Abstract #T18
Section: Animal Health
Session: Animal Health II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall B
Session: Animal Health II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall B
# T18
Risk factors for subclinical mastitis in grazing dairy cows.
R. R. Daros*1, M. J. Hötzel2, S. J. LeBlanc3, J. A. Bran2, A. J. Thompson1, M. A. G. von Keyserlingk1, 1Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, BC, Canada, 2Laboratório de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil, 3Population Medicine, Ontario Veterinary College, University of Guelph, Canada, Guelph, ON, Canada.
Key Words: health, pasture, gait score
Risk factors for subclinical mastitis in grazing dairy cows.
R. R. Daros*1, M. J. Hötzel2, S. J. LeBlanc3, J. A. Bran2, A. J. Thompson1, M. A. G. von Keyserlingk1, 1Animal Welfare Program, Faculty of Land and Food systems, University of British Columbia, Vancouver, BC, Canada, 2Laboratório de Etologia Aplicada e Bem-Estar Animal, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil, 3Population Medicine, Ontario Veterinary College, University of Guelph, Canada, Guelph, ON, Canada.
Mastitis is one of the greatest health challenges facing the dairy industry. Knowledge of potential risk factors is key to designing preventive protocols to manage this disease. The aims of this study were to determine risk factors for subclinical mastitis (SCM) in grazing cows. A total of 42 dairy farms in southern Brazil were visited twice, 4 mo apart. All farms used a rotational grazing system with 2 to 3 fresh paddocks per day. Breeds were Holstein, Jerseys and their crosses. At each visit, milk samples from every quarter from every lactating cow were subjected to a California Mastitis Test (CMT). Cows having at least one quarter with a CMT score ≥1 were considered positive for SCM. Individual cows were also locomotion scored (LS; scale 1 to 5, LS ≥3 as lame) while exiting the parlor. Continuous data were categorized to improve model fit as follows – DIM: early (<100 DIM), mid (101 to 200 DIM) or late (>200 DIM) lactation; BCS: thin (BCS <2.75), adequate (2.75 ≤ BCS ≤3.5) or over-conditioned (BCS >3.5); and parity: primiparous and multiparous. A multivariable logistic regression model (cow nested within farm as random effects) was used to identify risk factors for SCM. A total of 2,606 cows were assessed for SCM, however only 1,987 cows with complete data were used in the model. Prevalence of SCM was 47%. Risk factors for SCM included DIM, parity and lameness status. Mid-lactation and late-lactation cows were 1.4 (95% CI: 1.1 – 1.9; P < 0.01) and 2.2 (95% CI: 1.7 – 2.8; P < 0.01) times more likely to have SCM than early-lactation cows. Primiparous cows were less likely (OR = 0.4; 95% CI: 0.3 – 0.5; P < 0.01) to have SCM than multiparous cows. Lameness also increased the likelihood of a cow having SCM by 1.7 times (95% CI: 1.3 – 2.0; P < 0.01). Over-conditioned cows tended to have increased likelihood (OR = 1.5; 95% CI: 0.9 – 2.1; P = 0.09) of having SCM. Breed did not influence SCM. Our results suggest an association between lameness and SCM. Studies on the causal relationship between these 2 diseases, accounting for production, hygiene, and teat health, in grazing dairy cows should be considered to aid in the design of better prevention protocols for SCM.
Key Words: health, pasture, gait score
