Quarters Of Cows Research Articles

COMPARISON OF BACTERIAL PATHOGENS ASSOCIATED WITH DIFFERENT TYPES OF BOVINE MASTITIS AND THEIR ANTIBIOTIC RESISTANCE STATUS IN BANGLADESH

Background: Mastitis is one of the most prevalent complex diseases of mammals with high economic impact in dairy industry worldwide. Most of the published inland reports on bovine mastitis are mainly based on sub-clinical mastitis and some extent to clinical types. Objectives: The main objectives of this study are (a) to compare the bacterial pathogens associated with sub-clinical, clinical and chronic mastitis, and (b) to detect the antibiotic sensitivity and resistance status of the isolated bacteria from different types of mastitis. Materials and Methods: A total of 539 quarter milk samples, collected from lactating cows of Rajshahi and Mymensingh districts were subjected to standard bacterial culture and biochemical tests during the period of 2010-2011. Antibiogram test was done on bacteria isolated from sub-clinical (n = 444), acute (n = 35) and chronic (n = 60) mastitis cases include Staphylococcus spp., Streptococcus spp., Bacillus spp. and E. coli in 78.54%, 80% and 71.67% milk samples as a single and 21.46%, 20% and 28.33% as mixed infection, respectively. Results: The Staphylococcus spp. was recorded as major pathogen for all the sub-clinical (42.15%), acute (45.71%) and chronic (41.67%) mastitis cases. The right hind quarters were found significantly (p < 0.05) more affected with sub-clinical, acute and chronic types of mastitis than other three quarters in cows. The highest sensitivity (up to 100%) was recorded with gentamicin, ciprofloxacin, oxytetracycline and enrofloxacin against all the tested four organisms isolated from sub-clinical, clinical and chronic mastitis cases. Antibiotic resistance was highly prevalent, especially streptomycin (70-100%), amoxicillin (30-100%) and ampicillin (0-100%) against the four isolated bacteria of three different types of mastitis. Conclusions: It may be concluded that there is a need to establish a nationwide plan for monitoring the resistance of antibiotics and ensure the cautious use of antibiotics in the veterinary medical practices. Keywords: Bovine mastitis, Clinical mastitis, Subclinical mastitis, Chronic mastitis, Mastitic bacterial pathogens and Antibiogram

The Mastitis Pathogens Culture Collection.

The Mastitis Pathogen Culture Collection contains more than 16,000 mastitis-causing bacterial isolates from milk samples taken from cow quarters and bulk tanks in a national cohort of 91 dairy farms across Canada over a period of 2 years. These isolates are linked to demographic and production data that were recorded at the mammary gland, cow, and farm levels.

Expert evaluation of different infection types in dairy cow quarters naturally infected with Staphylococcus aureus or Streptococcus agalactiae

The purpose of this study was to improve the diagnostic recommendations for Staphylococcus aureus and Streptococcus agalactiae control using bacterial culture (BC), polymerase chain reaction (PCR) and somatic cell count (SCC) as diagnostic methods. The study was carried out in three steps: firstly, diagnostic test patterns for naturally infected quarters with Staph. aureus (24 quarters) and Strep. agalactiae (16 quarters) were created by sampling the quarters each day for 21 days and analysing the daily quarter milk samples using BC, PCR and SCC. Secondly, 30 mastitis experts were asked to group and describe the diagnostic test patterns and to establish a diagnosis for each group. The experts’ statements regarding the groups they established were subsequently examined using qualitative content analysis to assign “infection types” to the statements. Lastly, the test performance was estimated for BC, PCR and SCC using generalised logistic regression models with the interpreted statements as a reference for infection.The experts mainly identified the Staph. aureus quarter-patterns as persistent infections, while some had more dynamic patterns. Strep. agalactiae quarter-patterns mainly involved persistent infection, yet some appeared hard to diagnose and were assigned to almost all different infection types, while experts did not agree on the interpretation.Estimates of Se for detection of Staph. aureus infection were 95.9% [93.7; 97.3] for BC, 99.5% [98.3; 99.8] for PCR, and 96.1% [94.0; 97.5] for SCC. The corresponding Sp estimates were 74.5% [65.7; 81.7], 66% [57.2; 73.8] and 43.7% [36.2; 51.5] for BC, PCR and SCC, respectively.The Se estimates of BC and PCR for Strep. agalactiae infection were 100% [83.5; 100] and 99.9% [99.6; 100], respectively, whereas the Se of SCC detecting Strep. agalactiae infection was only 34.3% [26.4; 43.3]. This indicated that Strep. agalactiae-positive BC and PCR test results were more important than SCC results to the experts when diagnosing a quarter as infected. The Sp estimates of BC, PCR and SCC for Strep. agalactiae infection were 99% [72.8; 100], 97.7% [62.1; 99.9], and 65.7% [56.7; 73.7], respectively.We conclude that PCR and BC are highly sensitive in the detection of persistent and new infections as defined by the experts, although the Se was not always 100%. An accepted lower Sp suggests that experts place less emphasis on false-positive results. We recommend that efforts are made to develop consistent terminology to characterise intramammary infections over time so that the course of infection can be taken into account at diagnosis.

Intramammary antimicrobial treatment of subclinical mastitis and cow performance later in lactation

The aim of this study was to evaluate long-term therapeutic effects of antimicrobial treatment of recently acquired subclinical mastitis (RASCM) during lactation. Quarter-level clinical mastitis (CM) follow-up, composite somatic cell counts (SCC), and cow-level milk yield later in lactation were evaluated using follow-up data from 2 previously published linked randomized field trials. The first trial randomly assigned antimicrobial treatment with any intramammary product or negative control to culture-positive quarters of cows having a first elevated composite SCC after 2 consecutive low composite SCC measurements. Untreated cows that had a second elevated composite SCC at the next measurement and were staphylococci-positive (i.e., Staphylococcus aureus or non-aureus staphylococci) were randomly assigned to treatment or control. Quarter-level CM cases were reported by the participating herd personnel, and milk yield and composite SCC data were obtained from the regular test-day recording. Frailty survival models were used to evaluate the long-term therapeutic effects of antimicrobial treatment of RASCM on quarter-level CM follow-up. Mixed linear regression models were applied to quantify the effect on milk yield and composite SCC. Data of 638 quarters from 486 cows in 38 herds were available for statistical analyses, of which 229 quarters of 175 cows received antimicrobial treatment for RASCM. Antimicrobial treatment culminated in reduced composite SCC levels later in lactation but did not result in different milk yield levels or CM follow-up compared with control cows. Antimicrobial treatment of cows with RASCM should therefore only be considered in exceptional situations given the current focus on antimicrobial usage reduction in animal husbandry.

Antibacterial Activity of Some Medicinal Plants of Kashmir, J&K, India

The study was conducted to find out the activity of some medicinal plants against bacterial isolates. The bacterial isolates from milk samples of infected quarters of cows were investigated for in-vitro drug sensitivity by standard disc diffusion technique (Bauer et al., 1966). Cultural examination of milk samples was done by method described by Quin et al. (2004) in which predominant isolates were Staph. (55.55%), E. coli (22.22%), Strepto. agalactiae (16.66%) and other isolates as 5.5% and were subjected to in-vitro antibacterial sensitivity test to selected herbal extracts and standard antibiotic (cefuroxime) (Table-1). The four different aqueous concentrations of the herbs namely Fumaria indica, Adiantum capillus, Nepata cataria, Levandula stoeches and Borago officinalis collected from registered herbal shops prepared by standard procedure as 25mg/ml, 50mg/ml, 75mg/ml and 100mg/ml were used. The results indicated that aqueous extract of Fumaria indica, Adiantum capillus and Napeta cataria against Staphylococcus aureus, E.coli, Streptococcus agalactia and K. pneumonia exhibited maximum zone of inhibition 20.0±1.21, 21.0±0.19, 13.0±0.37 17.0±0.21; 18±0.41, 12±0.21, 13±0.31, 15±0.31 and 15±0.33, 16.01±0.19 14.09±0.37, 13.31±0.41 at 100 mg/ml respectively which was significantly low as compared to standard drug (cefuroxime) at 30 microgram concentration. Aqueous extract of Levandula stoeches against Staphylococcus aureus and E. coli exhibited maximum zone of inhibition 18.0±0.33 and 13.0±0.141 at 100 mg/ml respectively. Borago officinalis has shown nil to non-significant bacterial growth inhibition activity.

Association of claw disorders with subclinical intramammary infections in Egyptian dairy cows.

Aim:Bovine mastitis and lameness are the most common production diseases affecting dairy farms worldwide resulting in huge economic impact and impaired animal welfare. The objective of this field study was to investigate the association of infectious and non-infectious claw disorders with the occurrence of subclinical intramammary infections (IMIs) diagnosed by California mastitis test (CMT) in dairy cows under Egyptian conditions.Materials and Methods:A total of 43 dairy cows were included in this field study. Subclinical IMI was diagnosed by CMT on all lactating quarters of cows. A cow was considered to have subclinical IMI if it had at least one subclinically infected quarter (≥3). Cows were inspected carefully for claw disorders that recorded based on type and site. Locomotion and body condition scores were also recorded for each cow in addition to the limb affected. The association between the CMT and other explanatory variables was tested by Fisher’s exact test.Results:The prevalence of infectious and non-infectious claw disorders was 81.4% (35/43) and 32.6% (14/43), respectively. Digital dermatitis (DD) and heel horn erosion were the most prevalent infectious type with 79% (34/43) and 58% (25/43), respectively, while wall fissure was the most identified non-infectious one 11.6% (5/43). The prevalence of claw disorders in hind limbs was 88.4% (38/43) and 11.6% (5/43) in the forelimbs. Infectious claw disorders were significantly associated with the subclinical IMI diagnosed by CMT (p<0.05). Non-infectious claw affections, locomotion score, body condition score, and the affected limb had no association with the occurrence of subclinical IMI.Conclusion:DD is the highest prevalent claw disorder observed in dairy cows in Egypt. The hind limbs are more susceptible to claw disorders than the forelimbs. Infectious type of claw disorders is significantly associated with subclinical IMI diagnosed by CMT in dairy cows under Egyptian conditions indicating that the infectious types of claw affections may influence the udder health.

N-acetyl -β-D-glucosaminidase activity in cow milk as an indicator of mastitis.

Activity of lysosomal N-acetyl-β-d-glucosaminidase (NAGase) in milk has been used as an indicator of bovine mastitis. We studied NAGase activity of 808 milk samples from healthy quarters and quarters of cows with spontaneous subclinical and clinical mastitis. Associations between milk NAGase activity and milk somatic cell count (SCC), mastitis causing pathogen, quarter, parity, days in milk (DIM) and season were studied. In addition, the performance of NAGase activity in detecting clinical and subclinical mastitis and distinguishing infections caused by minor and major bacteria was investigated. Our results indicate that NAGase activity can be used to detect both subclinical and clinical mastitis with a high level of accuracy (0·85 and 0·99). Incomplete correlation between NAGase activity and SCC suggests that a substantial proportion of NAGase activity comes from damaged epithelial cells of the udder in addition to somatic cells. We therefore recommend determination of NAGase activity from quarter foremilk after at least six hours from the last milking using the method described. Samples should be frozen before analysis. NAGase activity should be interpreted according to DIM, at least during the first month of lactation. Based on the results of the present study, a reference value for normal milk NAGase activity of 0·1-1·04 pmoles 4-MU/min/μl for cows with ≥30 DIM (196 samples) could be proposed. We consider milk NAGase activity to be an accurate indicator of subclinical and clinical mastitis.

Rapid Communication: Colostrum immunoglobulin concentration in mammary quarters is repeatable in consecutive lactations of dairy cows.

Colostrum IgG concentration and yield vary tremendously among farms and cows and among quarters within cows. The present study quantified changes in quarter colostrum characteristics up to 3 successive lactations. First colostrum was quarter collected within 4 h after parturition in the first 2 consecutive lactations from 12 cows, and colostrum was obtained from 14 multiparous dairy cows in 2 consecutive lactations and 8 cows thereof in 3 consecutive lactations. Colostrum yield per quarter showed a high variation in both primiparous and multiparous dairy cows during consecutive lactations. Percentage distribution of colostrum yield among quarters within cows was similar from parity to parity. The differences in colostrum yield within the same quarter were higher in cows from the first to the second lactation compared with the differences within quarters of multiparous cows in consecutive lactations ( < 0.05). The intraclass correlation coefficient (ICC) for quarter colostrum yield was found to be similar in cows from the first to the second parity (ICC = 0.42) and within consecutive lactations of multiparous cows (ICC = 0.44). Whereas the position of the quarter did not influence colostrum yield in cows from the first to the second lactation, quarter colostrum yield in multiparous cows was higher in rear quarters than in front quarters ( < 0.05) with fewer changes in successive lactations. Concentration and mass of IgG in quarter-milked colostrum distinctly varied among quarters and cows in both primiparous and multiparous cows. In multiparous cows, higher values for quarter concentration and mass of IgG were observed when compared with primiparous cows, in particular in the rear quarters ( < 0.05). Relative differences of IgG concentration and mass within quarters were higher in consecutive lactations of multiparous cows compared with differences within quarters of cows in the first 2 lactations ( < 0.05). The ICC of colostral IgG concentration and mass within quarters of cows from the first to the second lactation was 0.52 and 0.67, respectively, and lower compared with the ICC of IgG concentration and mass within quarters during consecutive lactations of multiparous cows. In conclusion, IgG concentration and mass were shown to be more repeatable within quarters of multiparous dairy cows compared with the first 2 lactations of dairy cows. Contrarily, colostrum yield within quarters in consecutive lactations had only a moderate repeatability and seemed to be affected by factors other than genetics.

Evaluation of a lysostaphin-fusion protein as a dry-cow therapy for Staphylococcus aureus mastitis in dairy cattle

This study evaluated the efficacy of a recombinant lysostaphin fused to a protein transduction domain (rLYS-PTD) as a dry-cow therapy for the treatment of experimentally induced chronic, subclinical Staphylococcus aureus mastitis. Twenty-two Holstein dairy cows were experimentally infected with Staph. aureus in a single pair of diagonal mammary quarters approximately 45d before dry off. Staphylococcus aureus-infected mammary quarters of cows were randomly assigned to 1 of 2 treatment groups at dry off: (1) 279mg of rLYS-PTD in 50mL of vehicle (n=11 cows; 22 quarters) or (2) 50mL of vehicle solution (n=11 cows; 22 quarters) by intramammary infusion. All cows were followed for 30d postpartum to determine cure rates using bacteriologic culture, somatic cell counts, and clinical mastitis scores. No cures were recorded in either the treatment or control groups. Milk somatic cell count, bacterial colony counts, and mastitis scores did not significantly differ between treatment groups. In conclusion, rLYS-PTD was not an effective dry-cow therapeutic for chronic, subclinical Staph. aureus mastitis at the tested dose and formulation.

Intramammary infections and milk leakage following gradual or abrupt cessation of milking

The objective of this study was to evaluate the effect of milking cessation method (abrupt or gradual) and daily milk yield before dry-off on milk leakage following dry-off and intramammary infections (IMI) at calving. Data from 1,086 quarters of 285 cows from 5 Ohio dairy herds were analyzed. All cows that were due to be dried off within a week were assigned to the same study group to facilitate management. Abrupt-cessation cows kept the farm’s regular milking schedule through dry-off, and gradual-cessation cows were milked once daily for the final week of lactation. Aseptic technique was used to collect quarter foremilk samples at the time of enrollment (7 to 14 d before expected dry-off), the final milking before dry-off (D-O), and within 7 d of calving. Cows in the gradual-cessation group were observed for milk leakage during the period of once-daily milking. In the only herd that did not use internal teat sealants at dry-off, milk leakage after dry-off was recorded in both abrupt and gradual groups. Gradual cessation decreased milk production by 33.4% during the final week of lactation, causing milk yield at D-O to be lower for these cows compared with abrupt-cessation cows (13.2 vs. 19.8kg/d, respectively). Logistic regression models were used to model the probability of a quarter being infected at calving with any pathogen, accounting for clustering of quarters within cows and cows within herds. The final model investigating the probability of IMI at calving was stratified by parity of cows at the time of dry-off (primiparous and multiparous). Among quarters of cows that ended their first lactation, abrupt cessation of milking before dry-off and milk leakage after dry-off were associated with an increased risk of IMI at calving. Among quarters of multiparous cows, on the other hand, gradual cessation of milking before dry-off, presence of IMI at D-O, and thrice-daily milking during lactation increased the odds of IMI at calving. These results indicate that implementation of differing management practices near dry-off for different parity groups may improve mammary health within a herd.

Pathogen group specific risk factors for clinical mastitis, intramammary infection and blind quarters at the herd, cow and quarter level in smallholder dairy farms in Jimma, Ethiopia

A cross-sectional study on clinical mastitis, intramammary infection (IMI) and blind quarters was conducted on 50 smallholder dairy farms in Jimma, Ethiopia. A questionnaire was performed, and quarters of 211 cows were sampled and bacteriologically cultured. Risk factors at the herd, cow, and quarter level for clinical mastitis and (pathogen-specific) intramammary infection were studied using multilevel modeling. As well, factors associated with quarters being blind were studied. Eleven percent of the cows and 4% of the quarters had clinical mastitis whereas 85% of the cows and 51% of the quarters were infected. Eighteen percent of the cows had one or more blind quarter(s), whereas 6% of the quarters was blind. Non-aureus staphylococci were the most frequently isolated pathogens in both clinical mastitis cases and IMI. The odds of clinical mastitis was lower in herds where heifers were purchased in the last year [odds ratio (OR) with 95% confidence interval: 0.11 (0.01–0.90)], old cows (>4 years) [OR: 0.45 (0.18–1.14)], and quarters not showing teat injury [OR: 0.23 (0.07–0.77)]. The odds of IMI caused by any pathogen was higher in herds not practicing teat drying before milking (opposed to drying teats with 1 towel per cow) [OR: 1.68 (1.05–2.69)], cows in later lactation (>180 DIM opposed to ≤90 DIM) [OR: 1.81 (1.14–2.88)], cows with a high (>3) body condition score (BCS) [OR: 1.57 (1.06–2.31)], right quarters (opposed to a left quarter position) [OR: 1.47 (1.10–1.98)], and quarters showing teat injury [OR: 2.30 (0.97–5.43)]. Quarters of cows in herds practicing bucket-fed calf feeding (opposed to suckling) had higher odds of IMI caused by Staphylococcus aureus [OR: 6.05 (1.31–27.90)]. Except for BCS, IMI caused by non-aureus staphylococci was associated with the same risk factors as IMI caused by any pathogen. No access to feed and water immediately after milking [OR: 2.41 (1.26–4.60)], higher parity [OR: 3.60 (1.20–10.82)] and tick infestation [OR: 2.42 (1.02–5.71)] were risk factors for quarters being blind. In conclusion, replacement of old cows, prevention of teat injuries/lesions, drying teats with 1 towel per cow before milking, improving fertility in order to shorten the lactation period, allowing (restricted) suckling, access to feed and water immediately after milking, and improving tick control could improve udder health in Jimma.

Methylation analysis of CXCR1 in mammary gland tissue of cows with mastitis induced by Staphylococcus aureus.

Mastitis is the most important disease in the global dairy industry, and causes large economic losses. Staphylococcus aureus is one of most common pathogens that cause bovine mastitis. CXCR1 has been implicated as a prospective genetic marker for mastitis resistance in dairy cows; CXCR1 expression significantly increases when cows have mastitis. To investigate the mechanisms involved in its increased expression, bisulfite sequencing polymerase chain reaction (PCR) was used to detect the methylation status of CXCR1 CpG island, and quantitative fluorescence PCR was used to detect CXCR1 expression in bovine mammary tissue induced with S. aureus in three Chinese Holstein cows. No CpG island was found for bovine CXCR1 in the upstream 2-kb region, whereas one CpG island that contained 13 CpG sites was found in exon 1 of CXCR1. All of the CpG sites were under hypermethylation from 90 to 100% in the mammary tissues. When the mammary gland mRNA expression of CXCR1 was 12.10-fold higher in infected cow quarters than in uninfected quarters, the methylation levels of the CpG site at position 519 were significantly lower in the infected quarters than in the uninfected quarters. Pearson correlation analysis showed that the methylation level at position 519 was significantly negatively correlated with the CXCR1 mRNA expression level (P < 0.05). These results indicate that the methylation of the CpG site at position 519 may regulate CXCR1 expression in cows with mastitis induced by S. aureus, but further studies are needed to elucidate the mechanisms involved.

Investigations of efficacy of intramammary applied antimicrobials and glucocorticosteroides in the treatment of subclinical and clinical mastitis in cows

Inflammation of the mammary gland, mastitis in cows, presents one of the most acute problems in intensive dairy production, inflicting huge economic losses. In the course of one year, 80 samples were taken at investigated farms from udder quarters of cows with clinical mastitis and 160 samples from udder quarters of cows with subclinical mastitis. The efficacy of three preparations, A, B, and C, was examined in the treatment of clinical and subclinical mastitis in cows. The investigations indicate that antibiotic preparation A (neomycin, polimixine B, oleandomycin and prednisolone) exhibited a greater efficacy in the treatment of clinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Micrococcus sp., but a smaller efficacy in the treatment of subclinical mastitis caused by Staphylococcus aureus. Preparation B (amoxicillin, clavulanic acid and prednisolone) exhibited a higher efficacy in the treatment of clinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis and Micrococcus, but a weaker effect in the treatment of subclinical mastitis caused by Staphylococcus aureus. Preparation C (procaine penicillin G, streptomycin, neomycin sulfate and prednisolone acetate) exihibited efficacy in the treatment of clinical and subclinical mastitis caused by Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Micrococcus, Staphylococcus aureus and Esherichie coli.

Epidemiology of coagulase-negative staphylococci intramammary infection in dairy cattle and the effect of bacteriological culture misclassification

Objectives of this study were to identify the manageable risk factors associated with the lactational incidence, elimination, and prevalence of coagulase-negative staphylococci (CNS) intramammary infections (IMI) while taking into account the difficulties inherent to their diagnosis. A second objective was to evaluate the effect of CNS IMI misclassification in mastitis research. A cohort of 90 Canadian dairy herds was followed throughout 2007 to 2008. In each herd, series of quarter milk samples were collected from a subsample of cows and bacteriological culture was performed to identify prevalent, incident, and eliminated CNS IMI. Practices used on farms were captured using direct observations and a validated questionnaire. The relationships between herd CNS IMI prevalence and herd incidence and elimination rates were explored using linear regression. Manageable risk factors associated with the prevalence, incidence, or elimination of CNS IMI were identified via Bayesian analyses using a latent class model approach, allowing adjustment of the estimates for the imperfect sensitivity and specificity of bacteriological culture. After adjustment for the diagnostic test limitations, a mean CNS IMI quarter prevalence of 42.7% [95% confidence interval (CI): 34.7, 50.1] and incidence and elimination rates of 0.29 new IMI/quarter-month (95% CI: 0.21, 0.37) and 0.79 eliminated IMI/quarter-month (95% CI: 0.66, 0.91), respectively, were observed. Considerable biases of the estimates were observed when CNS IMI misclassification was ignored. These biases were important for measures of association with risk factors, were almost always toward the null value, and led to both type I and type II errors. Coagulase-negative staphylococci IMI incidence appeared to be a stronger determinant of herd IMI prevalence than IMI elimination rate. The majority of herds followed were already using blanket dry cow treatment and postmilking teat disinfection. A holistic approach considering associations with all 3 outcomes was used to interpret associations between manageable risk factors and CNS IMI. Sand and wood-based product bedding showed desirable associations with CNS IMI compared with straw bedding. Quarters of cows that had access to pasture during the sampling period had lower odds of acquiring a new CNS IMI and of having a prevalent CNS IMI. Many practices showed an association with only one of the CNS outcomes and should, therefore, be considered with caution.

Somatic cell count and bacteria shedding from mammary quarters in cows with subclinical mastitis

Samples of milk from 638 mammary quarters were examined for identification of mastitis pathogens, SCC and TBC. The analysis of SCC and TBC results was performed using descriptive statistics, T test for independent samples and linear regression models. The geometric means of the results of SCC (cells/mL) and TBC (CFU/mL) according to the results of microbiological examination were: no growth (52,000; 12,000), coagulase-negative staphylococci (85,000; 17,000), Staphylococcus aureus (587,000; 77,000), Streptococcus spp. than S. agalatiae (432,000; 108,000) and Streptococcus agalactiae (1,572,000; 333,000). Regression analysis showed increased release of different bacteria with the same increase of SCC according to the pathogen. The results suggest that the greater the intensity of the inflammatory process, greater release of bacteria from the mammary gland and the adoption of a program to control and prevention of mastitis is essential for maintaining a low bacterial load in the milk of herds.

The Concentration of Immunoglobulins A, G, and M in Cow Milk and Blood in Relation with Cow Seasonal Keeping and Pathogens Presence in the Udder

The Concentration of Immunoglobulins A, G, and M in Cow Milk and Blood in Relation with Cow Seasonal Keeping and Pathogens Presence in the UdderRecent studies show that immunoglobulins A, G, and M contribute significantly to the maintenance of udder health. Unfortunately, the concentration of immunoglobulins in cow milk during the middle period of lactation is low therefore the question of how to stimulate and maintain a sufficient level and spectrum of antibodies in the udder is topical. The aim of the present study was to evaluate the dynamics of the amount of immunoglobulins A, G, and M in cow milk and blood serum in relation with the cow seasonal keeping and presence of pathogens in the udder. The experimental part of the study was carried out on the dairy farm "Pērles", Valmiera region. Cows were kept in a cold loose housing system, grouped and fed differently depending on cow productivity and lactation period. Two times in the housing period and two times in the grazing period milk and blood were sampled from 16 dairy cows and examined for the concentration of immunoglobulins A, G, and M and for the presence of pathogens. Cows for the study were selected with the aim to analyze the milk obtained from clinically healthy udder quarters of cows of similar-age and productivity in the middle stage of lactation. It was determined that seasonal keeping of cows had significantly affected the concentration of immunoglobulins G and A in milk (p&lt;0.001), and of immunoglobulins A, G, and M in blood serum (p&lt;0.001). Some pathogenic bacteria species infecting the udder quarters had considerably influenced the values of immunoglobulins G, A, and M (p&lt;0.05,p&lt;0.001, andp&lt;0.001, respectively) in blood serum. A wide variation amplitude of immunoglobulin G, A, and M concentration in milk and blood serum was observed, which indicates the important role of the individual factor of an animal in the formation of animal defence response.

Serum concentration and mRNA expression in milk somatic cells of toll-like receptor 2, toll-like receptor 4, and cytokines in dairy cows following intramammary inoculation with Escherichia coli

The objective of the current study was to investigate the toll-like receptors (TLR), including the soluble forms sTLR2 and sTLR4, involved in innate immune responses of dairy cows to experimentally induced Escherichia coli mastitis. Six clinically healthy Holstein dairy cows received an intramammary inoculation of E. coli O111:K58 between 63 and 83 d postpartum. Concentrations of sTLR2 and sTLR4, the proinflammatory cytokines IL-6 and tumor necrosis factor-α (TNF-α), and acute phase proteins serum amyloid A (SAA) and haptoglobin (Hp) in blood were measured by ELISA. Furthermore, 10mL of milk was collected from challenged quarters immediately before inoculation and at 6, 12, 24, 48, and 72h after inoculation, and mRNA expression of selected genes, including TLR2, TLR4, IL-1β, IL-6, TNF-α, and IL-8, was quantified by real-time PCR. Escherichia coli intramammary infection elicited a decrease in the circulating levels of leukocytes. Rectal temperature was elevated at 6h postinoculation (PI). Similarly, the serum concentrations of TNF-α, IL-6, and SAA increased at 6h PI. However, serum concentrations of sTLR2, sTLR4, and Hp did not differ after challenge. The mRNA expression of TLR2, IL-1β, and IL-8 in milk somatic cells increased at 12h PI, whereas a decreased IL-6 mRNA expression was detected from 6 to 48h PI. In conclusion, we found that TLR2 mRNA expression increased in milk somatic cells collected from infected quarters of cows challenged with E. coli, whereas the concentrations of sTLR2 and sTLR4 remained unchanged after challenge. Thus, sTLR2 and sTLR4 may protect the host by sequestrating pathogen-associated molecular patterns during E. coli mastitis.

Immune response of bovine milk somatic cells to endotoxin in healthy quarters with normal and very low cell counts

Low somatic cell count (SCC) is a reliable indicator of high-quality milk free of pathogenic microorganisms. Thus, an important goal in dairy practice is to produce milk with low SCC. Selection for cows with low SCC can sometimes lead to extremely low SCC in single quarters. The cells in milk are, however, predominantly immune cells with important immune functions. To investigate the mammary immune competence of quarters with very low SCC, healthy udder quarters of cows with normal SCC of (40-100) x 10³ cells/ml and very low SCC of < 20 x 10³ cells/ml were challenged with lipopolysaccharide (LPS) from Escherichia coli. In the first experiment, SCC and cell viability after a challenge with 50 ng of LPS/quarter was investigated. In the second experiment, tumour necrosis factor α (TNF-α) concentration and lactate dehydrogenase (LDH) activity in milk, and mRNA expression of various innate immune factors in milk cells were measured after a challenge with 100 μg LPS/quarter. LPS challenge induced an increase of SCC. SCC levels reached were higher in quarters with normal SCC and maximum SCC was reached 1 h earlier than in very low SCC quarters. The increase of TNF-α concentrations in milk in response to LPS challenge was lower in quarters with very low SCC than in quarters with normal SCC. The viability of cells and the LDH activity in milk increased in response to LPS challenge, however, without a difference between the groups. The mRNA expression of IL-1β and IL-8 was increased in milk cells at 12 h after LPS challenge, whereas that of TNF-α and lactoferrin was not increased at the measured time points (12, 24 and 36 h after LPS challenge). No differences of mRNA expression of measured immune factors between normal and very low SCC samples were detected. The study showed that udder quarters with very low SCC responded with a less marked increase of SCC compared with quarters with normal SCC. This difference corresponded with simultaneously lower TNF-α concentrations in milk. However, the immune competence of the cells themselves based on mRNA expression of TNF-α, IL-8, IL-1β, and lactoferrin, did not differ. The results may indicate that very low SCC can impair the immune competence of udder quarters, because the immune response in udder quarters with lower SCC is less efficient as fewer cells contribute to the production of immunoregulators.

Factors associated with concentrations of select cytokine and acute phase proteins in dairy cows with naturally occurring clinical mastitis

The objective of the current observational study was to determine the potential associations between cow factors, clinical mastitis (CM) etiology, and concentrations of select acute phase proteins and cytokines in milk from affected quarters of cows with CM. Cows with CM (n=197) were grouped based on systemic disease severity, milk culture result, parity, days in milk (DIM), previous CM occurrence, and season of the year when CM occurred. Concentrations of lipopolysaccharide-binding protein (LBP), haptoglobin (Hp), BSA, IFN-γ, tumor necrosis factor-α (TNF-α), IL-1β, IL-8, IL-10, IL-12, transforming growth factor (TGF)-α, and TGF-β and activity of lactate dehydrogenase (LDH) were evaluated. Differences in the least squares means log10 transformed concentrations of these proteins were compared using multiple linear regression mixed models. The milk concentrations of LBP, Hp, IL-1β, IL-10, and IL-12, and activity of LDH in milk were higher in cows with moderate to severe versus mild systemic disease. The concentrations of Hp, BSA, IL-1β, and IL-10 in milk were higher in cows with a gram-negative versus gram-positive milk culture result. Season of the year when CM occurred was associated with the concentration of all proteins evaluated except for IL-1β and IL-12. Concentrations were higher in the winter versus summer except for Hp and TGF-β, for which the opposite was true. Concentrations of LBP, IL-10, and IL-12, and LDH activity in milk were associated with DIM group. Except for LBP, these proteins were lower in cows with CM during the first 60 DIM versus those in mid or later lactation. Interferon-γ, TNF-α, and IL-8 were undetectable in 67, 31, and 20% of samples, respectively. Detection of IFN-γ and IL-8 was associated with season, and detection of TNF-α and IL-8 was associated with systemic disease severity. The current study provides the most comprehensive report of milk concentrations of innate immune response proteins in cows with naturally occurring CM and identifies factors that potentially influence those concentrations. Further investigation into the seasonal variation of cytokine production and its potential effect on the outcome of CM is warranted. Furthermore, the results of this study provide useful data for planning future studies examining the role of the innate immune response in CM.

A randomized controlled trial to compare the use of homeopathy and internal Teat Sealers for the prevention of mastitis in organically farmed dairy cows during the dry period and 100 days post-calving

Routine use of antibiotics to prevent mastitis in dairy cows is prohibited by organic farming regulations. Internal Teat Sealers have been proposed as an alternative. We compared two drying-off (DO) supporting measures (Internal Teat Sealer and Homeopathy) to an untreated control group to assess their protective effects against clinical mastitis and intra-mammary infections during dry period of dairy cows. A field trial with 102 dairy cows from 13 Swiss organic dairy farms was conducted. Cows were randomly assigned to one of three groups within a herd. In the Internal Teat Sealer group (ITS; 36 cows) cows were treated with the commercial ORBESEAL (Pfizer) in all four quarters immediately after the last milking. In the Homeopathy group (HDT; 32 cows) the cows were treated per-orally by a herd-specific homeopathic formulation consisting of two remedies in 1:10(6) dilution over 5 days before and after DO. The untreated group received no therapy (U; 34 cows). For ITS, HDT and U the clinical mastitis incidence rates for the first 100 days post-calving were 11%, 9% and 3%, respectively, and the proportion of normally secreting quarters was (quarter somatic cell count (SCC) [QSCC]<100,000/ml) 70%, 68%, and 65%, respectively. Power analysis indicates that a proportion of 75% would support the rejection of null hypothesis in the HDT, and 74% in the ITS group against untreated control. Quarters of cows with SCC<200,000/ml at DO showed significantly higher normal secretion in HDT group (odds ratio [OR] 9.69) compared to untreated control, whereas Teat Sealing lead to an OR of 3.09 (not significant, post hoc power 31.3%). Under the studied conditions herd-specific homeopathic dry cow therapy was effective in increasing the number of animals with normal milk secretion after subsequent parturition, compared to untreated control. It may be an effective alternative to Teat Sealing, particularly in animals with relatively low SCCs. Further research is required to confirm these results, and under different environmental conditions.