Herd Cell Count Research Articles

Treating clinical mastitis in dairy herds: a role for on farm culture?

The focus on the rational use of antibiotics in dairy herds has meant that mastitis control has received renewed interest, particularly around prevention of new infections and alternative treatment strategies. The former has seen the development of a new industry initiative (QuarterPRO) to help advisors and farmers reduce the rate of new infections and index cases. The latter has seen widespread uptake of the selective use of intramammary antibiotic for infected cows at drying-off, a reminder to the veterinary profession as well as clients about the general lack of evidence for the use of parenteral antibiotic in combination with intramammary antibiotic for mild and moderate clinical mastitis events, and finally the potential to select intramammary antibiotic treatment for clinical mastitis using on farm culture (OFC). It is important that veterinary surgeons are aware of the research around the development and use of OFC and the suitability of individual herds for this approach. Whereas antibiotics may not be required for mild clinical mastitis events caused by some pathogens, particularly Escherichia coli, it is important that clinical mastitis events (particularly first cases in a lactation cycle) caused by Gram-positive pathogens such as Streptococcus spp. and Staphylococcus aureus are treated with intramammary antibiotic to optimise chance of cure and reduce risk of transmission. With this in mind, we need to consider individual herd cell count data, herd pathogen profile and ensure careful monitoring of outcomes for clinical mastitis cases in herds that are selecting treatment based on OFC, particularly for index (first) cases in a cow's lactation.

Translactational associations of dry off management, milking activity, and somatic cell count in herds with automated milking systems

The objective of this study was to evaluate associations of dry off management factors, milking activity and production data, and somatic cell count prior to dry off and early in the subsequent lactation of cows milked by automated systems. Data were collected for 342 cows from five farms, for two milk tests prior to dry off, and for the two milk tests post calving. The results suggest that the post-calving milking performance of cows milked by automated systems may be more associated with individual cow traits than with their dry off management.

Factors livestock and milking associated with risk of mastitis in cattle dairy farms in aboveground of the Tunisia coastal semi-arid

This study was carried out in the Sahel of Tunisia (Monastir region) on a sample covering 40 cattle herd’s type above ground. We deduced the mastitis risk factors during the survey during visits for breeding and milking as well as from morphological and hygienic cow’s assessments. The data’s descriptive analysis has highlighted some significant effect factors on cellular levels and the risk of developing mastitis. For individual cell count (ICC), the significant effect factors (P <0.05) are: free stall, milking machine cleaning with only water, the poor condition of the piping, not elimination of the first milk jets and bad cleanliness of udders and the back legs of cows, whereas the herd cell count (HCC), the significant factors (P <0.05) are: cleaning the milking machine with water only, the frequency pulse (FP) is too high or low.

A multiarm randomized field trial evaluating strategies for udder health improvement in Swiss dairy herds

The aims of this study were to quantify the effectiveness of specialist advice about udder health in Swiss dairy herds and to compare 3 different udder health improvement strategies against a negative control group. In 2010, 100 Swiss dairy herds with a high (between 200,000 and 300,000 cells/mL) yield-corrected bulk milk somatic cell count (YCBMSCC) were recruited for a 1-yr multiarm randomized field trial. The herds were visited between September and December 2011 to evaluate udder health-management practices and then randomly allocated into 1 of 4 study arms containing 25 herds each. The negative control study arm received neither recommendations for improving udder health nor any active support. The remaining 75 farmers received a herd-specific report with recommendations to improve udder health management. The positive control study arm received no further active support during 2012. The veterinarian study arm received additional support in the form of monthly visits by their herd veterinarian. Finally, the study group study arm received support in the form of bimonthly study group meetings where different topics concerning udder health were discussed. One year later, implementation of recommendations and changes in udder health were assessed. Of the recommendations given, 44.3% were completely implemented, 23.1% partially, and 32.6% were not implemented. No differences in implementation of recommendations were noted between the 3 study arms. At study enrollment, farmers were asked for the study arm of their preference but were subsequently randomly assigned to 1 of the 4 study arms. Farmers that were assigned to the study arm of their preference implemented more recommendations than farmers assigned to a study arm not of their preference. No decrease in the within-herd prevalence of cows that had a high (≥200,000 cells/mL) composite somatic cell count was observed in herds that had a YCBMSCC ≥200,000 cells/mL at the start of intervention. However, the 3 study arms with intervention (positive control, the veterinarian, and the study groups) prevented an increase in the within-herd prevalence of cows that had a high somatic cell count in herds with a low YCBMSCC at the start of the intervention compared with the negative control study arm. In the year after sending the report, herds assigned to the study group study arm had a reduced incidence rate of treated mastitis cases in comparison with the year before sending the report.

The relationship between compost bedded pack performance, management, and bacterial counts

The objective of this study was to assess the relationships among temperature, moisture, carbon-to-nitrogen (C:N) ratio, space per cow, and bacterial counts from bedding material collected from compost bedded pack (CBP) barns. A field survey of 42 routinely aerated CBP barns was conducted in Kentucky between October 2010 and March 2011. Two bedding material samples of 1,064.7cm3 each were collected during a single site visit from 9 evenly distributed locations throughout each barn and thoroughly mixed to create a composite sample representative of the entire CBP. Bacterial counts were determined for coliforms, Escherichia coli, streptococci, staphylococci, and Bacillus spp. University of Kentucky Regulatory Services (Lexington) laboratory personnel performed nutrient analyses to determine moisture, carbon, and nitrogen contents. Surface and 10.2-cm pack depth temperatures were collected for each of the 9 evenly distributed locations and the mean calculated to produce a composite temperature. Space per cow was calculated as the total CBP area divided by number of cows housed on the CBP. The GLM procedure of SAS (SAS Institute Inc., Cary, NC) generated models to describe factors affecting bacterial counts. Bacterial counts were 6.3±0.6, 6.0±0.6, 7.2±0.7, 7.9±0.5, and 7.6±0.5 log10cfu/g of dry matter for coliform, Escherichia coli, streptococci, staphylococci, and Bacillus spp., respectively. Composite temperature, CBP moisture, C:N ratio, and space per cow had no effect on coliform counts. Escherichia coli reached a peak concentration when the C:N ratio was between 30:1 and 35:1. Staphylococci counts increased as ambient temperature increased. Streptococci counts decreased with increased space per cow and composite temperature and increased with increasing ambient temperature and moisture. Streptococci counts peaked at a C:N ratio ranging from 16:1 to 18:1. Bacillus spp. counts were reduced with increasing moisture, C:N ratio, and ambient temperature. Mastitis-causing bacteria thrive in similar conditions to that of composting bacteria and microbes, making elimination of these at higher temperatures (55 to 65°C) difficult in an active composting environment. Producers must use recommended milking procedures and other preventative practices to maintain low somatic cell count in herds with a CBP barn.

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.

Effet des conditions de traite sur la santé mammaire des vaches laitières et estimation des pertes en lait consécutives dans la région de Mahdia en Tunisie

L’objectif de ce travail a consisté à évaluer la situation sanitaire mammaire des vaches à partir du taux cellulaire du troupeau (TCT) et du comptage cellulaire individuel (CCI), et à estimer les pertes quantitatives en lait liées aux numérations cellulaires élevées. L’étude a été réalisée sur un échantillon de 30 élevages bovins de type hors-sol dans la région de Mahdia en Tunisie. Le diagnostic sanitaire mammaire a été effectué par la méthode de numération cellulaire directe sur lait de mélange et sur lait individuel. Les résultats ont montré que 87 p. 100 des élevages étudiés avaient des TCT supérieurs à 200 000 cell./ml et 69 p. 100 des vaches avaient des CCI supérieurs à 200 000 cell./ml. Les pertes quantitatives en lait consécutives à des taux cellulaires élevés ont été relativement importantes. Environ 23 p. 100 des élevages ont présenté des pertes en lait supérieures à 5 p. 100 de la production totale du troupeau et 15 p. 100 des vaches ont eu des pertes de lactation de 16 p. 100. Cette situation nécessiterait une intervention efficace de lutte contre les mammites, tout en essayant de maîtriser les facteurs de risque. L’étude des conditions de traite en relation avec les TCT et les CCI a montré que les pratiques de traite n’ont pas eu d’influence sur les taux cellulaires étudiés alors que les paramètres de fonctionnement de la machine à traire ont enregistré des corrélations significatives.

Herd characteristics and management practices associated with bulk-tank somatic cell counts in herds in official Dairy Herd Improvement Association programs in Ohio.

To identify herd characteristics and management practices associated with bulk-tank somatic cell counts (BTSCC) in dairy herds in Ohio enrolled in official Dairy Herd Improvement Association (DHIA) programs. 186 dairies in Ohio. All herds in official DHIA programs in 9 counties were asked to participate. Extensive information regarding herd characteristics and management practices was obtained, using a standardized questionnaire. Bulk-tank milk samples were requested from all participating herds for bacterial culture. Official DHIA test-day records for January 1997 were obtained from all herds enrolled in official DHIA programs in the 9 counties. Potential associations were identified, using multivariable ANOVA. Participation was 186 of 479 (39%) herds. Streptococcus agalactiae and Mycoplasma spp were not isolated from bulk-tank milk samples. Staphylococcus aureus was isolated from 64 of 172 (37%) of the herds. The BTSCC were inversely associated with peak daily milk production, postmilking teat disinfection, percentage of eligible cows in the herd detected in estrus, and directly related to the extent to which BTSCC was perceived as a herd problem during the preceding 2 years. Type of housing for nonlactating cows and product used for treatment of nonlactating cows also were significantly associated with BTSCC. Consideration of herd characteristics and implementation of management practices associated with BTSCC could result in increased milk yield and production of milk with lower BTSCC.

Epidemiological Analyses of the Associations between bovine udder health and milking machine and milking management

This paper presents data from 158 dairy herds in northern Norway. The influence of the milking machine and milking management on the prevalence of subclinical mastitis and herd cell counts was calculated from a least squares model by a backward elimination procedure. It was shown that 16–45% of the herd udder health variation found at the start of the programme could be associated with milking machine and milking management variables. The following variables were found to be of significance: number of clusters in the herd, vaccum, function and vaccum regulator, undulation of pipeline, limping of pulsator, rate of pulsator, type of claw-piece, hygienic/-technical condition of liner, preparation time, air admission during application of teat cups, overmilking and machine-on time.

Epidemiological analyses of the associations between bovine udder health and housing

Data from a mastitis control programme involving 158 herds in northern Norway are presented. The association between housing factors and indoor climate variables, and the prevalence of subclinical mastitis and herd cell count was calculated from a least squares model by a backward elimination procedure. Ten to 23% of the herd udder health variation at the start of the programme was associated with environmental variables. The following variables were found to be of significance: herd size, hoof trimming, lactation age, stall floor surface, type of stall, stall width, stall length, presence or absence of a grating over dung channel, single-/double-glazed windows and ambient humidity.

Streptococcus Agalactiae in the Smaller Herd. Its Incidence in Relationship to Somatic Cell Counts

SUMMARY In view of the finding that 38% of herds producing bulk tank milk supplies were excreting Streptococcus agalactiae, a survey of smaller herds was carried out in the province over a one year period. The milk was supplied to creameries in churns, and each representative herd supply was tested monthly for somatic cells, Str. agalactiae and inhibitory substances. Str. agalactiae was found to be present in 198 (37 · 6%) of 526 herds, the sample incidence being 662 (10 · 7%) of 6214 monthly samples tested. 44% of the 198 herds were positive only once, 12% twice, 7% three times and so on, 5 herds being culturally positive 11 times and 3 herds were positive on 12 successive months. The mean cell count of all 526 herds was 522 000 cells/ml the lowest annual herd mean being 140 000 cells/ml and the highest 2 748 000 cells/ml. Despite the influence of infections other than Str. agalactiae on herd cell counts, a very high correlation was obtained between the frequency of isolation and the mean cell counts of herds infected (0 · 849). It was surprising however to find that over 30% of herds with annual cell count means of 1 × 10 6 cells/ml were positive. Only 40 (7 · 6%) of the 526 herds were IHS positive at > 0 · 05 i.u./ml, compared with 13 · 5% of bulk tank herds included in our previous survey.

Streptococcus Agalactiae in Dairy Herds. Its Incidence and Relationship to Cell Count and Inhibitory Substance Levels in Bulk Milk

SUMMARY Composite milk samples from 379 dairy herds were taken at monthly intervals for one year and cultured by intensive methods for Str. agalactiae. Studies were made in parallel to determine the presence of inhibitory substance residues, and to assess the somatic cell count of each sample by electronic counting techniques. Str. agalactiae was found to be present in 146 (38 · 52 per cent) of the 379 herds, the sample incidence being 12 · 3 per cent (519 of 4221 samples) ; 34 per cent of the 146 herds were positive only once, 16 per cent twice, 8 per cent three times and so on, only one herd being culturally positive on twelve successive months. The significance of the results is discussed, particularly in relationship to the annual cell count means of the herds involved. A good correlation was observed, the more frequently Str. agalactiae isolation being made, the higher the cell count. Despite the possible influence of infections other than Str. agalactiae on herd cell counts, a correlation coefficient of 0 · 75 was obtained. The bracketing of infected herds into cell count ranges illustrated that only 20 · 7 per cent had annual means of On a sample basis it was found that 1 · 73 per cent of the 4221 samples were IHS positive at > 0 · 05 i.u./ml; 5 · 2 per cent of these were from Str. agalactiae herds, while 1 · 24 per cent were from herds culturally negative. The organism was isolated from nine samples which were IHS positive.