Commercial Dairy Goat Research Articles

Prevalence of pasture-associated metazoal endoparasites in Bavarian dairy goat herds and farmers' approaches to parasite control.

The majority of dairy goat farms in Bavaria operate pasture-based systems. Endoparasites are therefore a common problem affecting health and productivity of these herds. Pooled faecal samples from 37 commercial dairy goat farms in Bavaria were examined by modified McMaster, flotation, sedimentation and Baermann funnel techniques. In addition, a questionnaire was used to gather information on farmers' perceptions and parasite management efforts. The average trichostrongyle faecal egg count across the 37 farms was 620 epg, with a median of 450 epg (1st quartile: 135 epg; 3rd quartile: 930 epg; range: < 30 to 3090 epg). Fasciola hepatica eggs were detected on four farms, Moniezia expansa eggs on one, Muellerius capillaris larvae on 13 and Dicrocoelium dendriticum eggs in none of the samples. Following coproculture third stage larvae of trichostrongyle species were identified morphologically. Sufficient larval numbers were obtained from samples from 23 farms. Haemonchus spp. was the most abundant larval genus and accounted for 30.4% of all larvae examined (n = 4868), followed by Trichostrongylus spp. (27.5%), Teladorsagia spp. (21.8%) and Oesophagostomum spp./Chabertia spp. (19.0%; these two genera were not differentiated). Further nematodes were identified according to their egg morphology: Nematodirus spp were present on nine farms, Skrjabinema spp. on nine, Trichuris spp. on five and Strongyloides spp. were not detected in any of the samples. The questionnaire results indicated a widespread lack of farmer awareness of appropriate parasite management and treatment measures. Farmer and veterinary education is therefore important to avoid future resistance problems caused by under-dosing or inappropriate treatments.

Ketonemia in dairy goats: Effect of dry period length and effect on lying behavior

In dairy animals, a successful transition from one lactation to the next includes minimizing negative energy balance. Cows experiencing excessive negative energy balance typically develop metabolic complications following parturition (e.g., ketosis); does are also susceptible before kidding (e.g., pregnancy toxemia). It is not known to what extent the provision and the length of the dry period affect these conditions in does. Furthermore, whereas clinical symptoms of these conditions include lethargy, behavioral changes resulting from ketosis and pregnancy toxemia have not been quantified in small ruminants. The aims of this study were to (1) describe the relationship between the dry period and negative energy balance, and (2) determine if lying behavior changes are indicative of the metabolic status of dairy goats. A total of 420 does on 10 commercial dairy goat farms in southern Ontario, Canada, were enrolled in the study (mean ± SD: 42±18 does/farm). Each doe was affixed with a data logger to measure lying behavior from 12 d before to 12 d after kidding. Blood samples were collected at least once before and at least once following kidding to determine blood β-hydroxybutyrate (BHBA) concentration as an indicator of negative energy balance. Does were categorized as healthy (HLTH; both pre- and postkidding samples BHBA <0.9 mmol/L), PREGTOX (prekidding BHBA ≥1.7 mmol/L), or KET (postkidding BHBA ≥1.7 mmol/L). Behaviors were analyzed according to 5 periods: P−2 (d −12 to d −2 relative to kidding), P−1 (d −1 relative to kidding), P0 (d 0, kidding day), P1 (d 1 relative to kidding), and P2 (d 2 to 12 relative to kidding). Dry period length and milk production after kidding were recorded when available. Farms ranged from 0 to 15% and 0 to 50% in prekidding and postkidding ketonemia, respectively. The HLTH does had shorter dry periods compared with PREGTOX and KET does (43 vs. 55 d, SE of the differences of means=4 d). One farm kept some does milking, while drying off others; on this farm more PREGTOX and KET does (11/28) were found in the dry group versus the continuously milked group (1/16). Overall, does that had ketonemia before kidding (PREGTOX) spent more time lying down compared with healthy does (16.1 vs. 12.7 h/d, SE of the differences of means=0.9). Both PREGTOX and HLTH does had increased lying bouts in P−2 compared with the day before (P−1) kidding [(mean (95% CI): 16.8 (15.8–17.8) vs. 20.5 (19.4–21.8) bout/d]. Compared with HLTH does, animals that were ketonemic following kidding (KET) had higher mean lying times throughout the study (14.5 vs. 13.5 h/d, SE=0.4). Previous work has shown a relationship between shorter and skipped dry periods and improved energy balance in dairy cows; the current study is the first to indicate a similar relationship in dairy goats. Furthermore, goats that developed ketonemia, particularly before kidding, displayed decreased activity, including longer lying times and fewer lying bouts in the days around kidding.

Technical note: Validation of data loggers for recording lying behavior in dairy goats

Changes in standing and lying behavior are frequently used in farm animals as indictors of comfort and health. In dairy goats, these behaviors have primarily been measured using labor-intensive video and live observation methodologies. The aim of this study was to validate accelerometer-based data loggers for use in goats. Two commercial dairy goat farms in Ontario were enrolled; goats were fitted with data loggers on their rear left legs and the pens were equipped with video. Data loggers compared well with video in identifying lying and standing events on both farms (farm 1 and 2, respectively: sensitivity=99.7 and 99.8%, specificity=99.5 and 99.4%, false readings=0.43 and 0.36%). The loggers were also able to record if the goat was lying on her left or right side (farm 1 only: sensitivity=99.9%, specificity=99.3%, false readings=0.38%), but these measures were only accurate if the loggers were attached with sufficient tension to prevent logger rotation. The mature does enrolled on farm 1 spent 14.5±1.0h/d lying down and frequently changed lying side even within a single lying bout (24±5 shifts/d between left and right sides and 16±5 lying bouts/d). The young goats on the second farm averaged just 8.5±3.2h/d in lying time, and spread this time over 8±4 bouts/d. Data loggers accurately measured lying time and lying bouts in mature does and younger goats on both farms, and lying laterality (e.g., left and right lying sides) in mature does on farm 1.

Prevalence and molecular identification of Chlamydia abortus in commercial dairy goat farms in a hot region in Mexico

The aim of this study was to determine the seroprevalence and presence of Chlamydia abortus in Saanen breed female goats from commercial dairy goat farms under intensive production in the municipality of Guanajuato, Mexico. Sera were collected to determine the prevalence of anti-C. abortus IgG antibodies using recombinant enzyme-linked immunosorbent assay (rELISA) and cell culture. Polymerase chain reaction (PCR) was used to prove the presence of the pathogen in swab samples collected from the vagina and rectum of selected animals. Additionally, foetal tissue samples from a sudden abortion were collected. C. abortus prevalence in female goats of commercial milking farms sampled in Guanajuato, Mexico, was 4.87% (n = 246). Seropositive animals were found in six out of nine (66.6%) dairy goat farms sampled, and prevalence among animals in individual farms ranged between 3.44 and 13.51%. C. abortus was detected using PCR in spleen tissue from the aborted foetus. PCR-based detection, as well as isolation from vaginal and rectal swabs, was not possible in the present study. Isolation through cell culture was also unsuccessful from aborted foetal tissue samples. In conclusion, the results from rELISA and PCR show that C. abortus is present in dairy goat farms in the state of Guanajuato, Mexico.

Expanding the contribution of dairy goats in efficient and sustainable production systems

Goats contribute significantly to human nutrition, food security and income of resource-poor small farmers in Asia, Africa and beyond. Because of the high content of mono- and polyunsaturated fatty acids in goat milk, it is beneficial for human health resulting in it being sold at premium prices of three to nine times the price of cow milk in countries like China, Malaysia, Indonesia and Thailand. Goats play a significant role in farming systems that directly impact on the capacity of rural farmers striving for the objective of sustainable food production systems. Increasing sustainable food production, particularly of animal proteins, presents major challenges to these small farms in the face of massive demands that are driven by rapid growth of human populations and increased availability of disposable income. In the last two decades, expanding market demand for goat milk has resulted in the establishment of commercial dairy goat farms in several newly developed South-east Asian countries. Major challenges to expanding production exist, and include ways to utilise the well-adapted features inherent in goats and their potential production to benefit the small and commercial farmers alike. Increasing the knowledge base is a priority to stimulate improved production systems and, increased the income of dairy goat farmers and other people involved in the industry. The recent establishment of the Asian-Australasian Dairy Goat Network supported jointly by FAO and Universiti Putra Malaysia, and national programs of participating countries, are committed to address these objectives and facilitate much-needed improvements to sustain dairy goat production systems in Asia and beyond.

Development and testing of an on-farm welfare assessment protocol for dairy goats

AbstractTo ensure that farm animal welfare issues are identified and addressed appropriately, there is a need for robust on-farm welfare assessment protocols. This paper describes the development of a comprehensive welfare assessment protocol for dairy goats(Capra hircus)and its testing on 30 commercial dairy goat farms in Norway. The protocol combines animal-based welfare indicators with measures of husbandry provisions to enable the identification of welfare problems and challenges inherent to the production system. The study also includes a first report of group level qualitative behavioural assessments (QBA) of goats. Due to reliability and validity issues related to behavioural assessments of human-animal interactions, indices of stockperson attitudes were incorporated as a complementary assessment of stockmanship. The most prevalent physical conditions observed were ocular discharge, skin lesions, udder asymmetry, calluses on knees and hocks, and overgrown claws. Moreover, fear levels appeared to be of particular concern in some herds. Significant associations were found between qualitative behavioural assessments and measures of health and stockmanship. Floor type was associated with four animal-based welfare outcomes. Reliability and validity of goat welfare indicators need to be further tested, and intervention plans and thresholds need to be determined so that advice can be tailored to the specific problems identified on each farm. We conclude that the protocol can work as a tool to identify welfare issues in dairy goat herds, and that this study may be a valuable contribution to the development of a much-needed welfare assessment protocol for dairy goats.

The 2007–2010 Q fever epidemic in the Netherlands: characteristics of notified acute Q fever patients and the association with dairy goat farming

We describe the Q fever epidemic in the Netherlands with emphasis on the epidemiological characteristics of acute Q fever patients and the association with veterinary factors. Data from 3264 notifications for acute Q fever in the period from 2007 through 2009 were analysed. The patients most affected were men, smokers and persons aged 40–60 years. Pneumonia was the most common clinical presentation (62% in 2007 and 2008). Only 3.2% of the patients were working in the agriculture sector and 0.5% in the meat-processing industry including abattoirs. Dairy goat farms with Coxiella burnetii-induced abortion waves were mainly located in the same area where human cases occurred. Airborne transmission of contaminated dust particles from commercial dairy goat farms in densely populated areas has probably caused this epidemic. In 2010, there was a sharp decline in the number of notified cases following the implementation of control measures on dairy goat and sheep farms such as vaccination, hygiene measures and culling of pregnant animals on infected farms. In combination with a rise in the human population with antibodies against C. burnetii, these have most likely ended the outbreak. Development of chronic Q fever in infected patients remains an important problem for years to come.

Breeding plan for commercial dairy goat production systems in southern Brazil

Commercial small dairy goat producers, exploiting European breeds and selling fluid milk, concentrate in the southeastern and southern States of Brazil. They are in need to access improved germplasm due to government regulations banning imports of living material. This paper reports the actions taken, the difficulties encountered and the preliminary results of a Dairy Goat Breeding Plan started in 2005 by EMBRAPA Goats and Sheep, the Brazilian Ministry of Agriculture, Livestock and Food and the Association of Goats and Sheep Breeders of Minas Gerais States. The plan's objective was to address the needed access to improved germplasm claimed by farmers, through conducting progeny tests. Participatory and community work took place to organize/implement the plan. A professional milk recording institution was recruited by farmers to collect individual milk records in the associated farms where bucks are progeny-tested. Selection criteria mainly designed to respond to the market demand, focused on milk yields, lactation lengths and reproductive characteristics. Twenty bucks of Saanen, French Alpine and Anglo-Nubian breeds are being tested through artificial insemination in 22 herds. Until August 2010, the databank contained 7872 milk test days. The averages for total milk yield in a complete lactation, milk yield in 305 days of lactation, lactation length and average daily yield were 768±16kg, 676±10kg, 278±4 days and 2.75±0.01kg/day, respectively. Herd effects were found important (P<0.01) with a wide range of averages in milk production which justifies well the progeny test to suit germplasm for also a wide range of environments. Breed effects were also important in differentiating total milk yields in a complete lactation (P<0.01) with Saanen goats having significantly greater yields than Alpine and crossbred goats. Linear and quadratic age effects were significant in changing milk yields. The establishment and implementation of the plan confronted difficulties that were not insurmountable and offered important lessons learned and recommendations for similar engagements for smallholder dairy goat production systems elsewhere. These included: (1) careful identification and involvement of stakeholders considering the enabling conditions needed and sustainability, (2) engagement, whenever possible, of organized and trusted systems for data collection with a long-term projection. Avoid organizations/persons distrusted by farmers, (3) consider the sustainability of the plan from inception and policy development to this end, (4) while designing the selection objectives and criteria, consider not only traits that respond to market trends, but also traits that farmers judge as important.

Seroprevalence and risk factors of Q fever in goats on commercial dairy goat farms in the Netherlands, 2009-2010

BackgroundThe aim of this study was to estimate the seroprevalence of Coxiella burnetii in dairy goat farms in the Netherlands and to identify risk factors for farm and goat seropositivity before mandatory vaccination started. We approached 334 eligible farms with more than 100 goats for serum sampling and a farm questionnaire. Per farm, median 21 goats were sampled. A farm was considered positive when at least one goat tested ELISA positive.ResultsIn total, 2,828 goat serum samples from 123 farms were available. Farm prevalence was 43.1% (95%CI: 34.3%-51.8%). Overall goat seroprevalence was 21.4% (95%CI: 19.9%-22.9%) and among the 53 positive farms 46.6% (95%CI: 43.8%-49.3%). Multivariable logistic regression analysis included 96 farms and showed that farm location within 8 kilometres proximity from a bulk milk PCR positive farm, location in a municipality with high cattle density (≥ 100 cattle per square kilometre), controlling nuisance animals through covering airspaces, presence of cats or dogs in the goat stable, straw imported from abroad or unknown origin and a herd size above 800 goats were independent risk factors associated with Q fever on farm level. At animal level almost identical risk factors were found, with use of windbreak curtain and artificial insemination as additional risk factors.ConclusionIn 2009-2010, the seroprevalence in dairy goats in the Netherlands increased on animal and farm level compared to a previous study in 2008. Risk factors suggest spread from relatively closely located bulk milk-infected small ruminant farms, next to introduction and spread from companion animals, imported straw and use of artificial insemination. In-depth studies investigating the role of artificial insemination and bedding material are needed, while simultaneously general biosecurity measures should be updated, such as avoiding companion animals and vermin entering the stables, next to advice on farm stable constructions on how to prevent introduction and minimize airborne transmission from affected dairy goat farms to prevent further spread to the near environment.

Assessment of welfare on 24 commercial UK dairy goat farms based on direct observations

The preliminary findings from an investigation into the health and welfare of goats on commercial dairy goat farms in the UK are described. An assessment protocol involving direct observations of...

An outbreak of septic pedal arthritis in a commercial dairy goat herd

The background level of foot lameness in adults was reported at 1-2 each month prior to a fairly rapid rise in new cases that developed over a four-week period. During this period, cases escalated to ten per week with approximately 75% occurring within 4-6 weeks of kidding. The cohort (changing in numbers as does kidded) contained between 150-200 freshlykidded goats at the time of this investigation. It was evident from records that mainly first lactation goats were affected; these were kidding at approximately 18-24 months of age.

Efficiency of feeding Duddingtonia flagrans chlamydospores to control nematode parasites of first-season grazing goats in France

A field trial, conducted over two consecutive years, was aimed at assessing the efficacy of the administration of spores of the nematophagous fungus Duddingtonia flagrans to young goats for the control of nematode parasite infections on a French commercial dairy goat flock. For both years, the first-year grazing kids were divided into two similarly managed groups (fungus and control groups): in 2003 a daily dose rate of 5 x 10(5) spores/kg body weight was given to the fungus-group animals, while in 2004 a daily dose rate of 10(6) spores/kg body weight was used; the other half of the kids, acting as control, did not receive the spores. Parameters measured every 3 weeks included nematode egg excretion, larval development in faecal cultures and pasture larval counts. Additionally, at the beginning, the middle and the end of each grazing season, the goats were weighed and blood samples for pepsinogen determination were collected. In 2003, similar results were recorded for all the measured parameters in the control and fungus groups. In contrast, in 2004, the kids receiving the spores showed lower faecal egg counts and pepsinogen levels at the end of the season and higher growth rate compared to kids of the control group.

Microbiological quality of goat's milk obtained under different production systems

In order to determine the safety of milk produced by smallholder dairy goat farms, a farm-based research study was conducted on commercial dairy goat farms to compare the microbiological quality of milk produced using 3 different types of dairy goat production systems (intensive, semi-intensive and extensive). A survey of dairy goat farms in and around Pretoria carried out by means of a questionnaire revealed that most of the smallholder dairy goat farms surveyed used an extensive type of production system. The method of milking varied with the type of production system, i.e. machine milking; bucket system machine milking and hand-milking, respectively. Udder half milk samples (n=270) were analysed, of which 31.1% were infected with bacteria. The lowest intra-mammary infection was found amongst goats in the herd under the extensive system (13.3%), compared with 43.3% and 36.7% infection rates under the intensive and semi-intensive production systems, respectively. Staphylococcus intermedius (coagulase positive), Staphylococcus epidermidis and Staphylococcus simulans (both coagulase negative), were the most common cause of intramammary infection with a prevalence of 85.7% of the infected udder halves. The remaining 14.3% of the infection was due to Staphylococcus aureus. Bacteriology of bulk milk samples on the other hand, showed that raw milk obtained by the bucket system milking machine had the lowest total bacterial count (16,450 colony forming units (CFU)/ml) compared to that by pipeline milking machine (36,300 CFU/ml) or hand-milking (48,000 CFU/ml). No significant relationship was found between the somatic cell counts (SCC) and presence of bacterial infection in goat milk In comparison with the herds under the other 2 production systems, it was shown that dairy goat farming under the extensive production system, where hand-milking was used, can be adequate for the production of safe raw goat milk.

Subclinical Mastitis and Antimicrobial Susceptibility of Staphylococcus caprae and Staphylococcus epidermidis Isolated from Two Italian Goat Herds

A total of 156 goats from 2 commercial dairy goat farms were monitored for intramammary infections during an entire lactation. Most of the infections (80.7%) observed were due to coagulase-negative staphylococci (CNS) species. In herd 1, nearly all of the infections (96%) were due to CNS species, with Staphylococcus caprae (SCAP) being the most common specific pathogen observed, accounting for about 43% of the infections. In herd 2, the proportion of the infections due to CNS was 67% and Staphylococcus epidermidis (SEPI) was the most common pathogen (48% of infections) and SCAP was not present. Linear somatic cell scores (SCS) were greater in milk from infected udder halves, with an average difference of 0.78 SCS. The SCS for infected udder halves was greater than noninfected for all CNS species, although differences among species were observed. The ranking across CNS species was SCAP>other CNS>SEPI>no infection. However, infections by SEPI tended to be more persistent. Increased SCS was associated with a statistically significant decrease in milk yield, but no effect was observed for intramammary infections (IMI). Ninety-seven isolates of CNS (53 SCAP and 44 SEPI) were investigated for in vitro susceptibility to several antimicrobial agents. Benzylpenicillin was the most effective antimicrobial agent against SCAP and SEPI. A concentration of 0.05μg/mL was sufficient to inhibit growth of 90% of SCAP colonies, and 0.10μg/mL yielded a similar effectiveness for SEPI. Amoxicillin and the combination of amoxicillin and clavulanic acid were only slightly less effective. Tetracycline (62.5μg/mL) and tilmicosin (500μg/mL) were the least effective treatments for SEPI and SCAP, respectively.

Relationships between infection with caprine arthritis encephalitis virus, intramammary bacterial infection and somatic cell counts in dairy goats

Somatic cell counts, the bacteriological condition of the milk and antibodies against caprine arthritis encephalitis virus (cAEv) were measured monthly throughout lactation in 121 lactating goats of the Murcia- Granada...

Prevalence of subclinical intramammary infection caused by Staphylococcus epidermidis in a commercial dairy goat herd

One herd with 138 lactating goats that had a high somatic cell count (SCC) in bulk tank milk was studied. Foremilk was sampled for bacteriology and SCC at two samplings 28 days apart on the Dairy Herd Improvement Association test day. Blood samples were obtained for serological analyses of caprine arthritis–encephalitis virus. Bacterial intramammary infection (IMI) was diagnosed when the same pathogen was isolated twice from the same udder half. The prevalence of IMI was 34%. Most of the pathogens isolated (95.7%) were Staphylococcus spp. Staphylococcus epidermidis was the predominant species (66.7%), and most of these had similar biochemical profiles. Seroprevalence of caprine arthritis–encephalitis virus infection as assayed by agar gel immunodiffusion was 94.3%. Composite SCC as compiled by the Dairy Herd Improvement Association averaged 10 6/ml for the first sampling and 1.27×10 6/ml for the second sampling. Uninfected right and left udder halves had a lower foremilk SCC (1.3 and 1.0×10 6/ml, respectively) than the infected right and left udder halves (1.74 and 1.66×10 6/ml), respectively, but only in the left halves was the difference significant. Halves infected by S. epidermidis averaged higher SCC (1.8×10 6/ml) than the halves infected by other staphylococci (1.5×10 6/ml). Milk SCC increased as parity increased.

Physiological threshold of somatic cell count and California Mastitis Test for diagnosis of caprine subclinical mastitis

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 × 10 3 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 × 10 3 and 172 × 10 3 for Score 0 and traces; 1014 × 10 3 and 531 × 10 3 for Score 1; 2912 × 10 3 and 2051 × 10 3 for Score 2; and 4950 × 10 3 and 4436 × 10 3 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.

Effect of breed and milking method on somatic cell count, standard plate count and composition of goat milk

This study was conducted on three commercial dairy goat farms (A, B, C), on which does were milked using pipeline milking machines, milking buckets and by hand, respectively. Six to eight mastitis-free milking does of Alpine and Nubian breeds were selected from each farm. Composite samples, made of equal volumes of evening and morning milk, were collected monthly throughout the lactation (March–October). Milk samples were analyzed for somatic cell count (SCC), standard plate count (SPC), and percentages of fat, protein, lactose and solids-non-fat (SNF). The overall means were 9.3 × 10 5 SCC ml −1, 9.1 × 10 −2 cfu ml −1 SPC, 4.08% fat, 3.20% protein, 4.41 % lactose and 8.28% SNF, respectively. There was no significant effect of breed or milking method on SCC. Overall monthly mean SCC increased as lactation advanced. During the entire lactation period, 51% of the milk samples contained above 1 million SCC ml −1. However, only traces (under 5 cfu ml −1) of mastitis-related pathogens were found in these high SCC samples. Nubian does produced milk with higher SPC, percent fat, protein and SNF than Alpine does ( P < 0.05). Milk by bucket milking had lower SPC than that by pipeline and hand milkings ( P < 0.05), although all milk samples were below the limits of the Pasteurized Milk Ordinance for Grade A raw milk. Pooled data showed that SCC had a minor but positive correlation with SPC ( r = 0.14, P < 0.05, n = 312).

Effects of stage of lactation, production, parity and season on somatic cell counts in infected and uninfected dairy goats

A commercial dairy goat farm with 380 Alpine milking does maintained monthly records of milk production and somatic cell counts (SCC). Composite milk samples from all lactating does were cultured for mastitis pathogens every 6 months. Dairy Herd Improvement Association records were combined with culture results. Goats' SCC increased with intramammary infection (IMI). Increasing stage of lactation was also associated with increased SCC in goats with or without diagnosis of IMI. Lower mature equivalent milk production and increased parity were also associated with higher cell counts. Goats lactating during October, December and January (months with highest mean DIM) had increased SCC. Non-infected goats frequently had SCC greater than 1 000 000 ml −1. Much (approximately 90%) of the difference in goats' SCC was not due to IMI. Of the variation in SCC among does, 77% was unexplained. Alternative tests for goat milk quality would be beneficial for the industry.

Mycoplasma Infection in a Commercial Goat Dairy Caused byMycoplasma AgalactiaeandMycoplasma MycoidesSubsp.Mycoides(Caprine Biotype)

A commercial dairy goat herd of 600 animals experienced sudden onset of arthritis/polyarthritis, clinical mastitis, and sudden death in does. The offending infectious agents were Mycoplasma agalactiae and M. mycoides subsp. mycoides (caprine biotype). The disease syndrome began approximately 4 weeks following the 1) introduction into the herd of a lactating doe with no apparent clinical signs and 2) a breakdown of proper hygienic conditions in the milking parlor. Over a period of 3 weeks, 90 does (15%) either died or were culled because of arthritis/polyarthritis and mastitis. A management decision resulted in only the does affected with M. mycoides subsp. mycoides being submitted for necropsy; those affected with M. agalactiae, which were in a different "string," were not submitted for evaluation. Gross necropsy of the does affected with M. mycoides subsp. mycoides showed purulent discharges from the udders, enlarged supramammary lymph nodes, enlarged and firm spleens, and swollen livers. Microscopic findings were characterized by a loss of vascular integrity and diffuse fluid leakage in multiple organs. Antibiotic therapy with tylosin was attempted but was not successful. The outbreak was terminated following the removal or segregation of affected does and implementation of hygienic conditions in the milking parlor.