Pathogen effects on milk yield and composition in chronic subclinical mastitis in dairy cows

Author(s)

Goncalves, J. L. ^[1] ; Kamphuis, C. ^[2] ; Vernooij, H. ^[3] ; Araujo, Jr., J. P. ^[4] ; Grenfell, R. C. ^[5] ; Juliano, L. ^[5] ; Anderson, K. L. ^[6] ; Hogeveen, H. ^[2] ; dos Santos, V, M.

Affiliation

^[1] V, Univ Sao Paulo, Sch Vet Med & Anim Sci, Dept Anim Sci, Pirassununga, SP - Brazil

^[2] Wageningen Univ, Business Econ Grp, Hollandseweg 1, NL-6706 KN Wageningen - Netherlands

^[3] Univ Utrecht, Dept Farm Anim Hlth, Yalelaan 7, NL-3584 CN Utrecht - Netherlands

^[4] Julio de Mesquita Filho State Univ Sao Paulo UNES, Inst Biosci, Botucatu, SP - Brazil

^[5] Fed Univ Sao Paulo UNIFESP, Dept Biophys, Sao Paulo, SP - Brazil

^[6] North Carolina State Univ, Coll Vet Med, Dept Populat Hlth & Pathobiol, Raleigh, NC - USA

• Document type: Journal article
• Source: VETERINARY JOURNAL; v. 262, AUG 2020.
• Web of Science Citations: 0

Abstract

This study aimed to evaluate the effects of chronic subclinical mastitis (CSM) on milk production and component yields in dairy cows. A total of six herds located in the Midwest area of Sao Paulo State, Brazil were selected. Herds were visited once every 2 weeks to measure milk yield and to collect milk samples from lactating Holstein cows. Milk samples were collected at two stages (1 and 2), and each stage comprised three milk samplings. In stage 1, a total of 117 of 647 cows were diagnosed with CSM based on at least two of three repeated somatic cell counts (SCC) > 2000,000 cells/mL and positive bacterial milk culture results (BC). Cows with CSM were selected for the second stage. In stage 2, selected cows had quarter sampling aseptically collected for BC analyses prior to milking, and quarter milk yield was measured. Milk components (total protein, fat, lactose, and total solids) were measured using mid-infrared spectroscopy. Mammary quarters were considered healthy if all three repeated SCC results were <= 200,000 cells/mL and no bacterial growth was detected on BC. All quarters with positive bacterial growth were classified as having (non-chronic) subclinical mastitis when only one of three SCC results were > 200,000 cells/mL, and CSM when at least two of three SCC results were > 200,000 cells/mL. The effects of CSM by type of pathogen on milk and components yield were assessed using a linear mixed model. Mammary quarters with CSM caused by major pathogens had milk loss of 1.1 kg/quarter milking in comparison to healthy quarters. Milk losses were 0.8 and 1.3 kg/quarter milking when CSM was caused by Staphylococcus aureus or environmental streptococci, respectively. In addition, healthy quarters produced more milk components than quarters with CSM caused by major pathogens. Minor pathogens causing CSM (non-aureus staphylococci and Corynebacterium spp.) had no effect on milk yield. Quarters with CSM had lower milk and component yields when compared with healthy quarters. Milk losses varied according to the type of pathogen and were higher when associated with major pathogens such as S. aureus and environmental streptococci compared with healthy quarters. (c) 2020 Published by Elsevier Ltd. (AU)

• FAPESP's process: 15/04570-1 - Impact of subclinical mastitis on cost of production and milk quality in dairy herds
• Grantee: Juliano Leonel Gonçalves
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 13/23613-8 - Impact of subclinical mastitis on cost of production and milk quality in dairy herds
• Grantee: Juliano Leonel Gonçalves
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/07914-8 - FoRC - Food Research Center
• Grantee: Bernadette Dora Gombossy de Melo Franco
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/17411-6 - Economic impact and profile of etiologic agents of bovine mastitis
• Grantee: Marcos Veiga dos Santos
• Support Opportunities: Regular Research Grants