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Quinolones interact with bacterial DNA gyrase and topoisomerase IV, the subunits of which are encoded by gyrA/gyrB and parC/parE, respectively. The aim of this study was to evaluate the relationship between changes in these genes and quinolone susceptibility of Mycoplasma capricolum subsp. capricolum (Mcc). Using in vitro selected resistant mutants and field isolates from goats, predicted amino acid changes in gyrA, gyrB and parC were associated with higher minimum inhibitory concentration values for quinolones. Alterations in parC predicted amino acid sequences were most frequently associated with quinolone resistance in Mcc.

The risk of zoonoses spreading from birds to humans is lower, quantitatively speaking, than the risk of transmission between other host groups, because the two taxonomic groups share fewer pathogens. Nevertheless, birds have a number of epidemiological characteristics that make them extremely important hosts in the transmission and maintenance of zoonoses, including their susceptibility to pathogens that are extremely hazardous to humans (such as highly pathogenic avian influenza virus, West Nile virus and Chlamydia psittaci) and their ability to travel long distances, especially in the case of migratory birds. The fact that the human diet includes poultry products (meat, eggs and their by-products) also means that most human cases of foodborne zoonoses are infections of avian origin. Lastly, close contact between humans and pet birds or urban birds leads to interactions of public health concern. This article sets out to describe the main factors that determine the role of birds in the epidemiology of zoonotic infections.

The minimum inhibitory concentration (MIC) and minimum mycoplasmacidal concentration (MMC) of 17 antimicrobials against 41 Spanish caprine isolates of Mycoplasma mycoides subsp. capri (Mmc) obtained from different specimens (milk, external auricular canal and semen) were determined using a liquid microdilution method. For half of the isolates, the MIC was also estimated for seven of the antimicrobials using an epsilometric test (ET), in order to compare both methods and assess the validity of ET. Mutations in genes gyrA, gyrB, parC and parE conferring fluoroquinolone resistance, which have been recently described in Mmc, were investigated using PCR. The anatomical origin of the isolate had no effect on its antimicrobial susceptibility. Moxifloxacin and doxycycline had the lowest MIC values. The rest of the fluoroquinolones studied (except norfloxacin), together with tylosin and clindamycin, also had low MIC values, although the MMC obtained for clindamycin was higher than for the other antimicrobials. For all the aminoglycosides, spiramycin and erythromycin, a notable level of resistance was observed. The ET was in close agreement with broth microdilution at low MICs, but not at intermediate or high MICs. The analysis of the genomic sequences revealed the presence of an amino acid substitution in codon 83 of the gene gyrA, which has not been described previously in Mmc.

The unexpected presence of Mycoplasma auris was evidenced in mastitis samples collected from a dairy goat herd under surveillance programmes of contagious agalactia (CA), a serious disease affecting Mediterranean small ruminant herds. Thus, control programs based on permanent analysis of milk from bulk tank and clinical mastitis, as well as ear swabs, are currently conducted in affected areas. In order to analyze the presence of CA- causing species, three, 11 and 18 of these samples were respectively collected from the same goat herd. Mycoplasmas were isolated in four milk samples from clinical mastitis and two ear swabs samples and no other pathogen was detected. The presence of CA-causing mycoplasmas was discarded by PCR. However, M. auris was identified in all the positive samples after the amplification and posterior PCR product sequencing of a partial fragment of their 16S-ribosomal ARN gene. As far as we know, these are the first isolations of M. auris from milk of goats with clinical mastitis.

This article reviews the diagnosis of mastitis in dairy goats. The benefits and shortcomings are discussed of both indirect diagnostic methods, such as the California mastitis test and somatic cell counts, and direct strategies, such as bacteriologic isolation and PCR identification. The important role of mycoplasmas in causing mastitis in regions where contagious agalactia is endemic makes their detection mandatory in routine diagnostic practice, despite complicating and lengthening protocols. In this context, we discuss both the conditions to be met prior to sampling and the analytical conditions of the sample along with the features of each diagnostic method.

This study examined the susceptibility to several antimicrobials of 28 isolates of Mycoplasma agalactiae obtained from goats in a region (southeastern Spain) where contagious agalactia is endemic. For each isolate, the minimum inhibitory concentration (MIC) against 12 antimicrobials of the quinolone, macrolide, aminoglycoside, and tetracycline families was determined. The antimicrobials with the lowest MIC were enrofloxacin, ciprofloxacin, tylosin, and doxycycline, all with MIC90 (concentration at which growth of 90% of the isolates is inhibited)1 µg/mL. Norfloxacin (a quinolone) showed a wide MIC range (0.1-12.8 µg/mL), suggesting a resistance mechanism toward this antimicrobial that was not elicited by enrofloxacin or ciprofloxacin (the other quinolones tested). Erythromycin showed the highest MIC90 such that its use against Mycoplasma agalactiae is not recommended. Finally, Mycoplasma agalactiae isolates obtained from goat herds with clinical symptoms of contagious agalactia featured higher MIC90 and MIC50 (concentration at which growth of 50% of the isolates is inhibited) values for many of the antimicrobials compared with isolates from asymptomatic animals. The relationship between the extensive use of antimicrobials in herds with clinical contagious agalactia and variations in MIC requires further study.

The presence of goat males carriers of the main causal agents of contagious agalactia, Mycoplasma agalactiae (Ma) and Mycoplasma mycoides subsp. capri (Mmc), is a high risk factor for the spread of the infection in artificial insemination centres. The present study was designed to assess the efficacy of a 5 day course of marbofloxacin given intramuscularly (2 mg kg−1 day−1) in terms of its capacity to reverse the carrier state of goat buck populations naturally infected with one or both mycoplasmas (Mmc, n = 25; Mmc + Ma, n = 2). Before and after treatment, ear swabs and semen samples were culture- and PCR-checked for both mycoplasmas. We also evaluated the impact of this treatment on semen quality (sperm count, motility and daily sperm production) by monitoring these variables of 594 semen samples collected during pre- and post-treatment periods of 48 days each. All bucks examined tested positive for the presence of Ma and Mmc before and after treatment though Mycoplasma spp. never was identified in semen. Sperm motility was significantly reduced in response to treatment (from 72.9% to 56.9%), although some recovery was observed at the end of the study (40 days after treatment). Ejaculate volume and concentration remained unchanged throughout the study. Our findings indicate that systemic marbofloxacin therapy is unable to eliminate mycoplasmas from the external auditory canal of male goats, and that it also causes a transient detrimental effect on sperm motility. Other strategies to control the presence of mycoplasma carriers in goat artificial insemination centres need to be assessed.

Many goat artificial insemination (AI) centers in Spain have adopted new measures to control contagious agalactia (CA). To avoid the introduction of male goats carrying mycoplasma organisms subclinically in their external ear canal (auricular carriers) in these centers, two ear swabs and a blood sample are obtained from all candidate animals for polymerase chain reaction (PCR), culture (swabs) and serologic tests to detect the presence of mycoplasmas. In addition, the semen produced at these centers is routinely cultured and PCR tested also to detect the presence of mycoplasmas. One y after the introduction of this program, we tested 48 ear swabs and 24 blood samples from 24 candidates for admission to these AI Centers. Three of these ear swab samples (3/48, 6.25%) scored positive for the presence of mycoplasmas; Mycoplasma agalactiae (Ma) was detected in two samples and Mycoplasma mycoides subsp. capri (Mmc) in one. All animals were serologically negative for Ma. Also, out of 173 semen samples obtained from 137 admitted animals (2 and 3 samples were obtained in 16 and 10 bucks, respectively), one (1/173, 0.56%) was positive for Mmc. Our findings suggest that ear swab and semen samples are useful tools to control CA at AI Centers. The introduction of this program has also resulted in the first detection of Mmc in semen from a naturally infected goat, confirming the ability of this mycoplasma to colonize the reproductive tract of male goats. These results highlight the need to improve control measures in semen producing centers to minimize the risk of CA transmission.

This study was designed to monitor the presence of Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri (Mmc) in 66 dairy goat herds of a genetic improvement programme in a region of Spain where contagious agalactia is endemic. Over a whole lactation period, 300 bulk tank milk and 381 milk samples from goats with clinical mastitis were subjected to polymerase chain reaction (PCR) to detect the two mycoplasma species. The presence of mycoplasmas (either species or both) was detected in 66.7% of the herds and M. agalactiae was identified in 95.45% of these positives herds. In a given infected herd, mycoplasmas were not continuously detected over the whole study period. Our findings indicate that in an endemic area, M. agalactiae and Mmc can be monitored through PCR analysis of mastitic milk and bulk tank milk (BTM) samples. Over a lactation period we recommend testing multiple BTM samples on a herd. No relationship was observed between the use of inactivated mycoplasma vaccines and the PCR detection of both mycoplasmas.

Goat milk samples routinely obtained by milk distributing companies and quality control laboratories are preserved using azidiol (AZ) or bronopol (BR). This study was designed to determine if these treated goat milk samples are suitable for Mycoplasma ( M. ) agalactiae detection by PCR. The effects of these preservatives on the limits of M. agalactiae direct PCR detection were established using samples inoculated with mycoplasma cultures. Samples inoculated with a determined concentration of M. agalactiae showed no differences among the 3 preservation methods and in all cases the limits of detection of the PCR assays were 10 3 CFU ml. In addition, 300 bulk tank milk (BTM) samples from 45 herds from an infected area were each divided into three aliquots subjected to different preservation treatments (no preservative, NP, AZ or, BR) and then PCR tested. Of the 300 BTM samples, 43 different ones scored a positive result for M. agalactiae in at least one condition distributed in this way, 32 NP aliquots (74.4% of the positive samples), 27 BP aliquots (62.8%) and 27 AZ aliquots (62.8%). Among the three preservation methods, no significant differences were found ( p > 0.05) and the difference in results was attributed to the sensitivity increasement when analyzing more than one time a BTM sample. These results suggest that the PCR technique can be used as a rapid diagnostic method to detect M. agalactiae in AZ or BR preserved goat milk samples. The possible use of such samples for health programmes would have considerable cost benefits.

Contagious agalactia (CA) is among the most significant diseases affecting small ruminant populations in Mediterranean countries. This study was designed to detect the excretion in semen of CA-causing mycoplasmas in goats (Capra hircus) reared in Spain, where the disease is considered endemic. Culture techniques and PCR were conducted on 147 semen samples collected from 113 goat bucks to detect mycoplasmas. No animal showed clinical symptoms of CA at the moment of the screening. M. agalactiae was identified using both diagnostic methods in three semen samples collected from three different bucks. These animals belonged to a group of animals in which semen had been analyzed twice and only the second sample proved positive, suggesting the possibility of intermittent excretion. This is the first report of the isolation of M. agalactiae from semen collected from naturally infected goats. Future studies should investigate whether semen could be a real source of CA infection by determining if the agent may be transmitted during natural service or when semen is used for artificial insemination.

This study was designed to evaluate the effects of different storage conditions on total bacterial count (TBC) determinations made in goat bulk tank milk using an automated flow cytometry method. The storage conditions tested were storage temperature (refrigeration at 4 and 10 degrees C or freezing at -20 degrees C), the use of a preservative (no preservative, NP; azidiol, AZ; or bronopol, BR), and the age of the milk samples for each analytical condition (storage times at 4 degrees C: from 0 h to 5 d for NP; and from 0 h to 22 d for AZ and BR; storage times at 10 degrees C: from 24 h to 2 d for NP and from 24 h to 22 for AZ and BR; storage times at -20 degrees C: from 24 h to 22 d for NP, AZ, and BR). Significant effects on individual bacterial count (IBC) variation were shown by the bulk tank milk sample, preservative, storage temperature, interaction preservative x storage temperature, and milk age within the interaction preservative x storage temperature. In preserved samples, the highest IBC were obtained for AZ and the lowest counts were obtained in samples preserved with BR. Because of the variation in IBC recorded in BR-preserved samples, we recommend that BR should not be used for TBC determinations using the automated flow cytometry method. The NP samples stored at 4 and 10 degrees C showed significantly higher IBC at 24 h postcollection, also invalidating these analytical conditions for TBC analyses. The practical implications of our findings are that goat milk samples preserved with AZ and stored at 10 or 4 degrees C are appropriate for TBC by the BactoScan flow cytometry method for up to 24 h and 11 d postcollection, respectively.

This study compares the performance of 4 antimicrobial residue screening tests [brilliant black reduction test AiM (Analytik in Milch Produktions- und Vertriebs GmbH, München, Germany), Delvotest MCS (DSM Food Specialties, Delft, the Netherlands), Eclipse 100 test (ZEU-Inmunotec SL, Zaragoza, Spain), and Copan Milk Test (Copan Italia S.p.a., Brescia, Italy)] used to detect 20 antimicrobial agents (aminoglycosides, macrolides, tetracyclines, sulfonamides, and quinolones) in goat's milk, according to International Dairy Federation guidelines. Composite milk samples from 30 antibiotic-free goats were used to prepare spiked milk samples and 11,520 analytical determinations were carried out. According to a logistic regression model, agreement coefficients were greater than 98% for most of the antibiotics, with higher b values obtained for macrolides. Neither tetracyclines nor quinolones were detected at European Union maximum residue limits. Only the Copan Milk Test and the Delvotest MCS were able to detect 3 antimicrobials below their maximum residue limits (neomycin, tylosin, and sulfadimethoxine). Given that these tests are used in control programs for goat's milk, our results indicate their sensitivity would need to be improved to guarantee safety for consumers.

This study was designed to compare the ELISA method of diagnosing caprine arthritis encephalitis virus (CAEV) using two different samples: milk whey or blood samples. A commercial CAEV diagnosis kit (ELISA Kit MVV/CAEV serum monocupule, Institut Pourquier, France), was used and determination was carried out on paired samples of blood and milk from 66 lactating dairy goats of known CAEV infection status belonging to two herds. Serum samples were pre-diluted 1:20 and whey samples 1:2. All animals whose sera tested positive for the virus (37/66) also showed a positive whey sample result, and the same agreement was obtained for a negative result (29/66). In no sample was the outcome of the test dubious. Through ANOVA, it was determined that mean S/P ratios for whey (1.551 ± 1.55) and serum (1.719 ± 1.38) did not significantly differ (P > 0.05). Our findings indicate full agreement (Kappa = 1) in terms of the two sample types producing a positive or negative result and a high correlation coefficient (r = 0.92) between the mean S/P ratios recorded for the two data sets. In conclusion, the use of ELISA on whey samples is an appropriate method of diagnosing CAEV with its obvious benefits of non-invasive sample collection and reduced costs over traditional serological diagnosis methods. This simpler method will be especially useful for CAEV surveillance in dairy goats.

A 7 month prospective cohort study was designed to determine if feeding bromelain to dairy goats influenced the MSCC, milk yield, milk composition and the incidence of IMI. Forty-four clinically normal goats from 2nd to 6th parities were studied. Daily bromelain dosage was 7.4 grams/animal (185-mg/Kg weight). Samples for diagnostic bacteriology were collected from each udder half every 2 weeks. Samples for MSCC and composition were obtained every 42 days. Milk yield was also recorded every 42 days. Bromelain affected milk protein and fat but not MSCC, milk yield or milk lactose. Bromelain did not decrease the MSCC in healthy goats. Milk protein and fat increased in the bromelain treated group (P0.01), which is important for dairymen because premiums are paid milk fat and protein content. No clinical mastitis was detected in the goats for the total study period and incidence rate of subclinical IMI was 5.7%. Relative risk was 1.50 (0.28RR8.12) which means that the bromelain had no significant effect on IMI (P0.05). In addition, the use of pineapple by-products could be especially important in tropical countries were pineapple waste seems to be a pollution problem.

This cross-sectional study performed on dairy goat herds was designed to establish the relationship between the presence of Mycoplasma species in bulk-tank milk samples from different farms and the bulk-tank milk somatic cell count (BTMSCC) in an area where contagious agalactia (CA) is endemic. Three BTMSCC thresholds, used in payment schemes or as legal requirements for milk quality in Europe and the USA, were considered: (1) 2,000,000 cells/ml; (2) 1,500,000 cells/ml and (3) 1,000,000 cells/ml. Of the 1068 milk samples tested, 7.9% (n = 84) showed the presence of Mycoplasma spp. (Mycoplasma agalactiae 82% and Mycoplasma mycoides subsp. mycoides large colony 17%). Somatic cell counts for bulk-tank samples containing mycoplasmas were higher than those recorded for negative samples (1,176,000 cells/ml vs. 875,000 cells/ml; P

Contagious agalactia (CA) is an infectious syndrome caused by several species of mycoplasma and classically characterized by the triad of mammary, joint and eye symptoms, although further symptoms may also appear. CA is the most serious disease of whatever they affect in small dairy ruminants and so there is an urgent need for administrative bodies and farmers to join forces and design serious strategies with the final aim of completely eradicating the disease. CA is endemic in the Mediterranean and certain Asian and African regions, while in America it is described as sporadic. The emergence of CA in a non-infected herd is almost always linked to the introduction of carriers of CA or to contact with infected herds. It normally implies the rapid spread of clinical problems in the herd coinciding with the period of parturitions and the start of lactation. In endemic areas, this disease provokes subclinical or mild clinical symptoms, and the lack of an established, systemized diagnostic procedure implies, that many infected herds pass unnoticed and may act as a permanent source of infection. Enzyme-linked immunosorbent assay (ELISA) techniques are recommended for the detection of antibodies, but the systematic vaccination of herds in endemic areas prevents the use of serology to detect infected herds. Then, culture and polymerase chain reaction (PCR) techniques must be used. In clinical outbreaks, control measures should be directed towards limiting the economic losses of the herd and avoiding the spread of the disease by isolating the infected herd, antibiotic treatment, selective culling, disinfection measures and the classic prevention measures for mastitis (correct functioning and maintenance of milking equipment, the milking routine, teat dipping, etc.). In chronically infected herds, control measures should be directed to restrict disease spread by way of prevention measures for mastitis, detection and culling of animals with lesions, the administration of antimycoplasma drugs to all animals at the end of lactation, adequate management of replacement animals and, perhaps, vaccination.

This manuscript reviews the most recent knowledge about small ruminant mastitis, pointing out the etiological, epidemiological and control aspects of mastitis. The prevalence of subclinical mastitis in small ruminants averages 5–30%, but the annual incidence of clinical mastitis is generally lower than 5%. Staphylococcus spp., are the most prevalent pathogens responsible for intramammary infection in small ruminants. Mastitis caused by Staphylococcus aureus should be eliminated because of the severity of the clinical symptoms and also because of the risk of contamination of milk products by thermostable toxins. The public health impact of other pathogens causing mastitis is also emphasized in this review, and the efficacy of diagnostic tools is discussed, especially diagnostic bacteriological tests and determination of milk somatic cell counts (MSCC). Several mastitis control strategies are discussed, such

The purpose of the present study was to assess the presence of Mycoplasma agalactiae (Ma), the main causative agent of ovine contagious agalactia (CA), in semen of naturally infected rams. Therefore, semen samples from 167 rams residing in three different artificial insemination (AI) centers of a CA-endemic area were studied by microbiological and molecular techniques. In addition, serial ejaculates from the same rams were evaluated to determine the excretion dynamics of Ma. Of the 384 samples studied, Ma was detected in 56 (14.58%) which belonged to 44 different rams (26.35%). These findings confirm the ability of Ma to be excreted in semen of asymptomatic rams. Furthermore, these results also evidence the presence of these asymptomatic carriers of Ma in ovine AI centers, representing a serious health risk regarding the spread and maintenance of CA, especially in endemic areas. Moreover, the excretion of Ma in semen also points to the risk of venereal transmission of this disease. The current results highlight the need to implement control measures to prevent the admission of infected rams in AI centers and the necessity to continuously monitor semen samples to effectively detect infected individuals.

The viability of Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri (Mmc) was assessed in goat colostrum treated at different temperatures. Samples of colostrum were inoculated with reference strains of M. agalactiae (PG2) and Mmc (PG3) and heated at 56 °C or 60 °C for 0, 30, 60, 90 or 120 min. Viable colonies of M. agalactiae were recovered after all treatments and there was a significant reduction in the concentration of viable M. agalactiae after 30 min at 56 °C and 60 °C. No viable colonies of Mmc were observed after 60 min at 60 °C.

Pathogens involved in goats mastitis and the strategies for their prevention and control are revised. Staphylococcus aureus is an important clinical pathogen but coagulase negative staphylococci (CNS) are the most prevalent in subclinical mastitis (more than 50% in most of the studies). Incorrect milking machine routines are usually involved in high prevalence of CNS. Contagious agalactia (CA) is an important disease affecting goats and antibiotic treatment and vaccination are controversial. Streptococci and Gram negative bacilli (GNB) are major intramammary pathogens but not very frequent in goats and are associated with poor hygienic conditions in housing and the milking parlour. Because of the lower prevalence of GNB mastitis in goats than cows, physiological and environmental factors protecting goats from GNB infection are discussed. Other pathogens affecting the caprine mammary gland are also discussed, such as Arcanobacterium pyogenes, Bacillus spp., Clostridium perfringens, Nocardia asteroides and lentiviruses (caprine arthritis-encephalitis virus).

Mycoplasma agalactiae (Ma) is the main causative agent of ovine contagious agalactia, which is a serious disease of small ruminants. In endemic areas, its most common clinical situation consists of chronically infected herds, and asymptomatic infected individuals represent an epidemiological risk regarding the transmission of this disease. The aim of this work was to detect the presence of asymptomatic rams infected with Ma in different artificial insemination centers, and to determine the most effective way to identify these individuals so as to implement adequate surveillance protocols. For this purpose, 215 rams and 14 teaser sheep were sampled taking auricular, nasal, and vaginal swabs and serum samples. In addition, ejaculates from 147 rams were analyzed. These samples were subjected to specific culture and molecular techniques to isolate and identify mycoplasmas, and to a serological test to detect antibodies against Ma. Mycoplasma agalactiae was detected in 47 (4.4%) of the 1077 samples analyzed, and also one individual resulted seropositive. Thus, 37 (17.2%) of the 215 studied rams were infected with Ma. The specimens which proportionally yielded the greatest number of positive results for this pathogen were semen samples (13.6%), followed by nasal swabs (5.8%). In contrast, the sampling of the external auricular canal and the serological analyses resulted insufficient to effectively detect infected individuals. Asymptomatic rams infected with Ma were detected in all the analyzed artificial insemination centers, highlighting the need to implement adequate surveillance protocols to prevent the presence of these individuals in these centers, reducing the risk of transmitting contagious agalactia.

The antibiotic susceptibility of 32 strains of Staphylococcus aureus isolated from the mastitic milk of dairy goats was evaluated. The antibiotics tested were 3 fluoroquinolones that have been developed especially for use in veterinary medicine: danofloxacin, marbofloxacin, and orbifloxacin. Minimum inhibitory concentration (MIC) tests were performed according to the microdilution broth method. The MIC(90) (concentration at which 90% inhibition is achieved) values obtained were 0.5, 1, and 1 mg/L for danofloxacin, marbofloxacin, and orbifloxacin, respectively. Danofloxacin was the most active fluoroquinolone tested against Staph. aureus strains isolated from milk; however, specific testing is required before using these drugs as therapy for the control of clinical mammary infections in goats.

Contagious agalactia affects goats and is caused by several species of mycoplasma including Mycoplasma agalactiae and Mycoplasma mycoides subsp. capri (Mmc). Male goats, latently infected with M. agalactiae and Mmc, were identified at a dairy goat breeding artificial insemination centre. In three samplings, conducted over 1 year, ear swabs were assessed for both of the above organisms using culture and PCR techniques. Serological examination for antibodies against these organisms was performed at each time-point and conjunctival, nasal, rectal and preputial swabs were taken from a sub-sample of animals. Mycoplasma mycoides subsp. capri and M. agalactiae were detected in 80 and four ear swabs, respectively and serology confirmed the presence of both agents. A point prevalence of 0.06 goats infected with Mmc at the first sampling point increased to 0.97 at the last sampling, suggesting spread of infection. Both organisms were also detected in preputial and conjunctival swabs suggesting the shedding of these pathogens by other routes. These findings should inform World Organisation for Animal Health (OIE) guidelines on avoiding the introduction of such pathogens into artificial insemination centres and suggest the need to review current recommendations.

In a cross-sectional study, 324 lactating goats of the Murciano–Granadina breed were randomly selected from 18 herds. Animals were in late lactation and bacteriological analyses including mycoplasmas were made from aseptic milk samples individualy taken from udder halves. The presence of intramammary infection (IMI) was studied in relation to goat parity. Three parity groups were considered: first and second; third, fourth and fifth; and six and greater parities. Prevalence of IMI was 22% of halves and 34% of animals. Most of isolates were Staphylococci (70%). Using the prevalence ratio (PR) and confidence interval (CI), we saw a positive statistical association between subclinical intramammary infection and greater than fifth parity (PR=1.80; 95% CI=1.21, 2.68).

Three hundred and sixty-nine milk samples from half udders of 188 Murciano-Granadina goats in the second and third month of lactation, from ten commercial dairy goat herds were studied. Bacteriological analyses, California Mastitis Test (CMT) and somatic cell count (SCO by Fossomatic Counter were performed. The best SCC threshold for defining subclinical mastitis was 500 × 103 cells ml−1, but this threshold had a poor positive predictive value (28.5%) and only 62.3% of samples were correctly classified. Arithmetical and geometrical means of SCC showed statistical differences between infected and uninfected glands. Arithmetical and geometrical means of SCC per microlitre for each CMT score were, respectively: 312 × 103 and 172 × 103 for Score 0 and traces; 1014 × 103 and 531 × 103 for Score 1; 2912 × 103 and 2051 × 103 for Score 2; and 4950 × 103 and 4436 × 103 for Score 3. The CMT Scores 2 and 3 discriminated between infected and uninfected udder glands. The results show that both tests could be used in the period of study to detect a high percentage of true uninfected glands but the percentage of false positives was high.

Ten herds of Murciano-Granadina goats were examined to determine prevalence and aetiology of subclinical mastitis in Murcia (Spain). In the 369 milk samples analysed from 188 animals, intramammary infection was present in 18% of the glands and 30% of the goats. Prevalence of infection in the different herds ranged from 7% to 34% of the glands and 17% to 44% of the goats. Sixty-nine bacterial isolates were found, comprising staphylococci (71%), corynebacteria (12%), mycoplasmas (9%), enterobacteria (3%), pasteurellas (3%), streptococci (1%) and yeast (1%). Among the 49 staphylococcus isolates, Staphylococcus caprae (22%), Staphylococcus epidermidis (20%) and Staphylococcus chromogenes (12%) were the most frequent of the 12 species identified. Staphylococcus aureus (6%) had a low prevalence, and only one isolate was coagulase positive. S. caprae showed the highest prevalence among the herds, and mycoplasmas and S. epidermidis were most responsible for bilateral infections (60% of those detected).

Male goats admitted to artificial insemination centres come from herds that have shown no clinical symptoms of contagious agalactia (CA) for the last 6 mo. However, prior reports suggest that this control measure may not be completely effective. This study was designed to detect the presence of CA-causing mycoplasmas in 9 Spanish centres, comprising 159 goats (147 males and 12 teaser does) of 8 different breeds. A microbiological study was conducted during 8 mo on 448 samples (318 ear swabs, 119 semen samples and 11 milk samples). In 86 samples (84 swabs, 1 semen sample and 1 milk sample), CA-causative mycoplasmas were detected by PCR or culture, and 52 animals (49 goat males and 3 teaser does) tested positive. Most of these positive animals were auricular carriers (n = 50), mainly of Mycoplasma mycoides subsp. capri (Mmc), although some M. agalactiae (Ma) and, interestingly, M. capricolum subsp. capricolum (Mcc) carriers were also identified. At least 1 animal infected by CA-causing mycoplasmas was detected in 8 of the 9 centres (88.8%) although in most (66.7%) no infected animals or only 1 or 2 positive animals were identified. Our results indicate the presence of CA carriers as asymptomatic animals in reproductive programmes. These findings have already prompted efficient measures to detect and avoid the entry of these carriers in Spanish centres. We recommend similar measures for all centres in areas where CA is endemic.

This study was conducted to compare the detection limits (DL) of several antibiotic residue screening tests with the maximum residue limits (MRL) authorized by the EU according to the guidance for the standardized evaluation of microbial inhibitor tests of the International Dairy Federation. Composite antibiotic-free milk samples from 30 primiparous Murciano-Granadina goats in good health condition were used to prepare test samples spiked with different concentrations of each antimicrobial. In total, 5,760 analytical determinations of 10 beta-lactam antibiotics (penicillin-G, ampicillin, amoxicillin, cloxacillin, oxacillin, dicloxacillin, cefadroxyl, cefalexin, cefoperazone, and cefuroxime) were performed using 4 antibiotic residue screening tests: the brilliant black reduction test BRT AiM (AiM-Analytik in Milch Produktions-und Vertriebs GmbH, München, Germany), Delvotest MCS (DSM Food Specialties, Delft, the Netherlands), Eclipse 100 (ZEU-Inmunotec SL, Zaragoza, Spain), and the Copan Milk Test (CMT; Copan Italia SpA, Brescia, Italy). For each method, we estimated the detection limits of the antimicrobial agents using a logistic regression model. Using the CMT and Delvotest on samples spiked with the 8 antibiotics for which MRL were available, DL were at or below the MRL. The BRT test provided DL at or below the MRL for all of the agents except cefalexin, whereas the Eclipse 100 method failed to detect 4 antibiotics (ampicillin, amoxicillin, cloxacillin, and cefoperazone) at MRL or below. Logistic regression-determined levels of agreement were highest for the CMT method (98.6 to 100%) and lowest for Eclipse 100 (66.3 to 100%). In general, agreement levels indicated good correlation between observed results and those predicted by logistic regression. The lowest b values (closely related to test sensitivity) were recorded for the cephalosporins (0.074 to 0.430) and highest for penicillin G, ampicillin, and amoxicillin (11.270 to 11.504). Delvotest and CMT best fulfilled IDF criteria for the ideal test for detecting antibiotic residues in milk.

This study was designed to assess the possible effects of mycoplasmas on the quality of milk produced by goat herds in a contagious agalactia (CA) endemic area with absence of classical symptoms. Several factors related to milk quality (percentages of fat, total protein, lactose and total solids, standard plate counts (SPC) and presence of Staphylococcus aureus) were compared in mycoplasma-infected and non-infected herds. To define the CA status of 26 herds on the island of Lanzarote (Spain), where CA is endemic, 570 individual milk samples and 266 bulk tank milk (BTM) samples were microbiologically analysed for the presence of Mycoplasma spp. A herd was considered infected by mycoplasmas when at least a sample (individual or BTM) was positive. BTM samples were also used to determine milk quality parameters. Mycoplasma infection was confirmed in 13 herds. A total of 31, 10 and 11 strains of Mycoplasma mycoides subsp. mycoides LC (MmmLC), Mp. agalactiae and Mp. capricolum subsp. capricolum were isolated. No significant differences were observed between the least square means of the variables fat, total protein, lactose and total solids or SPC recorded for the infected v. non-infected herds. The Staph. aureus status of a herd was also found to be independent of the presence of Mycoplasma spp. Our findings indicate that neither the presence of mycoplasmas in a goat herd with absence of classical symptoms seem to compromise the quality of the BTM.

The aim of this research was to evaluate the Milko-Scan FT 6000 (Foss Electric, Hillerod, Denmark) for determining the freezing point (FP) of goat's milk under different analytical conditions. The FP was determined in duplicate in 1,800 milk aliquots obtained from 45 bulk tank milk samples from 10 Murciano-Granadina goat herds, using the MilkoScan method and a reference thermistor cryoscopy method (Advanced Instrument Inc., Norwood, MA). Five different preservation strategies--no preservative, preservation with azidiol (0.006 or 0.018 g of sodium azide/100 mL), and preservation with bronopol (0.020 or 0.040 g/100 mL)--were then used to preserve the milk. For each preservation strategy, 8 different amounts of water were added (0, 1, 2, 3, 4, 5, 6, or 7% total volume). The results obtained with each method under these 40 analytical conditions were examined by comparison of means, comparison of the standard deviations of repeatability (s(r) and its relative value s(r)%), and a regression analysis. Under most analytical conditions, the FP was recorded as lower by the MilkoScan method, with a mean difference of 1.5 m degrees C compared with the reference method. Both methods showed similar repeatabilities (the overall s(r)% was 0.22% for the MilkoScan method and 0.20% for the reference method). In comparisons of the 2 methods, the highest regression coefficients were obtained with aliquots containing >3% added water. The best regression coefficients (0.85 to 1.02) were obtained for milk samples preserved with bronopol at 0.020 g/100 mL. These results allow the MilkoScan method to be used with goat's milk for screening purposes. The factors of added water, preservative, analytical method, lactose concentration, and the effect of the bulk tank milk sample within each lactose group contributed significantly to the observed variation in FP. For practical purposes, either of the bronopol concentrations could be used when determining the FP of goat's milk with the methods tested. However, the increase in the concentration of sodium azide in the azidiol formula contributed to an important reduction in the FP recorded. Thus, the type and concentration of preservative should be taken into account when interpreting FP values.

This study was designed to evaluate the effects of different test conditions on the somatic cell count (SCC) and composition of goat milk. To this end, 3600 tests were performed on 1800 aliquots taken from 40 goat milk samples using a combined instrument set-up based on flow cytometry for SCC and Fourier transform infrared analysis for fat, total protein, lactose, total solids, and freezing point determinations. The conditions tested were storage temperature (refrigeration and freezing), use of a preservative [no preservative (NP), azidiol (AZ), and bronopol (BR)], and age of the milk samples at each storage temperature (24 h to 42 d at refrigeration temperature and 21 to 105 d at freezing temperature). Significant effects on logSCC variation were shown by the storage temperature, the preservation treatment, the interaction of storage temperature x preservation treatment, and milk age within the interaction of storage temperature x preservative. Highest counts were recorded in the BR-preserved milk samples (logSCC = 5.877), and lowest counts were recorded in milk samples preserved using AZ (logSCC = 5.803). The use of frozen/thawed samples led to a significantly decreased logSCC for the treatments AZ and NP; the logSCC was not modified when BR-preserved frozen/thawed samples were analyzed. During storage, variations in the SCC observed for BR-preserved samples stored at refrigeration temperature for up to 25 d and at freezing temperature for all times tested were always < 10%. The preservation treatment was the main factor affecting the milk composition variables examined. Highest values of most variables were obtained in the BR-preserved samples, and the lowest values were obtained in the AZ-preserved samples. The freezing point was lower in the preserved samples than in the NP samples. The levels of milk constituents recorded in the BR-preserved samples were independent of both the storage temperature and age of milk sample. Our findings indicate that the freezing point of goat milk must be interpreted according to the preservative used.

From 19 herds of Murciano-Granadina goats, weekly bulk tank somatic cell count (BTSCC) were performed from October to April, and suspicious milk (n = 182), synovial fluid, and ocular swabs (n = 15) from diseased goats were processed for mycoplasma isolation and identification. Also BTSCC from 65 herds were determined (n = 2693). A mixed model procedure was used to establish the effect of the herd and the lactation month on the BTSCC. Monthly rolling values were calculated for each herd using data collected over the preceding 3 complete months, and 4 different BTSCC thresholds were considered: 1,750,000, 1,500,000, 1,000,000, and 750,000 cells/mL. The mean log BTSCC for the 7-mo study period was 5.89 +/- 0.28 for herds without mycoplasma detection from clinical cases, 5.91 +/- 0.31 for mycoplasma-infected herds without clinical contagious agalactia (CA), and 6.47 +/- 0.32 for the herd with clinical CA. The posthoc tests revealed that only the herd that suffered a clinical CA outbreak showed counts that were significantly higher. No significant differences were found for BTSCC between herds not showing clinical episodes of CA, regardless of whether the mycoplasma had been isolated or not. The 1,750,000-cells/mL threshold would only be surpassed by a few herds with serious mastitis problems (clinical outbreak of CA for example). Seventy percent of the goat herds studied were in compliance with the proposed European Union legal limit of 1,500,000 cells/mL for goat milk.

A total of 1304 goat udder halves were sampled monthly during an entire lactation (6262 samples) with the aim of identifying factors affecting milk somatic cell count (SCC). Bacteriological analyses for identification of mastitis pathogens were carried out on all samples and SCC was also determined. All animals were examined for infection by caprine arthritis-encephalitis virus (CAEV) using a commercial ELISA test kit. Results obtained were arranged in two databases (whole-lactation average half-udder database and monthly half-udder database) and two mixed models were applied. Random effects of half udder nested into flock and fixed effects of flock, intramammary infection (IMI) status, number of kids born, length of lactation and interaction of parity with IMI status were significant for the first database. CAEV infection and its interaction with IMI status was not significant. Milk SCC was significantly increased for infected udder halves and milk from udder halves infected with minor pathogens had lower SCC than udder halves infected with major pathogens. For healthy udder halves, SCC was higher in older animals but this effect was not evident in halves with IMI. Multiple birth and short-duration lactation were factors associated with elevated milk SCC. The second mixed model considered repeated measures in time for consecutive samplings throughout lactation (stage of lactation) which was also a significant factor with increasing stage of lactation. The influence of all these factors should be taken into account in the establishment of more reliable diagnostic SCC thresholds for IMI.

The goal of this study was to determine the persistence of caprine intramammary pathogens throughout lactation and to detect the bias in diagnoses when a single milk sample was used. We studied 131 goats throughout 7 mo of lactation. Goats were sampled monthly, and 1834 milk samples were bacteriologically analyzed. One hundred sixty-eight pathogens were isolated: 82.5% were micrococci, 9.5% were Gram-negative bacilli, and 8% were corynebacteria. An intramammary infection (IMI) was considered a true, persistent IMI when the same pathogen was isolated two or more times consecutively from the same half of the udder. One hundred one samples were considered to be truly positive, which produced persistent IMI caused by nine different species (eight Staphylococcus spp. and one Pseudomonas sp.). Statistical relationships were found between staphylococci and true-positive diagnosis and between corynebacteria and false-positive diagnosis. No relationship involving Gram-negative bacilli was detected. A single milk sample had a positive predictive value (60%), high sensitivity (96.2%), high specificity (96.1%), and highly negative predictive value (99.8%).