High Prevalence Of Subclinical Mastitis Research Articles

Studies on Subclinical Mastitis in Sirohi Goats in Southern Rajasthan with Reference to Prevalence and Diagnostic Aspects

Mastitis is an economically important disease in goats. In the present study, a total of 100 quarter milk samples were collected from 50 apparently healthy Sirohi Goats in Udaipur district. The culture examination of these samples revealed the prevalence of subclinical mastitis in Sirohi goats as 26 (26/100) % and 34 (17/50) % on udder quarter basis and animal basis, respectively. The highest prevalence of subclinical mastitis was observed in 3rd lactation (50 %). Among the different isolates, staphylococci were found as most prevalent organism accounting for 37.50 (12/32) %, followed by streptococci 28.12 (9/32) %, E. coli 18.75 (6/32) %, bacilli 9.37 (3/32) % and Corynebacterium spp. 6.25 (2/32) %. The threshold values of modified California mastitis test, total somatic cell count and electrical conductivity in subclinical mastitic milk samples were observed to be +1, 1.0 million cells/ml of milk and 6.0 mS/cm, respectively.

Prevalence of Mastitis in Lactating Bovines and Associated Coliforms Among Selected Pastoral Herds in Parts of Kaduna State, Nigeria

It has been established by various researchers that bovine mastitis which is simply an inflammation of mammary gland is a complex and costly diseases in dairy herds globally. This study therefore was aimed at assessing the prevalence of clinical and subclinical mastitis among lactating bovines from pastoral herds. A total of 147 bovines were selected from 30 pastoral herds within 7 Fulani settlements in Kaduna State, Nigeria. Prevalence of Clinical mastitis was assessed by the result of physical examination of udders and milk by palpation and visual inspection. The California Mastitis Reagent was used according to the manufacturer’s instructions to detect the prevalence of Subclinical Mastitis. The CMT positive samples were bacteriologically analyzed following standard microbiological procedures for the presence of coliform bacteria. The results obtained revealed that 19.7% (29/147) of animals examined was positive for subclinical mastitis at cow level. The highest prevalence of subclinical mastitis was recorded among bovines from settlements G in Birnin Local Government Area of Kaduna State, while bovine’s raw milk samples collected from settlements C and E in Chikun and Zaria Local Government Areas of Kaduna State haboured the lowest number of 1(0.7%) each, and no Coliform bacteria (0.00%) was isolated in the samples collected from settlement D in Soba Local Government Area. In this study, a total prevalence of 8.2% was established for coliforms associated with subclinical mastitis among pastoral herds based on phenotypic identification. Furthermore, the species of coliforms associated with bovine mastitis within the study population based on the findings in this study were (Klebsiella pneumonia) 7(4.8%) and (Escherichia coli) 5(3.4%). Hence, this study confirmed that the consumption of raw milk from CMT positive commercial bovines is a potential threat to public health as the isolated species of coliforms have been implicated in several human diseases.

Prevalence of Subclinical Mastitis in the Local Goats in the Province of Laghouat (ALGERIA)

Subclinical mastitis is a disease of the udder that passes mostly unnoticed. Or several germs associated with it and their presence in milk constitutes a major risk to consumer health. Our study aims to determine the prevalence of subclinical mastitis in local goats in Laghouat region (Algeria). We undertook a study based on the detection of sub-clinical mastitis by Califirnian Mastitis Test (CMT) in 60 goats aged 1 to 9 years and weighing 18 to 45 kg of live weight and whose lactation number varies from 2 to 8. We found a prevalence of subclinical mastitis reaching 46.6%. A clearly significant difference (P <0.05) is reported on this prevalence compared to age. The highest rate is recorded especially in goats aged between 3 to 7 years with 62% of detected subclinical mastitis, followed by the older goats (over 7 years) with a prevalence of 27%, and at the end the youngest goats (1-3 years) with a prevalence of 11%. A significant difference was also recorded between the different lactation ranks (P <0.05). The goats having the highest rank of lactation were most affected by subclinical mastitis. Prevalence of 46%, 31%, 11% and 8% respectively are found for the 6th rank of lactation and more, 4 lactations, 5 lactations and 1 lactation. We noticed that the majority of diagnosed mastitis were caused by poor hygiene conditions. This study allows us to conclude that there is a high prevalence of subclinical mastitis in the local goats in the province of Laghouat (Algeria).

Investigation On The Etiology Of Subclinical Mastitis In Jersey And Hybrid Jersey Dairy Cows

Abstract The aim of this study was to investigate the etiology of subclinical mastitis (SCM) in dairy Jersey cows with the use of bacteriological and molecular identification methods. In the study 121 Jersey and 78 hybrid Jersey cows with SCM were observed in the Samsun district of Turkey. A total of 411 California mastitis test (CMT) positive milk samples from these animals were examined bacteriologically. The prevalence of subclinical mastitis was 54.75% and 67.2% in Jerseys and hybrids, respectively. On bacteriological examination, a total of 92 strains were isolated from 411 milk samples. The most prevalent bacteria were Staphylococcus spp. (69.56%). Among them 24 isolates were Staphylococcus aureus (26.08%) the other isolates were Streptococcus dysgalactiae (23.91%), Enterococcus spp. (3.26%) and Streptococcus agalactiae (3.26%). All strains were identified with bacteriological culture methods, as well as by Polymerase Chain Reaction (PCR). Gram-negative bacteria were not isolated. In conclusion, the etiology of SCM in full blood and hybrid Jersey dairy cows in Samsun and the prevalence of bacteria were determined. The relatively high prevalence of SCM indicates the potential need for the consideration of some factors contributing to the formation of mastitis (e.g. management) as well as bacterial agents. The present study and further studies may be useful to develop mastitis vaccines by means of providing true vaccine strain sources.

A systematic review and meta-analysis of prevalence of subclinical mastitis in dairy cows in India.

The purpose of the study was to provide the pooled estimate of the prevalence of subclinical mastitis among dairy cows in India and to examine the consistency of those estimates between published studies. We have conducted a systematic review of prevalence of subclinical mastitis in dairy cows for the period 1995-2014 using electronic and non-electronic databases. Meta-analysis of 28 studies was done under random effects model using Metaprop package in R software. The pooled estimate of prevalence of subclinical mastitis on cow-basis was obtained using 6344 cows from 25 studies and was found to be 46.35% (95% CI 39.38; 53.46). Meta-analysis for quarter-wise prevalence of subclinical mastitis was carried out using 18,721 udder quarters of dairy cows from 23 studies, and the pooled estimate of prevalence of subclinical mastitis on quarter-basis was found to be 23.25% (95% CI 18.15; 29.27). Meta-analysis showed that there is statistically high heterogeneity for the prevalence estimates between published studies. The present study reported that there is high prevalence of subclinical mastitis in dairy cows in India, which might be responsible for low productivity in lactating cows in India over the years and needs to be controlled by adopting scientific, managemental, and therapeutic measures. Dairy farmers can reduce incidence and economic losses due to subclinical mastitis under the guidance of field veterinarians.

Prevalence of sub-clinical mastitis in high yielding crossbred cows using Draminski mastitis detector

The subclinical mastitis (SCM) causes great economical loss in dairy farms due to reduction in milk production. The objectives of the study were to know the prevalence of subclinical mastitis in lactating cows using Draminski mastitis detector and to evaluate the efficacy of intramammary infusion against SCM in lactating dairy cows. The study was conducted in crossbred dairy cattle in peri-urban dairy production system within seven kilometers around the artificial insemination Centre, Bangladesh Agricultural University, Mymensingh during April, 2011 to May, 2012. The overall prevalence of SCM in lactating cows was 55.1%. The highest prevalence of SCM was 84.4% in more than 7 years old cows. The prevalence of SCM was significantly (p<0.001) increasing with the advancement of the age. The prevalence of SCM was significantly (p<0.05) higher (73.7%) in cows producing more than 15 liters of milk. Cows with 75% Holstein Friesian genotype experienced more SCM (63.0%) than other genotypes. An increased prevalence of SCM with increased number of parity in cows was also observed. The prevalence of SCM was significantly (p<0.001) higher in cows with parity more than five. The highest prevalence of SCM was recorded in left hind quarter (32.3%) but the difference was not significant (p>0.05) statistically. The efficacy of Neomastipra-JR5® as intra mammary infusion against SCM in lactating cows was 78.2%. Draminski mastitis detector could be a potential candidate for the diagnosis of SCM in dairy animals in Bangladesh context. But before introducing this machine in the field it should be validated either by comparing with a gold standard test like somatic cell counter or by using latent class evaluation in a multi-test approach. DOI: http://dx.doi.org/10.3329/bjvm.v11i1.17731 Bangl. J. Vet. Med. (2013). 11 (1): 37-41

Risk factors associated with subclinical mastitis as detected by California Mastitis Test in smallholder dairy farms in Jimma, Ethiopia using multilevel modelling

The prevalence of subclinical mastitis and associated risk factors at the herd, cow and quarter level were studied using multilevel modelling in smallholder dairy farms in Jimma, Ethiopia. Forty-two herds, out of the 55 dairy farms located in Jimma (76%), were visited, a questionnaire was performed, and 635 quarters belonging to 176 lactating cows were screened to detect the presence of subclinical mastitis using the California Mastitis Test (CMT). Sixty-two percent of the cows and 51% of the quarters were subclinically infected. Quarters from cows in later stage of lactation (>180DIM) [opposed to early lactation (<90DIM)] were more likely to be subclinically infected (OR=2.40, 95% CI=1.44–3.99). Overall, quarters from cows milked by squeezing (as opposed to stripping) were less likely to be subclinically infected (OR=0.45, 95% CI=0.29–0.71), although quarters from cows with tick-infested udders were more likely to be subclinically infected when milked by squeezing (as opposed to stripping). The milking technique did not influence the likelihood of infection in cows without ticks on the udder. This study stresses the high prevalence of subclinical mastitis in smallholder dairy farms in Jimma and a lack of awareness of the existence of the disease among dairy farmers. Implementation of a mastitis prevention program adapted to the local needs, including a focus on milking technique, application of appropriate tick control measurements as well as fertility management, allowing cows to be dried-off at a more appropriate moment, are needed. To conclude, milking by squeezing instead of stripping, but not of cows with tick-infested udders, as well as fertility management could reduce the subclinical mastitis prevalence (and incidence) on the short term.

Assessment of sub-clinical mastitis and its associated risk factors in dairy livestock of Lamjung, Nepal

INTRODUCTION: Mastitis is one among the top three threats faced by dairy farmers. The study was carried out to assess sub-clinical mastitis, management practices and associated risk factors for mastitis. MATERIALS AND METHODS: A cross sectional study was conducted in Chandreshwor and Archalbot VDCs of Lamjung district taking 63 dairy livestock randomly each from a herd along with questionnaire survey to respective owner. Tem ml of milk sample from each quarter was taken in a sterilized syringe for further laboratory investigation. California Mastitis Test (CMT) was performed at farmer’s shed. Organisms were identified based on colony characteristics, Gram's staining and various biochemical tests. RESULTS: On CMT, subclinical mastitis was 46.1% (n=29) and 30.15% (n=76) on animal and quarter basis respectively, however, culture showed, 28.6% and 24.2%. Streptococcal mastitis was the commonest (11.1%) followed by coliform (9.5%) and staphylococcal (7.9%). Mastitis was highest in left fore quarter (34.92%) followed by left hind (31.76%), right hind (28.57%) and right fore (25.39%). Coliform &amp; Staphylococcal mastitis was highest in left fore and right hind quarter respectively. Most of dairy animals (86%) were on zero grazing, 30% (n=19) of the farmers had forage trees and only 29% (n=18) had known about subclinical mastitis. The average milk production was 3.5 ±1.47 liters. Subclinical mastitis was associated significantly (p&lt;0.01) with livestock yielding more than 3 lt per lactation. CONCLUSIONS: There was high prevalence of subclinical mastitis in dairy livestock at Lamjung due to poor management, unhygienic shed, and little knowledge on subclinical mastitis. DOI: http://dx.doi.org/10.3126/ijim.v2i2.8322 Int J Infect Microbiol 2013;2(2):49-54

Effect of somatic cell count and mastitis pathogens on milk composition in Gyr cows

BackgroundGyr cows are well adapted to tropical conditions, resistant to some tropical diseases and have satisfactory milk production. However, Gyr dairy herds have a high prevalence of subclinical mastitis, which negatively affects their milk yield and composition. The objectives of this study were (i) to evaluate the effects of seasonality, mammary quarter location (rear x front), mastitis-causing pathogen species, and somatic cell count (SCC) on milk composition in Gyr cows with mammary quarters as the experimental units and (ii) to evaluate the effects of seasonality and somatic cell count (SCC) on milk composition in Gyr cows with cows as the experimental units. A total of 221 lactating Gyr cows from three commercial dairy farms were selected for this study. Individual foremilk quarter samples and composite milk samples were collected once a month over one year from all lactating cows for analysis of SCC, milk composition, and bacteriological culture.ResultsSubclinical mastitis reduced lactose, nonfat solids and total solids content, but no difference was found in the protein and fat content between infected and uninfected quarters. Seasonality influenced milk composition both in mammary quarters and composite milk samples. Nevertheless, there was no effect of mammary quarter position on milk composition. Mastitis-causing pathogens affected protein, lactose, nonfat solids, and total solids content, but not milk fat content. Somatic cell count levels affected milk composition in both mammary quarters and composite samples of milk.ConclusionsIntramammary infections in Gyr cows alter milk composition; however, the degree of change depends on the mastitis-causing pathogen. Somatic cell count is negatively associated with reduced lactose and nonfat solids content in milk. Seasonality significantly affects milk composition, in which the concentration of lactose, fat, protein, nonfat solids and total solids differs between dry and wet seasons in Gyr cows.

UDDER-HALVE-WISE COMPARATIVE PREVALENCE OF CLINICAL AND SUB-CLINICAL MASTITIS IN LACTATING GOATS WITH THEIR BACTERIAL PATHOGENS AND ANTIBIOTIC SENSITIVITY PATTERNS IN BANGLADESH

Goats are the major parts of subsidiary economy of the rural people in Bangladesh. Dairy animals including lactating goats are prone to the intramammary infection (IMI) and associated with a lot of economic impact on the farmers but the reports on caprine mastitis are very limited in inland literature. This study was undertaken to determine the udder-halve-wise comparative prevalence of clinical and sub-clinical caprine mastitis with their associated bacterial pathogens and antibiotic sensitivity patterns during the period from January to May 2010. The teat and udder of a lactating population of 1025 Black Bengal goats maintained under rural (village) condition in two different districts (Joypurhat and Mymensingh) of Bangladesh were physically examined, of which 54 (5.27%) goats had clinical mastitis which constituted as experimental animals for this study. Of the 54 selected goats, 59 (54.63%) udder-halves were affected with clinical mastitis whereas the remaining 49 (45.37%) udder-halves of the selected goats were found physically normal. Out of 59 udder-halves, 49 (90.74%) were unilaterally and 5 (9.26%) were bilaterally affected with clinical mastitis. The prevalence of clinical mastitis was found significantly (p &lt; 0.01) higher in left udder-haves (H = 47; 79.66%) in comparison to the right (H = 12; 20.34%) udder-halves. Milk samples collected from all the 108 udder-halves were examined bacteriologically, of which 102 (94.44%) udder-halves had bacterial infection. No significant differences was observed on the status of bacterial pathogens between clinically (H = 55; 93.22%) and sub-clinically (H = 47; 95.92%) affected udder-halves, and between the single (CH = 45; 76.27% and SCH = 35; 71.43%) and mixed (CH = 10; 16.95% and SCH = 12; 24.49%) bacterial infections in both the clinical and sub-clinical mastitis udder-halves. The major bacterial pathogens isolated were Staphylococcus spp. which showed to be highest frequency (38.98%), followed by Escherichia coli (27.12%) and Bacillus spp. (10.17%) as a single clinical IMI whereas mixed IMI were also detected in both clinically and sub-clinically affected udder-halves. Antibiotic sensitivity results showed a relatively high level of resistance to ampicillin, amoxycillin and streptomycin, whereas gentamicin and ciprofloxacin were found to be the most effective drugs. These results indicate the high prevalence of sub-clinical mastitis in apparently normal quarters of lactating goats than those had clinical mastitis in other udder-halves, and therefore, there is a need for the prudent use of antibacterial in animal health and production through bacteriological and antibiogram studies in Bangladesh.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13456

PREVALENCE OF SUBCLINICAL MASTITIS IN DAIRY COWS IN SELECTED AREAS OF BANGLADESH

This research was carried out to determine the prevalence of subclinical mastitis in lactating Dairy Cow of Bangladesh Agricultural University dairy farm (BAUDF) and rural areas of Tangail sadar upazila of Bangladesh during the period of July 2009 to April 2010. A total of 200 milk samples (40 from BAUDF and 160 from Tangail sadar upazila) were collected for this study which were subjected to physical examination and subsequently screened for subclinical mastitis using three indirect tests viz. White Side Test (WST), California Mastitis Test (CMT), and Surf Field Mastitis Test (SFMT). Overall prevalence of subclinical mastitis (SCM) in lactating dairy cows found in this study was 29%. Cows were infected with SCM 29.5%, 27.5% and 25.5% detection by CMT, WST and SFMT respectively. Higher prevalence of SCM was detected in milch crossbred cows (36.36%) in comparison to local bred cows (24.61%) maintained under extensive management system in Rural area of Tangail sadar upazila. The prevalence of SCM was recorded in 31.58%, 30.76% and 68.75% in cows of local area of Tangail sadar upazila, and 25.0%, 40.0% and 71.42% in cows of BAU,DF during the early, mid and late stages of lactation respectively. The highest prevalence of SCM was recorded during the early lactation stage in both the local breed cows (30.0%) and cows of BAUDF (45.83%) in comparison to their respective mid and late stages of lactation. The prevalence of SCM was highest in lactating cows having third lactation and high yielding (cows produced &gt;10 liter milk per day) both in local breed and crossbred cows.DOI = http://dx.doi.org/10.3329/bjvm.v9i1.11216 Bangl. J. Vet. Med. (2011). 9(1): 73-78

Identificación de biotipos de Staphyloccocus aureus en vacas lecheras de producción familiar con mastitis subclínica en la región centro-este del Estado de México

Mastitis causes great economic loss in dairy farms. One of the main agents involved is Staphylococcus aureus, which is important not only in public health but in herd health as well. The aim of this study was to determine S. aureus frequency and the predominant biotypes in cows presenting subclinical mastitis from family dairy farms in the Central-Eastern zone of the State of Mexico. A transversal study was conducted considering 269 dairy cows in different lactation periods and herd information was taken through a closed questionnaire. Individual milk samples were taken and California test was used for mastitis detection. Biotypes were identified using soy tripticase agar with violet cristal added (1:100,000). Results show a subclinical mastitis prevalence of 48.3 % (CI95% 42.22 to 54.47) and for clinical mastitis 6.1 % (CI95% 3.44 to 9.48).62 S. aureus isolations were obtained, from which 79 % were biotype C (Human), 11.3 % A (Bovine), 6.5 % E (Canine) and 3.2 % from non specific hosts. Herd size represented a risk factor associated to S. aureus frequency, especially when the herd was larger than 13 cows (OR=5.63, CI95% 1.72 to 18.21). In the family dairy herds there was a high prevalence of subclinical mastitis associated to the infection produced by S. aureus Biotypes C and A, considered important in public health.

Subclinical mastitis and associated risk factors on dairy farms in New South Wales

To determine the current prevalence of subclinical mastitis (SCM) and associated risk factors on dairy farms in New South Wales. A survey was sent to 382 dairy farmers to acquire information on the relevant risk factors associated with SCM. The average herd prevalence of SCM among the 189 respondents (response rate 49.5%) was 29%. Farmers who had herds with a low prevalence (<20% cows with individual somatic cell count (ISCC) >2 × 10⁵ cells/mL) more frequently wore gloves during milking (26% vs 62%), used individual paper towels for udder preparation (16% vs 62%), fed cows directly after milking (47% vs 87%) and more frequently treated cows with high ISCC (69% vs 80%) than farmers who had herds with a high prevalence of SCM (>30% cows with ISCC >2 × 10⁵ cells/mL). The latter more often used selective dry cow therapy (52% vs 24%), compared with low prevalence herds. The prevalence of SCM in this cross-sectional study is comparable or lower than reported in other studies from North America and the European Union. The outcome provides a benchmark for the current focus of the NSW dairy industry on the management practices associated with a low prevalence of SCM, such as wearing gloves, using paper towels and feeding cows directly after milking.

Prevalence of clinical and subclinical mastitis and quality of milk on smallholder dairy farms in Tanzania

A cross sectional study was conducted during October and November 2006 on 69 smallholder dairy farms with lactating cows in Mvomero and Njombe districts Tanzania, to determine the prevalence of mastitis and to assess the milk quality on the study farms. Clinical mastitis was investigated using clinical changes of udder and milk at animal level. Cow-side California Mastitis Test (CMT) and microbiological cultures were used to assess subclinical mastitis at quarter level. Milk quality was determined on bulk milk samples at herd level using alcohol and acidity tests, butter fat content, total solids, ash content as well as Delvotest for antimicrobial residues. Overall prevalence of clinical mastitis at herd level in both districts was 21.7% (n = 69). Based on CMT, prevalence of subclinical mastitis at animal level was 51.6% (n = 91). Prevalence of bacterial isolates at animal level was 35.2% (n = 91) while for fungal it was 16.7% (n = 90). Based on CMT results, prevalence of subclinical mastitis at quarter level was 30% (n = 353), while for bacteria and fungi it was 16% and 6% respectively. Contamination of milk with antimicrobial residues was 4.5% (n = 67). The milk quality parameters for most of the milk samples were within acceptable levels. Findings in this study have demonstrated high prevalence of subclinical mastitis that may contribute to low productivity of dairy cattle in both districts. About 20% of CMT subclinical cases had no involvement of microbial pathogens that suggested the need for minimal interventions with antimicrobial agents. These findings call for use of udder disinfectants and improved milking hygiene as intervention strategies to control mastitis on the smallholder dairy farms in Tanzania.

Prevalence and determinants of mastitis and milk-borne zoonoses in smallholder dairy farming sector in Kibaha and Morogoro districts in Eastern Tanzania.

SummaryA study was carried out to establish the prevalence and determinants of mastitis and milk‐borne zoonoses in smallholder dairy farms in Kibaha and Morogoro districts (Tanzania). A total of 57 herds comprising 114 milking cows in Kibaha and 48 herds consisting of 96 milking animals in Morogoro were included in the study. A questionnaire survey was used to assess the socio‐economic determinants of mastitis, whereas California mastitis test (CMT) and microbiological assessment of milk was carried out to establish the status of mastitis and responsible aetiological agents. Seroconversion for brucellosis was evaluated using enzyme‐linked immunosorbent assay (ELISA). Animals were also tuberculin‐tested using a single comparative intradermal method and milk samples were cultured for isolation of Mycobacterium species. Based on CMT, the cow‐based prevalence of subclinical mastitis was 82.4% in Kibaha and 62.4% in Morogoro. Of the 919‐quarter milk samples cultured, 8.2% were positive for aerobic bacteria with predominant isolates being Staphylococcus epidermidis (2.8%), Staph. aureus (1.7%), Streptococcus agalactiae (1.2%) and Staph. intermedius (1.1%). There was a strong association between CMT positivity and bacteriological isolation [relative risk (RR) = 2.60; P = 0.02]. Fungal growth was observed in 21.8% (n = 881) of the samples and the isolates were yeast (19.2%), Mucor (2.5%) and Aspergillus (0.1%). Bucket feeding of calves was associated with increased risk of a quarter being CMT positive (RR = 1.24; P = 0.000), while residual calf suckling was associated with decreased risk of positivity (RR = 0.86; P = 0.015). Earth floor was associated with increased risk of CMT positivity at quarter level (RR = 1.13; P = 0.041) and Jersey breed was identified as a risk factor to mastitis. The prevalence of bovine tuberculosis was 0.4% (n = 259) and 1.7% (n = 181) in Kibaha and Morogoro, respectively. Similarly, the prevalence of brucellosis was 1% (n = 208) in Kibaha and 1.9% (n = 104) in Morogoro. Findings from this study have demonstrated a high prevalence of subclinical mastitis and existence of health risks to milk consumers despite the low prevalence of tuberculosis and brucellosis in the study herds.

Study on risk factors and their association with subclinical mastitis in lactating dairy cows in Trinidad.

A cross-sectional study was conducted on dairy farms in eight milking centres in Trinidad to determine the prevalence of risk factors for mastitis and to assess their relationship to occurrence of subclinical mastitis. The California mastitis test (CMT) was used to determine the prevalence of subclinical mastitis by estimating the somatic cell counts in bulk and composite milk. Of a total of 177 dairy farms studied, 121 (68.4%), 39 (22.0%) and 17 (9.6%) practised semi-intensive, extensive and intensive management systems, respectively. A total of 129 (72.9%), 37 (20.9%) and 11 (6.2%) farms milked cows in parlours, stanchions and pasture/out-on-field, respectively. Based on sanitary practices, 40 (22.6%), 123 (69.5%), and 14 (7.9%) farms were classified as good, fair, and poor, respectively, while 76 (42.9%) and 60 (33.9%) farms reported to rarely experience and frequently experience water shortages, respectively. Amongst the 177 farms, only seven (4.0%) used machine-milking primarily, 152 (85.9%) screened for mastitis as a routine, 18 (10.2%) teat dipped, and 49 (27.7%) practised dry cow therapy. To detect mastitis, of 152 farms involved, 20 (13.2%) used the strip cup while only two (1.3%) employed the CMT. Pipe-borne water delivered directly from the hose was the only source of water to 91 (51.4%) farms while seven (4.0%) and eight (4.5%) farms used only well and surface water (ponds and rivers), respectively. Based on bulk milk samples, the farm prevalence of subclinical mastitis was 60.5% (107 of 177) with a range from 33.3% (centre 5H) to 100.0% (centre 2B). The difference was statistically significant (P < 0.01; chi 2). However, using composite milk, the farm prevalence of subclinical mastitis was 52.5% (93 of 177) with a range from 21.2% (centre 5H) to 92.9% (centre 2B) and again, the difference in prevalence was statistically significant (P < 0.001; chi 2). Subclinical mastitis was detected in 150 (45.0%) of 333 lactating cows screened and the range of prevalence was from 17.9% (centre 5H) to 56.3% (centre 1C). The difference was statistically significant (P < 0.001; chi 2). Of a total of 14 risk factors for mastitis studied which were related to animal husbandry, personnel, mastitis control and water, only two, the herd size and practice of dry cow therapy were significantly (P < 0.05; chi 2) associated with subclinical mastitis. It was concluded that the high prevalence of subclinical mastitis in Trinidad dairy herds could significantly reduce milk production with associated economic loss. Although a majority of the risk factors studied were not found to be significantly associated with the occurrence of subclinical mastitis possibly due to confounding factors, the need to eliminate or reduce these risk factors cannot be over-emphasized.

Post-milking teat dip use in dairy herds with high or low somatic cell counts

Summary Milk samples for bacteriologic culture were submitted from 71 dairy herds, 24 with low somatic cell count (scc) and 47 with high scc and high prevalence of subclinical mastitis. At the time of sample submission to the Mastitis Diagnostic Laboratory of Pennsylvania State University, information regarding the herd mastitis control practices was collected. A combined program of post-milking teat dipping (pmtd) and antibiotic treatment of all cows at the start of the nonlactating period was practiced more frequently for herds with low scc, (P &lt; 0.001) than for herds with high scc. Among all herds for which pmtd was practiced, a higher proportion (P &lt; 0.001) of those for which chlorhexidine-based products were used had low scc than high scc. Conversely, a higher proportion of herds for which a dip with an acrylic latex barrier was used had high scc rather than low scc (P = 0.002). For herds with high prevalence of sub- clinical mastitis, and despite a program of pmtd and treatment of all cows at the start of the nonlactating period, a change to a different germicidal teat dip product may be indicated to help reduce prevalence of infection.

HOST DETERMINANTS BASED COMPARATIVE PREVALENCE OF SUBCLINICAL MASTITIS IN LACTATING HOLSTEIN-FRIESIAN CROSS COWS AND RED CHITTAGONG COWS IN BANGLADESH

A comparative prevalence of sub-clinical mastitis (SCM) based on host risk factors was studied by using California Mastitis Test (CMT) in 96 Holstein-Friesian cross cows (HFCC) of Abu Baker Dairy Farm at Pansha Upazilla in Rajbari district and 20 Red Chittagong cows (RCC) of Bangladesh Agricultural University Dairy Farm (BAUDF), Mymensingh during the period from January to June 2008. Out of the 116 lactating cows examined, 51 (43.97%) showed positive reactivity to CMT. Similar prevalence rate of SCM was recorded in both the HFCC (43.75%) and RCC (45.0%). The overall prevalence of SCM on the basis of lactation stages showed that all the three lactation stages had SCM but there was a tendency to increase its prevalence rates from early (30.43%), mid (32.26%) to late (69.23%) stages. The highest prevalence of SCM was recorded at late lactation stage in both the HFCC (68.75%) and RCC (71.43%) in comparison to their respective mid and early lactation stages. The parity-wise prevalence of SCM was recorded as 18.42%, 55.0%, 66.67%, 75.0% and 75.0% in HFCC whereas, it was 20.0%, 20.0%, 66.67%, 75.0% and 66.67% in RCC at their 1st, 2nd, 3rd, 4th and 5th parity, respectively. This study recorded a relationship between the increased prevalence of SCM with decreased of milk production in both the groups of lactating cows. The respective prevalence of SCM at high, medium and low level of milk production in HFC (14.29%, 33.33% and 70.59%) and RCC (14.29%, 50.00% and 71.42%) were found significantly (p &lt; 0.01) correlated with milk production. An overall 19.18% quarters was affected with SCM, of which 4.31%, 7.33% and 7.38% showed mild, moderate and severe reaction to CMT. However, comparatively, higher percentage of quarter infection was recorded in HFCC (20.31%) than RCC (13.75%). It may be concluded from these observations that both the HFCC and RCC should be monitored by using CMT for the detection of SCM in order to provide rational treatment and control it to make the dairy farming profitable. DOI = 10.3329/bjvm.v8i1.7397 Bangl. J. Vet. Med. (2010). 8(1): 17-21