Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Failure costs associated with mastitis in smallholder dairy farms keeping Holstein Friesian × Zebu crossbreed cows
Mekonnen, S.A. ; Koop, G. ; Getaneh, A.M. ; Lam, T.J.G.M. ; Hogeveen, H. - \ 2019
Animal 13 (2019)11. - ISSN 1751-7311 - p. 2650 - 2659.
clinical mastitis - dairy - failure cost - smallholder farms - subclinical mastitis

Mastitis is a costly disease and in many areas of the world, these costs have been quantified to support farmers in their decision making with regard to prevention of mastitis. Although for subsaharan circumstances estimates have been made for the costs of subclinical mastitis (SCM), farm-specific cost estimations comprising both clinical mastitis (CM) and SCM are lacking. In this paper, we quantified failure costs of both CM and SCM on 150 Ethiopian market-oriented dairy farms keeping Holstein Friesian × Zebu breed cows. Data about CM were collected by face-to-face interviews and the prevalence of SCM was estimated for each farm using the California mastitis test. All other relevant information needed to calculate the failure costs, such as the consequences of mastitis and price levels, was collected during the farm visits, except for the parameter for milk production losses due to SCM, which was based on literature estimates and subjected to sensitivity analyses. The average total failure costs of mastitis was estimated to be 4 765 Ethiopian Birr (ETB) (1 ETB = 0.0449 USD) per farm per year of which SCM contributed 54% of the costs. The average total failure costs per lactating cow per farm per year were 1 961 ETB, with a large variation between farms (range 0 to 35 084 ETB). This large variation in failure costs between farms was mainly driven by variation in incidence of CM and prevalence of SCM. Milk production losses made the largest contribution (80%), whereas culling contributed 13% to 17% to the total failure costs. In our estimates, costs of veterinary services, drugs, discarded milk and labour made a minor contribution to the total failure costs of mastitis. Relative to the income of dairy farmers in North Western Ethiopia; the total failure costs of mastitis are high. In general, Ethiopian farmers are aware of the negative consequences of CM, but creating awareness of the high costs of SCM and showing large variation between farmers may be instrumental in motivating farmers to also take preventive measures for SCM.

Intramammary antimicrobial treatment of subclinical mastitis and cow performance later in lactation
Borne, Bart H.P. van den; Schaik, Gerdien van; Lam, Theo J.G.M. ; Nielen, Mirjam ; Frankena, Klaas - \ 2019
Journal of Dairy Science 102 (2019)5. - ISSN 0022-0302 - p. 4441 - 4451.
antimicrobial - clinical mastitis - dairy cow - milk yield - somatic cell count

The aim of this study was to evaluate long-term therapeutic effects of antimicrobial treatment of recently acquired subclinical mastitis (RASCM) during lactation. Quarter-level clinical mastitis (CM) follow-up, composite somatic cell counts (SCC), and cow-level milk yield later in lactation were evaluated using follow-up data from 2 previously published linked randomized field trials. The first trial randomly assigned antimicrobial treatment with any intramammary product or negative control to culture-positive quarters of cows having a first elevated composite SCC after 2 consecutive low composite SCC measurements. Untreated cows that had a second elevated composite SCC at the next measurement and were staphylococci-positive (i.e., Staphylococcus aureus or non-aureus staphylococci) were randomly assigned to treatment or control. Quarter-level CM cases were reported by the participating herd personnel, and milk yield and composite SCC data were obtained from the regular test-day recording. Frailty survival models were used to evaluate the long-term therapeutic effects of antimicrobial treatment of RASCM on quarter-level CM follow-up. Mixed linear regression models were applied to quantify the effect on milk yield and composite SCC. Data of 638 quarters from 486 cows in 38 herds were available for statistical analyses, of which 229 quarters of 175 cows received antimicrobial treatment for RASCM. Antimicrobial treatment culminated in reduced composite SCC levels later in lactation but did not result in different milk yield levels or CM follow-up compared with control cows. Antimicrobial treatment of cows with RASCM should therefore only be considered in exceptional situations given the current focus on antimicrobial usage reduction in animal husbandry.

Integration of epidemiology into the genetic analysis of mastitis in Swedisch Holstein
Windig, J.J. ; Urioste, J.I. ; Strandberg, E. - \ 2013
Journal of Dairy Science 96 (2013)4. - ISSN 0022-0302 - p. 2617 - 2626.
somatic-cell count - 1st 3 lactations - random regression-model - clinical mastitis - dairy-cattle - environment interaction - canadian holsteins - traits - score - parameters
Heritability of mastitis (and diseases in general) tends to be low. One possible cause is that no clear distinction can be made between resistant and nonresistant animals, because healthy animals include animals that have not been exposed to pathogens and resistant animals. To account for this, we quantified the prevalence of clinical mastitis (CM) and subclinical mastitis (SCM) in 2,069 Swedish Holstein herds as a measure of exposure. Herd prevalence averaged 26.5% for SCM and 6.4% for CM; 61% of the first lactations of 177,309 cows were classified as having at least one case of SCM and 10% as having CM. In a reaction norm approach, heritability of (S)CM was quantified as a function of herd prevalence of (S)CM. The best-fitting model was a second-order polynomial of first-lactation cow SCM as a function of herd prevalence SCM, and a first-order (linear) polynomial of first-lactation cow CM as a function of CM herd prevalence. Heritability for SCM ranged from 0.069 to 0.105 and for CM from 0.016 to 0.032. For both, we found no clear effect of herd prevalence on their heritability. Genetic correlations within traits across herd prevalences were all greater than 0.92. Whether relationships among prevalence, exposure, disease, and genetics were as expected is a matter of discussion, but reaction norm analyses may be a valuable tool for epidemiological genetics.
Applying additive logistic regression to data derived from sensors monitoring behavioral and physiological characteristics of dairy cows to detect lameness
Kamphuis, C. ; Frank, E. ; Burke, J. ; Verkerk, G.A. ; Jago, J. - \ 2013
Journal of Dairy Science 96 (2013)11. - ISSN 0022-0302 - p. 7043 - 7053.
clinical mastitis - cattle - locomotion - systems - herds - time - milk
The hypothesis was that sensors currently available on farm that monitor behavioral and physiological characteristics have potential for the detection of lameness in dairy cows. This was tested by applying additive logistic regression to variables derived from sensor data. Data were collected between November 2010 and June 2012 on 5 commercial pasture-based dairy farms. Sensor data from weigh scales (liveweight), pedometers (activity), and milk meters (milking order, unadjusted and adjusted milk yield in the first 2min of milking, total milk yield, and milking duration) were collected at every milking from 4,904 cows. Lameness events were recorded by farmers who were trained in detecting lameness before the study commenced. A total of 318 lameness events affecting 292 cows were available for statistical analyses. For each lameness event, the lame cow's sensor data for a time period of 14d before observation date were randomly matched by farm and date to 10 healthy cows (i.e., cows that were not lame and had no other health event recorded for the matched time period). Sensor data relating to the 14-d time periods were used for developing univariable (using one source of sensor data) and multivariable (using multiple sources of sensor data) models. Model development involved the use of additive logistic regression by applying the LogitBoost algorithm with a regression tree as base learner. The model's output was a probability estimate for lameness, given the sensor data collected during the 14-d time period. Models were validated using leave-one-farm-out cross-validation and, as a result of this validation, each cow in the data set (318 lame and 3,180 nonlame cows) received a probability estimate for lameness. Based on the area under the curve (AUC), results indicated that univariable models had low predictive potential, with the highest AUC values found for liveweight (AUC=0.66), activity (AUC=0.60), and milking order (AUC=0.65). Combining these 3 sensors improved AUC to 0.74. Detection performance of this combined model varied between farms but it consistently and significantly outperformed univariable models across farms at a fixed specificity of 80%. Still, detection performance was not high enough to be implemented in practice on large, pasture-based dairy farms. Future research may improve performance by developing variables based on sensor data of liveweight, activity, and milking order, but that better describe changes in sensor data patterns when cows go lame.
Early host response in the mammary gland after experimental Streptococcus uberis challenge in heifers
Greeff, A. de; Zadoks, R.N. ; Ruuls, L. ; Toussaint, M. ; Nguyen, T.K. ; Downing, A. ; Rebel, J.M.J. ; Stockhofe-Zurwieden, N. ; Smith, H.E. - \ 2013
Journal of Dairy Science 96 (2013)6. - ISSN 0022-0302 - p. 3723 - 3736.
innate immune-response - lipopolysaccharide-binding protein - clinical mastitis - intramammary infections - staphylococcus-aureus - lipoteichoic acid - bovine mastitis - dairy-cattle - 2 strains - epidemiology
Streptococcus uberis is a highly prevalent causative agent of bovine mastitis, which leads to large economic losses in the dairy industry. The aim of this study was to examine the host response during acute inflammation after experimental challenge with capsulated Strep. uberis. Gene expression in response to Strep. uberis was compared between infected and control quarters in 3 animals. All quarters (n=16) were sampled at 16 different locations. Microarray data showed that 239 genes were differentially expressed between infected and control quarters. No differences in gene expression were observed between the different locations. Microarray data were confirmed for several genes using quantitative PCR analysis. Genes differentially expressed due to early Strep. uberis mastitis represented several stages of the process of infection: (1) pathogen recognition; (2) chemoattraction of neutrophils; (3) tissue repair mechanisms; and (4) bactericidal activity. Three different pathogen recognition genes were induced: ficolins, lipopolysaccharide binding protein, and toll-like receptor 2. Calgranulins were found to be the most strongly upregulated genes during early inflammation. By histology and immunohistochemistry, we demonstrated that changes in gene expression in response to Strep. uberis were induced both in infiltrating somatic milk cells and in mammary epithelial cells, demonstrating that the latter cell type plays a role in milk production as well as immune responsiveness. Given the rapid development of inflammation or mastitis after infection, early diagnosis of (Strep. uberis) mastitis is required for prevention of disease and spread of the pathogen. Insight into host responses could help to design immunomodulatory therapies to dampen inflammation after (early) diagnosis of Strep. uberis mastitis. Future research should focus on development of these early diagnostics and immunomodulatory components for mastitis treatment.
Suitability of cross-bred cows for organic farms based on cross-breeding effects on production and functional traits
Haas, Y. de; Smolders, E.A.A. ; Hoorneman, J.N. ; Nauta, W.J. ; Veerkamp, R.F. - \ 2013
Animal 7 (2013)4. - ISSN 1751-7311 - p. 655 - 665.
conventional dairy herds - somatic-cell counts - milk-production - reproductive-performance - genetic-parameters - clinical mastitis - udder health - short-communication - energy-balance - cattle
Data from 113 Dutch organic farms were analysed to determine the effect of cross-breeding on production and functional traits. In total, data on 33 788 lactations between January 2003 and February 2009 from 15 015 cows were available. Holstein–Friesian pure-bred cows produced most kg of milk in 305 days, but with the lowest percentages of fat and protein of all pure-bred cows in the data set. Cross-breeding Holstein dairy cows with other breeds (Brown Swiss, Dutch Friesian, Groningen White Headed, Jersey, Meuse Rhine Yssel, Montbéliarde or Fleckvieh) decreased milk production, but improved fertility and udder health in most cross-bred animals. In most breeds, heterosis had a significant effect (P <0.05) on milk (kg in 305 days), fat and protein-corrected milk production (kg in 305 days) and calving interval (CI) in the favourable direction (i.e. more milk, shorter CI), but unfavourably for somatic cell count (higher cell count). Recombination was unfavourable for the milk production traits, but favourable for the functional traits (fertility and udder health). Farm characteristics, like soil type or housing system, affected the regression coefficients on breed components significantly. The effect of the Holstein breed on milk yield was twice as large in cubicle housing as in other housing systems. Jerseys had a negative effect on fertility only on farms on sandy soils. Hence, breed effects differ across farming systems in the organic farming and farmers can use such information to dovetail their farming system with the type of cow they use.
Mastitis alert preferences of farmers milking with automatic milking systems
Mollenhorst, H. ; Rijkaart, L.J. ; Hogeveen, H. - \ 2012
Journal of Dairy Science 95 (2012)5. - ISSN 0022-0302 - p. 2523 - 2530.
clinical mastitis - conductivity
The aim of this study was to assess farmers’ preferences for the performance characteristics of mastitis detection systems. Additionally, we looked at whether certain groups of farmers could be distinguished with specific preferences. Farmers’ opinions concerning mastitis detection systems, as well as general information about the farm and the farmer, were investigated with a standard questionnaire. The second part of the questionnaire was specifically aimed at elucidating preferences. Definitions of time windows and performance parameters, such as sensitivity and specificity, were incorporated into characteristics of a detection system (attributes) that reflect farmers’ daily experience. Based on data from 139 farmers, we concluded that, on average, they prefer a clinical mastitis detection system that produces a low number of false alerts, while alerting in good time and with emphasis on the more severe cases. These 3 attributes were evaluated as more important than the 3 other attributes, representing the costs of the detection system, the number of missed cases, and how long before clinical signs alerts need to be given. Variation in importance per attribute, however, was high, denoting that farmers’ preferences differ considerably. Although some significant relationships were found between farm characteristics and attributes, no clear groups of farmers with specific preferences could be distinguished. Based on these results, we advise making detection systems adaptable for the farmers to satisfy their preferences and to match the circumstances on the farm. Furthermore, these results support that for evaluation of detection algorithms comparisons have to be made at high levels of specificity (e.g., 99%) and time windows have to be kept small (preferably no more than 24 h). Key words: adaptive conjoint analysis, automatic milking system, farmer preference, mastitis detection
The role of communication in improving udder health
Jansen, J. ; Lam, T.G.J.M. - \ 2012
Veterinary Clinics of North America-Food Animal Practice 28 (2012)2. - ISSN 0749-0720 - p. 363 - 379.
somatic-cell count - dutch dairy farmers - management-practices - planned behavior - clinical mastitis - united-states - belief model - herds - knowledge - attitudes
This article gives insight into farmers' behavior and mindset toward mastitis management and into the way these can be affected by communication strategies. Elements of farmer mindset are important determining factors in executing mastitis control, including perceived severity and perceived efficacy of mastitis management measures. Veterinary practitioners can be important intermediaries in communication about udder health, provided that they are aware of their role as proactive advisor and apply the accompanying communication skills. Prevention of complex diseases such as mastitis requires customized communication strategies as well as an integrated approach between various stakeholders and different scientific disciplines.
Genetic relationships among mastitis and alternative somatic cell count traits in the first 3 lactations of Swedish Holsteins
Urioste, J.I. ; Franzén, J. ; Windig, J.J. ; Strandberg, E. - \ 2012
Journal of Dairy Science 95 (2012)6. - ISSN 0022-0302 - p. 3428 - 3434.
norwegian red cows - clinical mastitis - subclinical mastitis - dairy-cattle - parameters - selection - models - score
The objectives of this study were to estimate heritabilities of, and genetic correlations among, clinical mastitis (CM), subclinical mastitis (SCM), and alternative somatic cell count (SCC) traits in the first 3 lactations of Swedish Holstein cows, and to estimate genetic correlations for the alternative traits across lactations. Data from cows having their first calving between 2002 and 2009 were used. The alternative SCC traits were based on information on CM and monthly test-day (TD) records of SCC traits of 178,613, 116,079, and 64,474 lactations in first, second, or third parity, respectively. Sires had an average of 230, 165, or 124 daughters in the data (parities 1, 2, or 3, respectively). Subclinical mastitis was defined as the number of periods with an SCC >150,000 cell/mL and without a treatment for CM. Average TD SCC between 5 and 150 d was used as a reference trait. The alternative SCC traits analyzed were 1) presence of at least 1 TD SCC between 41,000 and 80,000 cell/mL (TD41-80), 2) at least 1 TD SCC >500,000 cells/mL, 3) standard deviation of log SCC over the lactation, 4) number of infection peaks, and 5) average days diseased per peak. The same variables in different parities were treated as distinct traits. The statistical model considered the effects of herd-year, year, month, age at calving, animal, and residual. Heritability estimates were 0.07 to 0.08 for CM, 0.12 to 0.17 for SCM, and 0.14 for SCC150. For the alternative traits, heritability estimates were 0.12 to 0.17 for standard deviation of log SCC, TD SCC >500,000 cells/mL, and average days diseased per peak, and 0.06 to 0.10 for TD41-80 and number of infection peaks. Genetic correlations between CM with SCM were 0.62 to 0.74, and correlations for these traits with the alternative SCC traits were positive and very high (0.67 to 0.82 for CM, and 0.94 to 0.99 for SCM). Trait TD41-80 was the only alternative trait that showed negative, favorable, genetic correlations with CM (-0.22 to -0.50) and SCM (-0.48 to -0.85) because it is associated with healthy cows. Genetic correlations among the alternative traits in all 3 parities were high (0.93 to 0.99, 0.92 to 0.98, and 0.78 to 0.99, respectively). The only exception was TD41-80, which showed moderate to strong negative correlations with the rest of the traits. Genetic correlations of the same trait across parities were in general positive and very high (0.83 to 0.99). In conclusion, these alternative SCC traits could be used in practical breeding programs aiming to improve udder health in dairy cattle.
Natural antibodies related to metabolic and mammary health in dairy cows
Knegsel, A.T.M. van; Hostens, M. ; Vries Reilingh, G. de; Lammers, A. ; Kemp, B. ; Opsomer, G. ; Parmentier, H.K. - \ 2012
Preventive Veterinary Medicine 103 (2012)4. - ISSN 0167-5877 - p. 287 - 297.
conjugated linoleic-acid - early lactation - clinical mastitis - transition period - energy-balance - fc-receptor - periparturient period - immune-response - ketone-bodies - fatty liver
Natural antibodies (NAb) are defined as antibodies that circulate in normal healthy individuals under the absence of deliberate antigenic stimulation. Two types of NAb are distinguished: NAb towards exogenous antigens and NAb towards autoantigens (N(A)Ab). The objectives of the current study were threefold. First, we studied the relation between metabolic health and concentrations of NAb binding keyhole limpet hemocyanin (KLH) or lipopolysaccharide (LPS) in milk and plasma of dairy cows in early lactation. Second, we determined the presence of N(A)Ab binding transferrin, myosin and thyroglobulin in bovine milk. Third, we studied the relation between N(A)Ab in bovine milk and mammary health. For the first objective, dairy cows were either fed a control (C) (n = 8) or a diet where 2 kg of concentrates were replaced by an iso-energetic concentrate containing marine algae (ALG) from week -3 till 8 postpartum (experiment 1). Plasma and milk samples were analyzed weekly for NAb binding either KLH or LPS. Plasma was analyzed for glucose, non-esterified fatty acids (NEFA) and ß-hydroxybutyrate (BHBA). For the second and third objective, milk samples were collected weekly from 96 dairy cows from week 2 till 9 postpartum and analyzed for milk composition and N(A)Ab binding myosin, transferrin and thyroglobulin (experiment 2). For both datasets, N(A)Ab titers are expressed as 2log values of the highest dilution giving a positive reaction. Data are expressed as means ± SEM. Repeated observations were analyzed in a mixed model. In experiment 1, no diet effect (P > 0.05) was observed on NAb binding LPS in plasma or milk, NAb binding KLH in milk was greater (P = 0.05) for cows fed the control diet. Concentration of NAb binding KLH and LPS in plasma was negatively related to plasma NEFA concentration (P <0.05). In experiment 2, NAb binding myosin (5.66 ± 0.06), thyroglobulin (4.85 ± 0.06), and transferrin (5.76 ± 0.07) were identified in milk. Clinical mastitis incidence (9%) tended to be positively related to concentration of NAb binding myosin (P = 0.06) and negatively related to Nab binding transferrin (P = 0.08). In conclusion, NAb binding KLH and LPS in plasma and milk are related to metabolic health, as indicated by plasma NEFA concentration. Furthermore, this study demonstrates the presence of N(A)Ab in bovine milk and shows trends for a relation between N(A)Ab binding auto-antigens and mastitis. Future studies should confirm these trends and shed light on the predictive value of N(A)Ab in bovine milk for mammary health
Economic aspects of mastitis: New developments
Hogeveen, H. ; Huijps, K. ; Lam, T.J.G.M. - \ 2011
New Zealand Veterinary Journal 59 (2011)1. - ISSN 0048-0169 - p. 16 - 23.
somatic-cell count - pasteurized fluid milk - subclinical mastitis - partial budget - dairy-cattle - clinical mastitis - simulation-model - bovine mastitis - shelf-life - costs
Good udder health is not only important for the dairy farmer but, because of increasing interest of consumers in the way dairy products are produced, also for the dairy production chain as a whole. An important role of veterinarians is in advising on production diseases such as mastitis. A large part of this advice is given around the planning of management to maintain or improve the udder health status of a farm. Mastitis is a costly disease, due to losses (a reduction of output due to mastitis) and expenditure (additional inputs to reduce the level of mastitis). Worldwide, published estimates of the economic losses of clinical mastitis range from €61 to €97 per cow on a farm, with large differences between farms, e.g. in The Netherlands, losses due to clinical and subclinical mastitis varied between €17 and €198 per cow per year. Moreover, farmers tended to underestimate these costs. This indicates that for a large proportion of farms there are many avoidable losses. In order to provide good support to farmers' decision-making, it is important to describe the mastitis setting not only in terms of disease, e.g. incidence of clinical mastitis, but also in monetary terms; and to make good decisions, it is necessary to provide the dairy farmer with information on the additional expenditure and reduced losses associated with alternative decisions. Six out of 18 preventive measures were shown to have a positive nett benefit, viz blanket use of dry-cow therapy, keeping cows standing after milking, back-flushing of the milk cluster after milking a cow with clinical mastitis, application of a treatment protocol, washing dirty udders, and the use of milkers' gloves. For those measures that included a large amount of routine labour or investment, the reduced losses did not outweigh the additional expenditure. The advisor cannot expect that measures that are cost-effective are always implemented. Reasons for this are the objectives of the dairy farmer can be other than maximisation of profit, resources to improve the mastitis situation compete with other fields of management, risk involved with the decision, economic behaviour of the dairy farmer, and valuation of the cost factors by the dairy farmer. For all decision-makers this means that, although financial incentives do have an effect on the management of mastitis, it is not always sufficient to show the economic benefits of improved management to induce an improvement of management of mastitis.
Marker-assisted breeding value estimation for mastitis resistance in Finnish Ayrshire cattle
Mulder, H.A. ; Lidauer, M. ; Vilkki, J.H. ; Strandén, I. ; Veerkamp, R.F. - \ 2011
Journal of Dairy Science 94 (2011)8. - ISSN 0022-0302 - p. 4164 - 4173.
quantitative trait loci - somatic-cell score - dairy-cattle - genetic evaluations - clinical mastitis - count traits - prediction - selection - haplotypes - conformation
Marker-assisted breeding value estimation is expected to increase the accuracy of estimated breeding values, especially for traits with low heritability. Several quantitative trait loci (QTL) have been found for somatic cell score and clinical mastitis. The objective of this study was to demonstrate marker-assisted breeding value estimation, combining data of genotyped and ungenotyped animals in a large pedigree population using either identical-by-descent (IBD) or identical-by-state (IBS) haplotypes for some previously identified QTL regions for somatic cell score and clinical mastitis in Finnish Ayrshire cattle. For both methods, QTL variances were estimated based on daughter yield deviations of genotyped bulls. The QTL explained only a small proportion of genetic variance, especially with IBS haplotypes. Using IBD haplotypes gave more reranking of bulls and cows than using IBS haplotypes. Cross-validation showed no increase in predictive ability when using IBS haplotypes compared with conventional breeding value estimation, whereas a decrease in predictive ability was observed with IBD haplotypes. Furthermore, computing time was lower and convergence was better with IBS haplotypes than with IBD haplotypes. In this study on mastitis resistance in Finnish Ayrshire, conventional breeding value estimation would be advocated because of the lack in improvement of accuracy and predictive ability when using marker-assisted breeding value estimation. However, in situations where IBS haplotypes would explain 10 to 20% or more of the genetic variance, marker-assisted breeding value estimation with IBS haplotypes may yield greater accuracy and predictive ability than conventional breeding value estimation.
Effect of production system, alternative treatments and calf rearing system on udder health in organic dairy cows
Wagenaar, J.P. ; Klocke, P. ; Butler, G. ; Smolders, E.A.A. ; Nielsen, J.H. ; Canever, A. ; Leifert, C. - \ 2011
NJAS Wageningen Journal of Life Sciences 58 (2011)3-4. - ISSN 1573-5214 - p. 157 - 162.
intramammary infections - clinical mastitis - teat seal - milk - management - input - herds - pathogens - efficacy - farms
In the last decade the main goals of organic dairying have been to attain acceptable levels of milk production, increase opportunities for animals to perform species own behaviour, resulting in improved animal welfare and animal health, and minimize the use of therapeutic interventions, including the reduction of the (preventive) use of antibiotics. Maintaining animal health without the use of therapeutic interventions is a major challenge for organic dairy farmers. In particular, udder health remains a major problem in both conventional and organic farming. In the QualityLowInputFood (QLIF) project udder health status and management were assessed in different production systems and European regions. These studies suggest that good udder health can be maintained in organic or low-input farming management systems. Novel strategies to control mastitis were evaluated and the potential of using internal teat sealers for the control of environment-associated pathogens was shown. Also oral application of a herd profile based single homeopathic remedy combined with homeopathic silica had a significant effect on cows with a relative low somatic cell count before drying-off. Suckling systems in calf rearing, as an integrated management approach, did not result in better udder health. None of the studies presented identified new variables affecting udder health. QLIF studies also demonstrated the importance of comparing udder health parameters in contrasting organic, low input and conventional production systems, since clear differences in antibiotic use against mastitis could be identified not only between organic and conventional systems, but also among dairy systems used in different EU-countries. Although alternative treatments used in organic systems could not be shown to be fully effective, results suggest that the use of individual or combined alternative strategies to improve udder health on organic or low-input farms warrants further investigation. Based on the results obtained it is recommended that future research should focus on identifying the reasons for variability in udder health between organic farms that use different management protocols to identify ‘best current practice’ when carrying out this research.
Pathogen group specific risk factors at herd, heifer and quarter levels for intramammary infections in early lactating dairy heifers
Piepers, S. ; Peeters, K. ; Opsomer, G. ; Barkema, H.W. ; Frankena, K. ; Vliegher, S. de - \ 2011
Preventive Veterinary Medicine 99 (2011)2-4. - ISSN 0167-5877 - p. 91 - 101.
coagulase-negative staphylococci - somatic-cell counts - clinical mastitis - environmental mastitis - subclinical mastitis - growth-inhibition - milk-production - udder health - teat apices - horn flies
Risk factors for intramammary infections caused by coagulase-negative staphylococci, contagious major pathogens and environmental major pathogens in early lactating heifers were evaluated at the herd, heifer and quarter levels. In total, 764 quarters of 191 dairy heifers in 20 randomly selected farms in Flanders (Belgium) were sampled. Quarter milk samples were collected between 1 and 4 days in milk and between 5 and 8 days in milk for bacteriological culture. Data were analyzed using multivariable, multilevel logistic regression analysis. Higher average herd milk somatic cell count (>200,000 cells/mL), not having an effective fly control strategy, contact with lactating cows prior to calving and moderate to severe udder edema prior to calving increased the odds of intramammary infections caused by contagious major pathogens. Poor heifer hygiene and lack of mineral/vitamin supplementation prior to calving were risk factors for intramammary infection caused by environmental major pathogens. Teat apex colonization with coagulase-negative staphylococci prior to calving seemed to protect quarters against intramammary infections caused by major pathogens. Poor heifer hygiene before calving, a non-clipped udder and not practicing of teat dipping prior to calving increased the odds of intramammary infection with coagulase-negative staphylococci. Although management is important in the prevention and control of intramammary infections in early lactating heifers, most variation in the prevalence of intramammary infections resided at the heifer and quarter levels, indicating that the susceptibility for intramammary infections around calving is mainly determined by heifer and quarter characteristics.
The effect of subclinical mastitis on milk yield in dairy goats
Koop, G. ; Werven, T. van; Schuiling, H.J. ; Nielen, M. van - \ 2010
Journal of Dairy Science 93 (2010)12. - ISSN 0022-0302 - p. 5809 - 5817.
somatic-cell counts - intramammary infection - risk-factors - staphylococcus-caprae - clinical mastitis - bovine mastitis - mammary-gland - lactation - parity - cows
The aims of this study were to estimate milk yield (MY) losses associated with subclinical intramammary infection (IMI) in dairy goats and to assess if somatic cell count (SCC) can be used to estimate such MY losses. We used 2 data sets to study these questions. The first data set consisted of 5 herds. Milk production and SCC were recorded during 1 lactation. From approximately 100 does in each herd, milk samples were collected on 3 occasions during lactation for bacteriological culture. Linear mixed regression was used to estimate the effect of IMI on MY. The second data set consisted of 6 large herds, in which some of the goats had an extended lactation (>= 2 yr). Milk yield and SCC data were recorded without bacteriological culture. The data showed that bacterial infection was related to an increase in SCC. Infections with major pathogens were rare and associated with a decreased MY; infection with coagulase-negative staphylococci did not affect MY, whereas infection with Corynebacterium bovis was associated with increased MY. A negative correlation was observed between SCC and MY, but the data suggested that this negative correlation was attenuated rather than caused by IMI. Furthermore, SCC seemed to be affected by MY via a dilution effect. Hypotheses about biological mechanisms behind these observations are discussed. This paper shows that MY losses caused by subclinical udder infections are limited in goats, and that SCC cannot be used to estimate the magnitude of these losses.
Genetic parameters for somatic cell score according to udder infection status in Valle del Belice dairy sheep and impact of imperfect diagnosis of infection.
Riggio, V. ; Portolano, B. ; Bovenhuis, H. ; Scatassa, S. ; Bishop, S.C. - \ 2010
Genetics, Selection, Evolution 42 (2010). - ISSN 0999-193X - 9 p.
milk-yield - subclinical mastitis - protein percentage - clinical mastitis - mixture model - count - ewes - cattle - lactation - pathogens
Background Somatic cell score (SCS) has been promoted as a selection criterion to improve mastitis resistance. However, SCS from healthy and infected animals may be considered as separate traits. Moreover, imperfect sensitivity and specificity could influence animals' classification and impact on estimated variance components. This study was aimed at: (1) estimating the heritability of bacteria negative SCS, bacteria positive SCS, and infection status, (2) estimating phenotypic and genetic correlations between bacteria negative and bacteria positive SCS, and the genetic correlation between bacteria negative SCS and infection status, and (3) evaluating the impact of imperfect diagnosis of infection on variance component estimates. Methods Data on SCS and udder infection status for 1,120 ewes were collected from four Valle del Belice flocks. The pedigree file included 1,603 animals. The SCS dataset was split according to whether animals were infected or not at the time of sampling. A repeatability test-day animal model was used to estimate genetic parameters for SCS traits and the heritability of infection status. The genetic correlation between bacteria negative SCS and infection status was estimated using an MCMC threshold model, implemented by Gibbs Sampling. Results The heritability was 0.10 for bacteria negative SCS, 0.03 for bacteria positive SCS, and 0.09 for infection status, on the liability scale. The genetic correlation between bacteria negative and bacteria positive SCS was 0.62, suggesting that they may be genetically different traits. The genetic correlation between bacteria negative SCS and infection status was 0.51. We demonstrate that imperfect diagnosis of infection leads to underestimation of differences between bacteria negative and bacteria positive SCS, and we derive formulae to predict impacts on estimated genetic parameters. Conclusions The results suggest that bacteria negative and bacteria positive SCS are genetically different traits. A positive genetic correlation between bacteria negative SCS and liability to infection was found, suggesting that the approach of selecting animals for decreased SCS should help to reduce mastitis prevalence. However, the results show that imperfect diagnosis of infection has an impact on estimated genetic parameters, which may reduce the efficiency of selection strategies aiming at distinguishing between bacteria negative and bacteria positive SCS
Bioeconomic modeling of lactational antimicrobial treatment of new bovine subclinical intramammary infections caused by contagious pathogens
Borne, B.H.P. van den; Halasa, T. ; Schaik, G. van; Hogeveen, H. ; Nielen, M. - \ 2010
Journal of Dairy Science 93 (2010). - ISSN 0022-0302 - p. 4034 - 4044.
staphylococcus-aureus mastitis - field gel-electrophoresis - norwegian dairy-cattle - somatic-cell counts - streptococcus-uberis - clinical mastitis - milk-yield - bacteriological cure - economic-benefits - herds
This study determined the direct and indirect epidemiologic and economic effects of lactational treatment of new bovine subclinical intramammary infections (IMI) caused by contagious pathogens using an existing bioeconomic model. The dynamic and stochastic model simulated the dynamics of Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli during lactation and the dry period in a 100-cow dairy herd during 1 quota year. Input parameters on cure were obtained from recent Dutch field data. The costs of clinical IMI, subclinical IMI, and intervention were calculated into the combined total annual net costs of IMI per herd. The cost effectiveness of 4 scenarios with lactational intervention was determined; scenarios included no intervention, treatment after 1 mo of infection, treatment after 2 mo of infection, and treatment after 1 mo of infection and culling of uncured cows after 2 mo of infection. Model behavior was observed for variation in parameter input values. Compared with no lactational intervention, lactational intervention of new subclinical IMI resulted in fewer clinical flare ups, less transmission within the herd, and much lower combined total annual net costs of IMI in dairy herds. Antimicrobial treatment of IMI after 1 mo of infection and culling of uncured cows after 2 mo of infection resulted in the lowest costs, whereas treatment after 2 mo of infection was associated with the highest costs between the scenarios with intervention. Changing the probability of cure resulted in a nonlinear change in the cumulative incidence of IMI cases and associated costs. Lactational treatment was able to prevent IMI epidemics in dairy herds at high transmission rates of Strep. uberis, Strep. dysgalactiae, and E. coli. Lactational treatment did not limit the spread of Staph. aureus at high transmission rates, although the associated costs were lower compared with no intervention. To improve udder health in a dairy herd, lactational treatment of contagious subclinical IMI must therefore be preceded by management measures that lower the transmission rate. Lactational treatment of environmental subclinical IMI seemed less cost effective. Detection of subclinical IMI needs improvement to be able to most effectively treat subclinical IMI caused by contagious pathogens during lactation. Key words: subclinical mastitis; antimicrobial treatment; stochastic economic model; transmission
Relationship between udder health and hygiene on farms with an automatic milking system
Dohmen, W. ; Neijenhuis, F. ; Hogeveen, H. - \ 2010
Journal of Dairy Science 93 (2010)9. - ISSN 0022-0302 - p. 4019 - 4033.
somatic-cell count - clinical mastitis - quality - management - association - scores - herds
Poor hygiene is an important risk factor for reduced udder health. Because the teat cleaning process is done automatically on farms with an automatic milking system (AMS), hygiene management might differ. The aim of this study was to determine the relationship between hygiene and udder health on farms with an AMS at the farm level as well as at the cow level. Information on hygiene and udder health was collected on 151 Dutch dairy farms with an AMS. Teams of 2 veterinary students collected data with the use of a partially open-ended questionnaire and scoring protocols for hygiene of the cows, cleanliness of the AMS, and functioning of the AMS. Milk production records from the Dutch dairy herd information association were also collected. Stepwise general linear models were used to analyze the relation between hygiene and udder health at farm level. Dependent variables were average herd somatic cell count (SCC), the average percentage of new cows with a high SCC, and the incidence rate of clinical mastitis, all in the year preceding the farm visit. The annual average herd SCC was positively related to the proportion of cows with dirty teats before milking and the proportion of cows with dirty thighs. The annual average percentage of new cows with a high SCC was positively related to the proportion of cows with dirty teats before milking and the proportion of milkings where teats were not covered with teat disinfecting spray by the AMS. The annual incidence rate of clinical mastitis was positively related to the frequency of replacing the milking filters. At the cow level, hygiene scores of the udder, thighs, and legs (range 1 to 4, where 1 is clean and 4 is very dirty) were related with cow SCC from the milk production test day closest to the farm visit using a general linear mixed model. The relationship between cow SCC and the hygiene score of the udder was positive. Key words: udder health; hygiene; automatic milking system
Combining somatic cell count traits optimal selection against mastitis
Windig, J.J. ; Ouweltjes, W. ; Napel, J. ten; Jong, de, G. ; Veerkamp, R.F. ; Haas, Y. de - \ 2010
Journal of Dairy Science 93 (2010)4. - ISSN 0022-0302 - p. 1690 - 1701.
1st 3 lactations - clinical mastitis - genetic-parameters - dairy-cattle - score - cows - infection - indexes - model
Test-day records of somatic cell counts (SCC) can be used to define alternative traits to decrease genetic susceptibility to clinical mastitis (CM) and subclinical mastitis (SCM). This paper examines which combination of alternative SCC traits can be used best to reduce both CM and SCM and whether direct information on CM is useful in this respect. Genetic correlations between 10 SCC traits and CM and SCM were estimated from 3 independent data sets. The SCC traits with the strongest correlations with CM differed from those with the strongest correlations with SCM. Selection index calculations were made for a breeding goal of 50% CM and 50% SCM resistance using these correlations. They indicated that a combination of 5 SCC traits (SCC early and late in lactation, suspicion of infection based on increased SCC, extent of increased SCC, and presence of a peak pattern in SCC) gave a high accuracy, almost without loss, compared with the full set of 10 SCC traits. The estimated accuracy of this index was 0.91, assuming that the correlations had been estimated without error. To take errors in estimation into account, correlations were resampled from a normal distribution with mean and standard errors as originally estimated. The accuracy of the index calculated with the original correlations was then recalculated using the resampled correlations. The average accuracy based on 50,000 resamplings decreased to 0.81. Use of direct information on CM improved the accuracy (uncorrected for errors in correlations) only slightly, to 0.92.
A simulation model to calculate costs and benefits of dry period
Halasa, T. ; Nielen, M. ; Werven, T. van; Hogeveen, H. - \ 2010
Livestock Science 129 (2010). - ISSN 1871-1413 - p. 80 - 87.
clinical mastitis - intramammary infections - cow therapy - teat sealant - management - efficacy - associations - metaanalysis - prevention - strategies
Abstract An existing dynamic and stochastic bio-economic model of intramammary infection (IMI) caused by Staphylococcus aureus, Streptococcus uberis, Streptococcus dysgalactiae, and Escherichia coli was extended to model the dynamics of IMI during the dry period. These dynamics were modeled on the basis of a Greenwood model. The extended model was used to calculate the cost-effectiveness of different dry period interventions in relation to the annual net costs of IMI in a herd of 100 dairy cows at the start. The interventions were blanket dry cow therapy (BDCT) as the default scenario, BDCT combined with teat sealant (TS), selective dry cow therapy (SDCT) or TS, and SDCT combined with TS. Input parameters of the dynamics of IMI during the dry period and the economic parameters were based on literature. The costs of clinical and subclinical IMI during lactation, clinical IMI during the dry period, and the cost of intervention were used to calculate the combined total annual net cost of IMI per herd. The combined total annual net cost of IMI using the other intervention scenarios was compared to the default scenario (BDCT) to estimate the cost-effectiveness of the other intervention scenarios. Sensitivity analysis was conducted on the parameters involved. The results showed that a considerable number of cows acquire new IMI during the dry period and start the new lactation with IMI. Furthermore, the average combined total annual net cost of IMI per herd using BDCT was € 8800, distributed as € 4561 due to clinical IMI, and € 3063 due to subclinical IMI during lactation, € 88 due to clinical IMI during the dry period, and € 1088 due to antibiotic therapy and labor costs at dry off. On average, application of BDCT combined with TS resulted in € 378 higher combined total annual net cost of IMI compared to the BDCT scenario. Similarly, the SDCT scenarios resulted in higher average combined total annual net costs of IMI compared to the BDCT scenario. The SDCT or TS was on average € 443 higher and the SDCT combined with TS was on average € 635 higher. Sensitivity analysis results showed that the rate of new IMI during the dry period was the most influential parameter on the average combined total annual net cost of IMI. Although the difference between the 4 simulated scenarios was minor, on average BDCT had the lowest combined total annual net cost of IMI.
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