Diagnosis of subclinical mastitis in Santa Inês and Morada Nova sheep in southeastern Brazil

Abstract

The objective of this study was to evaluate different screening limits for the California mastitis test (CMT) and the somatic cell count (SCC) in previous diagnoses of subclinical mastitis in Santa Inês and Morada Nova ewes, which were reared under the same management conditions. Additionally, cutoff points were defined for SCC in accordance with the sensitivity and specificity of the test. A total of 907 mammary halves were subjected to CMT and SCC. The disease was confirmed by means of microbiological identification. Coagulase-negative staphylococci (CNS) were the microorganisms with highest occurrence. The CMT score of 1+ provided adequate sensitivity and specificity at all periods of lactation investigated. This score showed good agreement with SCC, >400,000 cells mL(-1). Higher cell counts favored higher diagnostic specificity. They can be used when producers have financial difficulties relating to treatment or culling of sheep with subclinical mastitis. However, producers should be warned about the risk of false-negative results in the flock.

Predisposing factors for bacterial mastitis in ewes

“…With regard to precipitation, Zafalon, Santana, Pilon, and Júnior (2016) have reported higher frequency of subclinical mastitis in ewes during rainiest periods. This is probably due to difficulties in maintaining environmental hygiene.…”

Food safety and quality. Scientific proceedings

“…Pričom až 73,17 % bakteriologicky pozitívnych vzoriek sa nachádzalo v PSB skupinách s PSB vyšším ako 400 × 10 3 buniek/ml. Zafalon et al (2016) a Hussein et al (2016 stanovili ako limitujúcu hodnotu pre detekciu subklinickej mastitídy práve 400 × 10 3 buniek/ml. Spanu et al ( 2011) zaznamenali 5,6 až 7,5-krát vyššiu pravdepodobnosť výskytu subklinickej mastitídy pri bahniciach s PSB nad 400 × 10 3 buniek/ml počas troch a viac mesiacov.…”

Potential Novel Biomarkers for Mastitis Diagnosis in Sheep

“…Laboratory diagnostics play an important role in the improvement of production efficiency and the control of diseases including mastitis [25]. Mastitis cases might be classified as clinical or subclinical.…”

“…One of the on-the-spot tests such as the California Mastitis Test (CMT) can help to diagnose SM in ewes, but unlike in dairy cattle, the CMT is infrequently used to detect increases in bulk milk somatic cell counts, although it may have some application in dairy sheep. CMT has some limitations because it was originally developed for cows, and also due to its subjective nature, which can lead to inaccuracies in the interpretation of the results [25,26].…”

“…Likewise, there is no consensus in the literature regarding a cut-off value of SCC in sheep milk [25,27]. Moreover, even if the SCC in milk is considered a standard indicator of SM in cows it may not be a specific sign of the inflammatory status of the mammary gland in sheep, due to variability due to numerous factors other than intramammary infections including age, breed, management system, physiological stage of the animal (lactation stage, dry period), season, numbers of lambs born, and other factors [28].…”