Somatic Cell Count Research Articles

Effect of post-milking teat dipping on milk quality and udder health of crossbred cows.

We aimed to determine the efficacy of different post-milking teat dips in the prevention of intramammary infection and teat condition scores in common crossbred cows (Holstein Frisian × Tharparkar) found in Indian sub-tropical conditions. Eighty healthy crossbred cows were selected and randomly divided into four groups: untreated control, 1% w/v iodine, 5% v/v lactic acid and finally essential oil mix (eucalyptus, lavender, peppermint, and tea tree oils). Samples were collected quarter-wise (n = 308). Sampling as well as teat scoring was done simultaneously. 1st sample was collected before starting teat dipping, followed by 15th day in milk (DIM), 45th DIM and 90th DIM, respectively. The study found that post-milking teat dipping significantly reduced the mean California mastitis test score, somatic cell count and electrical conductivity of the milk in the treatment groups compared to the control group, and also improved milk yield in the treatment groups. There were no differences between the individual treatments. The study also found a significant reduction in teat end condition and teat skin condition after 90 d of post-milking teat dipping.

The effect of ambient temperature and relative humidity in postpartum dairy cows on productive and reproductive performance and biochemical blood indices in the subsequent lactation

Abstract This study evaluated the effects of ambient temperature (T) and relative humidity (RH) during the postpartum transition period on dairy cows’ milk performance, fertility, and immunometabolic blood indices in the subsequent lactation. A total of 100 Polish Holstein-Friesian cows originating from five commercial dairy farms were categorized into three groups based on average T (<16 °C, 16-20 °C and >20 °C) and RH (<65%, 65-75%, and >75%) on the calving day (0d), and days 7, 14, 21 after calving. With increasing T and RH postpartum, the average daily milk yield during the first 150 days in milk decreased gradually, and the differences between T <16 °C and >20 °C and RH <65% and >75% groups were approx. 3.48 and 2.78 kg, respectively. Milk of cows exposed to increased T and RH was lower in protein, and lactose and higher in fat, milk urea, and somatic cell count. It was also characterized by altered fat composition. Ambient T during the postpartum period had a negative effect on cows’ fertility, which, however, was not affected by RH. The increasing T from <16 °C to >20 °C resulted in the later manifestation of the first estrous (by 27.7 days), a more extended artificial insemination service period (by 19.4 days), a higher number of insemination services per conception (by 0.92 on average), more days open (by 43.3 days), and a longer calving interval (by 43.3 days). Within ranges used in this study, increasing T and RH during the period from d 0 to d 14 postpartum led to decreased body condition score on day 21 by approx. 0.48 and 0.51 points, respectively. Furthermore, T and RH on a calving day were associated with altered biochemical blood indices on d 21 after calving, indicating a more severe negative energy balance and a state of inflammation. The results of this study suggest that dairy cows that calve when T >16 °C should be provided cooling to ensure optimal environmental conditions for high milk production and prevent economic losses associated with reduced milk yield and low fertility.

Influence of the new wavy teat liner “Stimulor StressLess” on milk yield performance and its quality in dairy cows: Results of a field study

The ideal milking system meets the physiological needs of dairy cows to increase milk yield, achieve better milk quality and maintain healthy udders. Therefore, the settings of the milking machine and the properties of the teat cup liners are very important on dairy farms. The aim of the present study was to test a new teat cup liner “Stimulor StressLess” (SSL) in two commercial dairy farms and to investigate its influence on daily milk production and quality having different experimental settings. For this purpose, 40 dairy cows of different breeds in Tirol, Austria (farm 1) were investigated for 6 months, where 3 months represent the control phase (Gr 1) and milked with conventional teat liners, and the second 3 months phase (Gr 2) was the experimental phase and milked with SSL teat cup liners. On the second farm 90 dairy cows of Simmental breed in Baden-Württemberg, Germany (farm 2) were examined for one year equally divided in the first 6 months of control phase and second 6 months of treatment phase. All cows on both farms had the same stage of lactation and lactation number. During the study period, the daily milk production of each cow was recorded and milk samples were collected to determine the ingredients. The results showed that higher daily milk production and better milk quality were observed after using the new SSL teat cup liner in the existing milking machines. However, the use of the new teat cup liner SSL was more efficient in the longer treatment in farm 2 than in farm 1. In addition, after the use of the new SSL teat cup liner, the udders remained healthy throughout the study period, showing lower somatic cell counts (SCC). It can be concluded that high milk yield and better milk quality can be achieved by using SSL teat cup liners, as they are adapted to all teat shapes and dimensions.

Influence of the new wavy teat liner “Stimulor StressLess” on milk yield performance and its quality in dairy cows: Results of a field study

The ideal milking system meets the physiological needs of dairy cows to increase milk yield, achieve better milk quality and maintain healthy udders. Therefore, the settings of the milking machine and the properties of the teat cup liners are very important on dairy farms. The aim of the present study was to test a new teat cup liner “Stimulor StressLess” (SSL) in two commercial dairy farms and to investigate its influence on daily milk production and quality having different experimental settings. For this purpose, 40 dairy cows of different breeds in Tirol, Austria (farm 1) were investigated for 6 months, where 3 months represent the control phase (Gr 1) and milked with conventional teat liners, and the second 3 months phase (Gr 2) was the experimental phase and milked with SSL teat cup liners. On the second farm 90 dairy cows of Simmental breed in Baden-Württemberg, Germany (farm 2) were examined for one year equally divided in the first 6 months of control phase and second 6 months of treatment phase. All cows on both farms had the same stage of lactation and lactation number. During the study period, the daily milk production of each cow was recorded and milk samples were collected to determine the ingredients. The results showed that higher daily milk production and better milk quality were observed after using the new SSL teat cup liner in the existing milking machines. However, the use of the new teat cup liner SSL was more efficient in the longer treatment in farm 2 than in farm 1. In addition, after the use of the new SSL teat cup liner, the udders remained healthy throughout the study period, showing lower somatic cell counts (SCC). It can be concluded that high milk yield and better milk quality can be achieved by using SSL teat cup liners, as they are adapted to all teat shapes and dimensions.

Transcriptomic and Metabolomics Joint Analyses Reveal the Influence of Gene and Metabolite Expression in Blood on the Lactation Performance of Dual-Purpose Cattle (Bos taurus).

Blood is an important component for maintaining animal lives and synthesizing sugars, lipids, and proteins in organs. Revealing the relationship between genes and metabolite expression and milk somatic cell count (SCC), milk fat percentage, milk protein percentage, and lactose percentage in blood is helpful for understanding the molecular regulation mechanism of milk formation. Therefore, we separated the buffy coat and plasma from the blood of Xinjiang Brown cattle (XJBC) and Chinese Simmental cattle (CSC), which exhibit high and low SCC/milk fat percentage/milk protein percentage/lactose percentages, respectively. The expression of genes in blood and the metabolites in plasma was detected via RNA-Seq and LC-MS/MS, respectively. Based on the weighted gene coexpression network analysis (WGCNA) and functional enrichment analysis of differentially expressed genes (DEGs), we further found that the expression of genes in the blood mainly affected the SCC and milk fat percentage. Immune or inflammatory-response-related pathways were involved in the regulation of SCC, milk fat percentage, milk protein percentage, and lactose percentage. The joint analysis of the metabolome and transcriptome further indicated that, in blood, the metabolism pathways of purine, glutathione, glycerophospholipid, glycine, arginine, and proline are also associated with SCC, while lipid metabolism and amino-acid-related metabolism pathways are associated with milk fat percentage and milk protein percentage, respectively. Finally, related SCC, milk fat percentage, and milk protein percentage DEGs and DEMs were mainly identified in the blood.

Molecular Characteristics and Processing Technologies of Dairy Products from Non-Traditional Species.

Non-bovine dairy animals, commonly referred to as non-traditional dairy species, include goats, sheep, yaks, buffalo, donkeys, alpacas, llamas, and other less commonly farmed species. These animals have been integral to livestock systems since ancient times, providing milk and other essential products. Despite their historical significance, dairy production from many of these species remains predominantly confined to rural areas in developing countries, where scientific advancements and technical improvements are often limited. As a consequence of this, the scientific literature and technological developments in the processing and characterization of dairy products from these species have lagged behind those for cow's milk. This review aims to compile and analyze existing research on dairy products derived from non-traditional animals, focusing on their molecular characteristics, including proteins (alpha, beta, kappa, and total casein), fats (cholesterol and total fat), lactose, albumin, ash, total solids, and somatic cell count, among others, for each of these species. Additionally, we discuss emerging technologies employed in their processing, encompassing both non-thermal methods (such as high-pressure processing, pulsed electric fields, ultrasound processing, UV-C irradiation, gamma radiation, microfiltration, and cold plasma processing) and thermal methods (such as ohmic heating). This review also explores the specific potential applications and challenges of implementing these technologies. By synthesizing recent findings, we aim to stimulate further research into innovative technologies and strategies that can enhance the quality and yield of non-bovine dairy products. Understanding the unique properties of milk from these species may lead to new opportunities for product development, improved processing methods, and increased commercialization in both developing and developed markets.

RELAÇÃO ENTRE BOAS PRÁTICAS DE ORDENHA, ÍNDICES DE QUALIDADE DE LEITE E BEM-ESTAR ANIMAL

Milk quality is directly related to milking management practices and herd health, with mastitis being one of the main diseases that compromise milk production. This study aimed to evaluate the impact of good milking practices on milk quality and animal welfare, with an emphasis on reducing mastitis and somatic cell count (SCC). The research was carried out at Fazenda Roxa, in Candeal-BA, with 70 cows, 40 of which were in lactation. Milk samples were collected before and after the implementation of good practices, which included reorganization of the milking line, disinfection of teats, cup testing for mastitis detection, and training of milkers. The results showed a significant reduction in SCC, from 1,100,000 cells/ml to 550,000 cells/ml, within the limits of the Ministério da Agricultura, Pecuária e Abastecimento (MAPA). Furthermore, there was a decrease in the incidence of clinical mastitis, indicating the effectiveness of good practices in improving milk quality. The study also showed that such practices contribute to animal welfare and the production of healthier milk, with economic benefits for producers. The implementation of these practices is essential to ensure the production of healthy milk, with positive impacts on the quality of food products and food safety.

Computational Identification of Milk Trait Regulation Through Transcription Factor Cooperation in Murciano-Granadina Goats.

The Murciano-Granadina goat (MUG) is a renowned dairy breed, known for its adaptability and resilience, as well as for its exceptional milk traits characterized by high protein and fat content, along with low somatic cell counts. These traits are governed by complex biological processes, crucial in shaping phenotypic diversity. Thus, it is imperative to explore the factors regulating milk production and lactation for this breed. In this study, we investigated the genetic architecture of seven milk traits in MUGs, employing a two-step computational analysis to examine genotype-phenotype associations. Initially, a random forest algorithm identified the relative importance of each single-nucleotide polymorphism (SNP) in determining the traits of interest. The second step applied an information theory-based approach to exploring the complex genetic architecture of quantitative milk traits, focusing on epistatic interactions that may have been overlooked in the first step. These approaches allowed us to identify an almost distinct set of candidate genes for each trait. In contrast, by analyzing the promoter regions of these genes, we revealed common regulatory networks among the milk traits under study. These findings are crucial for understanding the molecular mechanisms underlying gene regulation, and they highlight the pivotal role of transcription factors (TFs) and their preferential interactions in the development of these traits. Notably, TFs such as DBP, HAND1E47, HOXA4, PPARA, and THAP1 were consistently identified for all traits, highlighting their important roles in immunity within the mammary gland and milk production during lactation.

Metabolic Fingerprinting of Blood and Urine of Dairy Cows Affected by Bovine Leukemia Virus: A Mass Spectrometry Approach.

This study investigated metabolic changes associated with bovine leukemia virus (BLV) infection in dairy cows, focusing on pre-parturition alterations. Metabolite identification in serum and urine samples was performed using a targeted metabolomics method, employing the TMIC Prime kit in combination with flow injection analysis and liquid chromatography-tandem mass spectrometry. Of 145 cows examined, 42 (28.9%) were BLV-seropositive. Around 38% of infected cows showed high somatic cell counts indicative of subclinical mastitis, with 15 experiencing additional health issues such as ketosis, milk fever, and lameness. Despite these conditions, no significant differences in milk yield or composition were observed between the infected and control groups. Metabolomic analysis conducted at -8 and -4 weeks prepartum revealed significant metabolic differences between BLV-infected and healthy cows. At -8 weeks, 30 serum metabolites were altered, including sphingomyelins, lysophosphatidylcholines, amino acids, and acylcarnitines, suggesting disruptions in membrane integrity, energy metabolism, and immune function indicative of early neoplastic transformations. By -4 weeks, the number of altered metabolites decreased to 17, continuing to reflect metabolic disruptions in cows with leukemia. Multivariate analysis highlighted distinct metabolic profiles between infected and control cows, identifying key discriminating metabolites such as choline, aspartic acid, phenylalanine, and arginine. Urine metabolomics revealed significant prepartum shifts in metabolites related to glucose, asymmetric dimethylarginine, and pyruvic acid, among others. The research confirmed metabolomics' efficacy in defining a BLV infection metabolic profile, elucidating leukosis-associated metabolic disruptions. This approach facilitates the identification of BLV-infected cows and enhances understanding of infection pathophysiology, providing a foundation for advanced management and intervention strategies in dairy herds. The study underscores the profound impact of leukosis on metabolic processes and highlights urine metabolomics' utility in non-invasively detecting BLV infection, offering the potential for improved herd health management.

Bactericidal activities and biochemical features of 16 antimicrobial peptides against bovine-mastitis causative pathogens

Mastitis, often caused by bacterial infection, is an inflammatory condition affecting the mammary glands. The condition is particularly prevalent in dairy cattle. Current treatment of bovine mastitis heavily relies on the use of antibiotics. To identify alternative solutions to antibiotic use, we evaluated the antimicrobial activity of 14 cathelicidins reported from 10 animal species. In conjunction, we assessed two bacteriocins against the bovine-mastitis causative bacterial panel, consisting of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Streptococcus agalactiae, Streptococcus dysgalactiae, and Streptococcus equi. Among the antimicrobial peptides (AMPs), cc-CATH3, ML-CATH, and PD-CATH proved to be highly active (minimum inhibitory concentration of 2–41 μg/mL, 0.2–10.3 μM) against all bacterial strains in the panel and field isolates from milk, with elevated somatic cell counts (≥ 500,000 cells/mL). Of the AMPs tested in this study, ML-CATH presented the highest level of effectiveness in controlling mastitis-associated bacterial strains while also possessing minimal cytotoxicity and functional stability against pH change and a high salt condition. The results of in silico analyses on the biochemical features of 12 helical cathelicidins revealed that the charge of AMPs appears to be a major determinant in killing Gram-negative bacteria. Furthermore, we observed a unique motif, “N(n≥3)-P(n≥1)-N(n≥3)”, from the sequences of PMAP-36, cc-CATH3, ML-CATH, and PD-CATH that exhibits potent antimicrobial activity against a broad spectrum of bacteria compared to others. Our findings support the proposition that AMPs could serve as effective antimicrobial alternatives to conventional antibiotics in treating complex animal diseases caused by microbial infection, such as bovine mastitis.

Increase in dairy production of goats with subclinical nematode infection using injectable eprinomectin

The effect of the treatment with an injectable product containing eprinomectin on milk yield, milk composition, and somatic cell count (SCC) was investigated in naturally infected dairy goats with low gastrointestinal nematode faecal egg and pulmonary larval counts. The study involved 394 lactating goats and was conducted on a farm in southern Spain. Before treatment, faeces from all animals were analysed to establish two homogeneous groups according to the gastrointestinal nematode egg counts (185 treated and 209 untreated). On day 0, each goat in the treatment group received a single subcutaneous injection of 12 mg of eprinomectin (0.6 ml of Eprecis®, CEVA, Spain). The control goats were left untreated. Faecal egg counts and coprocultures were performed on days 0, 30, 60, and 90 post-treatment. Milk samples were taken on days 0, 30, 60, 90, and 120 and analysed to determine individual production and milk composition parameters, including fat (F), protein (P), lactose (L), total dry extract (TDE), and SCC. Examination of faecal samples indicated that the goats were mainly infected with gastrointestinal strongylids of the genera Teladorsagia and Trichostrongylus and Muellerius lungworms. The percentage reduction of gastrointestinal nematode faecal egg counts on days 30, 60, and 90 was 97.55 % (90 % CI = 95.1 % - 99.9 %), 90.65 % (90 % CI = 83.7 % - 97.6 %) and 87.5 % (90 % CI = 79.5 % - 95.5 %), respectively, and that of lung larval counts in faeces was 98.48 % (90 % CI = 96.3 % - 100 %), 96.91 % (90 % CI = 84.2 % - 98.9 %), and 82.05 % (90 % CI = 66.9 % - 97.2 %), respectively. Milk yield was consistently and significantly higher in the treated group than in the control group (p = 0.004). The treated goats showed a 4 % increase in daily milk yield (60 ml/day) compared with the untreated goats. There was a significant decrease in F and TDE in the treated goats compared with the untreated goats, but eprinomectin did not affect P, L, and SCC. The estimated economic benefit of using injectable eprinomectin was around 6.46€ per goat over the 120-day period. In conclusion, treatment with injectable eprinomectin has an economical positive effect on milk yield in goats, even those infected with a low burden of gastrointestinal and pulmonary nematodes.

Cytokine profile, differential somatic cell count, and oxidative status of Italian Mediterranean buffalo milk affected by the temperature-humidity index.

In the context of climate change, there has been an increased interest in improving management practices for animals genetically adapted to extreme environmental conditions, such as buffaloes. The temperature-humidity index (THI) is used to determine the severity of heat stress in livestock. This study aimed to evaluate the cytokine profile, oxidative staus, differential somatic cell count (DCC), and the surface expression and activity of myeloperoxidase (MPO) in the somatic cells (SCs) of buffalo. Milk samples (n = 216) were collected from the spring to summer season under three different THI classes (THI < 72; ≤72 THI < 76, and THI ≥ 76). The cytokine profile was determined using ELISA, and the expression of DSCC and MPO was determined by flow cytometry. MPO activity was performed on SC extracts using a specific ELISA kit. Oxidative status was determined by the antioxidant/oxidant balance combining the free radical scavenging activity levels, and reactive oxygen and nitrogenous species. The results on the cytokine profile showed that at the THI ≥ 76 the levels of both IL-10 and IFN-γ were highest. IL-1β secretion was lower at the THI < 72 than at the THI values ranging from ≤72 THI < 76. Higher levels of both TNF-α and IL-12 were registered in both THI < 72 and THI ≥ 76 classes. The level of IL-4 was higher in the THI ≥ 76 class than in the ≤72 to <76 range. Data on DCC showed a decrease in the percentage of macrophages and lymphocytes as the THI increased from the ≤72 to <76 range to THI ≥ 76. Furthermore, the highest percentage of polymorphonuclear leukocyte (PMNLs) was registered in both ≤72 to <76 and THI ≥ 76 classes. The MPO activity and surface expression on SC were lower at a THI above 76, which could be associated with an absence of inflammation. A condition of oxidative imbalance was registered as demonstrated by the lower levels of antioxidant/oxidant balance along with increasing THI. Present data demonstrated that buffaloes were able to modulate the alteration of immune response activated by heat stress throughout a series of cross-linked mechanisms involving cytokine networks, different somatic cell distribution, and oxidative status.

Mycoplasma bovis 5'-nucleotidase is a virulence factor conferring mammary fitness in bovine mastitis.

Nucleases and 5' nucleotidase (5'-NT) play essential roles in cell biology and are often associated with bacterial virulence. In Mycoplasma spp., which have limited metabolic capacities and rely on nutrient availability, these enzymes are of significant importance for nucleotide salvage. This study explores the potential role of 2 membrane-associated lipoproteins, the major nuclease MnuA and 5'-NT, in Mycoplasma bovis mastitis. Mutants deficient in MnuA (mnuA::Tn) and in 5'-NT (0690::Tn) were identified through genome-wide transposon mutagenesis of M. bovis PG45 type strain and their fitness and virulence were assessed both in vitro, in axenic medium, and in vivo, using murine and cow mastitis models. The mnuA::Tn mutant demonstrated reduced nuclease activity, while 0690::Tn exhibited slow log-phase growth and impaired hydrolase activity towards nucleotides as well as deoxynucleotides (dAMP and dGMP). In comparison to the parent strain, the 0690::Tn mutant displayed markedly reduced fitness, as evidenced by a significant decrease or even absence in post-challenge mycoplasma counts in murine and cow mammary tissues, respectively. Moreover, the 0690::Tn mutant failed to induce mastitis in both experimental models. Conversely, the mnuA::Tn mutant induced inflammation in murine mammary glands, characterized by neutrophil infiltration and increased expression of major inflammatory genes. In cows, the mnuA::Tn was able to cause an increase in somatic cell counts in a manner comparable to the wild type, recruit neutrophils, and induce mastitis. Collectively, these findings provide complementary insights, revealing that disruption of 5'-NT significantly attenuated M. bovis pathogenicity, whereas a MnuA-deficient mutant retained the ability to cause mastitis.

Relationship of season with milk characteristics, yield, and shelf life of cheese in a hot climate

E Objective: the objective of the study was to identify whether there is a relationship between the environmental conditions of high temperature and humidity with the parameters of cheese yield and shelf life of Oaxaca-type cheese, made throughout two different times of the year, delimited by environmental temperature, in the Mexicali Valley, Baja California, Mexico. Design/ Methodology/ Approach: from January to November, ambient temperature and relative humidity, characteristics of the milk used at the time of reception (temperature, acidity, density, somatic cell count and microorganism count), yield, and shelf life of the cheese were recorded. These variables were related to season (summer and winter) and to different Temperature and Humidity Index– THI intervals. An analysis of variance was performed, also, the relationship among sets of variables by Pearson correlation, and the multiple mean difference with the Tukey test (p ≤ 0.05). Results: significant differences were observed in the density, acidity, temperature, somatic cell count and cheese yield of milk due to the effect of the time of year. In addition, an 11% decrease in cheese yield was found as the maximum THI exceeded 77 units. The shelf life showed positive significant difference (p ≤ 0.05) when milk was pasteurized, but it was not affected by the THI. Limitations/ Implications of the study: this study was limited to a single period of analysis; so, it is necessary to monitor, and include additional milk quality variables. Conclusions: heat environmental conditions negatively impact the characteristics of the milk, therefore reducing the yield of Oaxaca-type cheese. The microbiological characteristics are unfavorable during the hot season; the pasteurization of milk is the main factor that increases the shelf life of the cheese.

Impact of training dairy farm personnel on milking routine compliance, udder health, and milk quality

Among various farm procedures, an appropriate milking routine is crucial for reducing mastitis and enhancing milk safety and quality. However, inadequate compliance with milking routines remains a primary factor contributing to variability of milk quality among herds. Training farm workers is essential for ensuring compliance with milking routines, which directly impacts milk quality and udder health. In this study, we aimed to assess the impact of a training session on dairy farm workers' understanding of the milking routine, behavioral changes during milking, and subsequent effects on milk quality and udder health. Farm workers (n = 112) from 16 commercial dairy farms in Michigan and Ohio participated in the project. The training session was delivered using an active learning approach prioritizing group discussions, and focused on the pathogenesis, identification, and risk factors for mastitis, and the rationale and importance of each step in the milking routine. Pre- and post-training evaluations were conducted to measure changes in knowledge, parlor evaluations were performed to determine behavioral change, and data from clinical mastitis cases and bulk tank somatic cell count were used to estimate udder health and milk quality. Segmented and linear mixed regression analyses were used to assess the impact of the training intervention. Participants were mostly milking technicians (61.1%) with 70% of them having less than 1 year of experience and a median tenure in their jobs of 9 mo. Knowledge of the milking routine increased from 49.3% to 67.6% of correct answers after training. Based on parlor evaluations, the pre-milking disinfectant contact time increased by 9 s per cow. The percentage of milkings with inadequate preparation time decreased from 69% (before training) to 48% (after training). The proportion of insufficient teat coverage during post-milking disinfection decreased from 9.8% (77 out of 782) before training to 5.9% (34 out of 572) after training. There was a significant increase in clinical mastitis cases during the immediate week after the training. Additionally, the upward trend in bulk tank somatic cell count was halted. Our results suggest an improvement in overall mastitis identification and milk quality, underscoring the importance of targeted training programs for farm workers in improving milking routine compliance, enhancing milk quality, and promoting better udder health.

Somatic cell count in dairy goats I: association with infectious and non-infectious factors

BackgroundIntramammary infections negatively affect milk quality, animal welfare and productivity in the dairy industry. Somatic cell count (SCC) is the most used screening tool to detect subclinical mastitis caused by intramammary infections. In dairy goats, SCC is greatly influenced by non-infectious factors, which complicates the interpretation. The aim of this research paper was to determine the association between SCC, intramammary infections and non-infectious factors including parity, season, lactation stage, and milk yield in dairy goats. In this longitudinal study, 451 goats from four Norwegian dairy goat herds were sampled for bacteriology and SCC up to nine times during two lactations. Factors like parity, milk yield, and stage of lactation were retrieved from the Norwegian goat recording system.ResultsThe most prevalent udder pathogen findings were Staphylococcus caprae (6.8%), Staphylococcus warneri (6.3%), and Staphylococcus epidermidis (3.8%), all of which had a mild but significant impact on SCC. Staphylococcus aureus was detected in 3.6% of the udder halves and had a major effect on SCC. Parity, stage of lactation, season, and milk yield significantly influenced SCC.ConclusionsThis study highlights that intramammary infections caused by Staphylococcus aureus, along with factors such as increasing parity and the seasonal effects of pasturing, significantly influence the SCC. Understanding these key contributors is essential for improving udder health management and improving milk quality in goat milk production.

Milk somatic cell count, composition and yield of multi-breed dairy cattle in Ethiopia

Milk somatic cell count, composition and yield of multi-breed dairy cattle in Ethiopia

Digital Holographic Microscopy in Veterinary Medicine-A Feasibility Study to Analyze Label-Free Leukocytes in Blood and Milk of Dairy Cows.

For several years, the determination of a differential cell count of a raw milk sample has been proposed as a more accurate tool for monitoring the udder health of dairy cows compared with using the absolute somatic cell count. However, the required sample preparation and staining process can be labor- and cost-intensive. Therefore, the aim of our study was to demonstrate the feasibility of analyzing unlabeled blood and milk leukocytes from dairy cows by means of digital holographic microscopy (DHM). For this, we trained three different machine learning methods, i.e., k-Nearest Neighbor, Random Forests, and Support Vector Machine, on sorted leukocyte populations (granulocytes, lymphocytes, and monocytes/macrophages) isolated from blood and milk samples of three dairy cows by using fluorescence-activated cell sorting. Afterward, those classifiers were applied to differentiate unlabeled blood and milk samples analyzed by DHM. A total of 70 blood and 70 milk samples were used. Those samples were collected from five clinically healthy cows at 14-time points within a study period of 26 days. The outcome was compared with the results of the same samples analyzed by flow cytometry and (in the case of blood samples) also to routine analysis in an external laboratory. Moreover, a standard vaccination was used as an immune stimulus during the study to check for changes in cell morphology or cell counts. When applied to isolated leukocytes, Random Forests performed best, with a specificity of 0.93 for blood and 0.84 for milk cells and a sensitivity of 0.90 and 0.81, respectively. Although the results of the three analytical methods differed, it could be demonstrated that a DHM analysis is applicable for blood and milk leukocyte samples with high reliability. Compared with the flow cytometric results, Random Forests showed an MAE of 0.11 (SD = 0.04), an RMSE of 0.13 (SD = 0.14), and an MRE of 1.00 (SD = 1.11) for all blood leukocyte counts and an MAE of 0.20 (SD = 0.11), an RMSE of 0.21 (SD = 0.11) and an MRE of 1.95 (SD = 2.17) for all milk cell populations. Further studies with larger sample sizes and varying immune cell compositions are required to establish method-specific reference ranges.

Factors influencing somatic cell count and leukocyte composition in cow milk: a field study

In recent years, there has been a proliferation of studies investigating the composition of somatic cell count (SCC) of milk, focusing on neutrophils (NEU), lymphocytes (LYM), and macrophages (MAC). These 3 components are indeed crucial for the animal's immune response to mastitis-causing pathogens. The study examined various factors influencing somatic cell count and leucocyte components in cow milk, including lactation stage, parity, and milk electrical conductivity, using data from 179 dairy cows across 6 farms throughout the entire lactation. Statistical analyses, including mixed models and logistic regression, were employed to investigate the relationships between these variables and identify risk factors for high SCC levels. Results showed that factors such as parity and lactation stage were significantly associated with somatic cell composition. In particular, the highest milk NEU values (>60% of the total leucocytic fraction) and lowest MAC values (<20%) were found at the beginning and the end of lactation, that are the critical periods for udder health. High milk electrical conductivity, low milk production, number of parity, and poor hygiene scores were identified as contributing to increased SCC. Additionally, elevated percentages of NEU and LYM in milk were associated with increased risk of high SCC values, indicating potential udder health issues.

The quality and technological parameters of milk obtained from dairy cows with subclinical mastitis

Mastitis is one of the most common diseases in dairy cattle. It significantly reduces milk quality and yield, thus incurring economic losses for farmers. This study investigates the impact of various bacterial pathogens on the somatic cell count, milk composition, and technological properties of milk samples from 302 clinically healthy Polish Holstein-Friesian cows kept under intensive rearing conditions. Of the 462 milk samples analyzed, 85.06% were contaminated with bacteria. The majority were coagulase-negative staphylococci (52.60%).-Escherichia coli, Streptococcus dysgalactiae, Streptococcus uberis, or Staphylococcus aureus, or Streptococcus agalactiae, a major pathogen, were identified in 16.66% of samples; their presence was associated with higher SCC levels. Additionally, contamination with S. aureus or S. agalactiae had prolonged clotting time, adversely affected curd and whey quality, with curd yield remaining unaltered. Bacterial contamination did not appear to significantly impact the yield of milk or its main components, viz. protein, casein, lactose, fat, total solids, solid nonfat, free fatty acid or citric acid. Although pH, freezing point depression (FDP), and acidity also remained unaffected by bacterial contamination, they were significantly influenced by herd-year-season of calving and herd-year-time of sampling interaction effects. The results indicate that the presence of bacteria causing subclinical mastitis negatively influences milk processing potential. However, fixed linear regression indicated that the number of colony-forming units (cfu/ml) only had a significant influence on FPD and clotting time, and as such, the number of bacteria in a sample did not influence milk yield or quality during subclinical chronic mastitis.