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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Relationship between resumption of ovarian activity, days open, energy balance and metabolic status in dairy cows with different dry period lengths in early lactation
Ma, J. ; Hoeij, R.J. van; Lam, T.J.G.M. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2019
In: Proceedings of the 17th International Conference on Production Diseases in Farm Animals. - Bern, Switserland : University of Bern - ISBN 9783906813936 - p. 176 - 176.
Negative energy balance (NEB) in dairy cows results from a fast increase in milk production post calving while feed intake is limited in this period. NEB is accompanied with an altered metabolic status, which triggers metabolic disorders. Metabolic status in early lactation is related with reproductive performance, e.g. reduced concentrations of insulin and IGF-I, which contributes to reduced follicular responsiveness to gonadotrophic stimulation, and thus prevents the dominant follicle to ovulate, resulting in a delay in the resumption of cyclicity. Omitting or shortening the dry period (DP), adjusting dietary energy level or feeding different dietary energy sources is of interest because that could minimize the risk of NEB, postpartum metabolic diseases and suboptimal fertility like delayed resumption of postpartum ovarian cyclicity. The aim of this study is to investigate the effect of DP length, dietary energy level, dietary energy source and interactions among these factors on fertility (resumption of ovarian cyclicity and days open) of dairy cows postpartum. Additionally, the relation between energy balance and metabolic status of dairy cows during early lactation and resumption of ovarian cyclicity and days open will be evaluated.
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.

De Droogstand
Knegsel, A.T.M. van; Hoeij, R.J. van; Lam, T.J.G.M. - \ 2017
In: Handboek Uiergezondheid Rund / Lam, Theo, De Vliegher, Sarne, Nijmegen : Communication In Practice - ISBN 9789082232127 - p. 197 - 206.
Cow characteristics and their association with udder health after different dry period lengths
Hoeij, R.J. van; Lam, T.J.G.M. ; Koning, D.B. de; Steeneveld, W. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2016
Journal of Dairy Science 99 (2016)10. - ISSN 0022-0302 - p. 8330 - 8340.
Clinical mastitis - Continuous milking - Decision making - Somatic cell count

Shortening or omitting the dry period (DP) in dairy cows is of interest because of potential beneficial effects on energy balance and metabolic health. Reported effects of a short or omitted dry period on udder health are ambiguous. This study aimed to evaluate the effect of no DP (0 d), a short DP (30 d), or a conventional DP (60 d) on the occurrence of intramammary infections (IMI) during the precalving period and on somatic cell counts (SCC), elevations of SCC (SCC ≥ 200,000 cells/mL), and clinical mastitis in the subsequent lactation. The study also aimed to analyze which prepartum cow characteristics are associated with udder health after different DP lengths. Holstein-Friesian dairy cows (n = 167) were randomly assigned to a DP length (0, 30, or 60 d). Cows with a 0-d DP had a greater occurrence of chronic IMI and a lower occurrence of cured IMI during the precalving period than cows with a 30-d or 60-d DP. Postpartum average SCC for lactation was greater in cows with a 0-d DP than in cows with a 30-d or 60-d DP. The number of cows with at least 1 elevation of SCC, the number of elevations of SCC per affected cow, the number of cows treated for clinical mastitis, and the number of cases of mastitis per affected cow did not differ among DP lengths. Cow characteristics related to postpartum average SCC for lactation were DP length, parity, and the following interactions: DP length with prepartum elevation of SCC, DP length with fat- and protein-corrected milk (FPCM) reduction between 150 and 67 d prepartum, DP length with parity and with average SCC for lactation, and last FPCM before the conventional drying-off day with average SCC for lactation. Cows with prepartum parity 1 had a lower occurrence of at least 1 elevation of SCC in subsequent lactation compared with cows with parity >2. Last SCC before the conventional drying-off day was positively associated with occurrence of clinical mastitis in the subsequent lactation. In this study, DP length was not a risk factor for either elevation of SCC or occurrence of clinical mastitis in the subsequent lactation. The identified cow characteristics could be used in a decision support model to optimize DP length for individual cows.

Effect of different scenarios for selective dry-cow therapy on udder health, antimicrobial usage, and economics
Scherpenzeel, C.G.M. ; Uijl, I.E.M. den; Schaik, G. van; Riekerink, Olde R.G.M. ; Hogeveen, H. ; Lam, T.J.G.M. - \ 2016
Journal of Dairy Science 99 (2016)5. - ISSN 0022-0302 - p. 3753 - 3764.
Antimicrobial reduction - Dry-cow therapy - Economics - Mastitis

The goal of dry-cow therapy (DCT) is to reduce the prevalence of intramammary infections (IMI) by eliminating existing IMI at drying off and preventing new IMI from occurring during the dry period. Due to public health concerns, however, preventive use of antimicrobials has become questionable. In this study, we evaluated the effects of 8 scenarios for selecting animals for DCT, taking into account variation in parity and cow-level somatic cell count (SCC) at drying off. The aim of this study was to evaluate udder health, antimicrobial usage, and economics at the herd level when using different scenarios for selecting cows for DCT. To enable calculation and comparison of the effects of different scenarios to select cows for DCT in an "average" herd, we created an example herd, with a virtual herd size of 100 dairy cows to be calving during a year. Udder health, antimicrobial usage, and economics were evaluated during the dry period and the first 100 d in lactation, the period during which the greatest effect of DCT is expected. This leads to an estimated 13,551 cow-days at risk during a year in a 100-cow dairy herd. In addition to a blanket DCT (BDCT) scenario, we developed 7 scenarios to select cows for DCT based on SCC. The scenarios covered a range of possible approaches to select low-SCC cows for DCT, all based on cow-level SCC thresholds on the last milk recording before drying off. The incidence rate of clinical mastitis in the example herd varied from 11.6 to 14.5 cases of clinical mastitis per 10,000 cow-days at risk in the different scenarios, and the prevalence of subclinical mastitis varied from 38.8% in scenario 1 (BDCT) to 48.3% in scenario 8. Total antimicrobial usage for DCT and clinical mastitis treatment varied over the scenarios from 1.27 (scenario 8) to 3.15 animal daily dosages (BDCT), leading to a maximum reduction in antimicrobial usage of 60% for scenario 8 compared with BDCT. The total costs for each of the scenarios showed little variation, varying from €4,893 for scenario 5 to €5,383 for scenario 8. The effect of selective DCT compared with BDCT on udder health, antimicrobial usage, and economics is influenced by the SCC criteria used to select cows for DCT. Scenario 2 resulted in the lowest increases in clinical and subclinical mastitis compared with BDCT. The greatest reduction in antimicrobial usage was achieved under scenario 8. From an economic perspective, lowest costs were achieved with scenario 5. Drying off dairy cows with antimicrobials has an effect on udder health, antimicrobial usage, and economics.

The effect of dry period length and dietary energy source on somatic cell count and udder health
Hoeij, R.J. van; Lam, T.J.G.M. ; Steeneveld, W. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
In: The effect of dry period length and dietary energy source on somatic cell count and udder health. - Merelbeke :
Effect of dry period length and dietary energy source on somatic cell count and udder health
Hoeij, R.J. van; Lam, T.J.G.M. ; Steeneveld, W. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
In: Proceedings of the 3rd Dairycare COST ACTION Conference. -
Social influences on the duration of antibiotic treatment of clinical mastitis in dairy cows
Swinkels, J.M. ; Hilkens, A. ; Zoche-Golob, V. ; Krömker, V. ; Buddiger, M. ; Jansen, J. ; Lam, T.J.G.M. - \ 2015
Journal of Dairy Science 98 (2015)4. - ISSN 0022-0302 - p. 2369 - 2380.
Antibiotic treatment - Clinical mastitis - Dairy cow - Social influence

Clinical mastitis of dairy cows is a visible inflammation of the udder, which is usually caused by bacteria and treated with antibiotics. Although pressure is increasing to reduce antibiotic usage in livestock in the European Union, feedback from the field suggests that clinical mastitis treatment is frequently repeated after the initial per-label treatment, thereby extending treatment duration. The aim of this study was to explore the social factors influencing farmers' decision-making on the duration of antibiotic treatment of clinical mastitis. In total, 38 dairy farmers in the Netherlands (n. = 17) and Germany (n. = 21) were interviewed in a qualitative semi-structured way. Extended treatment was defined as any treatment longer than that given in label directions. Of the 38 farmers, 30 reported routine and 7 occasional extended antibiotic treatment. The interviewed farmers were sensitive toward social norms of other farmers and recognition for good stockmanship. Extended treatment is perceived as part of the social norm of "being a good farmer." The participants' perception was that mastitis is not treated "thoroughly" if clinical symptoms were still visible at the time of cessation of treatment, because it may persist or recur. As a result, treatment was frequently extended by repeating the initial label treatment. Farmers, specifically the more "cow-oriented" farmers, expressed insecurity on how to treat mastitis effectively. This insecurity made them more sensitive to comply with other farmers' injunctive ("what ought to be") and descriptive ("what is done") norms and the perceived veterinarians' informational norm that extended treatment is better, resulting in an approved social norm. Social approval reduces the insecurity of being perceived as a poor farmer; thus, extended treatment is emotionally rewarded. This social reward apparently outweighs the higher costs of more waste milk and more antibiotic usage. Perceived positive reference groups with whom the farmer identifies and regularly communicates face to face, such as other farmers, the herd veterinarian, and other farm advisors, confirm the farmer's judgment on extending treatment and influences him or her toward socially accepted behavior. Society was the most negative reference group, barely influencing farmers' decision-making on treatment. The emotional gap between farmers and society is large and probably difficult to overcome. Legislation may reduce antibiotic usage, if doable and controllable. Evidence-based information on treatment efficacy or practical on-farm decision support indicating when to end treatment may be able to change social norms of "thorough" treatment, especially when communicated by a positive reference group such as veterinarians. Because prudent antibiotic use is hindered by perceived subjective norms on optimal duration of antibiotic treatment, more research is needed, particularly on the optimal duration of antibiotic treatment of specific pathogens as related to cure and recurrence of clinical mastitis.

The effect of different dry period lengths on somatic cell count and udder health
Hoeij, R.J. van; Lam, T.J.G.M. ; Steeneveld, W. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
Prevalence of claw disorders in young HF-animals with and without grazing: 1. non infectious diseases
Brummelman, B. ; Holzhauer, M. ; Frankena, K. ; Lam, T.J.G.M. - \ 2014
Tijdschrift voor Diergeneeskunde 139 (2014)7. - ISSN 0040-7453 - p. 26 - 33.
rundveehouderij - weiden - klauwen - diergezondheid - begrazing - voetziekten - huisvesting van koeien - laesies - dierenwelzijn - dierlijke productie - melkvee - cattle husbandry - pastures - claws - animal health - grazing - foot diseases - cow housing - lesions - animal welfare - animal production - dairy cattle - dairy-cows - first lactation - foot lesions - risk-factors - lameness - cattle - conformation - herds - hemorrhages - pasture
Ter bestudering van prevalentie van en effect van weidegang op klauwaandoeningen bij jonge runderen werden 10 melkveebedrijven gevolgd (vijf met en vijf zonder weidegang) in een twee jaar lang durend longitudinaal onderzoek. De achterklauwen van veertig dieren, bij aanvang jonger dan twee jaar, werden tussen mei 2008 en februari 2010 iedere drie maanden beoordeeld. In dit artikel worden de niet infectieuze klauwaandoeningen besproken. De prevalentie van zoolzweren (0,1%) en witte lijn-laesies (2,6%) was zeer laag, terwijl de prevalentie van zoolbloedingen (ZB) vanaf een leeftijd van negen maanden al boven de 20 procent lag. Dieren met weidegang hadden aan het einde van het weideseizoen significant minder ZB dan de dieren zonder weidegang. In de stalperiode nam de prevalentie van ZB bij dieren met weidegang toe tot boven het niveau van dieren zonder weidegang. Na afkalven trad een duidelijke toename op van de prevalentie van ZB tot een maximum (59%) op een leeftijd van dertig maanden.
Prevalence of claw disorders in young HF animals: 2. Infectious diseases
Brummelman, B. ; Holzhauer, M. ; Frankena, K. ; Lam, T.J.G.M. - \ 2014
Tijdschrift voor Diergeneeskunde 139 (2014)8. - ISSN 0040-7453 - p. 22 - 29.
digital dermatitis lesions - female dairy calves - risk-factors - sole ulcers - cattle - cows - netherlands - lameness - dynamics - farms
Associations between the decrease in bovine clinical mastitis and changes in dairy farmers' attitude, knowledge, and behavior in the Netherlands
Borne, B.H.P. van den; Jansen, J. ; Lam, T.J.G.M. ; Schaik, G. van - \ 2014
Research in Veterinary Science 97 (2014)2. - ISSN 0034-5288 - p. 226 - 229.
management-practices - control program - performance - health
The aim of this study was to associate changes in dairy farmers' self-reported attitude, knowledge, and behavior with the decrease in incidence rate of clinical mastitis (IRCM). Farmer-diagnosed clinical mastitis cases were obtained from two surveys conducted before (July 2004–June 2005) and at the end (2009) of a mastitis control program in the Netherlands. Information on farmers' attitude, knowledge, and behavior was also obtained by sending the famers the same questionnaire during both surveys. Multivariable linear regression models identified that the herd level 2004 IRCM explained 28% of the variation in the decrease of IRCM. Changes in farmers' attitude and knowledge, and changes in farmers' behavior additionally explained 24% and 5%, respectively. These results suggest that the way management measures are executed may be at least as important as the fact that they are executed. No control group was available for this study because the intervention was applied at the national level. We therefore do not claim any causal relationships.
Improving bovine udder health: A national mastitis control program in the Netherlands
Lam, T.J.G.M. ; Borne, B.H.P. van den; Jansen, J. ; Huijps, K. ; Veersen, J.C.L. ; Schaick, G. van; Hogeveen, H. - \ 2013
Journal of Dairy Science 96 (2013)2. - ISSN 0022-0302 - p. 1301 - 1311.
management-practices - dairy herds - milk quality - attitudes - communication - performance - farmers - associations - knowledge - england
Because of increasing bulk milk somatic cell counts and continuous clinical mastitis problems in a substantial number of herds, a national mastitis control program was started in 2005 to improve udder health in the Netherlands. The program started with founding the Dutch Udder Health Centre (UGCN), which had the task to coordinate the program. The program consisted of 2 parts: a research part and a knowledge-transfer part, which were integrated as much as possible. The knowledge-transfer part comprised 2 communication strategies: a central and a peripheral approach. The central approach was based on educating farmers using comprehensive science-based and rational argumentation about mastitis prevention and included on-farm study group meetings. Comprehensive education materials were developed for farmers that were internally motivated to improve udder health. In the peripheral approach it was tried to motivate farmers to implement certain management measures using nontechnical arguments. Mass media campaigns were used that focused on one single aspect of mastitis prevention. These communication strategies, as well as an integrated approach between various stakeholders and different scientific disciplines were used to reach as many farmers as possible. It should be noted that, because this intervention took place at a national level, no control group was available, as it would be impossible to isolate farmers from all forms of communication for 5 years. Based on several studies executed during and after the program, however, the results suggest that udder health seemed to have improved on a national level during the course of the program from 2005 to 2010. Within a cohort of dairy herds monitored during the program, the prevalence of subclinical mastitis did not change significantly (23.0 in 2004 vs. 22.2 in 2009). The incidence rate of clinical mastitis, however, decreased significantly, from 33.5 to 28.1 quarter cases per 100 cow years at risk. The most important elements of the farmers' mindset toward mastitis control also changed favorably. The simulated costs of mastitis per farm were reduced compared with a situation in which the mastitis would not have changed, with € 400 per year. When this amount is extrapolated to all Dutch farms, the sector as a whole reduced the total costs of mastitis by € 8 million per year. It is difficult to assign the improved udder health completely to the efforts of the program due to the lack of a control group. Nevertheless, investing € 8 million by the Dutch dairy industry in a 5-yr national mastitis control program likely improved udder health and seemed to pay for itself financially.
Hoe laat ik mijn klanten kwispelen : Veterinair communicatie handboek
Wessels, R. ; Lam, T.J.G.M. ; Jansen, J. - \ 2013
Nijmegen : St. Anna Advies - ISBN 9789090274911 - 228 p.
A longitudinal study into the effect of grazing on claw disorders in female calves and young dairy cows
Holzhauer, M. ; Brummelman, B. ; Frankena, K. ; Lam, T.J.G.M. - \ 2012
The Veterinary Journal 193 (2012)3. - ISSN 1090-0233 - p. 633 - 638.
digital dermatitis - risk-factors - sole hemorrhages - milk-production - new-zealand - lameness - prevalence - cattle - lesions - netherlands
To estimate the prevalence of claw disorders in youngstock and first parity heifers and to evaluate the effect of grazing on claw disorders, 10 Dutch dairy herds participated in a 2-year longitudinal study. Five herds were zero-grazed, while in the other five herds cows and youngstock had access to pasture during the summer. Twenty female calves 15%. The prevalence of DD increased considerably around first calving on both the grazing and the zero-grazing farms. The prevalence of IDHE increased with age while SH prevalence showed a more fluctuating pattern. Digital dermatitis was less frequently observed in pastured animals than in permanently housed animals (OR = 0.12–0.64 depending on month of observation; P <0.05), with the strongest effect being seen during the period when the herds which grazed cattle actually had animals at pasture (May to August). Grazing was also associated with lower levels of IDHE and SH, again particularly during the grazing season.
The effect of an acidified, ionized copper sulphate solution on digital dermatitis in dairy cows
Holzhauer, M. ; Bartels, C.J. ; Bergsten, C. ; Riet, M.M.J. van; Frankena, K. ; Lam, T.J.G.M. - \ 2012
The Veterinary Journal 193 (2012)3. - ISSN 1090-0233 - p. 659 - 663.
level risk-factors - herd-level - cattle - formaldehyde - strategies - footbaths - lameness - netherlands - prevalence - formalin
Digital dermatitis (DD) is the most important infectious claw disorder in dairy cattle and herd-based foot bathing with antibacterials, such as 4% formalin, is often used to prevent it. However, there is a lack of long-term studies of the effectiveness of such regimes and in this study the preventive and curative effect of 4% formalin was compared with that of an acidified, ionized copper sulphate solution over a 4-month period on a commercial 120-cow dairy farm. The cows were walked through a split-leg footbath where left claws were treated with an acidified copper solution twice daily for 5 days/week, while right claws were treated with 4% formalin twice daily for 1 day/every second week. Hind claws were scored for the presence and severity of DD in a trimming chute at the start of the study and every 4 weeks throughout the study period. At the start of the study 21/110 cows had ulcerative DD lesions with 10 on the left hind foot, 8 on the right and 3 on both. These lesions, as well as any new lesions which arose during the study, were treatedwith chlortetracycline spray. During the study 440 observations were made and seven new DD lesionswere recorded on left feet (copper treated) and 20 on right feet (formalin treated). Based on survival analysis, the risk of developing a new ulcerative DD lesion on copper-treated (left hind) feet was almost three times less (RR = 0.37, 95% CI 0.16–0.91) than formalin-treated (right hind) feet. Cure rates of DD lesions were not different between copper and formalin.
Current status and future challenges in mastitis research
Hogeveen, H. ; Pyorala, S. ; Persson Waller, K. ; Hogan, J.S. ; Lam, T.J.G.M. ; Oliver, S.P. ; Schukken, Y.H. ; Barkema, H.W. ; Hillerton, J.E. - \ 2011
In: Proceedings of the 50th Annual Meeting of the National Mastitis Council, 23-26 January, 2011, Arlington, USA. - - p. 36 - 48.
Costs and benefits of mastitis management measures on individual dairy farms
Soest, F. van; Huipjs, K. ; Dohmen, W. ; Olde Riekerink, R. ; Santman-Berends, I. ; Sampimon, O.C. ; Lam, T.J.G.M. ; Hogeveen, H. - \ 2011
In: Proceedings of the International Conference on Udder Health and Communication, Utrecht, The Netherlands, 25-27 October 2011. - Wageningen : Wageningen Academic Publishers - p. 213 - 220.
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.
Natural antibodies in bovine milk and blood plasma: variability among cows, repeatability within cows and relation between milk and plasma titers
Ploegaert, T.C.W. ; Tijhaar, E. ; Lam, T.J.G.M. ; Taverne-Thiele, J.J. ; Poel, J.J. van der; Arendonk, J.A.M. van; Savelkoul, H.F.J. ; Parmentier, H.K. - \ 2011
Veterinary Immunology and Immunopathology 144 (2011)1-2. - ISSN 0165-2427 - p. 88 - 94.
mammary-gland - immune - autoantibodies - complement - responses - innate - period
Innate immunity plays an important role in preventing (barrier function) or combating infection (effector function). An important humoral component of innate immunity is formed by natural antibodies (NAb). The objectives of this study were to determine presence, variation among cows and repeatability within cows over time of total NAb titers directed to the pathogen-associated molecular patterns lipopolysaccharide, lipoteichoic acid (LTA) and peptidoglycan, and titers of NAb directed to the glycoprotein keyhole limpet hemocyanin in milk and plasma of individual cows. Furthermore in milk the antibody isotypes IgG1, IgG2, IgM and IgA binding LTA were analyzed. Ten milk and blood samples were obtained from each of 20 clinically healthy dairy cows from first to seventh parity during a period of 3 weeks. Total NAb binding lipopolysaccharide, LTA, peptidoglycan, and keyhole limpet hemocyanin were detected in milk and plasma, with titers considerably higher in plasma than in milk. Total NAb titers showed significant variation among cows, and repeatability within cows over time (ranging from 0.60 to 0.93). Titers of NAb in milk and plasma were positively correlated (correlation ranging from 0.69 to 0.91). Natural antibodies in milk binding LTA were of all 4 isotypes tested, although IgG2 was on average only present at low titers. All 4 isotypes in milk binding LTA also showed variation among cows, and repeatability within cows over time (ranging from 0.84 to 0.92). We conclude that NAb can be measured in a consistent and repeatable manner in bovine milk and blood plasma.
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