAS IMI. In conclusion, the NAS species affects SCC and persistent IMI differently but not milk yield.
43.	Persson Waller, Karin (author) Microbial aetiology of acute clinical mastitis and agent-specific risk factors 2009 In: Veterinary Microbiology. - : Elsevier BV. - 0378-1135 .- 1873-2542. ; 137, s. 90-97 Journal article (peer-reviewed)abstract A nation wide study on the microbial aetiology of cases of acute clinical mastitis in Swedish dairy cows was conducted with the aim to investigate changes in the microbial panorama compared to a previous study performed 1994-1995. Another aim was to investigate some agent-specific environmental and individual risk factors. Milk samples were collected from 987 udder quarter cases from 829 cows during six 2-month periods from May 2002 to April 2003, and data on risk factors and demography were collected at sampling by means of a questionnaire. In total, 1056 bacteriological diagnoses were made. The most frequently isolated bacterial species was Staphylococcus aureus constituting 21.3% of the diagnoses, followed by Escherichia coli (15.9%), Streptococcus dysgalactiae (15.6%), Streptococcus uberis (11.1%), coagulase-negative staphylococci (6.2%), Arcano-bacterium pyogenes (6.1%) and Klebsiella spp. (4.2%). Samples with no growth or contamination constituted 10.6% and 4.5% of the diagnoses, respectively. A major shift in the panorama of udder pathogens was not observed compared to the survey in 1994-1995. Isolation of Klebsiella spp. was strongly associated with the use of sawdust as bedding material. On the other hand, using sawdust as bedding reduced the risk of isolating S. uberis relative to using straw or peat. The risk of isolating E. coli increased with increasing milk yield and was higher in loose housing systems than in tie stalls. Isolation of S. aureus was associated with tie stalls, and A. pyogenes with low yielding cows and teat lesions. S. dysgalactiae infections were also associated with teat lesions. (C) 2008 Elsevier B.V. All rights reserved.
44.	Persson Waller, Karin, et al. (author) Prevalence and risk factors for udder cleft dermatitis in dairy cattle 2014 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 97, s. 310-318 Journal article (peer-reviewed)
45.	Persson Waller, Karin (author) Selective approach to dry cow therapy 2019 In: Veterinary Record. - : Wiley. - 0042-4900 .- 2042-7670. ; 184, s. 29-30 Journal article (peer-reviewed)
46.	Persson Waller, Karin, et al. (author) Sensitivity and specificity of PCR analysis and bacteriological culture of milk samples for identification of intramammary infections in dairy cows using latent class analysis 2016 In: Preventive Veterinary Medicine. - : Elsevier BV. - 0167-5877 .- 1873-1716. ; 135, s. 123–131- Journal article (peer-reviewed)abstract Real-time PCR analysis of milk samples is a fast method to identify intramammary infections (IMI) in dairy cows, and has the potential to be used for routine analysis of test milking composite milk samples. However, the results of the PCR analysis can be difficult to interpret. The objective of this study was to compare the sensitivity (Se) and specificity (Sp) of PCR analysis of composite milk samples, and conventional bacteriological culturing (BC) of quarter milk samples, when used to identify cows with IMI. The comparisons were performed for IMI with four common udder pathogens; Staphylococcus aureus (S aureus), Streptococcus dysgalactiae (Str dysgalactiae), Str uberis and coagulase negative staphylococci (CoNS). The Se and Sp of real-time PCR (Sep(CR); Sp(PCR)) and BC (Se-BC; Se-BC) was simultaneously estimated using latent class analysis (LCA), studying one pathogen at the time. Milk samples from 970 dairy cows from 25 herds were included. Aseptically collected quarter milk samples taken at the day before test milking (TM), at the day of TM, and at the day after TM, were analyzed using BC. Non-aseptically collected composite milk samples taken at the day of TM were analyzed using PCR. Moreover, the composite milk somatic cell count (SCC) was recorded and summarized by diagnostic test and bacterial finding. LCA was first performed using only test results from samples taken at the day of TM, but in a second analysis BC results from the three consecutive samplings, interpreted in parallel, were included. The Se-PCR was significantly higher than the Se-BC for S aureus, Str dysgalactiae and CoNS in the first analysis, but only for CoNS in the second analysis. The Sp(PCR) was significantly lower than the Sp(BC) for Str dysgalactiae and CoNS. In conclusion, using PCR analysis of composite milk samples, as a diagnostic tool for identifying cows with IMI increased the Se for all the pathogens investigated (although not always significantly), while Sp in general remained on a similar level, compared to BC of quarter milk samples. The use of repeated quarter milk sampling improved the Se-BC, making the results of PCR analysis and BC more similar. However, the SCC of cows with IMI according to BC was higher than for cows with IMI according to PCR, suggesting that some of the cows with IMI according to PCR did not have an active inflammation. Hence, extra caution is needed when decisions about treatment of IMI are based on PCR. (C) 2016 Elsevier B.V. All rights reserved.
47.	Persson Waller, Karin, et al. (author) Short communication: Relationships between alpha-lactalbumin and quality traits in bulk milk 2010 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 93, s. 4577-4581 Journal article (peer-reviewed)abstract The main objective of this study was to investigate whether the alpha-lactalbumin (alpha-LA) content; of bulk milk is related with sortie known inflammatory markers and milk quality traits. An additional objective was to study whether combining alpha-LA, haptoglobin (Hp), and serum amyloid A (SAA) in an acute phase index (API) could be useful as an alternative marker for bulk milk quality. For the dairy industry, it is of great importance to receive high quality bulk milk for manufacture of liquid milk and dairy products. The somatic cell count (SCC) is currently used as an indirect marker for bulk milk quality, but because it is somewhat; insensitive and unspecific, interest exists in alternative markers. Bulk milk samples were analyzed for alpha-LA, SCC, polymorphonuclear leukocyte count, Hp. SAA, fat, lactose, total protein and casein contents, casein number, protein composition, proteolysis, and coagulating properties. No significant differences were found in SCC, polymorphonuclear leukocyte count, Hp, or SAA between milk samples containing low, medium, or high concentrations of alpha-LA. Differences between alpha-LA groups were, however, found in some milk quality traits because high alpha-LA concentration was related to low concentrations of alpha(s1)-, alpha(s2)-, and beta-caseins and high concentrations of lactose and beta-lactoglobulin. A high API was related to low lactose content and casein number. Samples with high SCC contained less casein and had a lower casein number than milk with a low SCC, and proteolysis was significantly higher in high SCC milk than in low SCC milk. Neither alpha-LA nor API proved to be a better marker than SCC for the quality traits investigated, and alpha-LA was not; considered to be a useful inflammatory marker in bulk milk.
48.	Persson Waller, Karin, et al. (author) Udder health of early-lactation primiparous dairy cows based on somatic cell count categories 2020 In: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 103, s. 9430-9445 Journal article (peer-reviewed)abstract The aims were to investigate the prevalence of intramammary infection in early-lactation primiparous dairy cows (PC) in Sweden using milk recording cow composite somatic cell count (CSCC) categories based on classification of CSCC at the first 2 milk recordings after calving as low or high using cut-offs indicating intramarnmary infection. We also wanted to evaluate if herd-specific patterns in CSCC categories among PC can be identified to indicate success and problem herds as well as cow-level associations between CSCC categories and breed and sire, and herd-level associations between CSCC categories and herd size, milk production, production system, milking system, and year. A total of 1,597 dairy herds were included. Inclusion criteria were enrolment in the Swedish official milk recording scheme and having production data from at least 10 PC per year during 2014, 2015, and 2016. Herd (size, SCC, milk production, production system, milking system) and cow (breed, lactation number, calving date, CSCC, milk production) data were collected from the Swedish official milk recording scheme. Each PC was assigned a CSCC category (low-low, low-high, high-high, high-low, or inconclusive) based on the CSCC at the first 2 milk recordings using the following cutoffs. At each milk recording a CSCC <= 75,000 cells/mL was considered low and a CSCC >100,000 cells/mL was considered high, whereas a CSCC in between those values was considered inconclusive. Associations between CSCC categories arid breed or sire of the PC were analyzed using multivariable multinomial logistic regression models. Associations at herd level between number of PC in a CSCC category and herd variables were analyzed using multivariable Poisson or negative binomial regression models. The annual proportions of CSCC categories for all PC were 51.3%, 5.5%, 15.5%, 13.7%, and 14.0% for the low-low, low-high, high-low, high-high, and inconclusive categories, respectively. The distribution of CSCC categories varied markedly between herds. Overall, the median herd prevalence was 50.2 to 54.2% and 11.7 to 13.2% per year for the low-low and high-high categories, respectively. At cow level, both breed and sire were significantly associated with CSCC categories, showing for example that a higher proportion of Jersey PC were categorized as high-high compared with Swedish Holstein (SH) and Swedish Red (SR) PC, and that PC of certain SIT and SR sires more often were categorized as low-low or high-high cows than PC of other sires within each breed. All herd factors, except conventional and organic production, were significantly associated with the proportion of PC in a CSCC category at herd level. For example, the proportion of PC in the low-low category was significantly lower in larger herds (>80 cows) compared with smaller herds (<80 cows) and significantly lower in automatic milking system herds than in herds with other milking systems, but significantly higher in herds with higher milk production. Overall, the results indicate a substantial need for prevention of sub-clinical mastitis in early-lactation PC as only 50% of these cows had low CSCC at both milk recordings after calving. Moreover, we conclude that CSCC categories may be a useful tool for identifying success and problem herds.
49.	Persson Waller, Karin (author) Vaccination against Staphylococcus aureus mastitis in two Swedish dairy herds 2015 In: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 57 Journal article (peer-reviewed)abstract Background: Staphylococcus aureus is a common udder pathogen in dairy cows, and may cause severe mastitis problems in some herds. In herds where normal control measures are not successful, vaccination might be an additional tool to use if sufficiently efficient. The aim of the present study was to evaluate the efficacy of a commercially available vaccine (Startvac (R), Hipra, Spain) in two commercial Swedish dairy herds where the control programs for S. aureus mastitis had been unsuccessful. Within each herd cows were randomly assigned to vaccine or control groups, and effects on udder health and milk production during 120 days after calving, and survival during the following lactation were evaluated.Results: A field study was performed in two high producing Swedish herds having approximately 600 (herd A) and 200 (herd B) cows. During 12 months, cows with odd numbers were vaccinated three times around calving according to label protocol, while cows with even numbers constituted the not vaccinated control group. Quarter milk samples for bacteriological culturing were collected from all cases of clinical and subclinical mastitis. The outcome was evaluated during 120 days after calving using data on SCC and daily milk yield at monthly milk recordings, and incidence of mastitis due to S. aureus, coagulase-negative staphylococci, streptococci and coliforms. Cow survival throughout lactation was also studied. In herd A, 239 and 240 cows were included in the vaccinated and control groups, respectively. Corresponding numbers for herd B was 126 and 151 cows. Significant differences between vaccinated and control groups were not found in any of the parameters investigated.Conclusions: Vaccination with a commercial polyvalent vaccine did not have any beneficial effects on udder health, milk production or survival in two commercial dairy herds with mastitis problems due to S. aureus.
50.	Persson Waller, Karin, et al. (author) Variations of serum levels of α-tocopherol and β-carotene in Sweden dairy herds with low and high calf mortality 2010 Conference paper (other academic/artistic)

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