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Mediation analysis to estimate direct and indirect milk losses associated with bacterial load in bovine subclinical mammary infections

  • J. Detilleux (a1), L. Theron (a2), J.-N. Duprez (a3), E. Reding (a4), N. Moula (a1), M. Detilleux (a1), C. Bertozzi (a4), C. Hanzen (a2) and J. Mainil (a3)...

Abstract

Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e. direct losses) or to effects of the immune response triggered by the presence of mammary pathogens (i.e. indirect losses). Test-day milk somatic cell counts (SCC) and number of bacterial colony forming units (CFU) found in milk samples are putative measures of the level of immune response and of the bacterial load, respectively. Mediation models, in which one independent variable affects a second variable which, in turn, affects a third one, are conceivable models to estimate direct and indirect losses. Here, we evaluated the feasibility of a mediation model in which test-day SCC and milk were regressed toward bacterial CFU measured at three selected sampling dates, 1 week apart. We applied this method on cows free of clinical signs and with records on up to 3 test-days before and after the date of the first bacteriological samples. Most bacteriological cultures were negative (52.38%), others contained either staphylococci (23.08%), streptococci (9.16%), mixed bacteria (8.79%) or were contaminated (6.59%). Only losses mediated by an increase in SCC were significantly different from null. In cows with three consecutive bacteriological positive results, we estimated a decreased milk yield of 0.28 kg per day for each unit increase in log2-transformed CFU that elicited one unit increase in log2-transformed SCC. In cows with one or two bacteriological positive results, indirect milk loss was not significantly different from null although test-day milk decreased by 0.74 kg per day for each unit increase of log2-transformed SCC. These results highlight the importance of milk losses that are mediated by an increase in SCC during mammary infection and the feasibility of decomposing total milk loss into its direct and indirect components.

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Corresponding author

E-mail: jdetilleux@ulg.ac.be

References

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Albert, JM and Nelson, S 2011. Generalized causal mediation analysis. Biometrics 67, 10281038.
Burton, JL and Erskine, RJ 2003. Immunity and mastitis. Some new ideas for an old disease. The Veterinary Clinics Food Animal Practice 19, 145.
Burvenich, C, Paape, MJ, Hill, AW, Guidry, AJ, Miller, RH, Heyneman, R, Kremer, WD and Brand, A 1994. Role of the neutrophil leucocyte in the local and systemic reactions during experimentally induced E. coli mastitis in cows immediately after calving. Veterinary Quartely 16, 4550.
Capuco, AV, Paape, MJ and Nickerson, SC 1986. In vitro study of polymorphonuclear leukocyte damage to mammary tissue of lactating cows. American Journal of Veterinary Research 47, 663669.
Daniel, RM, De Stavola, BL, Cousens, SN and Vansteelandt, S 2015. Causal mediation analysis with multiple mediators. Biometrics 71, 114.
de Haas, Y, Barkema, HW and Veerkamp, RF 2002. The effect of pathogen specific clinical mastitis on the lactation curve for somatic cell count. Journal of Dairy Science 85, 13141323.
Detilleux, J, Kastelic, JP and Barkema, HW 2015. Mediation analysis to estimate direct and indirect milk losses due to clinical mastitis in dairy cattle. Preventive Veterinary Medicine 118, 449456.
Detilleux, JC, Kehrli, ME Jr., Stabel, JR, Freeman, AE and Kelley, DH 1995. Study of immunological dysfunction in periparturient Holstein cattle selected for high and average milk production. Veterinary Immunology and Immunopathology 44, 251267.
Detilleux, J, Theron, L, Duprez, J-N, Reding, E, Humblet, M-F, Planchon, V, Delfosse, C, Bertozzi, C, Mainil, J and Hanzen, C 2013. Structural equation models to estimate risk of infection and tolerance to bovine mastitis. Genetics Selection Evolution, doi: 10.1186/1297-9686-45-6, Published online by BioMed Central 6 March 2013.
Dohoo, I 2001. Setting SCC cut points for cow and herd interpretation. Paper present at the 40th Annual Meeting of the National Mastitis Council, 11 to 14 February 2001, Reno, Nevada.
Fritz, MS and MacKinnon, DP 2007. Required sample size to detect the mediated effect. Psychological Science 18, 233239.
Gröhn, YT, Wilson, DJ, Gonzalez, RN, Hertl, JA, Schulte, H, Bennett, G and Schukken, YH 2003. Effect of pathogen-specific clinical mastitis on milk yield in dairy cows. Journal of Dairy Science 87, 33583374.
Hagnestam-Nielsen, C, Emanuelson, U, Berglund, B and Strandberg, E 2009. Relationship between somatic cell count and milk yield in different stages of lactation. Journal of Dairy Science 92, 31243133.
Halasa, T, Nielen, M, De Roos, APW, Van Hoorne, R, de Jong, G and Lam, TJGM 2009. Production loss due to new subclinical mastitis in Dutch dairy cows estimated with a test-day model. Journal of Dairy Science 92, 599606.
Hertl, JA, Schukken, YH, Welcome, FL, Tauer, LW and Gröhn, YT 2014. Pathogen-specific effects on milk yield in repeated clinical mastitis episodes in Holstein dairy cows. Journal of Dairy Science 97, 14651480.
Judd, CM and Kenny, DA 1981. Process analysis: estimating mediation in treatment evaluations. Evaluation Review 5, 602619.
Kause, A, van Dalen, S and Bovenhuis, H 2012. Genetics of ascites resistance and tolerance in chicken: a random regression approach. G3 Genes Genomes Genetics 2, 527535.
Kenny, DA and Judd, CM 2014. Power anomalies in testing mediation. Psychological Science 25, 334339.
Lauzon, K, Zhao, X, Bouetard, A, Delbecchi, L, Paquette, B and Lacasse, P 2005. Antioxidants to prevent bovine neutrophil-induces mammary epithelial cell damage. Journal of Dairy Science 88, 42954303.
Leitner, G, Yadlin, B, Glickman, A, Chaffer, M and Saran, A 2000. Systemic and local immune response of cows to intramammary infection with Staphylococcus aureus . Research in Veterinary Science 2000 (69), 181184.
Lin, LK 1989. A concordance correlation coefficient to evaluate reproducibility. Biometrics 45, 255268.
McDougall, S, Bryan, MA and Tiddly, RM 2009. Effect of treatment with the nonsteroidal anti-inflammatory meloxicam on milk production, somatic cell count, probability of re-treatment, and culling of dairy cows with mild clinical mastitis. Journal of Dairy Science 92, 44214431.
Mehrzad, J, Duchateau, L and Burvenich, C 2005. High milk neutrophil chemiluminescence limits the severity of bovine coliform mastitis. Veterinary Research 36, 101116.
Preacher, KJ and Kelley, K 2011. Effect size measures for mediation models: quantitative strategies for communicating indirect effects. Psychological Methods 16, 93115.
Reding, E, Theron, L, Detilleux, J, Bertozzi, C and Hanzen, C 2011. LAECEA: un outil fédérateur à la décision pour le suivi de la santé mammaire dans les élevages bovins laitiers wallons. Paper presented at the 18th Annual Meeting of the 3R Rencontres Recherches Ruminants, Paris, 3 to 4 December 2011, Paris, France.
Reksen, O, Solverod, L and Osteras, O 2007. Relationships between milk culture results and milk yield in Norwegian dairy cattle. Journal of Dairy Science 90, 46704678.
Schneider, DS and Aires, JS 2008. Two ways to survive infection: what resistance and tolerance can teach us about treating infectious diseases. Nature Reviews Immunology 8, 889995.
Seegers, H, Fourichon, C and Beaudeau, F 2003. Production effects related to mastitis and mastitis economics in dairy herds. Veterinary Research 34, 475491.
Sharma, N, Singh, NK and Bhadwal, MS 2011. A relationship of somatic cell counts and mastitis: an overview. Asian-Australian Journal of Animal Science 24, 429438.
Ten Have, TR and Joffe, MM 2012. A review of causal estimation of effects in mediation analyses. Statistical Methods in Medical Research 21, 77107.
Thompson-Crispi, KA, Sewalem, A, Miglior, F and Mallard, BA 2012. Genetic parameters of adaptive immune response traits in Canadian Holsteins. Journal of Dairy Science 95, 401409.
Tofighi, D and MacKinnon, DP 2011. RMediation: an R package for mediation analysis confidence intervals. Behavior Research Methods 42, 692700.
VanderWeele, TJ 2012. Invited commentary: structural equation models and epidemiologic analysis. American Journal of Epidemiology 176, 608612.
VanderWeele, TJ and Vansteelandt, S 2014. Mediation analysis with multiple mediators. Epidemiological Methods 2, 95115.
Vansteelandt, S and VanderWeele, TJ 2012. Natural direct and indirect effects on the exposed: effect decomposition under weaker assumptions. Biometrics 6, 10191027.
Zhao, X and Lacasse, P 2008. Mammary tissue damage during bovine mastitis: causes and control. Journal of Animal Science 86, 5765.

Keywords

Mediation analysis to estimate direct and indirect milk losses associated with bacterial load in bovine subclinical mammary infections

  • J. Detilleux (a1), L. Theron (a2), J.-N. Duprez (a3), E. Reding (a4), N. Moula (a1), M. Detilleux (a1), C. Bertozzi (a4), C. Hanzen (a2) and J. Mainil (a3)...

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