Evaluation of intervention strategies for subclinical and clinical mastitis CPH Cattle seminar, 31. October 2018 Maya Gussmann, Wilma Steeneveld, Carsten Kirkeby, Henk Hogeveen, Michael Farre, Tariq Halasa
Objective Identify cost-effective intervention strategies for subclinical and clinical mastitis 2
The model: Simulating a dairy herd Lactating cows Dry cows Heifers Calves Calving area 3
The model: Simulating IMI S. agalactiae Opportunistic pathogens Contagious pathogens S. aureus S. uberis Environmental pathogens E. coli S. uberis 4
The model: Simulating IMI 5
The model: Simulating consequences of IMI Somatic Cell Count Milk yield Treatment of clinical Dry cow treatment Culling probability 6
Simulating clinical IMI interventions 3 day intramammary treatment Reactive culling: Testing before treatment, estimate recovery probability, cull cows with low probability (<50%) Testing before treatment, estimate recovery probability, cull cows with low probability (<75%), don t cull high producing cows 7
Simulating subclincial and clinical IMI interventions 3 intervention strategies for clinical IMI Combined with intervention measures for subclinical IMI: Testing of cows after 2 high SCC, after 1 month cull still infected cows Cull bottom 25%, treat rest Treat top 25% for 5 days, treat rest for 3 days 8
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure But don t cull high producers Herd 1 (S. aureus) Basic3 187,666 42 136 123 16 CullBottom 200,491 27 122 149 45 TreatTopLonger 201,029 27 122 158 43 Before50 196,995 30 111 47 24 CullBottom 206,342 14 83 86 34 TreatTopLonger 205,975 14 84 92 35 notculltop 196,704 32 113 32 29 CullBottom 205,383 16 87 76 40 TreatTopLonger 204,240 15 85 79 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 9
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure But don t cull high producers Herd 1 (S. aureus) Basic3 187,666 42 136 123 16 CullBottom 200,491 27 122 149 45 TreatTopLonger 201,029 27 122 158 43 Before50 196,995 30 111 47 24 CullBottom 206,342 14 83 86 34 TreatTopLonger 205,975 14 84 92 35 notculltop 196,704 32 113 32 29 CullBottom 205,383 16 87 76 40 TreatTopLonger 204,240 15 85 79 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 10
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure But don t cull high producers Herd 1 (S. aureus) Basic3 187,666 42 136 123 16 CullBottom 200,491 27 122 149 45 TreatTopLonger 201,029 27 122 158 43 Before50 196,995 30 111 47 24 CullBottom 206,342 14 83 86 34 TreatTopLonger 205,975 14 84 92 35 notculltop 196,704 32 113 32 29 CullBottom 205,383 16 87 76 40 TreatTopLonger 204,240 15 85 79 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 11
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure Herd 2 (S. agalactiae) Basic3 155,170 21 130 62 22 CullBottom 200,333 13 97 107 39 TreatTopLonger 200,494 13 96 115 38 Before50 157,690 21 126 50 24 CullBottom 200,286 13 96 104 39 TreatTopLonger 200,367 13 96 112 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 12
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure Herd 2 (S. agalactiae) Basic3 155,170 21 130 62 22 CullBottom 200,333 13 97 107 39 TreatTopLonger 200,494 13 96 115 38 Before50 157,690 21 126 50 24 CullBottom 200,286 13 96 104 39 TreatTopLonger 200,367 13 96 112 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 13
Simulating subclinical and clinical IMI interventions Treatment: Strategy Gross income Clinical IMI Subclinical IMI Treatment days Culled cows 3 days Cull cows with low probability for cure Herd 2 (S. agalactiae) Basic3 155,170 21 130 62 22 CullBottom 200,333 13 97 107 39 TreatTopLonger 200,494 13 96 115 38 Before50 157,690 21 126 50 24 CullBottom 200,286 13 96 104 39 TreatTopLonger 200,367 13 96 112 39 CullBottom Cull bottom 25%, treat others TreatTopLonger Treat top 25% for 5 days instead of 3 14
Conclusion Intervention strategies for clinical and subclinical IMI can cost-effectively reduce IMI incidence. Strategy should be chosen herd-specific. This comes at the price of increased antibiotic usage or culling. High culling costs may lead to less cost-effective strategies. 15
Questions? Thank you for your attention. 16