The use of antibiotics in Swedish food-producing animals, such as dairy cows, is low compared with other countries in the European Union. Moreover, Sweden has relatively stable and low levels of antibiotic resistance in bacteria isolated from animals. Among dairy cows, mastitis is the most common disease treated with antibiotics. The aim of the present paper was to describe the Swedish approach to prudent use of antibiotics in bovine mastitis with focus on the development of national policies and guidelines for such use. Some information on Swedish dairy cow statistics, general use of antibiotics in dairy cows, as well as bacterial findings and antibiotic resistance in IMI is also given. According to Swedish legislation, policies and guidelines for veterinarians, the use of antibiotics in bovine mastitis must be restrictive and selective. Based on prevalence and antibiotic resistance of intramammary infectious agents, benzylpenicillin is the drug of choice. Moreover, antibiotic treatment is only recommended for acute cases of clinical mastitis caused by penicillin-sensitive bacteria. To further reduce the use of antibiotics and improve udder health in dairy herds, measures to prevent new IMI, such as good external and internal biosecurity, are essential. Prevention is always better than cure as healthy cows have no need for antibiotics.
Buffalo farming in Bangladesh plays a key role in enhancing food security by providing a valuable protein source through milk and meat production. Water buffalo are well-adapted to harsh climate conditions due to their robust immune systems, while they may adapt with minimal feed availability compared to dairy cows. Despite its adaptability and importance, buffalo farming has been underprioritized compared to cattle farming due to several challenges, such as a lack of awareness among farmers of modern dairy practices, limited access to good quality feed, poor breeding programs, improper management practices, and inadequate veterinary services. Furthermore, the lack of a dedicated buffalo product chain, fragmented market, and limited policy support have further impeded the development of this sector, leading to reduced profitability. Despite similar climatic conditions, Bangladesh’s buffalo population remains underexploited, contributing minimally to global buffalo milk production. In contrast, several neighboring countries, including India, Pakistan, and Nepal, lead global buffalo milk production, highlighting a significant gap in Bangladesh’s buffalo sector. Despite these constraints, buffalo farming holds great potential, particularly for producing high-nutrient products such as yogurt and cheese, which are popular in many regions. Recognizing the potential of buffalo farming, the government and other organizations are collaborating on initiatives such as enhanced breeding programs, policy support, and extension services for farmers. This review highlights the challenges and prospects of water buffalo farming, including the need for strategic interventions and key research areas to exploit the potential in dairy enterprises in Bangladesh.
The quality of milk is influenced by the microbial load related to the shelf life of milk and its spoilage. The water buffalo milk supply is a vital asset for the dairy chain in Bangladesh. However, no systematic study has been conducted to assess the quality of water buffalo milk. This cross-sectional study aims to cover this gap by measuring milk quality indicators such as the bulk milk somatic cell count (BMSCC), bacterial counts, and their correlations from farm to collection center along the milk supply chain. One hundred and thirty-two milk samples were collected from three different nodes of the milk supply chain: at the producer level from farms (n = 45), from middlemen (n = 42), and from collection centers (n = 45). Bulk milk somatic cell counts at the farm and different bacterial counts such as the total bacterial count (TBC), total Staphylococcus aureus count (TSA), total non-aureus Staphylococcal count (TNAS), total Enterobacteriaceae count (TEC) along the milk chain were determined. The geometric mean of BMSCC was 4.1 x 105 (95 % CI: 3.4 x 105 - 4.8 x 105) cells/ mL at the farm level. An increase in TBC, TSA, TNAS and TEC were observed in the milk collection center. TBC, TNAS and TEC were significantly increased (P <= 0.01) along the milk supply chain, except TSA. Significant positive correlations for TNAS with TBC (r = 0.55, P <= 0.001) and TNAS with BMSCC (r = 0.35, P <= 0.05) at farm level; TEC with TBC (r = 0.40, P <= 0.05) at middlemen; TNAS with TBC (r = 0.31, P <= 0.05) and TEC with TBC (r = 0.39, P <= 0.05) at the collection centers were observed. The study findings highlight the heavy contamination risk, emphasizing public health threat harboring pathogenic bacteria such as Salmonella, E. coli, S. aureus linked to foodborne illness. A continuous monitoring system is needed to ensure safe and quality milk.
Keeping cattle outdoors year-around is considered an attractive alternative to indoor winter-housing, due to lower investment costs and better welfare. However, hair loss, attributed to lice, may impair cattle's thermal balance during harsh winters. During the winters of 2019-2021, outdoor cattle in Sweden were studied for the prevalence and development of hair loss, while surveys were conducted among the farmers on their perceptions and attitudes around hair loss. Of the 463 groups of cattle from 75 farms enrolled in a welfare control program issued by the Swedish Board of Agriculture, 25.7% (n = 119) had at least one animal with hair loss. When we followed up a subset of animals (n = 3673) which did not receive prophylactic delousing, 15.7% developed hair loss. Hair loss occurrence increased between visits within each winter in these animals, suggesting a contagious etiology. Logistic regression analyses, using the information collected in the control program and the hair loss outcome, showed that preventive delousing before November was effective, alongside keeping animals clean and the group size small. Meanwhile, being older (>2 years) and having access to bedding materials was shown to increase the risk at an animal-level. Some groups (n = 34) had no hair loss despite receiving no prophylactic delousing. Based on the survey conducted among the farmers (n = 15), groups with lower hair loss prevalence belonged to farmers who were more observant of hair loss and gave prompt treatment. This study provides knowledge useful to limit delousing interventions without compromising animal welfare.
AbstractControlling foodborne pathogens in buffalo milk is crucial for ensuring food safety. This study estimated the prevalence of nine target genes representing seven critical foodborne bacteria in milk and milk products, and identified factors associated with their presence in buffalo milk chain nodes in Bangladesh. One hundred and forty-three milk samples from bulk tank milk (n = 34), middlemen (n = 37), milk collection centers (n = 37), and milk product shops (n = 35) were collected and analyzed using RT-PCR. Escherichia (E.) coli, represented through yccT genes, was the most prevalent throughout the milk chain (81–97%). Chi-squared tests were performed to identify the potential risk factors associated with the presence of foodborne bacteria encoded for different genes. At the middleman level, the prevalence of E. coli was associated with the Mymensingh, Noakhali, and Bhola districts (P = 0.01). The prevalence of Listeria monocytogenes, represented through inlA genes, and Yersinia (Y.) enterocolitica, represented through yst genes, were the highest at the farm level (65–79%). The prevalence of both bacteria in bulk milk was associated with the Noakhali and Bhola districts (P < 0.05). The prevalence of Y. enterocolitica in bulk milk was also associated with late autumn and spring (P = 0.01) and was higher in buffalo-cow mixed milk than in pure buffalo milk at the milk collection center level (P < 0.01). The gene stx2 encoding for Shiga toxin-producing (STEC) E. coli was detected in 74% of the milk products. At the middleman level, the prevalence of STEC E. coli was associated with the use of cloths or tissues when drying milk containers (P = 0.01). Salmonella enterica, represented through the presence of invA gene, was most commonly detected (14%) at the milk collection center. The use of plastic milk containers was associated with a higher prevalence of Staphylococcus aureus, represented through htrA genes, at milk product shops (P < 0.05). These results suggest that raw milk consumers in Bangladesh are at risk if they purchase and consume unpasteurized milk.
A cross-sectional study was conducted to estimate the prevalence of intramammary infection (IMI) associated bacteria and to identify risk factors for pathogen group-specific IMI in water buffalo in Bangladesh. A California Mastitis Test (CMT) and bacteriological cultures were performed on 1,374 quarter milk samples collected from 763 water buffalo from 244 buffalo farms in nine districts in Bangladesh. Quarter, buffalo, and farm-related data were obtained through questionnaires and visual observations. A total of 618 quarter samples were found to be culture positive. Non-aureus staphylococci were the predominant IMI-associated bacterial species, and Staphylococcus (S.) chromogenes, S. hyicus, and S. epidermidis were the most common bacteria found. The proportion of non-aureus staphylococci or Mammaliicoccus sciuri (NASM), S. aureus, and other bacterial species identified in the buffalo quarter samples varied between buffalo farms. Therefore, different management practices, buffalo breeding factors, and nutrition were considered and further analyzed when estimating the IMI odds ratio (OR). The odds of IMI by any pathogen (OR: 1.8) or by NASM (OR: 2.2) was high in buffalo herds with poor milking hygiene. Poor cleanliness of the hind quarters had a high odds of IMI caused by any pathogen (OR: 2.0) or NASM (OR: 1.9). Twice daily milking (OR: 3.1) and farms with buffalo purchased from another herd (OR: 2.0) were associated with IMI by any pathogen. Asymmetrical udders were associated with IMI-caused by any bacteria (OR: 1.7). A poor body condition score showed higher odds of IMI by any pathogen (OR: 1.4) or by NASM (OR: 1.7). This study shows that the prevalence of IMI in water buffalo was high and varied between farms. In accordance with the literature, our data highlight that IMI can be partly controlled through better farm management, primarily by improving hygiene, milking management, breeding, and nutrition.
Small ruminant lentivirus causes severe economic losses, and negatively affects animal welfare in goat herds across the world. The aim of this study was to describe the clinical and pathological consequences of the disease in an affected goat herd, as well as to sequence the virus in infected animals. Seventy-six percent of the sampled animals were small ruminant lentivirus seropositive. The most prominent signs of disease were respiratory signs found in clinical examinations and chronic interstitial pneumonia found at postmortem examination. All animals with pneumonia also showed evidence of infection with Muellerius capillaris. The cell count in bulk milk was high and most likely related to the high small ruminant lentivirus seroprevalence within the herd. Small ruminant lentivirus was successfully detected in the lungs, bronchial lymph nodes and udder tissues using polymerase chain reaction. The phylogenetic analysis of the obtained sequences revealed the highest similarity with small ruminant lentiviruses in group C, which consists of viruses which have previously been found in Norwegian goats and sheep.
Subclinical mastitis (SCM) in water buffalo is responsible for reduced milk yield and quality. This cross-sectional study was carried out to a) estimate the prevalence of SCM, b) identify risk factors associated with SCM, and c) identify farm-level risk factors associated with bulk milk somatic cell count (BMSCC). The buffalo farms included in this study represented five rearing systems: free-range, semi-free-range, household, semi-intensive, and intensive, providing a total of 3491 functional quarters of 880 lactating buffalo on 248 farms. The California mastitis test score was used to identify SCM. Bulk milk samples (n = 242) were used for farm-level BMSCC. Quarter and buffalo-level risk factors for SCM were measured using questionnaires and observations. The overall SCM prevalence was high at 27.9% at the quarter-level (25th and 75th percentiles: 8.3% and 41.7%) and 51.5% at buffalo-level (25th and 75th percentiles: 33.3% and 66.7%). The geometric mean BMSCC was 217,000 cells/mL of milk (ranging from 36,000-1,213,000 cells/mL), which is low on average, but some farms could improve substantially. The buffalo rearing system, udder location (left versus right), teat shape, udder asymmetry, number of milkers, and having a quarantine facility were associated with buffalo udder health. Our findings suggest that mainly using free-range rearing systems may help decrease the prevalence of SCM primarily by employing buffalo breeding and better farm biosecurity, and udder health control strategies can be designed based on our findings.
Little has been published on the factors influencing the safety and quality of milk derived from water buffalo in Bangladesh. This study aims to describe the milk hygiene parameters and milk chain characteristics of unpasteurized raw milk sold to consumers in order to improve milk hygiene. A quantitative study design evaluated somatic cell counts, total bacterial counts, and specific gram-negative (Enterobacteria) and gram-positive (staphylococci) pathogens in 377 aseptically collected milk samples. Samples were collected at multiple nodes along the buffalo milk value chain: 122 bulk tank milk samples were collected at the farm level, 109 milk samples at the middlemen level, and 111 milk samples at the milk collection centers. In addition, 35 samples were taken from various milk products at the retail level. It was found that progressively increasing somatic cell counts and bacterial counts, including potential pathogens, occurred along the milk chain. A seasonal increase in spring was found, varying based on the farming system (semi-intensive versus intensive). Other factors included water purity and cleanliness of containers, mixing buffalo and cow's milk, and the location of the water buffalo milk producer (coastal or river basin). This study demonstrated how improving udder health and milk hygiene along the water buffalo milk value chain would increase the safety and quality of water buffalo milk in the study area.
Mastitis is the most prevalent and costly production disease in the dairy industry, but udder health advice that helps one herd might not be beneficial for another because of "local truths". It is therefore important to identify what mastitis control options may work in a specific herd in the conditions specific to the herd. We evaluated whether the Evolutionary Operation (EVOP) methodology could be used as a management tool to identify mastitis control options to improve udder health in dairy herds. Within an EVOP framework we conducted sequences of experiments, on each of two dairy farms in Sweden. The experiments covered interventions within 1) hygiene in cubicles, 2) milking routines, and 3) dry-off procedures. Automatically recorded somatic cell counts (SCCs) in milk were used as the response variable. The impact of the interventions on SCC was evaluated with multivariate dynamic linear models. Farmer and staff satisfaction was assessed through interviews. The EVOP methodology was successfully applied, and the farmers appreciated it. We observed herd-specific variation in the effect of the interventions, indicating that EVOP would be a feasible approach to tailor mastitis control options to individual herds. Our results indicate that the EVOP methodology could be a tool to identify and evaluate health management strategies on dairy farms.
BackgroundThe effects of climate change, loss of pastureland to other land usage and presence of large carnivores are the main reasons for the increase in supplementary feeding of semi-domesticated reindeer (Rangifer tarandus tarandus) in Fennoscandia over the last decades. Feeding might expose reindeer to stress and increased animal-to-animal contact, leading to an increased risk of infectious disease transmission, such as infectious keratoconjunctivitis (IKC). As it can develop rapidly and be very painful, IKC is described as an important animal welfare concern and a potential source of economic loss. The aim of this study was to investigate the current presence of IKC and potential associations between IKC and supplementary feeding through an online questionnaire survey, distributed among reindeer herders in Norway and Sweden in 2021.ResultsSeventy-six reindeer herders (33 from Norway and 43 from Sweden) responded to the questionnaire, representing 6% and 4% of the registered reindeer herding groups in Norway and Sweden, respectively. Infectious keratoconjunctivitis was common, with 54 (71%) of the 76 herders that responded having observed clinical signs during the past 10 years. These signs were mainly observed as increased lacrimation, causing "wet cheeks", but also as keratitis and conjunctivitis. Autumn and winter were the seasons in which IKC was observed most. The herders reported several measures, such as slaughter and isolation of affected reindeer, to counteract the spread of disease. The herding year 2019/2020 was associated with reports of outbreaks of IKC in herds as well as being the herding year where most herders (80%) had performed supplementary feeding. A significant association was found between IKC and feeding performed in an enclosure (odds ratio = 15.20), while feeding on free-range areas had a non-significant, negative, relationship with the appearance of IKC outbreaks (odds ratio = 0.29). Finally, there was a trend in the data suggesting that IKC affected calves especially.ConclusionsInfectious keratoconjunctivitis is a common disease, mainly observed in winter and autumn. It usually has mild to moderately severe clinical signs. Our results imply that IKC is associated with stress and feeding situations and that calves might be more susceptible than adults, however, this needs to be confirmed with further studies, preferably at an individual animal level.
Mastitis is prevalent both in milk- and meat- and pelt producing sheep flocks and is an important disease with substantial effects on economy, animal welfare and antibiotic use, and in dairy flocks also on milk quality and safety. In meat- and pelt producing flocks, the farmers are mainly concerned by clinical mastitis (CM), and most cases of subclinical mastitis (SCM) are not detected and not dealt with, posing a risk for poor udder health in the flock. Studies on risk factors for SCM and/or intramammary infections (IMI) in meat producing flocks are scarce and specific risk factors for weaning and lambing are absent. The aim of this study was therefore to investigate associations between risk factors, at ewe and flock level, for IMI after lambing and at weaning in Swedish meat- and pelt producing ewes with clinically healthy udders. Twenty-two meat- and pelt producing flocks from different parts of Sweden were enrolled in this cross-sectional study. Udder half milk samples were collected at weaning and after lambing from ewes with clinically healthy udders, for bacteriological investigations. Data on ewe and flock level risk factors were recorded. In total, 753 ewes were sampled at least once, and the overall IMI prevalence was 22.5 %. Older ewes, ewes with three or more lambs, ewes that were hard to milk when collecting a milk sample, ewes in moderate size flocks, in flocks with hay as a bedding material and in flocks with less cases of CM had higher risk of IMI. Most of the risk factors associated with IMI in this study differed between weaning and lambing. This study has provided us with novel knowledge on how different factors influence udder health of meat- and pelt producing ewes.
Caprine arthritis encephalitis (CAE) and caseous lymphadenitis (CLA) are two infectious diseases affecting goat welfare and production throughout the world. There are no current data regarding their prevalence in Sweden, and the aim of this pilot study was therefore to estimate the occurrence in Swedish milk-producing goats, but also to assess the agreement between milk and sera as sample material for diagnosis and to investigate the association between the somatic cell count (SCC) in bulk milk and the occurrence of CAE and CLA. Serum, individual milk, and bulk-tank milk samples were collected from 214 dairy goats in 10 herds. All samples were analysed by ELISA to detect antibodies for CAE and CLA, and 14.6% of the goats were seropositive for CAE, whereas 19.3% of the goats were seropositive for CLA. The agreement between individual milk and serum samples was over 90% for both diseases and individual milk samples can therefore be considered as an alternative material for analysis in a future eradication programme. Based on the limited number of samples, there was also a significant correlation between bulk-milk test results and within-herd seroprevalence for both CAE and CLA. The SCC in bulk-milk samples was measured using a DeLaval cell counter. The medium SCC was 639,000 cells/mL and no association between SCC and CAE or CLA could be found. The results indicate that CAE and CLA are two common diseases in Swedish goat herds, but further studies based on a larger number of herds are needed to draw conclusions about the national prevalence. The results also indicate that milk can be used as a more cost-effective sampling media for diagnosing CAE and CLA compared to serology, which is the standard procedure today. Hopefully, the results can support the establishment of a successful programme to control the diseases, with the ambition to eradicate CAE and CLA in Sweden.
Mastitis is a major production disease, causing significant economic losses for dairy farmers in South-Asian countries, as well as other parts of the world. Udder health control programs (UHCP) have been established in developed countries as an effective strategy for mastitis control but have not yet been introduced in South-Asian low-income countries like Bangladesh, India, Pakistan, and Sri Lanka. To launch UHCP successfully in dairy herds in South-Asia, it is important to know the current prevalence and risk factors for subclinical mastitis (SCM). Therefore, a narrative literature review was conducted with the aim to describe the dairy sector, the prevalence of SCM and its causal agents, risk factors for mastitis occurrence and the control measures suggested by different studies conducted in the selected countries. The literature revealed that India had the highest cattle population. Milking was mainly done by hand in all of the studied countries. Stall feeding was done in Bangladesh and Sri Lanka and limited access to grazing was also reported in some farms in India and Pakistan. There was substantial variation in the prevalence of SCM between studies in all 4 countries, ranging from about 20% to about 80%, but the average prevalence across all studies was high (50%). The most common causal agents for SCM were non-aureus staphylococci (NAS), Staphylococcus (S.) aureus, Streptococcus spp. and Escherichia (E.) coli. The management related risk factors reported for SCM were stall feeding of cows, a higher stock density, cracked floors, open drains, the presence of flies, poor drainage, peri-parturient diseases, infrequent dung removal and earth floors. The control measures suggested in these studies were to improve the hygiene and sanitation of cows, to improve the cleanliness of farms and milker’s hands, to apply dry cow therapy, supplementing micronutrients and routine screening for SCM combined with taking intervention measures like isolation of cows or milking infected cows last, and proper treatment. Also, full hand milking, complete milking, machine milking, and providing feed and water immediately after milking have been recommended. Finally, we show that current literature often studies the same set of (non-manageable) risk factors, so more research is needed to obtain a comprehensive picture of the determinants of SCM. Randomized controlled trials are needed to truly quantify the effect of intervention under field conditions. Altogether, our work gives an overview of the udder health situation in South-Asia and provides the basis for the design of UHCP in this region.
Subclinical mastitis (SCM) in water buffalo is a production disease associated with decreased milk yield and impaired milk quality and safety. Water buffalo is an important livestock species in Bangladesh, but information about the occurrence and aetiology of SCM in this species is scarce. A cross-sectional study was conducted as part of the Udder Health Bangladesh Programme to (i) determine the occurrence of SCM and bulk milk somatic cell count (SCC) in water buffalo in Bangladesh, (ii) identify pathogens causing SCM and (iii) evaluate penicillin resistance in isolated staphylococci strains. Sixteen buffalo farms in the Bagerhat and Noakhali regions of Bangladesh were selected for study and a bulk milk sample was collected from each farm. In addition, 299 udder quarter milk samples were collected from 76 animals. The bulk milk samples were assessed by direct SCC and the quarter milk samples by California mastitis test (CMT). The occurrence of SCM calculated at quarter and animal level was 42.5 and 81.6%, respectively. Milk samples from 108 CMT-positive quarters in 48 animals and 38 randomly selected CMT-negative quarters in 24 animals were investigated using bacteriological culture. Estimated mean bulk milk SCC was 195 000 cells/ml milk (range 47 000- 587 000 cells/ml milk). On culture, estimated quarter-level intramammary infection (IMI) was 40.4%. The identity of isolated bacteria was confirmed by MALDI-TOF mass spectrometry. Non-aureus staphylococci (NAS) were the most common pathogens (24.7%) and, among 36 NAS tested, 36.1% were resistant to penicillin. Thus there was high occurrence of SCM on the study farms, with relatively high penicillin resistance in NAS. Further studies are needed to identify underlying risk factors and develop an udder health control strategy for water buffalo in Bangladesh.
Whole-genome sequencing was carried out on 30 Staphylococcus (S.) aureus isolates from dairy cows with subclinical mastitis from all five provinces of Rwanda. Twenty-five of the isolates produced enough sequence to be analyzed using core genome multilocus sequence typing (cg-MLST). The isolates group into three main clusters. The largest cluster contain isolates of sequence type (ST) 152 (n = 6) and the closely related ST1633 (n = 2). These sequence types have previously mainly been encountered in humans. The isolates of the second-largest cluster belong to ST5477 (n = 5),so far exclusively isolated from cows in Rwanda. The third cluster consists of isolates of ST97 (n = 4), which is a well-known bovine-adapted sequence type. These three clusters were all widespread over the country. Isolates of the usually human-adapted sequence types 1 (n = 2) and 5 (n= 1) were found and a single isolate of ST2430, previously found among humans in Africa. Finally, four isolates of novel sequence types were found: ST7108 (n = 2), ST7109 (n = 1), and ST7110 (n = 1). The blaZ penicillin resistance gene was found in 84% of the isolates and was in all cases corroborated by phenotypic resistance determination. Five (20%) of the isolates carried a tetracycline resistance gene, tet(K) or tetM, and three of these five also displayed phenotypic resistance while two isolates carried a tetM-gene but were yet tetracycline susceptible. Seven (28%) isolates carried the dfrG gene conferring resistance to trimethoprim. Four of these isolates indeed were resistant to trimethoprim while three isolates were sensitive. The str gene conferring resistance to aminoglycosides was found in three isolates; however, none of these displayed resistance to gentamycin. Our data revealed a high diversity of the sequence types of S. aureus isolates from cows with subclinical mastitis in Rwanda. Two major clusters of ST97 and ST5477 are likely to be bovine adapted and cause mastitis while the third cluster of ST152 usually have been found in humans and may signify a recent transmission of these types from human to cows, for example from hand milking. The high prevalence of this sequence type among dairy cows may pose zoonotic threat. The sequence types were widely distributed without any geographic correlation. Penicillin resistance, the most common type of resistance with a prevalence over 80%, but also tetracycline and trimethoprim resistance were displayed by several isolates.
This short communication addresses the hypothesis that the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) is low in dairy goats in Sweden. Methicillin-resistant S. aureus is a widespread zoonotic bacterium of clinical importance in both animals and humans. In Sweden, MRSA is rare among both animals and humans. However, MRSA has been detected in a few goat herds in Sweden with a high within-herd occurrence of mecC-MRSA, but only a limited number of herds were investigated and most of them were not producing milk for human consumption. The prevalence of MRSA among dairy goat herds in Sweden is not known and a cross-sectional prevalence study was therefore conducted. A total of 22 bulk milk samples from the same number of herds, and pooled swabs from nose, mouth, and perineum from 113 goats, were collected during August and September 2019 for bacteriological investigation. After culturing on selective media, suspected isolates were confirmed as S. aureus using MALDI-TOF and subjected to PCR targeting the mecA and mecC genes to confirm MRSA status. No samples were found to be positive for MRSA, and there are therefore no indications of a spread of MRSA in Swedish dairy goat herds.
Clinical mastitis (CM) is an important production disease in dairy cows, but much of the knowledge required to effectively control CM is lacking, specifically in low-income countries where most farms are small and have specific dairy management, such as regular udder cleaning and practicing hand milking. Therefore, we conducted a 6-month-long cohort study to (a) estimate the incidence rate of clinical mastitis (IRCM) at the cow and quarter level, (b) identify risk factors for the occurrence of CM, (c) describe the etiology of CM, and (d) quantify antimicrobial susceptibility (AMS) against commonly used antimicrobial agents in S. aureus and non-aureus Staphylococcus spp. (NAS) in dairy farms in the Chattogram region of Bangladesh. On 24 farms, all cows were monitored for CM during a 6-month period. Cases of CM were identified by trained farmers and milk samples were collected aseptically before administering any antimicrobial therapy. In total, 1383 lactating cows were enrolled, which totaled 446 cow-years at risk. During the study period, 196 new cases of CM occurred, resulting in an estimated crude IRCM of 43.9 cases per 100 cow-years, though this varied substantially between farms. Among the tested CM quarter samples, Streptococci (22.9%) followed by non-aureus staphylococci (20.3%) were the most frequently isolated pathogens and resistance of S. aureus and NAS against penicillin (2 out of 3 and 27 out of 39 isolates, respectively) and oxacillin (2 out of 3 and 38 out of 39 isolates, respectively) was common. The IRCM was associated with a high milk yield, 28 to 90 days in milk, and a higher body condition score. Our results show that there is substantial room for udder health improvement on most farms.