Different screening tests and milk somatic cell count for the prevalence of subclinical bovine mastitis in Bangladesh

Abstract

Identification of cows with subclinical mastitis (SCM) is an important tool for sustainable dairying and implementing effective mastitis control strategies. A total of 892 quarters milk samples from 228 lactating cows were screened by California mastitis test (CMT), White side test (WST), Surf field mastitis test (SFMT), and somatic cell count (SCC) to study the prevalence of bovine SCM in some selected areas of Bangladesh. Out of 228 cows, 148 (64.9%), 138 (60.5%), 132 (57.9%), and 164 (71.9%) were found positive for SCM by CMT, WST, SFMT, and SCC, respectively. The prevalence of bovine SCM was diagnosed 45.7, 40.2, 36.6, and 29.6% in Chittagong, Sirajgonj, Mymensingh, and Gazipur districts, respectively, based on a combination of all tests. The overall quarter-wise prevalence of SCM was 45.7, 43.5, 41.2, and 55.0% for CMT, WST, SFMT, and SCC. Single quarters and left front quarters were more prone to SCM (P < 0.05). Friesian crossbred cows (56.4%), BCS 2.0-2.5 (55.4%), and parity 4-6 (52.4%), the late lactation stage (5-8 months; 64.7%) and high yielding cows (16-20 L/day; 65.3%) were more susceptible to SCM (P < 0.05). The sensitivity of the CMT, WST, SFMT, and SCC was 65.8, 57.9, 51.0, and 82.5%; specificity 76.2, 72.4, 69.5, and 89.4%; percentage accuracy 70.0, 64.8, 59.9, and 85.2%; positive predictive value 75.2, 69.8, 64.9, and 92.7%, respectively. The categories of CMT reactions were strongly correlated with SCC (P < 0.05). Kappa value of SCC was higher than that of other tests (SCC>CMT>WST>SFMT). Thus, CMT was concluded to be the most accurate (r = 0.782) field diagnostic test after laboratory test like SCC (r = 0.924). However, the use of any single test may not be reliable in diagnosing SCM, while the result of CMT supported by SCC might be used effectively to pinpoint diagnosis of SCM in dairy animals than alone.

Subclinical mastitis in dairy cows: somatic cell counts and associated bacteria in Mymensingh, Bangladesh

“…Another study conducted by Katsande et al, (2013) showed comparatively lower prevalence (16.3%) of SCM in Zimbabwe. Previous studies in different regions of Bangladesh reported that the prevalence of SCM based on California Mastitis Test (CMT) varies from 29% to 37.6% (Islam et al, 2011;Islam et al, 2010) and based on SCC was 55% (Hoque et al, 2015). However, comparative higher prevalence of SCM indicates lack of awareness about SCM and farmers are not adapted to use different screening tools to detect SCM in timely fashion and maintain the udder and teat hygiene.…”

Prevalence and Economic Impacts of Retained Placenta and Subclinical Mastitis in Tanzanian Dairy Cows

“…Clinical mastitis includes gross abnormality in milk, physical abnormalities of udder and abnormality of cow with systemic involvement while subclinical mastitis does not produce visible effects on udder or milk quality but has important effects on milk composition, mainly an increase in somatic cell counts [23,24]). While it is easy to detect clinical mastitis (seeing clotted milk), subclinical mastitis can only be demonstrated using various tests such as California Mastitis Test (CMT), Whiteside test (WST), Surf field mastitis test (SFMT), sodium lauryl sulphate test (SLST), Microscopic Somatic Cell Count (MSCC) and Electrical Conductivity (EC) [25][26][27]. However, CMT has been recognized as a highly sensitive test to detect bovine subclinical mastitis [24,25].…”

Microbiome Dynamics of Bovine Mastitis Progression and Genomic Determinants

“…IMI may persist beyond the resolution of the clinical symptoms of CM, and sub-sequent RCM flare-ups may be observed 17 . Almost every dairy herd has cows with SCM 15 , and a variety of pathogens can establish chronic infections which may only occasionally manifest the clinical signs of mastitis 19 .…”

“…However, future studies should delve further into characterizing microbiome diversity with larger sample sizes and the inclusion of gut/rumen microbiome sampling in addition to the milk samples for direct testing of microbial transfer across this axis to confirm the shift of microbiome and associated functions.MethodsScreening for mastitis, and samplingDetails of the study population and collected samples are presented inSupplementary Table 1. The California Mastitis Test (CMT ® , Original Schalm reagent, ThechniVet, USA) was used to screen different states of mastitis (clinical mastitis, CM; recurrent clinical mastitis, RCM; subclinical mastitis, SCM)19 . Cows with CM (mild, moderate, and severe) typically have abnormalities in the milk such as clots and flakes, swelled, red and hard mammary gland or systemic illness.…”

“…Cows with CM (mild, moderate, and severe) typically have abnormalities in the milk such as clots and flakes, swelled, red and hard mammary gland or systemic illness. The RCM can be either a persistent CM of the bovine mammary gland by a mastitis pathogen or a reinfection of a quarter or udder after bacteriological cure of CM while the SCM is inflammation of the mammary gland that does not create visible changes in the milk or the udder6,11,[14][15][16][17][18][19] .A total of 20 milk samples (CM = 5, RCM = 6, SCM = 4, and healthy (H) = 5) from 20 lactating cows at early stages of lactation (within 10 -40 days of calving) were collected from five districts in Bangladesh: Gazipur = 8 (24.19 N, 90.47 E), Dhaka= 3 (23.81 N, 90.41 E), Manikgonj = 3 (23.86° N, 90.00° E), Chattogram = 4 (22.20 N, 91.98 E), Sirajgonj = 2 (24.31° N, 89.57° E). The sampling patterns followed the collection of one mastitis and one H milk samples from the same farm.…”