Cell Count In Cows Research Articles

ОЦЕНКА ВЛИЯНИЯ ВАКЦИНАЦИИ НА КАЧЕСТВО МОЛОКА КОРОВ

Producing high quality cow milk is a priority for agricultural enterprises. Mastitis has a major impact on milk quality due to the increased somatic cell count in milk and the bacterial contamination of milk with microorganisms. To solve this problem, an experiment was carried out to study the effect of vaccinating cows on the incidence of their mastitis and on the somatic cell count in the milk. During the study period, it was found that the cows in the experimental group (vaccinated animals) had 6.1 times less mastitis than the control group (unvaccinated animals). In the experimental group, the number of sick animals varied slightly over the months of the study, ranging from 14.1% to 17.5%. In the control group, this indicator was 4.7, 7.0 and 6.8 times higher in the first, second to third and fourth to sixth months of the study, respectively. The number of cows with subclinical mastitis in the control group was 5.0, 5.7 and 5.6 times higher than in the experimental group during the same study periods. The cows in the experimental group also developed clinical mastitis less frequently – 4.1, 10.1 and 9.1 times, respectively. The highest average somatic cell count in the milk of the cows of the experimental group was recorded in the first month after calving – 240 thousand cells/cm3. In the following months this indicator was lower ranging from 200 thousand cells/cm3 to 210 thousand cells/cm3. Individually, the somatic cell count of cows in the experimental group did not exceed the norm (up to 400 thousand cells/cm3). In the control group, this indicator was higher, ranging from 520 thousand cells/cm3 to 600 thousand cells/cm3, and the somatic cell data varied greatly, with a peak in the fourth month of the study. Thus, vaccination helps to reduce the incidence of mastitis in the animals and the somatic cell count in the milk, which has a positive effect on its quality.

Field study on plasma haptoglobin concentrations and total milk somatic cell counts in cows with untreated and treated mastitis

Field study on plasma haptoglobin concentrations and total milk somatic cell counts in cows with untreated and treated mastitis

Clinical forum: the responsible use of antimicrobial therapy in the control of clinical mastitis and somatic cell count in dairy herds

The reduction and rationalisation of antibiotics used in mastitis control is an increasingly important area of dairy herd health to consider with clients due to the outcomes of the O'Neill Report and the requirement to reduce overall usage of antibiotic in the livestock sector at a national level. There is much interest around a range of strategies to achieve a reduction in antibiotic use on farm, for example cow-side treatment decisions to not use intramammary therapy and deciding not to treat low cell count cows at drying-off. However, the key driver of a reduction in antibiotic use on farm remains strategies to reduce the rate of new clinical cases and new cell count infections on farm, and therefore avoiding the need for antibiotic treatment of infected cows. This article reviews some recent research literature around some of the areas mentioned, and seeks thoughts from panel members active in mastitis control on farm.

Effects of dry period length and dietary energy source on inflammatory biomarkers and oxidative stress in dairy cows

Negative energy balance in dairy cows in early lactation has been associated with increased inflammation and oxidative stress in these cows. The objective of this study was to evaluate the effects of dry period (DP) length and dietary energy source on inflammatory biomarkers and oxidative stress in dairy cows. Holstein-Friesian dairy cows (60 primiparous and 107 multiparous) were assigned randomly to a 3 × 2 factorial design with 3 DP length (0, 30, or 60 d) and 2 early lactation rations (glucogenic or lipogenic). Cows were fed a glucogenic or lipogenic ration from 10 d before the expected calving date. Blood was collected in wk -3, -2, -1, 1, 2, and 4 relative to calving. Dry period length affected inflammatory biomarkers and oxidative stress, especially in wk 1 and 2 after calving. Cows with a 0-d DP had higher levels of ceruloplasmin, cholesterol, and reactive oxygen metabolites, and they tended to have higher haptoglobin levels compared with cows with a 30- or 60-d DP. Cows with a 0-d DP had a lower plasma paraoxonase and bilirubin in the first 2 wk after calving and a lower liver functionality index compared with cows with a 60-d DP. Cows of parity >3 fed a glucogenic ration had higher cholesterol levels compared with cows of parity >3 fed a lipogenic ration. No interaction between DP length and ration was present for inflammatory biomarkers or oxidative stress variables. Plasma bilirubin levels for cows with a 0-d DP were negatively related to energy balance and metabolic status in these cows. Moreover, occurrence of clinical health problems (fever, mastitis, metritis, and retained placenta) was 41, 27, and 30% for cows with 0-, 30-, and 60-d DP, respectively. High levels of ceruloplasmin, cholesterol, and reactive oxygen metabolites in cows with 0-d DP were related to the occurrence of health problems in these cows. In conclusion, omitting the DP increased levels of ceruloplasmin, cholesterol, and reactive oxygen metabolites, and decreased levels of bilirubin and paraoxonase in plasma, independent of ration, compared with cows with a 60-d DP. These contrasting effects of DP length on inflammatory status could be explained in part by the improved energy balance and occurrence of health problems in these cows, but was not related to increased somatic cell count in cows with a 0-d DP. Cows with a 0-d DP had better energy balance, but also had higher levels of oxidative stress compared with cows with a 60-d DP. Moreover, occurrence of health problems did not differ between cows with different DP lengths.

Optimally achieving milk bulk tank somatic cell count thresholds

High somatic cell count in milk leads to reduced shelf life in fluid milk and lower processed yields in manufactured dairy products. As a result, farmers are often penalized for high bulk tank somatic cell count or paid a premium for low bulk tank somatic cell count. Many countries also require all milk from a farm to be lower than a specified regulated somatic cell count. Thus, farms often cull cows that have high somatic cell count to meet somatic cell count thresholds. Rather than naïvely cull the highest somatic cell count cows, a mathematical programming model was developed that determines the cows to be culled from the herd by maximizing the net present value of the herd, subject to meeting any specified bulk tank somatic cell count level. The model was applied to test-day cows on 2 New York State dairy farms. Results showed that the net present value of the herd was increased by using the model to meet the somatic cell count restriction compared with naïvely culling the highest somatic cell count cows. Implementation of the model would be straightforward in dairy management decision software.

Evaluation of the use of dry cow antibiotics in low somatic cell count cows

The goal of dry cow therapy (DCT) is to reduce the prevalence of intramammary infections (IMI) by eliminating existing IMI at drying off and preventing new IMI from occurring during the dry period. Due to public health concerns, however, preventive use of antibiotics has become questionable. This study evaluated selective DCT in 1,657 cows with low somatic cell count (SCC) at the last milk recording before drying off in 97 Dutch dairy herds. Low SCC was defined as <150,000 cells/mL for primiparous and <250,000 cells/mL for multiparous cows. A split-udder design was used in which 2 quarters of each cow were treated with dry cow antibiotics and the other 2 quarters remained as untreated controls. The effect of DCT on clinical mastitis (CM), bacteriological status, SCC, and antibiotic use were determined at the quarter level using logistic regression and chi-squared tests. The incidence rate of CM was found to be 1.7 times (95% confidence interval=1.4–2.1) higher in quarters dried off without antibiotics as compared with quarters dried off with antibiotics. Streptococcus uberis was the predominant organism causing CM in both groups. Somatic cell count at calving and 14 d in milk was significantly higher in quarters dried off without antibiotics (772,000 and 46,000 cells/mL, respectively) as compared with the quarters dried off with antibiotics (578,000 and 30,000 cells/mL, respectively). Quarters with an elevated SCC at drying off and quarters with a positive culture for major pathogens at drying off had a higher risk for an SCC above 200,000 cells/mL at 14 d in milk as compared with quarters with a low SCC at drying off and quarters with a negative culture for major pathogens at drying off. For quarters that were culture-positive for major pathogens at drying off, a trend for a higher risk on CM was also found. Selective DCT, not using DCT in cows that had a low SCC at the last milk recording before drying off, significantly increased the incidence rate of CM and SCC. The decrease in antibiotic use by drying off quarters without DCT was not compensated by an increase in antibiotic use for treating CM. Total antibiotic use related to mastitis was reduced by 85% in these quarters.

Evaluation of selective dry cow treatment following on-farm culture: Risk of postcalving intramammary infection and clinical mastitis in the subsequent lactation

The objective of the study was to evaluate the utility of a Petrifilm-based on-farm culture system when used to make selective antimicrobial treatment decisions on low somatic cell count cows (<200,000 cells/mL) at drying off. A total of 729 cows from 16 commercial dairy herds with a low bulk tank somatic cell count (<250,000 cells/mL) were randomly assigned to receive either blanket dry cow therapy (DCT) or Petrifilm-based selective DCT. Cows belonging to the blanket DCT group were infused with a commercial dry cow antimicrobial product and an internal teat sealant (ITS) at drying off. Using composite milk samples collected on the day before drying off, cows in the selective DCT group were treated at drying off based on the results obtained by the Petrifilm on-farm culture system with DCT + ITS (Petrifilm culture positive), or ITS alone (Petrifilm culture negative). Quarters of all cows were sampled for standard laboratory bacteriology on the day before drying off, at 3 to 4d in milk (DIM), at 5 to 18 DIM, and from the first case of clinical mastitis occurring within 120 DIM. Multilevel logistic regression was used to assess the effect of study group (blanket or selective DCT) and resulting dry cow treatment (DCT + ITS, or ITS alone) on the risk of intramammary infection (IMI) at calving and the risk of a first case of clinical mastitis between calving and 120 DIM. According to univariable analysis, no difference was observed between study groups with respect to quarter-level cure risk and new IMI risk over the dry period. Likewise, the risk of IMI at calving and the risk of clinical mastitis in the first 120 DIM was not different between quarters belonging to cows in the blanket DCT group and quarters belonging to cows in the selective DCT group. The results of this study indicate that selective DCT based on results obtained by the Petrifilm on-farm culture system achieved the same level of success with respect to treatment and prevention of IMI over the dry period as blanket DCT and did not affect the risk of clinical mastitis in the first 120d of the subsequent lactation.

Expert opinion on ranking risk factors for subclinical mastitis using a modified Delphi technique

AIM: To collate the expert opinion of Australian dairy practitioners on the relative importance of risk factors for subclinical mastitis in dairy cattle. METHODS: A modified Delphi technique was used to collect the data over two rounds. First, participants were asked to complete a survey involving ranking the level of importance of 42 risk factors on the incidence of subclinical mastitis on a scale from 1 to 10 for two categories of subclinical mastitis; contagious and environmental. After presenting and discussing the results of the first survey, the participants were asked to complete the same survey a second time. To rank the risk factors and identify the consensus amongst the participants, the median and total variation of answers were calculated and compared between the two surveys. RESULTS: The most important factors identified by the respondents after the second survey for contagious subclinical mastitis were: Teat Disinfection Post-milking, Management of High Cell Count Cows and Presence of Chronically Infected Mastitis Cows in the Herd. The most important factors for environmental subclinical mastitis were Cleanliness of the Environment and Technique of Teat Disinfection Post-milking. CONCLUSIONS: A movement toward consensus for the more important factors and a movement away from consensus for the less important factors in the second survey were observed. The most important factors for subclinical mastitis were found to be: teat disinfection post-milking, management of high cell count cows, presence of chronically infected mastitis cows in the herd and cleanliness of the environment.

Raised herd somatic cell count due to Staphylococcus aureus following the failure of an automatic teat spraying system

This study describes the failure of a single jet exit race automatic teat spray (ATS) system resulting in the spread of Staphylococcus aureus infection in a 135-cow dairy herd, which...

An analysis of somatic cell counts between 2005 and 2010 and the contribution of chronic high cell count cows

An analysis of somatic cell counts in over 41 million milk samples collected by NMR between 2005 and 2010 showed that the percentage of low cell count milk samples (below 200,000 cells/ml milk) has been increasing since 2007, passing 75% of samples collected in 2010. Of all high cell count samples, 57% originate from chronic, persistent high cell count cows. A strong correlation exists between herd cell count and the level of chronic cows in the herd. The need is discussed for greater monitoring of chronic cow numbers and more emphasis on preventing cows reaching chronic status.

Short communication: Effects of replacing part of corn silage and alfalfa hay with Leymus chinensis hay on milk production and composition

The objective of this research was to investigate the effects of replacing part of corn silage (CS) and alfalfa hay (AH) with Leymus chinensis hay on milk production and composition. Twenty multiparous Holstein dairy cows were used in a randomized block design for a 14-week period and 2 treatments. Treatments were (dry matter basis): (1) Non-Leymus chinensis hay diet (NLC; 35% CS, 15% AH) and (2) added Leymus chinensis hay diet (ALC; 30% CS, 10% AH, 10% Leymus chinensis hay). Adding Leymus chinensis hay increased neutral detergent fiber content and in vitro digestibility of the diet. Cows receiving the ALC diet had higher dry matter intake, milk yield, milk protein yield, lactose yield, solids-not-fat yield, and milk fat content compared with those fed the NLC diet. Somatic cell counts of cows decreased in the ALC compared with the NLC treatment. Cis-11 18:1 and 18:2 contents in milk increased, whereas trans-9 and cis-9 18:1 fatty acid contents decreased. Trans-9, cis-11 conjugated linoleic acid content was not influenced by adding Leymus chinensis hay to the diet. Leymus chinensis hay can be used to replace part of CS and AH in diets of dairy cows to get higher milk yield and good milk quality.

Association of Coagulase Negative Staphylococcal Species and Milk Somatic Cell Count of Cows from the Canadian National Cohort of Dairy Farms

Staphylococci are a diverse group of gram-positive cocci that can infect the cow's mammary gland. For the purposes of diagnosing intramammary infection (IMI), staphylococci are classified based on their ability to clot plasma (coagulase test) as either coagulase-positive or coagulase-negative. The most commonly isolated coagulase-positive staphylococci, S. aureus, is considered a major mastitis pathogen. In contrast, coagulase-negative staphylococci (CNS) have historically been classified as minor mastitis pathogens and are rarely, if ever, further differentiated when diagnosing an IMI. The assumption has been that, as a group, CNS cause minor elevations in milk somatic cell count (SCC). However, there has been recent interest in the role of CNS in mammary gland inflammation. The aim of this study was to evaluate the relationship between CNS species and mammary quarter SCC.

Treat the Treatable and Manage the Rest

Farm income for many dairies can be improved by increasing the value of milk by taking advantage of somatic cell count (SCC) based milk quality premiums and reducing treatment costs. Recent research has shown that the likelihood of an animal to have a repeat case of clinical mastitis after a first clinical case is about 30%. Pathogen-based treatment protocols should provide a science-based process for selecting the most appropriate treatment and duration of treatment resulting in high bacteriological cure rates and fewer repeated clinical cases. Many infections caused by gram-positive organisms, particularly streptococcal species, respond well to appropriate treatment; cure rates can approach 80% or higher. Most gram-negative pathogens respond poorly to intramammary treatment. Mastitis caused by other pathogens, such as yeast, are exacerbated by intramammary treatment and others, like Prototheca species and mycoplasma, have no known treatment. Generally the normal distribution of mastitis pathogens is about one-third gram-positive organisms, one-third gram-negative pathogens, and one-third no growth culture result, suggesting that pathogen-based treatment protocols have the potential for substantial savings.&#x0D; Duration of treatment for specific mastitis pathogens should have a major influence on cure rates, particularly for a range of streptococcal species and select Staphylococcus aureus infections.&#x0D; There are also opportunities to manage chronic subclinical infections which are often the major contributors to the bulk tank SCC. Milk from high cell count cows can be managed through treatment, segregation of high SCC milk at the quarter level, quarter dry-off, and culling.

Body Temperature and White Blood Cell Count in Postpartum Dairy Cows

The objectives of this study were to evaluate rectal temperature as a diagnostic tool in postpartum dairy cows and to compare body temperature and white blood cell counts in cows that remained healthy with those that became ill. Fifty Holstein dairy cows had complete physical examinations every four hours and a complete blood count once daily for the first 10 days after calving. Illness was defined as a rectal temperature of at least 104.5°F (40.3°C) in the absence of other clinical signs, or a clinical sign of illness other than increased temperature. Fifteen cows were diagnosed with illness and 35 remained healthy throughout the 10-day study period. No difference between mean rectal temperatures of cows that became ill and cows that remained healthy was found. Among cows that remained healthy, 23 (66%) had a rectal temperature of at least 103.1°F (39.5°C) at least once, 17 (49%) had a rectal temperature of at least 103.5°F (39.7°C) at least once and six (17%) had a rectal temperature of at least 104°F (40°C) at least once during the study period. Over the first three days after calving, mean total white blood cell counts and neutrophil counts were higher in healthy cows than in cows that became ill. Because rectal temperatures were frequently elevated in healthy postpartum cows, it was concluded that rectal temperature has low specificity for diagnosing illness in postpartum dairy cows in the absence of other clinical signs.

Genomic Typing of Enterococci Isolated from Bovine Mammary Glands and Environmental Sources

Enterococcal isolates (n=102) from various sources of bovine origin on 1 farm were characterized using pulsed field gel electrophoresis analysis of SmaI restriction patterns. Isolates originated from feed samples (n=6), bedding samples (n=15), and bovine quarter-milk samples (n=81). Isolates collected from milk samples included those from high-somatic cell count cows (n=42), postpartum milk samples (n=16), and clinical mastitis samples (n=23). Species evaluated included Enterococcus faecium (n=68), Enterococcus casseliflavus (n=29), and Enterococcus faecalis (n=5). A total of 20 clusters representing 44 isolates were detected when a similarity cut-off level of 75% was applied to interpret the pulsed field gel electrophoresis results. Fifteen of the clusters contained only isolates from milk samples. Four clusters contained isolates from bedding and milk samples. One cluster contained only isolates from feed samples. Clusters comprised of a single species represented 17 of the 20 total clusters. These results suggest enterococci from bovine origin were genetically diverse, whereas a limited number of isolates from various sources appeared to cluster together.

Effect of Polarized Light Treatment on Milk Production and Milk Somatic Cell Count of Cows

Treatment with linearly polarized light (LPL) is a widely used and recognized therapeutic method in human medicine for healing wounds, ulcers and a variety of other dermatological problems. Polarized light mobilizes the inadequately functioning defence mechanisms of the human body. The aim of the present experiment was to investigate the effect of LPL treatment on the udder of milking cows. Before the start of treatment, there was no significant difference between cows to be treated with LPL and the control cows in mean somatic cell counts (SCC) of milk samples taken separately by udder quarter and in the mean milk yield. The LPL treatment lasted for 20 min and was performed twice a day over a period of one month. Before treatment, the mean SCC of milk was 3.47 × 105 ± 910 in the group to be treated and 4.07 × 105 ± 920 in the control group. In a six-week period immediately after treatment, the mean SCC of the treated and the control group was 1.32 × 105 ± 825 and 2.63 × 105 ± 825, indicating a significant difference in favour of the treated group. Before the LPL treatment, the milk yield of cows in the group to be treated was 25.77 ± 1.2 kg/ day, while that of the control cows was 27.30 ± 1.4 kg/day. In a six-week period after treatment, the milk yield of cows in the treated and control groups was 28.83 ± 1.5 kg/day and 25.48 ± 1.4 kg/day, respectively. There is a significant difference between these values in favour of the treated group. The results show that a regular LPL treatment of the udder of cows can significantly reduce the SCC of milk and significantly increase the milk yield. The treatment can be applied during lactation without interfering with the milking regime.

Factors Affecting Milk Flow Traits in Dairy Cows: Results of a Field Study

The study of milk flow curves provides useful information for enhancing milking efficiency and protecting udder health by adapting milking machine and milking procedures to the physiological requirements of the cow. The aim of this experiment was to investigate, using field data, the relationships among traits of the milk flow curves, their sources of variation, and milking performances in terms of milk production, machine-on time, and udder health. A total of 2,486 milk flow curves of the whole udder were collected in 82 Italian Holstein-Friesian dairy herds in the Lombardy region of Italy. Approximately one-third (35.1%) of milk flow curves were classified as bimodal. Most flow characteristics were influenced by lactation number, days in milk, and peak flow but also strongly affected by premilking operations. Proper udder preparation, including forestripping and predipping, resulted in better milking performances compared with poor preparation, with greater milk yield per milking, shorter milking time, and lesser bimodality. Premilking delay time, between the start of teat stimulation and cup attachment, affected milking time significantly: The shortest milking time was obtained for a range of delay time between 1 and 60s. As the delay time increased, the percentage of bimodality dropped significantly. Increasing the number of clusters per operator led to greater percentages of bimodal curves. The greater somatic cell count of cows with bimodal curves supports the hypothesis of the negative effect of bimodality on udder health and indicates the importance of avoiding its occurrence using proper pre-milking procedures.

Visual appearance and CMT score of foremilk of individual quarters in relation to cell count of cows milked automatically

The objectives of the study were: to evaluate the interaction between visual appearance and California mastitis test (CMT) score of the foremilk in relation to the cell count of the milk; to evaluate the consequences of sorting milk according to these criteria; and to explore whether visual appearance and CMT score of foremilk depended on the time interval between milkings. Measuring somatic cell count (SCC) in composite milk only and discarding milk above certain thresholds will not ensure that milk from all cows with visually abnormal foremilk is withheld from delivery. Low thresholds of SCC will reduce the frequency of cows with abnormal milk but increase the discarding of milk from cows with visually normal foremilk. CMT score of foremilk differentiated better between cows with high and low SCC in composite milk than visual inspection of foremilk. CMT scores of foremilk decreased with increasing interval between milkings within cow, whereas the visual appearance was independent of the interval. We propose that visual appearance of the foremilk should be kept as a criterion for sorting milk at time of milking. For test purposes, the use of visual appearance of foremilk for differentiation between normal and abnormal milk has to be done on multiple milkings. Additionally, CMT scoring of foremilk improves correct classification of normal and abnormal quarters and especially when including data from the previous milking.

The Effect of an Intramammary Teat Seal on New Intramammary Infections

As concern over the possible overuse of antibacterials increases, attention has focused on reduction of antibiotic usage and on nonantibiotic alternatives. A nonantibiotic intramammary teat sealant, Teat Seal (Cross Vetpharm Group Ltd., Tallaght, Dublin, Ireland), has been available in Ireland, in combination with an intramammary tube of cloxacillin. Teat Seal has been reformulated for use in cows with low cell counts as an alternative to antibiotic dry cow therapy at the end of lactation. The product is now marketed as Orbeseal (Pfizer Animal Health). A comparison between this teat sealant and no treatment was made on new intramammary infections and clinical mastitis, on all cows within four herds, and on low cell count cows in three herds.No cases of clinical mastitis in the dry period were observed in cows treated with Teat Seal (n = 197), whereas a significant number (6 cows) were observed in the untreated cows (n = 204). In all herds, significantly more new infections at calving were found in the untreated group (62 cows in the untreated group compared with 21 cows in the Teat Seal group). In those quarters where infections were first detected at calving, the incidence of clinical mastitis was significantly greater in the untreated group. Quarters in both treatment groups that were infected at drying off with Corynebacterium spp. or coagulase-negative staphylococci were not protected against new infections and had an increased risk of new infection by Streptococcus uberis. The results will inform those restricting their use of antibiotic dry cow therapy in alternative management strategies and the additional risk of new intramammary infection.

Influence of Stages of Lactation, Parity and Season on Somatic Cell Counts in Cows

Influence of Stages of Lactation, Parity and Season on Somatic Cell Counts in Cows