Dairy Farms Research Articles

Retrospective analysis of prevalence and risk factors of bovine lameness in dairy farms in South Africa

Lameness is a crippling problem in the dairy industry, posing a significant welfare challenge and leading to premature culling. The study aimed to determine the seasonal prevalence of lameness in two different provinces of South Africa. The data was collected in two local municipalities (Mpofana and Raymond Mhlaba). However, the computer software systems of four randomly selected dairy farms were used to collect retrospective secondary data for lameness and predisposing factors (2018–2022). The data's targeted parameters include breed, parity, weight, stage of lactation, diseases diagnosed (lameness), age, and milk production trends. The highest prevalence was observed in uMpofana municipality (58.8%) compared to Raymond Mhlaba municipality (41.2%). Among cattle above nine years of age, the prevalence of lameness was the highest (36%), compared to 7-8-year-old (24%), 4-6-year-old (21.7%), and 1-3-year-old (14.3%) cattle. Additionally, the highest prevalence of lameness was observed during the summer season, followed by spring, winter, and autumn. The strongest association is kept for the right front leg (p<0.0001), followed by the left front leg (p<0.001), right back leg (p<0.001), and left back leg (p<0.001). In conclusion, this study provides baseline information on several key factors influencing the prevalence of lameness in dairy cattle in various farms in uMpofana municipality and Raymond Mhlaba municipality. The study findings could be used for farm managerial decision-making and epidemiological interventions. Given the high prevalence of lameness in dairy farms in uMpofana municipality, there is a need for more focused research aimed at identifying the specific causes of lameness in these localities.

Prevalence, Cross Contamination, Virulence, and Multidrug Resistance Profiles of Staphylococcus aureus Isolates from Four Middle-Scale Dairy Farms in Bareilly, Northern India.

Milk, a nutritious global important food commodity, serves as an excellent medium for microbial growth as well. The foodborne pathogen Staphylococcus aureus is a commensal member of human microflora that enters the food chain through poor hygienic practices and cross contamination and causes various clinical manifestations in humans. During this study, raw milk and swab samples (milker's hand, udder, towel, milking bucket, and farm floor) were collected from four middle-scale buffalo dairy farms. The results revealed S. aureus presence in 11.6% (n = 56/448) bucket raw milk samples and 2.6% (n = 12/448) udder raw milk samples. Contrarily, S. aureus prevalence was significantly higher in farm floors (100%, n = 84/84), towel (35.7%, n = 10/28), milking bucket (11.6%, n = 56/448), milker's hand (10.7%, n = 3/28), and udder swab samples (4.0%, n = 18/448). The chi-square test yielded p values of 0.000, 0.005, and 0.0011 for udder raw milk, udder swab, and milker's hand swab, respectively. The p values of the milking bucket (p = 0.048) and farm floors (p = 0.0183) confirmed their possible role in S. aureus cross contamination. Gene amplifications of nuclease and enterotoxin A indicate potential virulence of S. aureus isolates in collected samples. Antibiotic susceptibility testing revealed multidrug resistance in 44% (n = 239) of S. aureus isolates with the highest resistance of 61% against penicillin. Resistance against ampicillin, streptomycin, and lincomycin was observed. Fewer S. aureus isolates were resistant to kanamycin and erythromycin, whereas the lowest number of resistant isolates was observed against chloramphenicol. A high prevalence of S. aureus in the farm environment and milking equipment suggested the cross contamination of potentially enterotoxin-producing and multidrug-resistant S. aureus to raw milk. Therefore, good hygiene practices should be enforced to avoid foodborne and zoonotic infections.

Daily and seasonal use of vocalizations by nesting black‐tailed godwits

Ground‐nesting shorebirds must balance the need for acoustic communication at the nest with the constant threat posed by predators. Although it may seem likely that their calls are adapted to minimize detection by predators, little is known about how these birds communicate at the nest or whether they employ cryptic strategies to avoid predation. Using passive acoustic devices and software to analyse extensive acoustic data, we quantified and categorised the calls of black‐tailed godwits Limosa limosa limosa recorded throughout the whole incubation at eight nests at a dairy farm in the Netherlands in March–June 2021. While incubating, godwits frequently use five main call types, with distinct diurnal patterns and high variation in the number of calls between breeding pairs. Birds used two quiet calls, one for communication at the nest and a second without an easily suggested meaning. Three loud calls were presumably used for predator alert, territory establishment, and long‐range communication. Interestingly, although nests were close to each other and exposed to the same aerial predators, the involvement of incubating birds in predator alert calling consistently differed. Furthermore, we described the relationship between the number of predator alert calls and the probability of a godwit flying off the nest. Our findings show that incubating godwits predominantly use loud vocalizations during the day, with only a few calls at night, which were more frequent on nights with a full moon. These descriptive findings for a single godwit community should now be expanded to other contexts, experimental situations, and shorebird species.

Transmission of a human isolate of clade 2.3.4.4b A(H5N1) virus in ferrets.

Since 2020, there has been unprecedented global spread of highly pathogenic avian influenza A(H5N1) in wild bird populations with spillover into a variety of mammalian species and sporadically humans1. In March 2024, clade 2.3.4.4b A(H5N1) virus was first detected in dairy cattle in the U.S., with subsequent detection in numerous states2, leading to over a dozen confirmed human cases3,4. In this study, we employed the ferret model, a well-characterized species that permits concurrent investigation of viral pathogenicity and transmissibility5 in the evaluation of A/Texas/37/2024 (TX/37) A(H5N1) virus isolated from a dairy farm worker in Texas6. Here, we show that the virus has a remarkable ability for robust systemic infection in ferrets, leading to high levels of virus shedding and spread to naïve contacts. Ferrets inoculated with TX/37 rapidly exhibited a severe and fatal infection, characterized by viremia and extrapulmonary spread. The virus efficiently transmitted in a direct contact setting and was capable of indirect transmission via fomites. Airborne transmission was corroborated by the detection of infectious virus shed into the air by infected animals, albeit at lower levels compared to the highly transmissible human seasonal and swine-origin H1 subtype strains. Our results show that despite maintaining anavian-like receptor binding specificity, TX/37 displays heightened virulence, transmissibility, and airborne shedding relative to other clade 2.3.4.4b virus isolated prior to the 2024 cattle outbreaks7, underscoring the need for continued public health vigilance.

The Effect Of Good Dairy Farming Implementation On The Income Level And Efficiency Of Dairy Cows Farmers Businesses In West Malang Regency

The research aims to identify the implementation of Good Dairy Farming Practice, measure the income and efficiency of livestock business. The research was conducted in West Malang Regency from November 2021 to February 2022 in three sub-districts namely Pujon, Ngantang and Kasembon. Samples were taken as many as 100 using purposive sampling method. Data analysis was descriptive quantitative to identify the Good Dairy Farming Practice score, analysis of business efficiency with Cobb Douglass Production Function Regression, analysis of business income and influential factors with Multiple Linear Regression. The results showed that the application of GDFP with sufficient score categories is health aspects (2.84), milking hygiene aspects (2.76), feed nutrition and drinking water aspects (2.43), animal welfare aspects (2.87), environmental aspects (2.64), and unfavorable score category is socio-economic aspects (1.37). The average income of dairy farmers is IDR 70,959,024 per year. The results of income regression analysis showed that the variables of health and nutrition aspects had a very significant effect, the milking hygiene aspect had a significant effect, and the environmental aspect had a less significant effect. The results of the efficiency of the use of factors of milk production with a value of 1.215 showed increasing returns to scale. All aspects of GDFP are in the sufficient category and the socio-economic aspects are in the unfavorable category. This makes the farmer's income less than optimal.

Genomic Prediction and Genome-Wide Association Studies for Productivity, Conformation and Heat Tolerance Traits in Tropical Smallholder Dairy Cows.

Genomic selection (GS) and genome-wide association studies (GWAS) have not been investigated in Vietnamese dairy cattle, even for basic milk production traits, largely due to the scarcity of individual phenotype recording in smallholder dairy farms (SDFs). This study aimed to estimate heritability (h2) and test the applicability of GS and GWAS for milk production, body conformation and novel heat tolerance traits using single test day phenotypic data. Thirty-two SDFs located in either the north (a lowland vs. a highland) or the south (a lowland vs. a highland) of Vietnam were each visited for an afternoon and the next morning to collect phenotype data of all lactating cows (n = 345). Tail hair from each cow was sampled for subsequent genotyping with a 50K SNP chip at that same visit. Milk production traits (single-test day) were milk yield (MILK, kg/cow/day), energy corrected milk yield adjusted for body weight (ECMbw, kg/100 kg BW/day), fat (mFA, %), protein (mPR, %) and dry matter (mDM, %). Conformation traits were body weight (BW, kg) and body condition score (BCS, 1 = thin to 5 = obese). Heat tolerance traits were panting score (PS, 0 = normal to 4.5 = extremely heat-stressed) and infrared temperatures (IRTs, °C) at 11 areas on the external body surface of the cow (inner vulval lip, outer vulval surface, inner tail base surface, ocular area, muzzle, armpit area, paralumbar fossa area, fore udder, rear udder, forehoof and hind hoof), assessed by an Infrared Camera. Univariate linear mixed models and a 10-fold cross-validation approach were applied for GS. Univariate single SNP mixed linear models were applied for the GWAS. Estimated h2 (using the genotype information to build relationships among animals) were moderate (0.20-0.37) for ECMbw, mFA, mPR, mRE, BW, BCS and IRT at rear udder; low (0.08-0.19) for PS and other IRTs; and very low (≤ 0.07) for MILK, ECM and mDM. Accuracy of genomic estimated breeding values (GEBVs) was low (≤ 0.12) for MILK, ECM, mDM and IRT at hind hoof; and moderate to high (0.32-0.46) for all other traits. The most significant regions on chromosomes (BTA) associated with milk production traits were 0.47-1.18 Mb on BTA14. Moderate to high h2 and moderate accuracies of GEBVs for mFA, mPR, ECMbw, BCS, BW, PS and IRTs at rear udder and outer vulval surface suggested that GS using single test day phenotypic data could be applied for these traits. However, a greater sample size is required to decrease the bias of GEBVs by GS and increase the power of detecting significant quantitative trait loci (QTLs) by GWAS.

Assessment of Bacterial Contamination and Antimicrobial Resistance of Escherichia coli Isolates from Slovak Dairy Farms

The conditions in livestock housing are suitable for the survival of airborne microorganisms, mainly due to high temperatures, humidity, and the presence of organic material. The total count of airborne bacteria concentrations in cattle farms ranged from 3.01 log10 CFU/mL to 6.90 log10 CFU/mL; for coliform bacteria, they were from 2.18 log10 CFU/mL to 3.34 log10 CFU/mL; and for molds, they ranged from 3.00 log10 CFU/mL to 4.57 log10 CFU/mL. Bacteria resistant to antimicrobial substances and resistance genes can be spread on animal farms. Antimicrobial resistance in ubiquitous Escherichia coli isolated from cattle feces was investigated. Minimum inhibitory concentration (MIC) testing was utilized to identify phenotypic resistance profiles, and the PCR method was employed to detect the presence of resistant genes. A higher percentage of resistance was found to amikacin (65%), tetracycline (61%), streptomycin (56%), ampicillin (55%), and nalidixic acid (45%). Multidrug resistance was determined in up to 64.3% of the isolates studied. The most widespread resistance genes were blaTEM (85.7%), sul2 (66.7%), tetB (52.38%), and sul1 (47.6%). We found that 4.8% of the E. coli isolates had the blaCMY gene. We found that, despite phenotypic resistance, E. coli isolates do not necessarily carry genes conferring resistance to that particular antimicrobial agent.

Phenotypic and Molecular Characterization of Staphylococcus aureus in Dairy Farms from Henan Province and the Inner Mongolia Autonomous Region, China

Staphylococcus aureus, a prevalent pathogen associated with infectious and foodborne diseases, is also a significant cause of intramammary infections in dairy farms. This study aimed to determine the phenotypic and molecular characterization of S. aureus in two different stock sizes of dairy farms in Henan province (HN) and the Inner Mongolia autonomous region (IM), China, through biofilm formation, antimicrobial resistance, virulence, and molecular type of S. aureus isolates. In HN, 74 S. aureus isolates (60.7%) were recovered from 122 bulk tank milk samples, while in IM, 24 S. aureus isolates (17.4%) were detected from 161 samples soured from various origins. Notably, 25.7% (19/74) of isolates in HN and 20.8% (5/24) in IM exhibited multidrug-resistant (MDR) phenotypes. Molecular typing revealed distinct patterns: ST97 (n = 32) and spa type t189 (n = 20) predominated in HN, whereas ST50 (n = 13) and spa type t518 (n = 11) were prevalent in IM. Additionally, three isolates harbored both tsst-1 and lukF-PV genes, and two MRSA strains displayed a MDR phenotype in raw milk samples from HN. Biofilm formation was observed in 91.8% strains. Phylogenetic analysis identified two subpopulations (lineages 1 and 2). Among them, cluster 6 in lineage 2 comprised S. aureus strains from three sources within a farm, suggesting potential cross contamination during different stages in IM. Remarkably, among 19 MDR isolates in HN, ST398 MSSA strains exhibited a higher multidrug resistance compared to non-ST398 MSSA strains. This study underscores the high prevalence and diverse characteristics of S. aureus in raw milk, necessitating enhanced surveillance and control measures to mitigate associated risk.

The Influence of Crossbreeding on the Composition of Protein and Fat Fractions in Milk: A Comparison Between Purebred Polish Holstein Friesian and Polish Holstein Friesian × Swedish Red Cows

Background/Objectives: In this study, the differences in protein and fat bioactive components between the milk from purebred Polish Holstein Friesian (PHF) cows and PHF cows crossbred with Swedish Red (SRB) were investigated. The objective was to assess the impact of genetic variation on the nutritional quality of their milk. Methods: This study was conducted at the Warsaw University of Life Sciences’ (WULS) experimental dairy farm in Warsaw, Poland, and involved 60 primiparous cows divided into two groups: 30 PHF×SRB crossbred cows and 30 purebred PHF cows. All cows were housed in a free-stall system with an average lactation yield exceeding 10,000 kg/lactation. The milk composition analyses included total protein, casein, whey protein, fatty acid profiles, and vitamin content. Results: Milk from the PHF×SRB hybrids showed a significantly greater total protein content (3.53%) compared to that from the purebred PHF cows (3.28%). The casein content was higher in the hybrids’ milk (2.90%) than the purebreds’ milk (2.78%), while the whey protein levels were lower in the purebred milk (0.50%) than in the hybrid milk (0.63%). The hybrids exhibited higher concentrations of certain saturated fatty acids in their milk, while the purebreds’ milk contained greater amounts of beneficial unsaturated fatty acids and fat-soluble vitamins—E, D, and K. Conclusions: These results indicate that genetic selection through crossbreeding can enhance the nutritional quality of milk. The differences observed in protein, fatty-acid, and vitamin content underscore the role of the genotype in milk composition, suggesting that breeding strategies can optimize dairy products’ health benefits.

Milk production and viability of the various smallholder dairying models used in Zimbabwe.

An evaluation of milk yield, dairy products and viability of the smallholder dairy production models used in Zimbabwe was carried out. We used secondary data on 1167 smallholder dairy farmers. These were categorised into commercial dairying (119), Milk collection centre (MCC) bulking and processing (145), MCC bulking and delivering to processor (87), farm gate (468) and other (348) models. Data were analysed using SPSS version 25.0. The average daily milk yield per cows was highest in the Commercial dairying model (9.20 ± 0.4l) but was not significantly different from the MCC bulking and processing and MCC bulking and delivering to processor models. Average lactation milk yield per cow was highest (P < 0.05) in the commercial dairying model (2804.91 ± 133.9l) and was significantly different from the rest of the models. The processed milk products identified in the study were fermented milk, pasteurised milk and unspecified products but production volumes were very low in the respective models. There were no differences (P > 0.05) in gross margin across all the smallholder dairying models. The commercial dairying model surpassed all models on proportion of pure exotic dairy breeds, number of milking cows, milk yield. However, it was discovered that all models were underperforming but smallholder dairy farmers can be recommended to adopt the commercial dairying model if measures to improve milk yield per cow and reduce milk production costs are established.

Evaluation of Musca domestica attractiveness for different baits in traps in milk production environments

This study aimed to verify the effectiveness of plastic bottle novel trap model for muscoids adults’ collection in dairy farms from Sinop, Mato Grosso State, Brazil, as well as evaluate the attractiveness of different baits for Musca domestica attraction. It was used four different baits. A total of 18,491 flies were collected in 30 days of study. The most efficient bait was made with fish viscera. These results show the efficiency of this novel model of proposed trap and a new destination for these packages.

Quantitative and qualitative responses of dairy cattle herds’ production to proper feeding

The primary objectives include the development of the agro-industrial complex of the Republic of Moldova and ensuring the population has access to quality products. The assessment of qualitative and quantitative indicators of milk production and processing in the country, reflects the dynamics of the dairy industry’s development and highlights the main issues that need solutions; hence, research on this matter remains relevant. The aim of this study was to analyze both the quantitative and qualitative indicators of milk production, at the educational dairy farm of the Technical University in Moldova. Additionally, a review of research on the development of recipes based on feedstock and an examination of factors influencing the quality of dairy products were conducted. It was concluded that overall, the quality of milk at the educational dairy farm, in terms of fat and density content, and organoleptic properties, is good.

Development and testing of a measuring chamber for a device for express analysis of milk quality in a flow

Mechanization and robotization of dairy farms require the development of technologies for assessing the quality of manufactured products. Monitoring milk composition and milking duration in real time is especially important for prompt response to deviations in animal physiological state parameters and timely adjustment of rations when milk yields decrease. The first version of the scatterometric device for express analysis of milk quality used a glass measuring chamber with a simple round cross-section, but it did not ensure the reduction of the turbulent flow of the milk-air mixture to laminar. This study presents the development and testing of a prototype of a measuring chamber that provides deceleration and laminarization of the milk-air mixture flow. The device operates at a milking capacity of 1 to 6 l/min, flow speed from 0.2 to 1.8 m/s. In the developed measuring chamber, a special bypass is created at an angle of 45° so that it has a common slot with the main tube. In this bypass, the flow of the milk-air mixture is slowed down to reduce turbulence and the number of air bubbles that interfere with the operation of scatterometric devices. The measurement area of the device is located in the upper part of the bypass. As a result, the developed measuring chamber has an internal diameter of the main part of 15 mm, the bypass of 11 mm, and provides close to 100% filling of the branch with liquid at the moment of the milk plug passage. The developed measuring chamber allowed the new version of the express milk quality analysis device to achieve increased accuracy and stability of measurements.

Assessing antimicrobial resistance in pasture-based dairy farms: a 15-month surveillance study in New Zealand.

Antimicrobial resistance is a global public and animal health concern. Antimicrobial resistance genes (ARGs) have been detected in dairy farm environments globally; however, few longitudinal studies have utilized shotgun metagenomics for ARG surveillance in pasture-based systems. This 15-month study aimed to undertake a baseline survey using shotgun metagenomics to assess the relative abundance and diversity of ARGs in two pasture-based dairy farm environments in New Zealand with different management practices. There was no statistically significant difference in overall ARG relative abundance between the two dairy farms (P = 0.321) during the study period. Compared with overseas data, the relative abundance of ARG copies per 16S rRNA gene in feces (0.08-0.17), effluent (0.03-0.37), soil (0.20-0.63), and bulk tank milk (0.0-0.12) samples was low. Models comparing the presence or absence of resistance classes found in >10% of all feces, effluent, and soil samples demonstrated no statistically significant associations (P > 0.05) with "season," and only multi-metal (P = 0.020) and tetracycline (P = 0.0003) resistance were significant at the "farm" level. Effluent samples harbored the most diverse ARGs, some with a recognized public health risk, whereas soil samples had the highest ARG relative abundance but without recognized health risks. This highlights the importance of considering the genomic context and risk of ARGs in metagenomic data sets. This study suggests that antimicrobial resistance on pasture-based dairy farms is low and provides essential baseline ARG surveillance data for such farming systems.IMPORTANCEAntimicrobial resistance is a global threat to human and animal health. Despite the detection of antimicrobial resistance genes (ARGs) in dairy farm environments globally, longitudinal surveillance in pasture-based systems remains limited. This study assessed the relative abundance and diversity of ARGs in two New Zealand dairy farms with different management practices and provided important baseline ARG surveillance data on pasture-based dairy farms. The overall ARG relative abundance on these two farms was low, which provides further evidence for consumers of the safety of New Zealand's export products. Effluent samples harbored the most diverse range of ARGs, some of which were classified with a recognized risk to public health, whereas soil samples had the highest ARG relative abundance; however, the soil ARGs were not classified with a recognized public health risk. This emphasizes the need to consider genomic context and risk as well as ARG relative abundance in resistome studies.

Herd-Level Risk Factors Associated with Mycoplasma bovis Serostatus in Youngstock on Irish Dairy Farms

Mycoplasma bovis is a globally significant pathogen of cattle associated with a wide range of clinical syndromes, including respiratory disease, mastitis, arthritis, otitis, and reproductive failure. Since its detection in Ireland in 1994, M. bovis has become a significant contributor to morbidity and mortality in Irish cattle. This study aimed to investigate herd-level risk factors associated with M. bovis seropositivity in replacement dairy heifers, using data from 105 Irish dairy herds. Ten heifers per herd were sampled on three occasions: spring 2018, spring 2019, and autumn 2019. Seropositivity was evaluated using two thresholds: ≥1 positive heifer (Model ≥ 1POS) and ≥3 positive heifers (Model ≥ 3POS). M. bovis seropositivity varied over time, with at least one positive heifer in 50.4% (95% confidence interval (CI): 40.5–60.3) of herds in spring 2018, 35.2% (95% CI: 26.2–45.1) in spring 2019, and 45.7% (95% CI: 36.0–55.7) in autumn 2019. Herds with three or more positive heifers increased from 31.4% (95%CI: 22.7–41.2) in spring 2018 to 42.9% (95% CI: 33.2–52.9) by autumn 2019. Risk factors for M. bovis seropositivity included the purchase of cattle, which significantly raised the odds of seropositivity across multiple visit periods (Model ≥ 1POS: Odds ratio (OR) 3.84, p = 0.02; Model ≥ 3POS: OR 3.69, p = 0.02). Managing more than three land parcels, housing heifer calves separately from bull calves, and sharing airspace between calves and older animals also increased seropositivity risks. Conversely, more colostrum feeds reduced the risk of seropositivity (Model ≥ 1POS: OR 0.81, p = 0.05), while colostrum quality assessment and feeding waste milk showed a trend toward increased risk. These findings suggest the importance of robust biosecurity measures, including limiting cattle purchases, improving calf management, and enhancing colostrum feeding practices, to control the spread of M. bovis. This study provides valuable insights into the epidemiology of M. bovis in Irish dairy herds, emphasising the need for targeted biosecurity and surveillance to safeguard herd productivity.

Anaerobic digestion of dairy cow and goat manure: Comparative assessment of biodegradability and greenhouse gas mitigation

This study evaluated the anaerobic digestion (AD) of dairy cow and goat manure from dairy farming operations. The physicochemical characteristics, biodegradability and greenhouse gas emissions (GHG) reduction potential were assessed. Dairy goat manure exhibited higher volatile solids (16 % vs. 10 %) and 34 % greater chemical oxygen demand content (COD) compared to cow manure, indicating better suitability for AD. However, biochemical methane potential tests revealed higher methane yields from cow manure (81 % biodegradability) compared to goat manure (26 % biodegradability), attributed to slower hydrolysis rates and recalcitrant composition of goat manure. Both manures displayed suboptimal carbon-to-nitrogen ratios (<20:1) and excessive levels of mineral nutrients such as calcium. The ammonia–nitrogen and volatile fatty acid levels remained below threshold limits throughout the anaerobic digestion process, indicating no significant accumulation or inhibition. Recovering biogas through AD showed potential GHG reductions of 64 % (2.21 t CO2-eq/cow·year) and 69 % (0.27 t CO2-eq/goat·year) compared to conventional manure management practices. While pretreatment and co-digestion could enhance biogas production, further research is needed to optimise these strategies for efficient resource recovery and environmental sustainability in dairy farming operations.Abbreviations: AD, anaerobic digestion; AWMS, animal waste management systems; BMP, biochemical methane potential; CHNS, carbon, hydrogen, nitrogen, and sulphur; C/N, carbon-to-nitrogen, COD, chemical oxygen demand; GC-FID, gas chromatography-flame ionisation detection; GHG, greenhouse gas; GWPM, global warming potential of methane; He, helium; ICP-MS, inductively coupled plasma mass spectrometry; I/S, inoculum-to-substrate ratio; IPCC, International Panel on Climate Change; NH3-N, ammonia–nitrogen; SD, standard deviation; TBMP, theoretical biochemical methane potential; TN, total nitrogen; TS, total solids; VFAs, volatile fatty acids; VS, volatile solids.

Prevalence, antimicrobial resistance, virulence gene distribution and SCCmec typing of methicillin-resistant Staphylococcus aureus isolated from raw milk and dairy products

Background and Objectives: Researchers have focused on Staphylococcus aureus because it is transmitted through food, such as milk and dairy products, and causes human diseases. Prevalence, antimicrobial resistance, presence, and distribution of methicillin-resistant S. aureus (MRSA) virulence genes isolated from raw milk and dairy products were evaluated. Materials and Methods: 300 samples of dairy products were collected from Shahrekord, Iran. S. aureus was identified using biochemical tests and screened for sensitivity to 13 antibiotics to identify resistance genes. In addition, SCCmec typing was performed. Results: Out of 300, S. aureus was found in 82 samples. Raw milk had the highest contamination with S. aureus (60 of 82), followed by cheese (15 of 82), and butter (7 of 82). At least one resistance gene was present in every isolate of S. aureus. Virulence factors and enterotoxin-coding genes, such as sea, seb, sec, and sed were highly distributed. Conclusion: The results of this study revealed the presence of toxin-producing MRSA strains in raw milk and dairy products. MRSA in dairy farms is an important risk factor for the spread of staphylococcal infections; therefore, further studies are needed to find strategies for controlling the presence of S. aureus, especially MRSA, in dairy products.

Extended-spectrum beta-laktamase (ESBL) enzyme producing bacteria isolated from rectal swabs of around animals in dairy farms

This study aims to identify bacterial contamination of Klebsiella pneumoniae and Escherichia coli producing Extended Spectrum Beta Lactamase (ESBL) isolated from rectal swabs of local animals on a dairy farm in Deyeng Village, Kediri, East Java. Interviews and observations were conducted with farmers to obtain the required risk factor data (cleanliness of drinking and eating places, drinking water sources, and administration of antibiotics to livestock). The number of samples tested in this study was 34 samples, including 12 chicken samples, 8 goat samples, 5 duck samples, 4 rabbit samples, 3 cat samples and 2 goose samples. Samples were isolated on MCA media + cefotaxime 1 mg/l and isolated again on MCA media without the addition of antibiotics to multiply pure bacterial colonies. The tests carried out to determine the presence of ESBL-producing bacteria are biochemical tests, namely the IMViC test (Indole, Methyl red, Voges-Proskauer, Citrate Utilization), TSIA (Triple Sugar Iron Agar) test, gram staining, and the Double Disk Standard Method test using β-lactam disc antibiotics, namely cefotaxime 30μg, ceftazidime 30μg, and amoxycilline-clavulanate acid 30μg. The results of this research were that 6 samples or 17.6% of ESBL-producing bacteria were identified from poultry groups (chickens, ducks and geese) from dairy farms in Deyeng Village, Kediri Regency, East Java.

Effect of Subclinical Mastitis Detected in the First Month of Lactation on the Reproductive Performance of Dairy Cows in Western Algeria

Background: The current study aimed to detect in the first month of lactation the prevalence and risk factors of subclinical mastitis (SCM) and its effects on reproductive performance in dairy cows in western Algeria. Methods: 530 cows from 18 herds were examined in the study. California Mastitis Test (CMT) was used to screen subclinical mastitis for individual cows and a score of two or more for any quarter without any clinical symptoms and abnormalities in milk was considered as positive for SCM. Milk samples positive for subclinical mastitis were subjected to bacteriological analysis. Result: The present study revealed a prevalence of subclinical mastitis of 34.90%, (185 of 530). The most common pathogen identified from CMT-positive milk samples was Staphylococcus aureus with 35.62%. Logistic regression analysis showed that parity, farming system and milking method affect significantly the prevalence of SCM. Subclinical mastitis during the first month of lactation affected significantly the reproductive performance by increasing calving to first service interval (CFSI), calving-to-conception interval (CCI)and number of services per conception (NSPC). The results of this study highlight the importance of mastitis control programs in dairy farms by showing that a high frequency of subclinical mastitis caused by Staphylococcus aureus may have a negative impact on the reproductive performance of dairy cows.

Different sources of alfalfa hay alter the composition of rumen microbiota in mid-lactation Holstein cows without affecting production performance

Alfalfa hay is a commonly used and important feed ingredient in dairy production. To better expand the alfalfa supply market, it is of great significance to explore the impact of alfalfa hay from different sources on dairy cow production performance. This study compared the effects of imported alfalfa hay from America (AAH) and Spain (SAH) on lactation performance and rumen microbiota of cows. Three hundred and sixty healthy mid-lactation Holstein cows with similar body weight, milk yield, and parity were randomly divided into two groups fed diets based on AAH or SAH for a 70-day experimental period. Each group was composed of four pens, with 45 cows in each pen. Daily records were kept for MY per cow and dry matter intake per pen. Twelve randomly selected cows per group were sampled to collect milk, feces, rumen fluid, and blood. The findings revealed no significant differences between the two groups in terms of production performance, nutrient apparent digestibility, serum biochemical indices, or rumen fermentation parameters. However, rumen microbial composition differed significantly between the two groups of cows based on β-diversity. On the genus level, the relative abundance of Prevotella, Succinivibrionaceae_UCG-002 increased while that of NK4A214_group, Ruminococcus, norank_f_F082 and Lachnospiraceae_NK3A20_group decreased in the SAH group compared with AAH group. There was no significant correlation between these core differential bacteria and the molar proportions of acetate and propionate, the concentration of total volatile fatty acids, and milk yield. In conclusion, the feeding effects of SAH were similar to those of AAH. These findings provided a reference for the application of alfalfa hay from different sources and for the improvement of the economic benefit of dairy farms.