New advances in epizootiology and control of ewe mastitis

doi:10.1016/S0301-6226(02)00145-8

Livestock Production Science

Volume 79, Issue 1, January 2003, Pages 1-16

https://doi.org/10.1016/S0301-6226(02)00145-8 Get rights and content

Abstract

The lactation (or annual) incidence of clinical mastitis in the ewe is generally lower than 5%, while the prevalence of subclinical mastitis is variable and ranges from less than 10 to 50% or more. Staphylococcus aureus is the most frequent bacterium responsible for clinical mastitis (from 20 to at least 60%). Coagulase-negative staphylococci are the principal causative agents of subclinical mastitis (30–95%), mainly in dairy ewes. Somatic cell counts (SCC) represent a valuable tool for prevalence assessment and screening. At an individual level, the use of several successive SCC allows the efficient detection of subclinical mastitis and is a good predictor of persistance. Healthy udders regularly show a SCC value lower than 500 000 cells/ml throughout the lactation period; values for subclinically or chronically infected udders usually exceed one million cells/ml. At the flock level, bulk milk SCC can be used to determine the overall intramammary infection prevalence, with a good coefficient of determination (r²=0.845). Using SCC or the California Mastitis Test, and clinical examinations, ewes to be culled or treated can be identified. Immediate or delayed culling and intramammary antibiotherapy at drying-off are the main measures for the elimination of intramammary infections. Drying-off intramammary antibiotherapy is increasingly being performed in dairy ewes, as it provides a good bacteriological cure rate. Prevention is mainly directed against infections involving mammary sources, and includes milking machine control, milking routine optimisation, and post-milking teat disinfection. Control measures should take into account the peculiarities of dairy sheep breeding (e.g. flock size, seasonality, cost–benefit ratios, etc.).

Introduction

The term ‘mastitis’ means udder inflammation, whatever the origin, severity and evolution. Most often, mastitis is of bacterial origin. In the ewe, intramammary infections are mainly due to ‘non-specific’ bacteria, mycoplasmas or lentiviruses; the former are the sole subject of this review. From a clinical point of view, mastitis takes various forms: clinical mastitis is characterised by general signs (fever, anorexia, weakness, coma, etc.), or only local signs (udder inflammation and oedema, gangrena, asymmetry, sclerosis, abscesses, etc.) and functional signs (macroscopic or quantitative modifications of milk production). Subclinical mastitis is characterised by quantitative and qualitative functional modifications (especially an increase in somatic cell count).

Mastitis is important for three reasons:

•
economic (ewe and lamb mortality, treatment costs, reduced milk production, reduced lamb growth, milk payment on cellular quality in certain areas);
•
hygienic (risk of infection or intoxication of consumers by milk bacteria such as Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Salmonella spp., etc.). The main use of dairy ewe’s milk is traditionally cheese processing;
•
legal (E.U. Directive 46/92, modified by Directive 71/94, defining milk bacteriological quality and mentioning cellular quality).

Consequently, the control of mastitis and of hygienic quality of milk is the main goal for dairy and lamb-producing, sheep-breeding organisations.

Section snippets

Incidence

The lactation (or annual) rate of new clinical cases is often less than 5%, both in dairy and meat flocks. Epidemiologically, these cases are generally sporadic clinical mastitis.

In a few outbreaks (less than 1 or 2% of flocks), the incidence may be higher (exceeding 30–50%), causing mortality or culling of up to 90% of mastitic ewes in a flock (Watson and Buswell, 1984, Marco Melero, 1994, Kirk and Glenn, 1996, Bergonier et al., 1997, Lafi et al., 1998, Calavas et al., 1998). These epizootic

Clinical mastitis

Table 1 presents the results of studies of clinical mastitis in dairy ewes. Despite some differences in the methods, these data show the high prevalence of Staphylococcus aureus: from 17 to 57% of isolated bacteria (mean value approximately 36%, excluding Mycoplasma isolations). Coagulase-negative staphylococci (CNS), considered as minor pathogens in the cow, were isolated in 10.3–52.6% of clinical mastitis. The frequency of Streptococci, Pasteurella (including Mannheimia haemolytica, formerly

Sources

The main sources (primary sources) of staphylococci are clinically (chronically) and subclinically infected udders and infected teat injuries or viral lesions (Orf, i.e. Contagious Ecthyma). However, staphylococci, including S. aureus, are also carried by normal teat skin (without lesion), with a variable prevalence between flocks (Scott and Murphy, 1997; Bergonier et al., unpublished data).

Enterobacteria, Enterococci and Pseudomonas are found in the environment, the first two mainly in litter

Clinical diagnosis

Acute and peracute mastitis are generally easily diagnosed by dairy ewe farmers who know their animals well, with a slight behavioural modification inducing a more complete examination.

Local signs should be detected by inspection and palpation of the udder (and lymph nodes). Functional signs should be observed, at the beginning of milking, by foremilk inspection in a black-bottom container; this is only occasionally carried out, as the number of ewes and the milking routine do not allow these

Treatment

The literature on the treatment of mastitis in the ewe contains more general recommendations (extrapolated from data available for cattle) and clinical reports (without a control group) than controlled field trials; the latter mainly concern drying-off therapy. Currently, in France, only one treatment is officially indicated and authorised by the French Administration for dry ewe intramammary treatment (Longo and Pravieux, 2001). Under these conditions, many veterinary practitioners recommend,

Vaccination

A staphylococcal vaccine (exopolysaccharide), conceived and experimentally assessed in Spain (Amorena et al., 1994), was tested in a field trial in the Latxa breed. Two injections were performed during the month preceding and the month following lambing. The prevalence of intramammary subclinical infections was not significantly different between vaccinated and control groups during the entire lactation, but the frequency of clinical mastitis was reduced (Marco Melero, 1994).

To our knowledge,

Conclusions

The characteristics of the intramammary infections of ewes, together with their breeding peculiarities, justify the definition and validation of specific control plans. Usually, the epidemiological model is ‘reservoir’ mastitis, with transmission of Gram-positive bacteria (mainly Staphylococci) during milking. Compared with dairy cows, the control of mastitis must focus on measures targetting animal carriage and optimisation of the milking routine and hygiene. Much new data is now available, as

References (99)

B Amorena et al.
Use of liposome immunopotentiated exopolysaccharide as a component of an ovine mastitis staphylococcal vaccine
Vaccine
(1994)
A Bor et al.
Non-clinical intramammary infection in lactating ewes and its association with clinical mastitis
Br. Vet. J.
(1989)
J.F Buswell et al.
Antibiotic persistence and tolerance in the lactating sheep following a course of intramammary therapy
Br. Vet. J.
(1989)
D Calavas et al.
Classification of the clinical types of udder disease affecting nursing ewes
Small Rumin. Res.
(1998)
M De la Cruz et al.
Etiology and prevalence of subclinical mastitis in the Manchega sheep at mid-lactation
Small Rumin. Res.
(1994)
N.E East et al.
Disease of the udder (Symposium on Sheep and Goat Medicine)
Vet. Clin. North Am. (Large Anim. Pract.)
(1983)
G.C Fthenakis
Prevalence and aetiology of subclinical mastitis in ewes of southern Greece
Small Rumin. Res.
(1994)
G.C Fthenakis
California Mastitis Test and W.I. teside Test in diagnosis of subclinical mastitis in dairy ewes
Small Rumin. Res.
(1995)
M.C Gonzalez-Rodriguez et al.
Relations between somatic cell count and intramammary infection of the half udder in dairy ewes
J. Dairy Sci.
(1995)
M.C Gonzalez-Rodriguez et al.
Evaluation of the California Mastitis Test as a discriminant method to detect subclinical mastitis in ewes
Small Rumin. Res.
(1996)

S.Q Lafi et al.

Epidemiological studies of clinical and subclinical ovine mastitis in Awassi sheep in northern Jordan

Prev. Vet. Med.

(1998)

G Leitner et al.

Udder disease etiology, milk somatic cell counts and NAGase activity in Israeli Assaf sheep throughout lactation

Small Rumin. Res.

(2001)

S McDougall et al.

Relationships among somatic cell count, California Mastitis Test, impedance and bacteriological status of milk in goats and sheep in early lactation

Small Rumin. Res.

(2001)

P.J Maisi et al.

Detection of subclinical mastitis in ewes

Br. Vet. J.

(1987)

A.P Mavrogenis et al.

Use of somatic cell counts for the detection of subclinical mastitis in sheep

Small Rumin. Res.

(1995)

P Moroni et al.

Relationship between mammary gland infections and some milk immune parameters in Sardinian breed ewes

Small Rumin. Res.

(2001)

C Peris et al.

Variation in somatic cell counts. California mastitis test, and electrical conductivity among various fractions of ewe’s milk

J. Dairy Sci.

(1991)

R Rupp et al.

Genetic parameters for clinical mastitis, somatic cells score, production, udder type traits, and milking ease in first lactation Holsteins

J. Dairy Sci.

(1999)

P Saratsis et al.

Incidence risk and aetiology of mammary abnormalities in dry ewes in 10 flocks in southern Greece

Prev. Vet. Med.

(1998)

A Sevi et al.

Effect of parity on milk yield, composition, somatic cell count, renneting parameters and bacteria counts of Comisana ewes

Small Rumin. Res.

(2000)

A Tzora et al.

Mastitis in dairy ewes associated with Serratia marcescens

Small Rumin. Res.

(1998)

G.H Watkins et al.

A field investigation of subclinical mastits in sheep in southern England

Br. Vet. J.

(1991)

D.L Watson et al.

Modern aspects of sheep mastitis

Br. Vet. J.

(1984)

G Ahmad et al.

Dynamics and significance of ovine subclinical intramammary infections and their effects on lamb performances

Sheep Res. J.

(1992)

G Ahmad et al.

Ovine subclinical mastitis efficacy of dry treatment

Sheep Res. J.

(1992)

S Al Samarrae et al.

Mastitis in sheep in Iraq

Vet. Rec.

(1985)

J Arranz et al.

Evolucion de la caracteristicas morfologicas de la ubre de oveja Latxa a lo largo del periodo de ordeno

J Arranz et al.

Testing of the CMT method in the detection of subclinical mastitis in sheep

W Baumgartner et al.

Einfluss der laktationsperiod auf den zellgehalt von schafmilch

Dtsch. Tierarztl. Wochenschr.

(1992)

F Barillet et al.

Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep

Genet. Sel. Evol.

(2001)

T Baysal et al.

Konya ve yöresindeki koyunlarda klinik ve subklinik mastitis olgularindan aerob etken izolasyon ve identifikasyonu

Etlik Vet. Mikrob. Derg.

(1989)

F Beltran de Heredia et al.

Recuento de celulas somaticas en leche de oveja latxa

Med. Vet.

(1988)

E Berriatua et al.

Outbreak of subclinical mastitis in a flock of dairy sheep associated with Burkholderia cepacia complex infection

J. Clin. Microbiol.

(2001)

D Bergonier et al.

Détection des infections mammaires subcliniques chez la brebis laitière à l’aide des comptages de cellules somatiques: propositions de seuils physiologiques

D Bergonier et al.

Fréquence et persistance des staphylocoques coagulase négative au tarissement et relations avec les numérations cellulaires chez la brebis laitière

D Bergonier et al.

Facteurs de variation non infectieux des comptages de cellules somatiques chez les ovins et les caprins laitiers

D Bergonier et al.

Les mammites des ovins et des caprins laitiers: étiologie, épidémiologie, contrôle

D Bergonier et al.

Fréquence des différents germes responsables de mammites cliniques et subcliniques chez les petits ruminants laitiers

D Bergonier et al.

Etiologie et outils de dépistage des infections mammaires chez les ovins et les caprins

Bergonier, D., Lagriffoul, G., Berthelot, X., 2001. Le tarissement des brebis laitiéres: conduite et antibiothérapie....

P Billon et al.

Quantitative requirements of milking installations for small ruminants. A survey in different countries

A.R Burriel

Dynamics of intramammary infection in the sheep caused by coagulase-negative staphylococci and its influence on udder tissue and milk composition

Vet. Rec.

(1997)

A.R Burriel

Isolation of coagulase-negative staphylococci from the milk and environment of sheep

J. Dairy Res.

(1998)

A Carta et al.

Genetic aspects of udder morphology in Sarda primiparous ewes

A.M Cosseddu et al.

Some microbiological causes of the increase in somatic cells in sheep milk

R De Crémoux et al.

Situation des comptages de cellules somatiques du lait de brebis et de chèvre en France

L.F De la Fuente et al.

Amélioration génétique de la morphologie de la mamelle dans les races Churra, Latxa et Manchega

A Deutz et al.

Undersuchungen über den zllgehalt der milch und die verbreitung bakteriell bedingter euterentzündungen in niederösterreic. I. Schen schaf- und zeigenherden

Wien. Tierärztl. Mschr.

(1990)

M Eitam et al.

Direct and indirect detection of intramammary infection of the lactating ovine mammary gland

Cited by (167)

Factors affecting N-acetyl-β-D-glucosaminidase as an indicator for mastitis detection in dairy sheep
2024, Animal
The study of new indirect methods for mastitis detection is of great relevance both at the economic level of the farm and dairies, and in terms of consumer health, and animal welfare. These methods help us to monitor the disease and speed up the decision-making process on treatment of the affected animal and the destination of the milk. The main aim of this work was to study the effect of intramammary infection and other non-infectious factors on the activity of the enzyme N-acetyl-β-D-glucosaminidase (NAGase) in milk, in order to evaluate its use as an indicator for the early diagnosis of mastitis in sheep that could be less expensive, easier to measure and a better marker of inflammation or complementary to existing methods such as somatic cell count (SCC). Seven biweekly samplings were carried out, in which NAGase activity, SCC and milk were analyzed. Glands were classified according to their sanitary status based on the results of the SCC and bacteriological analysis. Non-infectious factors such as lactation stage, parity number and milking session had a statistically significant effect on NAGase values, finding the highest NAGase values at the onset and end of the study, in infectious mastitic glands of multiparous females and at morning milking. However, among the NAGase variation factors studied, the health status of the gland was the factor that caused the highest variation in enzyme levels, with infectious mastitic glands showing higher values than healthy glands. The predictive ability of NAGase was also studied by means of several logistic regression models, with the one that included NAGase together with lactation stage and parity obtaining the best results if sensitivity is to be prioritized, or the model that included NAGase, lactation stage, parity, milking and production if specificity is to be prioritized. From the results obtained, it can be concluded that the use of NAGase as an intramammary infection detection method in sheep can be useful when non-infectious factors that cause changes in the concentration of the enzyme are also considered.
A protocol to assess the welfare of dairy ewes: From science to the field
2024, Small Ruminant Research
There is growing societal demand for improved animal welfare. The stakeholders in the industry are also increasingly interested in information and expertise in this area. There is a scientific consensus that an objective assessment should be the foundation for discussions and actions in favour of better animal welfare. However, only a few protocols exist and most of them have been developed for meat-producing sheep and/or are more adapted for an extensive farming context and/or do not include all the five freedoms of animal welfare. Therefore, references are still scarce especially in the field of dairy ewe welfare. This makes the transition from science to practice difficult. The present study was carried out bearing two objectives in mind: (1) to develop a feasible protocol (EBBEL – Evaluation du Bien-être des Brebis en Elevage Laitier / Assessment of sheep welfare in dairy farms) to assess the welfare of dairy ewes and (2) to implement the protocol on a large scale (n = 81 dairy ewe farms under semi-intensive system) in the Roquefort region of France. The animals and the farms were examined in terms of satisfaction of 26 welfare indicators. The results were very informative about the points of excellence but also about those that need to be improved. The database that we developed can serve the scientific community when comparing different production contexts. Beyond the technical results, stakeholder participation in the design process was clearly positive for acceptance of the protocol in the field.
Invited review: A critical appraisal of mastitis vaccines for dairy cows
2021, Journal of Dairy Science
Infections of the mammary gland remain a frequent disease of dairy ruminants that negatively affect animal welfare, milk quality, farmer serenity, and farming profitability and cause an increase in use of antimicrobials. There is a need for efficacious vaccines to alleviate the burden of mastitis in dairy farming, but this need has not been satisfactorily fulfilled despite decades of research. A careful appraisal of past and current research on mastitis vaccines reveals the peculiarities but also the commonalities among mammary gland infections associated with the major mastitis pathogens Escherichia coli, Staphylococcus aureus, Streptococcus uberis, Streptococcus agalactiae, or Streptococcus dysgalactiae. A major pitfall is that the immune mechanisms of effective protection have not been fully identified. Until now, vaccine development has been directed toward the generation of antibodies. In this review, we drew up an inventory of the main approaches used to design vaccines that aim at the major pathogens for the mammary gland, and we critically appraised the current and tentative vaccines. In particular, we sought to relate efficacy to vaccine-induced defense mechanisms to shed light on some possible reasons for current vaccine shortcomings. Based on the lessons learned from past attempts and the recent results of current research, the design of effective vaccines may take a new turn in the years to come.
Effect of temporary cessation of milking on the innate immune components in goat milk
2021, Journal of Dairy Science
Temporary cessation of milking is widely used during the dry period of dairy cows. Temporary cessation of milking induces an increase in the somatic cell count (SCC) and level of several inflammatory components of milk, which is believed to be a local adaptation and defense mechanism of the mammary gland. In Japan, temporary cessation of milking combined with antibiotic administration is widely used to treat mastitis. The present study aimed to elucidate the role of the innate immune system during temporary cessation of milking in a goat model by investigating the concentration of several innate immune components in milk during and around the temporary cessation. In experiment 1, 6 goats were subjected to cessation of milking for 3 d in both udder halves, whereas in experiment 2, 6 other goats were subjected to cessation of milking for 3 d only in 1 udder half. In experiment 1, the milk yield was lower on d 5 and 6, whereas the mean SCC was higher on d 5 compared with d 0 before temporary milking cessation. The concentrations of goat DEFB1, S100A7, cathelicidin-2 and 7 (CATHL-2 and 7), IgA, and lactoferrin were increased after temporary cessation of milking. In experiment 2, the milk yield was lower between d 5 and 7, whereas the mean SCC was higher between d 4 and 7 compared with d 0. The concentrations of CATHL-2, IgA, and lactoferrin were increased after temporary cessation of milking only in the udder half subjected to milking cessation. These results suggest that temporary cessation of milking increase the SCC and concentration of several innate immune components in milk without infection, which may contribute to mastitis treatment.
Blood polymorphonuclear leukocyte responses against Staphylococcus aureus in primiparous and pluriparous Lacaune and Santa Inês ewes
2021, Small Ruminant Research
Citation Excerpt :
Therefore, the intracellular generation of ROS represents part of the main arsenal against invading bacteria (Rinaldi et al., 2007, 2008; Blagitz et al., 2013; Della Libera et al., 2015;). Although PMNLs provide the first line of defense against invading pathogens (Paape et al., 2003), and variations in susceptibility to infectious diseases, such as mastitis, among sheep breeds and parity have been reported (Larsgard and Vaabenoe, 1993; Bergonier and Berthelot, 2003; Takano et al., 2018), no previous study has investigated the variations in PMNL function on primiparous and pluriparous in dairy- (e.g., Lacaune) and meat-producing (e.g., Santa Inês) ewes, especially against Staphylococcus aureus. S. aureus is a primary etiological agent of clinical mastitis in ewes and can account for a large proportion of chronic subclinical intramammary infections (IMIs; Vasileiou et al., 2019).
In this study, we evaluated the viability, intracellular production of reactive oxygen species (ROS) and phagocytosis of Staphylococcus aureus by blood polymorphonuclear leukocytes (PMNLs) in primiparous and pluriparous Santa Inês and Lacaune ewes. Blood was collected from 14 Santa Inês ewes (seven primiparous and seven pluriparous) and 14 Lacaune ewes (seven primiparous and seven pluriparous). The viability of PMNLs, intracellular ROS production, and S. aureus phagocytosis were evaluated using flow cytometry. No parity effect on blood’s PMNLs functionality was found. However, comparing primiparous and pluriparous ewes, we noticed a difference in the opsonized phagocytic response to S. aureus, suggesting that pluriparous ewes could be better protected against S. aureus, although further field studies are needed. Antibody-mediated opsonization of S. aureus was associated with a lower intensity of S. aureus phagocytosis in both primiparous and pluriparous ewes, while it had no effect on the percentage of S. aureus phagocytosis. The percentage and geometric mean fluorescence intensity (GMFI) of S. aureus phagocytosis behaved differently in Lacaune and Santa Inês ewes, which could be explained by breed and farm effects. The intensity of intracellular ROS production by PMNLs when stimulated with S. aureus was higher than that of unstimulated basal PMNLs in both primiparous and pluriparous ewes, while no effect on the percentage of PMNLs that produced ROS was observed. Thus, our study provides novel insights into PMNLs’ functionality in primiparous and pluriparous ewes, which could impact their health, although further research is needed to extrapolate conclusions to the field.
Effect of abiotic and biotic factors on subclinical mastitis occurrence in low-input dairy sheep production systems
2021, Small Ruminant Research
This study aimed to explore the effect of abiotic [microclimate, management (MS) and milking system (MLS)] and biotic risk factors (microorganism group, age class of ewes, lactation month and ewe genotype) on the occurrence of subclinical mastitis in low-input dairy sheep farms. Samplings were carried out in 10 extensively and 10 semi-intensively managed low-input dairy sheep farms, with three milking systems: milking parlour machine (MPM), portable milking machine (PM) and hand milking (HM). Over two consecutive lactations, milk samples (n = 9624) were collected monthly in each farm, from 20 ewes (10 primi- and 10 multi-parous ewes). The ovine major histocompatibility complex (MHC) DQA2 gene was genotyped for all sampled ewes (n = 800). Ambient air temperature and relative humidity were recorded hourly at each farm, in order to calculate the temperature-humidity index (THI) affecting each sampled sheep. Daily milk yield (DMY) per ewe, pH, total bacterial count (TBC) and somatic cell count (SCC) of milk samples were measured. The fixed effects of microclimate, MS, MLS, bacterial pathogen (microorganism group), age class of ewes, lactation month, involved in milk SCC and subclinical mastitis occurrence, were explored with linear mixed-effects (LME) models. Milk samples with SCC 400 × 10³ (cells/mL) and ≥250/mL Colony Forming Units of one or two udder pathogens (in the microbiological examination) were defined as subclinical mastitis positive. Subclinical mastitis was found in 53 % (n = 1336) of microbiologically examined milk samples, with Staphylococcus spp. being the most prevalent amongst isolated pathogens. A positive correlation was found between SCC and TBC values (r = 0.687, p < 0.001, df = 1598). LME models revealed that subclinical mastitis prevalence was related to the age class of ewes (p < 0.05) and lactation month (p < 0.001), but not to MS or MLS (p> 0.05). MLS (p < 0.01), age class of animals (p < 0.05) and lactation month (p < 0.05) affected SCC of milk samples. The LME model, with SCC milk values ≥400 × 10³ as dependent variables, revealed a significant effect of microclimate (β = 0.014, SE = 0.004, p < 0.001) and microorganism group [F(1,162) = 4.29, p < 0.001] on SCC. The MHC DQA2 allele B1 ("0602") was found at a lower frequency in ewes with subclinical mastitis (p < 0.05). In conclusion, microclimate and MLS (from the abiotic factors) and microorganism group, age class of ewes and lactation month (from the biotic factors) had a significant effect on milk SCC, while age class of ewes and lactation month (from the biotic factors) had a significant effect on subclinical mastitis occurrence. To our knowledge, this is the first report exploring the effect of microclimate (THI), PM milking and DQA2 gene on subclinical mastitis of sheep reared under low-input management systems.

View all citing articles on Scopus

View full text

ReviewNew advances in epizootiology and control of ewe mastitis

Abstract

Introduction

Section snippets

Incidence

Clinical mastitis

Sources

Clinical diagnosis

Treatment

Vaccination

Conclusions

Vaccine

Br. Vet. J.

Br. Vet. J.

Small Rumin. Res.

Small Rumin. Res.

Vet. Clin. North Am. (Large Anim. Pract.)

Small Rumin. Res.

Small Rumin. Res.

J. Dairy Sci.

Small Rumin. Res.

Prev. Vet. Med.

Small Rumin. Res.

Small Rumin. Res.

Br. Vet. J.

Small Rumin. Res.

Small Rumin. Res.

J. Dairy Sci.

J. Dairy Sci.

Prev. Vet. Med.

Small Rumin. Res.

Small Rumin. Res.

Br. Vet. J.

Br. Vet. J.

Dynamics and significance of ovine subclinical intramammary infections and their effects on lamb performances

Sheep Res. J.

Ovine subclinical mastitis efficacy of dry treatment

Sheep Res. J.

Mastitis in sheep in Iraq

Vet. Rec.

Evolucion de la caracteristicas morfologicas de la ubre de oveja Latxa a lo largo del periodo de ordeno

Testing of the CMT method in the detection of subclinical mastitis in sheep

Einfluss der laktationsperiod auf den zellgehalt von schafmilch

Dtsch. Tierarztl. Wochenschr.

Genetic analysis for mastitis resistance and milk somatic cell score in French Lacaune dairy sheep

Genet. Sel. Evol.

Konya ve yöresindeki koyunlarda klinik ve subklinik mastitis olgularindan aerob etken izolasyon ve identifikasyonu

Etlik Vet. Mikrob. Derg.

Recuento de celulas somaticas en leche de oveja latxa

Med. Vet.

Outbreak of subclinical mastitis in a flock of dairy sheep associated with Burkholderia cepacia complex infection

J. Clin. Microbiol.

Détection des infections mammaires subcliniques chez la brebis laitière à l’aide des comptages de cellules somatiques: propositions de seuils physiologiques

Fréquence et persistance des staphylocoques coagulase négative au tarissement et relations avec les numérations cellulaires chez la brebis laitière

Facteurs de variation non infectieux des comptages de cellules somatiques chez les ovins et les caprins laitiers

Les mammites des ovins et des caprins laitiers: étiologie, épidémiologie, contrôle

Fréquence des différents germes responsables de mammites cliniques et subcliniques chez les petits ruminants laitiers

Etiologie et outils de dépistage des infections mammaires chez les ovins et les caprins

Quantitative requirements of milking installations for small ruminants. A survey in different countries

Dynamics of intramammary infection in the sheep caused by coagulase-negative staphylococci and its influence on udder tissue and milk composition

Vet. Rec.

Isolation of coagulase-negative staphylococci from the milk and environment of sheep

J. Dairy Res.

Genetic aspects of udder morphology in Sarda primiparous ewes

Some microbiological causes of the increase in somatic cells in sheep milk

Situation des comptages de cellules somatiques du lait de brebis et de chèvre en France

Amélioration génétique de la morphologie de la mamelle dans les races Churra, Latxa et Manchega

Undersuchungen über den zllgehalt der milch und die verbreitung bakteriell bedingter euterentzündungen in niederösterreic. I. Schen schaf- und zeigenherden

Wien. Tierärztl. Mschr.

Direct and indirect detection of intramammary infection of the lactating ovine mammary gland

Review
New advances in epizootiology and control of ewe mastitis