Determination Of Somatic Cell Count Research Articles

Mastitis in a flock of milking sheep.

Determination of somatic cell counts (SCC) becomes more and more important also for ewe's milk. SCC can be a useful indicator of milk quality for milk processors while it can be a mastitis indicator for sheep keepers and an important selection criterion for breeders. The objective of our study was to acquire basic information about factors influencing SCC variability in lambing ewes of the Tsigai (T) and Improved Valachian (IV) breeds. Somatic cell counts (SCC) were determined in 866 milk samples in 2017 and 2018, during lamb sucking and during milking period. An instrument Fossomatic 90 (Foss Electric, Hillerød, Denmark) was used for analysis. Average SCC varied from 270 to 1897 × 103 cells/ml during lamb sucking and from 268 to 2139 × 103 cells/ml during milking period. Differences between the sampling periods were statistically significant in 2017. An increase in SCC was observed at the end of both sucking and milking periods. An overall evaluation of lactation brought about the average SCC at 364 × 103 cells/ml in 2017 (log(10) SCC - 2,25) and at 1,091 × 103 cells/ml in 2018 (log(10) SCC - 2,68). The indicator log(10) was significantly influenced by breed in 2017 (T - 2,61; IV - 2,75). The effect of lactation number and number of sucking lambs did not have any significant influence on SCC.

INFRARED THERMOGRAPHY TO MAP THE UDDER HEALTH STATUS OF ZEBUINE DAIRY COWS

<p><strong>Background:</strong> Infrared thermography is a diagnostic imaging technique that detects the emission of heat by infrared radiation, indicating the temperature of a particular area. <strong>Objective</strong>: The objective of this study was to measure the magnitude of the udder temperature variation by infrared thermography for mastitis diagnosis of zebuine dairy cows in a tropical pasture-based system. <strong>Methodology:</strong> The udder temperature of Holstein-Gyr crossbred cows was measured with a FLIR<sup>®</sup> camera. Milk samples were collected for CMT and somatic cell count determination. The surface temperature of the mammary gland and rectal temperature were grouped according to udder health status of animals and were submitted to analysis of variance and correlation analysis. <strong>Results:</strong> The udder temperatures were higher for the clinical mastitis group (37.2±0.7 °C) than the subclinical mastitis (36.6±0.9 °C) and healthy udder (36.3 ±1.0 °C) groups. A weak positive correlation (r=0.18) was observed between somatic cell count (SCC) and udder temperature. A strong positive correlation (r=0.68) was observed between rectal temperature and udder temperature. <strong>Implications:</strong> The results of this work can be applied in the future in precision animal husbandry, generating more efficient strategies and practices for the diagnosis and control of mastitis, since it is a promising tool for easy and quick diagnosis of mastitis. <strong>Conclusions:</strong> Infrared thermography can be an effective method for diagnosing mastitis in cows. However, its use should be made with the complementary California mastitis test.<strong></strong></p>

The relationship of bovine milk somatic cell count to neutrophil level in samples of cow's milk assessed by an automatic cell counter.

This research communication describes the application of a fluorescent automatic cell counter Lactoscan SCC for simultaneous determination of somatic cell count and neutrophils in bovine milk. The obtained results were compared with results obtained by a flow cytometer and a light microscope. The Pearson correlations between the methods were calculated. A comparison between the main characteristics of the three kinds of analysis was made - the assay duration and the intra-assay precision. A relation between the SCC and neutrophil cells was observed in 55 milk samples. The obtained results confirm that the simultaneous determination of SCC and neutrophil analysis are necessary and support the early diagnosis of mastitis, the timely treatment of the animal and the avoidance of major economic losses.

TOTAL BACTERIAL COUNT, SOMATIC CELL COUNT AND PRESENCE OF AFLATOXIN M1 IN RAW MILK FROM THE “OVČE POLE” REGION, REPUBLIC OF NORTH MACEDONIA

Dairy product quality monitoring begins at the farm and ends in the hands of the consumer. Raw milk must also meet other quality standards; it should be free of drug residues, free of added water and free of sediment, contaminants and other abnormalities. In our researches, is taken somatic cells count, the number of bacteria and Aflatoxins as indicators of the quality of raw milk from the Ovče Pole region in the period January-June, 2018. For the needs of this research, an analysis was made of 1320 samples for the presence of bacteria in raw milk, determination of somatic cell count in 478 samples as well as identification and quantification of aflatoxin M1 in 60 samples.  The results from this study indicated determination acceptable count of somatic cells in 95.5 % of the samples from raw milk while in 2 samples of raw milk, the amount of aflatoxin M1 was above limits with highest amount of 0.58 mg/kg raw milk. According to European milk quality standards, in the biggest part of the samples (89.55 %), presence of bacteria does not meet the standard. From the analyzes made by the milk producers that were the subject of analysis in this research, it can be concluded that they do not adhere to good agricultural practice, the level of milk contamination is high due to poor hygiene, improper handling of milk after milking and insufficient education of farmers for hygiene in primary production.

Analysis of the relationship between milk production, milk composition and morphological udder measurements in Wallachian sheep

The aim of this study was to evaluate the potential of udder measurements for prediction of milk yield, milk components and somatic cell count in non-dairy Wallachian sheep. The study was performed on 38 ewes in the Beskids Mountains kept under extensive management on pasture. Milk production (MILK) as well as samples for milk component and somatic cell count determination were collected during two separate control days (42<sup>nd</sup> day and 100<sup>th</sup> day of lactation on average). Rear udder depth (RUD, cm), udder width (UW, cm), and teat length (TL, mm) were measured at each control day as well. Linear regressions of udder measurement characteristics showed a predictive character ability for MILK only. An increasing of 70 g MILK corresponded with a 1 cm increase of RUD (P < 0.01) or 1 cm increase of UW (P < 0.001). These positive linear relationships were supported by the positive partial correlation analysis between MILK and RUD (r = 0.503; P < 0.001) or MILK and UW (r = 0.627; P < 0.001). An increase of 1 mm TL was associated with a 10 g (P < 0.01) increase of MILK; however, correlations between these traits were not significant. Results of this study demonstrate an alternative way of MILK ability in non-dairy Wallachian sheep population in general. Correlation and regression analysis further estimated this expected potential in detail using udder measurement characteristics. Measurement of RUD and UW could serve as a tool for breeding and flock management in order to maintain and improve milk production; however, there was no obvious evidence for the prediction of milk composition characteristics and somatic cell count.

Insight in Leptin Gene Polymorphism and Impact on Milk Traits in Autochtonous Busha Cattle

Abstract Leptin, a biomolecule secreted by adipose tissue, enchances productivity in cattle, especially affecting milk traits. The aim of this study was to detect leptin gene polymorphism on exon 3 (A59V locus) and intron 2 (SAU3AI locus) in the endangered population of autochtonous Busha cattle and associations with milk traits. The study included 46 cows: 36 Busha and 10 half-bred. Milk analyses comprised determination of somatic cell counts, fat, protein, lactose, total solids and solids-not-fat (SNF) concentrations and freezing point depression (FPD). Polymorphisms were determined by PCR-RFLP technique. A single A59V genotype (CC) was affirmed, and two SAU3AI genotypes, AA and AB, with frequencies of 78.26% and 21.74%, respectively. Comparing the obtained results for chemical characteristics of milk between cows with AA and AB, no significant differences were found, except for SNF content and FPD values. Cows with AA genotype had significantly lower (p=0.021) average SNF content (8.74%) in milk compared to the average SNF content (9.28%) in those with genotype AB, while cows with genotype AA (−0.54°C) had significantly higher (p=0.004) average FPD values than those with AB genotype (−0.58°C). The absence of BB genotype and significant differences in the investigated functional traits between two SAU3AI genotypes and the absence of A59V polymorphism (presence of only CC genotype) show that the Busha cattle breed, although being an autochtonous low-producing native breed used for meat and milk production, harbours polymorphism on gentic markers characteristic of high production dairy cows.

Comparison between direct and indirect immunofluorescence method for determination of somatic cell count

A sensitive indirect immunofluorescence (IF) assay for bovine neutrophil and somatic cell counting was developed. The obtained indirect IF was compared with direct IF. The direct IF method uses a single-fluorophore-conjugated antibody directed against the target of interest. The indirect IF method uses two antibodies. The primary antibody is unconjugated. The secondary antibody is directed against the primary and has fluorescent marker. Calibration curves for somatic cells (SC) in buffer model solutions were obtained by both methods, using fluorescence spectrophotometry. The measured linear range of somatic cells by the direct method was from 2 × 104 to 3 × 106 cells and by the indirect method was from 3 × 104 to 3 × 106 cells. The signal obtained by the indirect method was higher than the direct method at low concentrations of SC (from 30,000 to 100 000 cells/mL). That signal amplification probably is due to more than one fluorescent secondary antibody coupling to bound primary antibody. The same effect is observed by fluorescence microscopy. Consequently, the indirect IF method is more sensitive than the direct IF method. Conjugated primary antibodies are more expensive than their unconjugated counterparts, and secondary antibodies are relatively inexpensive. Therefore, using the same conjugated secondary antibody to detect different primary antibodies is cost-effective. Furthermore, a two-color staining microscopic procedure was proposed for simultaneous estimation of total SC count and neutrophil cell count.

Quality of milk produced in small farms in Alagoas state and impact of application of good manufacturing practices to milking hygiene

The purpose of this study was to monitor improvements in the hygiene and sanitation conditions, and milk safety after application of Good Manufacturing Practices (GMP) to milking. A total of 106 farms were assessed in four stages of six months in the regions named agreste, dairy region, mid-backlands and high backlands of Alagoas. Two activities were executed in the project: monitoring of milk quality and safety; and application of GMP to pre-milking and milking processes. Milk samples underwent determination of Somatic Cell Count (SCC), Total Bacterial Count (TBC) and composition. The results correspond to milk components, determination of mammary health indicative parameters - SCC and milking hygiene - TBC. Regarding SCC, 73% of producers complied with the standards established by normative instruction IN 62 as of 2017. Regarding TBC, the use of GMP increased from 46.75% to 59.87% the average of all assessed properties that complied with the established standards. Less than 4% of the properties presented one million or higher TBC/mL of milk. Results of SCC after application of GMP remained basically the same. Regarding TBC, rate changes deriving from the application of GMP were significant.

Occurence of Mastitis in Dairy Cows Situated in Marginal Parts of Slovakia

Abstract A relatively large part of the Slovak territory consists of the “marginal regions”, which in terms of the economy of ruminants keeping can efficiently produce animal commodities only occasionally. The geographic, social and economic stability of these regions is strongly influenced by the rearing of ruminants and the associated market milk production. The aim of this study was to evaluate the prevalence and aetiological agents of mastitis in two herds of dairy cows situated in the marginal parts of Slovakia. In total, 530 of the Slovak spotted breed and Holstein cows were involved in the study. The diagnosis of mastitis was performed on the basis of the clinical examination of the udder, macroscopic evaluation of the milk, determination of somatic cell count (SCC), and the bacteriological examination of the milk. The prevalence of mastitis in the two herds of dairy cows ranged from 34.7 % to 18.8 %, respectively. From the total of 2120 quarter milk samples, 36.3 % were positive to the California mastitis test (CMT). Also, pathogenic microorganisms causing intramammary infection (IMI) were isolated from 25.6 % of the samples, which accounted for most subclinical mastitis forms (23.3 %), with the SCC under 400 000, mainly caused by coagulase-negative staphylococci (CoNS) and coliform bacteria E. coli and Enterobacter aerogenes. The clinical forms of mastitis accounted for 13.0 % of all infected cows and were caused mainly by the bacteria: Streptococcus uberis, Streptococcus agalactiae, Staphylococcus aureus and coagulasenegative staphylococci.

Somatic cell counts in bulk milk and their importance for milk processing

Bulk tank milk somatic cell counts are the indicator of the mammary gland health in the dairy herds and may be regarded as an indirect measure of milk quality. Elevated somatic cell counts are correlated with changes in milk composition The aim of this study was to assess the somatic cell counts that significantly affect the quality of milk and dairy products. We examined the somatic cell counts in bulk tank milk samples from 38 farms during the period of 6 months, from December to the May of the next year. The flow cytometry, Fossomatic was used for determination of somatic cell counts. In the same samples content of total proteins and lactose was determined by Milcoscan. Our results showed that average values for bulk tank milk samples were 273,605/ml from morning milking and 292,895/ml from evening milking. The average values for total proteins content from morning and evening milking are 3,31 and 3,34%, respectively. The average values for lactose content from morning and evening milking are 4,56 and 4,63%, respectively. The highest somatic cell count (516,000/ml) was detected in bulk tank milk sample from evening milk in the Winter and the lowest content of lactose was 4,46%. Our results showed that obtained values for bulk tank milk somatic cell counts did not significantly affected the content of total proteins and lactose.

Fluorescence microscopy methods for the determination of somatic cell count in raw cow's milk

Fluorescence microscopy methods for the determination of somatic cell count in raw cow's milk

Prevalence and etiological agents of subclinical mastitis at the end of lactation in nine dairy herds in North-East Poland.

The aim of this study was to evaluate the prevalence and etiological agents of subclinical mastitis at the end of lactation in nine dairy herds in North-East Poland. In total, 387 Polish HF were involved in the study. The diagnosis of mastitis was performed on the basis of clinical examination of the udder, macroscopic evaluation of milk, determination of somatic cell count and bacteriological examination of milk. Subclinical mastitis was found in an average of 36.7% (range from 21.0% to 53.1%) of cows and of 15.7% (range from 9.6% to 25.2%) of quarters. Coagulase negative staphylococci (CNS; 31.6% of quarters), Streptococcus (Str.) agalactiae (15.6% of quarters), Staphylococcus (Staph.) aureus (12.1% of quarters) and fungi (12.2% of quarters) were most frequently isolated from subclinical mastitis. Etiological agents of subclinical mastitis differed strongly between herds. The results of this study showed that the incidence of subclinical mastitis at the end of lactation in dairy herds in North-East Poland is high. CNS were the most frequently isolated from subclinical mastitis cases, however mastitis caused by the contagious pathogens Str. agalactiae and Staph. aureus is still a problem. The fungal infections of the mammary gland also play an important role.

Neke odlike mlijecnosti istarskih ovaca u poluintenzivnim proizvodnim uvjetima

Istrian sheep has the highest milk yield among indigenous Croatian sheep breeds though originally belongs to a group of sheep of combined production traits. Since milk of Istrian sheep is traditionally processed into cheese and that processing possibilities of milk, among other things, are defined by its chemical composition and hygienic quality, the aim of this study was to determine the influence of some environmental factors (year, parity, stage of lactation, season (month) of lambing) on daily and lactation milk yield, lactation length, milk chemical composition and the somatic cell count (SCC) in the milk of Istrian ewes. A total of 83 purebred, dairy Istrian sheep, during three consecutive lactations (from 2012 to 2014), were involved in this research. Due to conditions of feeding, care and housing, all ewes were kept in identical (semi-intensive) farming conditions throughout the whole study period. During milking period of lactation regular milking controls were carried out (AT method) and, on these occasions, individual milk samples for chemical composition analysis and determination of somatic cell count were taken. During average lactation length of 206 days Istrian ewes produced on average 190.77 kg of milk, or 1.1 kg of milk per day. Milk of Istrian ewes on average contained 6.81% fat, 5.90% protein, 4.32% lactose, 18.08% total solids and 11.31% non-fat solids. The geometric mean of SCC was 316*103*mL-1 of milk (log 5.50±0.02). A significant (P < 0.001) effect of the year is determined on the milk yield and the lactation length, as well as the chemical composition of milk (with the exception of protein) and SCC. Ewes in the fourth lactation achieved the highest average daily (P < 0.001) and lactation milk yield (P < 0.05), while the first-lambing ewes produced milk with the highest content of total solids, milk fat and proteins. Stage of lactation significantly (P < 0.001) affected the daily milk yield, milk chemical composition, as well as the somatic cell count in ewe’s milk. Ewes born in December produced significantly (P < 0.001) more milk than ewes born in January and February. There was a negative correlation between SCC (log10) and daily milk yield (P < 0.001), while the SCC (log10) was positively correlated (P < 0.001) with the contents of total solids, milk fat and proteins.

ROLE OF MILK TRI-IODOTHIRONIN (T3) AND SOME BIOCHEMICAL PARAMETERS ON UDDER STATUS IN DAIRY BUFFALOES

Transition from pregnancy to lactation in dairy bufallo cows involves considerable metabolic adaptation. Additional stress is incurred during infections such as post-partum mastitis. The effect of naturally acquired bacterial infection of the buffalo udders on the activity of the milk triiodothyronine (T3) content, from healthy (control) and inflamed quarters, was determined to develop a better understanding of thyroid metabolism in buffalo. The diagnostic procedure included history and clinical examination of the udder, macroscopic evaluation of secretions, the California Mastitis Test (CMT), determination of somatic cell counts, bacteriological examination of milk and some biochemical parameters (AST, ALP, LDH, Malondialdehyde, calcium, phosphorus, sodium and chloride) of the same milk samples. The associations between T3 and other milk constituents were investigated, as well as the relationships between the bacterial species isolated from milk and others biochemical parameters. Bacterial examination, somatic cell counts (SCC) and the percentages of milk constituents were analyzed in 42 buffalo cows suffering from subclinical mastitis in one or more than one udder quarters, as well as from 8 healthy control buffalo cows. In single bacterial isolation, E.coli was the highest isolated bacteria from different scores of SCC (19 %) followed by coagulase negative staphylococcus (CNS) and other streptococci (14.3 % for each) meanwhile the Staphylococcus aureus (S.aureus) was the lowest isolate (9.5%). On the other hand, in mixed bacterial infection E.coli with S.aureus and other strept. was the highest categegory (16.7 %) followed by S.aureus with E.coli (14.3 %) while CNS with E.coli was the lowest one (11.9 %) .It has been found that milk parameters from inflamed quarters were decreased when compared with controls. The decrease in the milk T3 from subclinical mastitic buffaloe cows was manifested when somatic cell counts were > 5 ×105 / ml milk. These results suggest that the marked decreased T3 level and different milk contents in mammary secretions during naturally occurring subclinical mastitis is associated with the severity of inflammation. Milk enzymes (AST, ALP and LDH) as well as Malondialdehyde, calcium and phosphorus were detected. Significant elevation of liver enzymes, sodium and chloride were noticed in subclinical mastitis cases than healthy control udder. This study confirms the close inter-relationship between the thyroid hormone (T3), biochemical parameters and different milk constituents and the severity of bacterial infection causes udder mastitis in addition to bufallo udder health.

Excretion of Coxiella burnetii in Cows with Secretion Disorder

Coxiella burnetii is the causative agent of a very important disease with zoonotic potential. Domestic ruminants are very important factor in transmission of this pathogen to humans. This pathogen can be found in feces, urine, lochia, placenta and milk of infected animals. Of all these routes, the excretion through milk lasts the longest, and can last over several lactations. In this paper, we examined the excretion dynamics of Coxiella burnetii through milk of seropositive cows and the levels of immunoglobulin G in milk and blood serum. Correlation between these parameters is also examined. Milk samples from infected cows were used for somatic cell count determination. The PCR method was used for determination of Coxiella burnetii genome. RID plates were used for determination of concentration of immunoglobulin. The excretion of the pathogen through milk differed between different stages of lactation: it was the lowest in the first stage (16.6%) and the highest in the second stage (80.0%). In the second stage the lowest concentration of immunoglobulin G was detected in milk serum (4.0 g). Somatic cell count was increased, some samples had very high values.

An experimental comparison of methods for somatic cell count determination in milk of various species of mammals

Somatic cell count (SCC) is important foodstuff, hygienic and health indicator of milk and animal mammary gland. The goal of this paper was to evaluate an ability of chosen methods to reach the SCC reliable results in various biological kinds (species) of milk. The various methods of SCC determination were compared in cow (CM), goat (GM), sheep (SM) and human (HM) milk: direct microscopy (DM); fluoro-opto-electronic (Fossomatic 90; Foss); fluorescent (DCC; De Laval). Used methods had cow milk calibration basically. The DM, Foss and DCC result relations about SCC were very close, mostly &gt; 0.92 (P &lt; 0.001) for CM, GM and SM. In CM the regression equations between methods were near ideal form y = 1x + 0. The mean differences SCC data sets between mentioned methods were small for CM, larger for SM and HM and the largest for GM. It is possible to convert all DCC results in SM, HM and GM to DM or Foss method. The conversion equations were stated from DCC: to DM in cow milk y = 1.1293x − 5.5029; to Foss in goat milk y = 3.603x − 3171.4; to Foss in sheep milk y = 1.3805x − 18.149; to Foss in human milk y = 2.6246x + 158.63. Assesment of conversion equations should be individual laboratory event. Results had relatively good correspondence among DM, Foss and DCC for SCC determination in CM, GM, SM and HM for milk quality control. DCC had lower results in small ruminants as compared to Foss calibrated on CM using DM. DCC in HM had lower results as Foss adjusted by CM at good correlation (0.84; P &lt; 0.001).

Prediction of total quarter milk somatic cell counts based on foremilk sampling

Determination of somatic cell count (SCC) is used worldwide in dairy practice to describe the hygienic status of the milk and the udder health of cows. When SCC is tested on a quarter level to detect single quarters with high SCC levels of cows for practical reasons, mostly foremilk samples after prestimulation (i.e. cleaning of the udder) are used. However, SCC is usually different in different milk fractions. Therefore, the goal of this study was the investigation of the use of foremilk samples for the estimation of total quarter SCC. A total of 378 milkings in 19 dairy cows were performed with a special milking device to drain quarter milk separately. Foremilk samples were taken after udder stimulation and before cluster attachment. SCC was measured in foremilk samples and in total quarter milk. Total quarter milk SCC could not be predicted precisely from foremilk SCC measurements. At relatively high foremilk SCC levels (>300 x 10(3) cells/ml) foremilk SCC were higher than total quarter milk. At around (50-300) x 10(3) cells/ml foremilk and total quarter SCC did not differ considerably. Most interestingly, if foremilk SCC was lower than 50 x 10(3) cells/ml the total quarter SCC was higher than foremilk SCC. In addition, individual cows showed dramatic variations in foremilk SCC that were not very well related to total quarter milk SCC. In conclusion, foremilk samples are useful to detect high quarter milk SCC to recognize possibly infected quarters, only if precise cell counts are not required. However, foremilk samples can be deceptive if very low cell numbers are to be detected.

Controlled clinical trial of the effect of a homoeopathic nosode on the somatic cell counts in the milk of clinically normal dairy cows

Cows in a 250-cow Holstein-Friesian herd were allocated at random to be treated with either a homoeopathic nosode or a negative control, both treatments being applied by means of an...

Studies on the use of Blu-Gard Spray ® in dairy sheep

The influence of Blu-Gard Spray ® on udder health was examined in a field study comprising of five lactating Austrian sheep flocks between December 2001 and May 2002. At the first visit the ewes were assigned; based on a random number list into a test group (TG) that was treated with the teat dip after the samples were taken and into a control group (CG) that did not take part in any udder hygiene programme. On monthly visits a total of 1245 milk samples were taken from 127 sheep in the control group and a total of 1215 samples of 128 sheep in the test group. The animals were clinically examined in the milking parlour (inspection and palpation) and milk samples were taken for the indirect (California Mastitis Test; CMT) and direct (Fossomatic) determination of somatic cell count (SCC), as well as for the bacteriological examination. There was an increase of pathological findings in inspection in both groups (TG: +3.6%; CG: +1.7%). The results of the palpation showed an increase of pathological findings by 0.8% in the test group, whereas the control group remained constant. Both the CMT and the direct SCC increased towards the end of the study. 93.6% of the bacteriological positive cases in the test group were coagulase-negative Staphylococci (CNS), 5.1% belonged to the group of streptococci and 1.3% of the infections were caused by Staphylococcus aureus. In the control group, 88.6% of the infections were caused by coagulase-negative Staphylococci. 5.4% belonged to the group of streptococci and in 2.4% of the cases S. aureus could be identified. In the test group, new infections with CNS appeared in one sheep in both udder halves, while in the control group one new infection of an udder half with CNS was observed. Since teat dips are used to reduce the rate of new infections and hardly any new infections occurred in this study, the use of Blu-Gard Spray ® did not show the same effect as it does in cattle. The product was easy to use and was gentle on the teat skin.

Clinical and histopathological aspects of naturally occurring mastitis caused by Listeria monocytogenes in cattle and ewes.

Listeria monocytogenes was isolated from the milk of two cows and two sheep with mastitis in one quarter and one udder half. The animals were observed over a period of 2-12 months. Clinical examination of the udder, bacteriological examinations and determination of somatic cell counts of milk samples were performed monthly. All four cases suffered from a subclinical mastitis characterized by an elevated somatic cell count (0.8-10.1 x 10(6) cells/ml), a persistent shedding of Listeria and by a normal appearance of the milk. The animals did not show any systemic reaction, but all animals developed an atrophy of the infected mammary gland. Histological examinations revealed a chronic interstitial mastitis with diffuse infiltration of lymphocytes, plasma cells and macrophages. All internal organs showed no abnormalities, no Listeria could be isolated. Listeria could however be isolated from the affected mammary parenchyma and from the mammary lymph node. The results of the bacteriological examination could be confirmed by means of PCR. Using PFGE, all the isolates from the same animal were identical. Immunohistochemical examination of the ovine mammary glands achieved a very strong immunoreactivity for CD5 cells. The mode of infection and the reaction of the immune system's defense of the ovine udders are discussed.