Association of California Mastitis Test Scores with Intramammary Infection Status in Lactating Dairy Cows Admitted to a Veterinary Teaching Hospital

Abstract

BackgroundSubclinical mastitis is of concern in veterinary hospitals because contagious mastitis pathogens might be unknowingly transmitted to susceptible cows and then back to their farm of origin.ObjectivesTo evaluate the California mastitis test (CMT) as an indicator of intramammary infection (IMI) in lactating dairy cows admitted to a veterinary hospital.AnimalsA total of 139 admissions of 128 lactating dairy cows admitted to the University of Illinois Veterinary Teaching Hospital over a 2‐year period.MethodsA retrospective study with a convenience sample was conducted. Medical records of cows with CMT results and milk culture results for the day of admission were reviewed. Breed, age, season, maximum CMT score for the 4 quarters, maximum CMT score difference, and clinical diagnosis were evaluated as predictors of IMI by the chi‐square test and stepwise logistic regression.ResultsAn IMI was identified in 51% of quarters. For cows admitted without evidence of clinical mastitis, the sensitivity of a CMT score ≥trace in predicting an IMI on a quarter or cow basis was 0.45 and 0.68, respectively. The distributions of maximal quarter CMT score and the maximum difference in quarter CMT score for cows without evidence of clinical mastitis did not differ (P = 0.28, P = 0.84, respectively) for cows with and without IMI. Stepwise logistic regression did not identify significant predictors of IMI in cows without clinical mastitis.ConclusionsLactating dairy cattle admitted to a veterinary hospital should be managed as if they have an IMI, even in the absence of clinical mastitis.

Evaluation of 3 esterase tests for the diagnosis of subclinical mastitis at dry-off and freshening in dairy cattle

“…A range of values for sensitivity (Se) and specificity (Sp) have been reported when using the CMT to diagnose SCM or IMI in quarters of dairy cows at various stages of lactation. A CMT result of trace or higher had Se of 0.50 and Sp of 0.73 for diagnosing IMI in a US herd with a high bulk tank SCC (Middleton et al, 2004); Se of 0.87 and Sp of 0.26 for diagnosing IMI in 2 Eng-lish herds (Bhutto et al, 2012); and Se of 0.45 and Sp of 0.56 for diagnosing IMI in cows admitted to a US Veterinary Teaching Hospital (Kandeel et al, 2018a). A CMT result of ≥1 had Se of 0.77 and Sp of 0.77 for diagnosing IMI in cows in South Africa (Fosgate et al, 2013).…”

Occurrence of mastitis and methicillin resistant <i>Staphylococcus aureus</i> in goats in Zaria, Kaduna State, Nigeria

“…It could also be due to an organism such as Mycoplasma species which requires a special media and cannot be identified in the routine bacterial isolation techniques (Hristov et al, 2016). Also, it has been reported that a CMT score of 1+ or higher is a good indicator of mastitis in goats which corresponds to a somatic cell count of greater than 0.8x10 6 cells/mL (Kandeel et al, 2018). CMT negative and trace results could be culture positive (false negative) and a number of samples with CMT scores of ≥ +1could also be culture negative (false positive; 20-40%) (Kandeel et al, 2018).…”

“…Also, it has been reported that a CMT score of 1+ or higher is a good indicator of mastitis in goats which corresponds to a somatic cell count of greater than 0.8x10 6 cells/mL (Kandeel et al, 2018). CMT negative and trace results could be culture positive (false negative) and a number of samples with CMT scores of ≥ +1could also be culture negative (false positive; 20-40%) (Kandeel et al, 2018). This result is in agreement with the reports of National Mastitis Council which states that 25-40% of milk samples of animals with clinical mastitis do not have a bacterial isolate.…”

“…Positive samples showed change in viscosity or gel formation within a few seconds. Results were read immediately as per manufacturer's recommendation and were scored as 0 (negative), ± (trace), 1+ (weak positive), 2+ (distinct positive), 3+ (strong positive) depending on the degree of viscosity and of gel formed as described (Kandeel et al, 2018). A goat was considered positive if at least one half of the udder was positive by CMT with or without the isolation of microorganisms.…”

Relatedness of California Mastitis Test Scores and Bacteriological Plate Counts in the Diagnosis of Subclinical Mastitis in White Fulani Cattle From Selected Dairy Herds&nbsp;

“…The CMT was performed and interpreted as described by Kandeel et al (2018). Brie y, 2 mL of fresh foremilk sample from each quarter was placed in the appropriate chamber of the CMT plastic paddle and mixed with 2 mL of CMT reagent at ambient temperature by gently moving the paddle in a circular motion.…”