Clinical report of a paralytic syndrome affecting stallions, mares and foals on a thoroughbred studfarm

An outbreak of ataxia and paralysis on a Thoroughbred studfarm is reported. The cause of the disease was attributed to equid herpesvirus (EHV1) infection which stemmed from a single 10-month abortion on the studfarm. Stallions, mares and foals were all affected but the most serious clinical signs occurred in the mares. there were 35 out of 39 mares, 2 out of 4 stallions and 5 out of 39 foals which exhibited signs of ataxia. Nine mares became recumbent and died or were euthanased. Treatment with betamethasone and antibiotics was given. The outbreak was contained to one area of the stud apart from secondary spread to 2 in-contact mares on different premises.     

Enzootic viral abortion on a stud farm in east Switzerland

An outbreak of abortion due to the equine herpesvirus-1 (EHV-1) in the eastern part of Switzerland is reviewed. Seven of eleven pregnant mares aborted within twenty-three days in January 1989. Four weeks later another foal died a few minutes after parturition. Three mares delivered live foals in February, March and April without any complications. The examination of the eight dead foals revealed an EHV-1 Infection. The clinical signs and the pathology are discussed. Severe complications during the early post-parturient time are in contrast to the uncomplicated outcome mentioned by other authors. Procedures for prevention and control are listed.     

The effect of uterine torsion on mare and foal survival: a retrospective study, 1985--2005

REASONS FOR PERFORMING STUDY: Anecdotal speculation suggests that prognosis for survival of mares and foals following correction of uterine torsion has improved over the past 30 years. OBJECTIVES: To determine statistically the outcome of uterine torsion according to duration of clinical signs, stage of gestation, parity, physical examination findings, method of correction, prognosis for survival and reproductive health of the mare, and prospects for the foal within the neonatal period. METHODS: This retrospective study combined cases from 4 equine referral hospitals. RESULTS: The stage of gestation at which uterine torsion occurred was a risk factor for survival of mare and foal. Overall mare survival was 53/63 (84%); when uterine torsion occurred at < 320 days gestation, 36/37 (97%) of mares survived compared to 17/26 (65%) survival rate when uterine torsion occurred at > or = 320 days gestation. Overall foal survival was 54% (29/54). When uterine torsion occurred at < 320 days gestation, 21/29 (72%) foals survived compared to 8/25 (32%) when uterine torsion occurred at > or = 320 days gestation. Thirty mares were discharged from the hospital carrying a viable fetus following uterine torsion correction and 25/30 (83%) of these mares delivered live foals that survived beyond the neonatal period. CONCLUSIONS: Prognosis for survival for mares and foals following uterine torsion is good and improves if torsion occurs < 320 days compared to > or = 320 days gestation. CLINICAL RELEVANCE: Gestational timing of uterine torsion should be considered when advising clients about the prognosis for survival of the mare and foal. The prognosis for a mare delivering a live foal is good if the mare is discharged from the hospital following uterine torsion correction with a viable fetus.     

Neonatal Equine Herpesvirus Type 1 Infection on a Thoroughbred Breeding Farm

Of 17 foals born on a Thoroughbred breeding farm between March and April 1995, infection with equine herpesvirus type 1 (EHV-1) was associated with neonatal morbidity in 5 foals, 3 of which died or were euthanized. Morbidity and mortality were associated with pulmonary inflammation, and EHV-1 was identified in the lungs of the 3 foals that died. All neonatal EHV-1 infections occurred in foals of mares housed in the same pasture and barn. No other clinical manifestations of EHV-1 infection (eg, abortion, neurologic disease, or respiratory disease) occurred during this outbreak. Three foals were treated with acyclovir (1 died, 2 survived), which may have influenced the clinical outcome in the surviving foals.     

An unusual case of generalized soft-tissue mineralization in a suckling foal

An atypical case of severe soft-tissue mineralization in a 3-week-old foal from a herd of Andalusian horses is described. The herd clinical history and the laboratory findings were compatible with a diagnosis of secondary hyperparathyroidism due to a mineral imbalance in the diet (low calcium and high phosphorus intake). Mares showed a marked increase in serum parathyroid hormone (PTH) approximately 10 times normal levels. Serum PTH was marginally elevated in foals. Clinical signs (unthriftiness, painful joints, lameness in one or more limbs, and stiff gait) were more pronounced in foals than in mares. Two foals died and necropsy of one of them revealed extensive soft-tissue mineralization of arterial walls and pulmonary parenchyma. Clinical signs in mares and foals resolved by 4 weeks after diet adjustment.     

Risk factors for clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on Dutch dairy farms

Risk factors for outbreaks in 1999 of clinical Salmonella enterica subsp. enterica serovar Typhimurium infection on dairy farms were studied in a matched case-control study with 47 case farms and 47 control farms. All 47 case farms experienced a clinical outbreak of salmonellosis which was confirmed with a positive bacteriologic culture for serovar Typhimurium in one or more samples. Serovar Typhimurium phage type 401 and 506 (definitive type 104, DT104) were the most frequently isolated phage types (13 isolates). On most farms (66%), clinical signs were seen only among adult cows. The most frequently reported clinical signs were diarrhoea (in 92% of the farms) and depression (in 79% of the farms).Control farms were matched on region and had no history of salmonellosis. A questionnaire was used to collect data on case and control farms. The relationship between serovar Typhimurium status of the farm and possible risk factors was tested using conditional logistic regression. Significant factors in the final model were presence of cats on the farm (OR=0.06), purchase of manure (OR=21.5), feeding colostrum only from own dam (OR=0.08), a non-seasonal calving pattern (OR=25), unrestricted grazing of lactating cows (OR=0.07), and a high mean mowing percentage of pasture (OR=1.02).     

Prevalence of Eimeria leuckarti (Flesch, 1883) and intensity of faecal oocyst output in a herd of horses during a summer grazing season

The prevalence of Eimeria leuckarti infection and the intensity of faecal oocyst output were determined in a herd of 14 mares and their foals in northwest Germany using a sedimentation technique at weekly intervals during a summer grazing season from May to September. None of the mares, but all foals shed oocysts on at least one occasion. The patent periods lasted up to 16 weeks. The mean intensity of oocyst output (0.1-33 o.p.g.) was very low. No clinical signs of gastrointestinal disorder were noticed in any of the foals during this study.     

An outbreak of Salmonella enterica serotype Choleraesuis in goitered gazelle (Gazella subgutrosa subgutrosa) and a Malayan tapir (Tapirus indicus)

An outbreak of Salmonella enterica serotype Choleraesuis enteritis occurred in two juvenile goitered gazelles and an adult Malayan tapir over a period of 5 wk at the Minnesota Zoo. Diagnosis was made postmortem on one gazelle and one tapir, and a second gazelle was diagnosed via fecal culture. The death of the tapir was attributed to S. enterica serovar Choleraesuis septicemia, while salmonellosis was considered to be a contributing factor besides ostertagiasis for the death of one goitered gazelle and for the diarrhea of another goitered gazelle. A third gazelle became ill in the same time period, but Salmonella infection was not confirmed by culture. All exhibited the clinical signs of profuse, watery diarrhea. The gazelles developed a protein-losing enteropathy, and the tapir showed signs of sepsis and endotoxemia. Serotyping and pulsed-field gel electrophoresis revealed the Salmonella isolates to be indistinguishable from each other. One year prior to this outbreak, Salmonella sp. was cultured from a Visayan warty pig (Sus cebifrons) housed in the same building as the tapir. After further investigation into the outbreak, spread of this pathogen was speculated to be associated with human movement across animal areas.     

Salmonellosis in young calves due to Salmonella enteritidis.

The clinical and epidemiological features of an outbreak of salmonellosis due to Salmonella enteritidis in a group of calves are described. The major clinical signs were dullness, pyrexia and diarrhoea. Five of the 15 calves died but deaths were mainly confined to the younger members of the group. The recovery of salmonella organisms from rectal swabs was maximal shortly before four of the five deaths occurred and declined rapidly thereafter. Only two of the surviving 10 calves developed significant flagellar agglutination titres.     

Herd-level diagnosis for Salmonella enterica subsp. enterica serovar Dublin infection in bovine dairy herds

Herd-level sensitivities of bacteriological and serological methods were compared in 79 bovine dairy herds, recently infected with Salmonella enterica subsp. enterica serovar Dublin. All farms experienced clinical signs of salmonellosis for the first time and had no history of vaccination against salmonellosis. At the start of the study, infection with serovar Dublin was confirmed with at least one positive bacteriologic culture for serovar Dublin from a clinical case (gold standard for herd infection).Bacteriological culture was done on samples of dung-pits, drinking water, bulk-milk filters, and faeces of animals with current or earlier clinical signs of salmonellosis. Blood samples of all animals and bulk-milk samples were tested using an ELISA.Herd-level sensitivity (HSe) of culture of dung-pits, drinking water, bulk-milk filters, and faeces of animals with current or earlier signs of salmonellosis was 45, 5, 7, and 38%, respectively. HSe for serology of all animals was 100%. If blood samples of all calves 4-6 months old were examined, at least one calf was seropositive on 91% of the infected farms. If serology was performed on samples of animals with current or earlier signs of salmonellosis, at least one animal was seropositive on 80% of the infected farms. HSe for bulk-milk samples was 54%. However, if clinical signs of salmonellosis were observed only in lactating animals, sensitivity of bulk-milk serology was 79%.Interesting combinations of methods were the combination of serology of bulk milk with either serology of animals with current or earlier signs of salmonellosis (HSe=91%), or serology of all calves of 4-6 months old (HSe=99%).     

Protective effects of vaccines against experimental salmonellosis in racing pigeons

Five inactivated and one attenuated vaccine produced for the prevention of salmonellosis in pigeons were compared in an experimental challenge model. The birds were vaccinated according to the recommendations of the manufacturers and they were infected by gavage with a Salmonella typhimurium (var copenhagen) pigeon strain. The challenged control animals showed severe weight loss, excessive water intake over a prolonged period, and excreted large numbers of salmonellae. None of the vaccines fully protected the pigeons, and only an inactivated oil adjuvant vaccine was able to reduce the severity of the clinical signs significantly. Mortality was low and tended to increase with the severity of the clinical signs. These results do not justify the preventive use of salmonella vaccination in pigeons. Nevertheless, the oil adjuvant vaccine may help in the effective cleaning of lofts after an outbreak of salmonellosis.     

Surgical treatment of uterine torsion using a ventral midline laparotomy in 19 mares

OBJECTIVE: To report on the outcome of surgical treatment of uterine torsion in preterm mares. DESIGN: Retrospective case series of pregnant mares with uterine torsion presented to the Clinic for Obstetrics, Gynaecology and Andrology of Large and Small Animals. METHODS: Hospital records of all pregnant mares that underwent ventral midline laparotomy for uterine torsion between 1998 and 2004 were reviewed. The signalment, history, clinical signs, results of diagnostic procedures, direction and degree of the uterine twist, treatment and outcome were retrieved from each case record. RESULTS: This study comprised 19 mares between months 5 and 11 of pregnancy (8.7 +/- 1.9) and suffering from uterine torsion. In all cases ventromedian laparotomy was carried out under general anaesthesia. Gastrointestinal disorders were also present in 52.6% of horses. Postoperative complications included subcutaneous seromas (five mares), peritonitis (one mare) and abortion (two mares). In four mares (21%) the operation was unsuccessful (i.e. these mares had to be euthanased intra- or postoperatively). Of the surviving 15 mares, 13 (86.6%) gave birth to viable foals at full term. The foals developed normally. Only two mares aborted. CONCLUSIONS: Because of its versatility the ventral midline approach should be considered for correction of uterine torsion. The approach has many advantages, including rapid and clear access to the abdominal cavity, safety, visual assessment of uterine wall viability, correction of concomitant gastrointestinal tract problems, and performance of hysterotomy or hysterectomy, if indicated. In this study, managing uterine torsion in this way resulted in a high percentage of cases (86.6%) in which pregnancy was maintained, with the birth of a viable, mature foal.     

The Effects of Ivermectin Given Postpartum on the Incidence and Severity of Foal Heat Diarrhea

Foal heat diarrhea (FHD) is a major factor in the management of foals between 2 and 3 wk of age. The objective of this on-farm study was to determine the efficacy of postpartum anthelmintic treatment of mares for reducing the incidence and/or the severity of FHD in foals caused by parasitic infestation. Twenty-four Quarter Horse mares and their foals were alternately assigned to a treated or non-treated group according to expected foaling date. Treatment consisted of oral administration of Zimectrin® (Farnam Companies, Inc., Phoenix, AZ) to the dam within 12 h post-foaling. From d l through 25, foals were weighed, and vital signs and severity or absence of diarrhea were recorded. Incidence scores of 0 to 3 were assigned to each foal based on severity of diarrhea: 0 = no affliction and 3 = severe, watery diarrhea. There was no difference in incidence scores because of treatment; however, there was a trend for foals from treated mares to experience more severe diarrhea with a shorter duration. There was no difference in BW gain related to treatment or nontreatment of mares. Postpartum administration of Zimectrin to mares did not significantly decrease the incidence or severity of diarrhea in foals. Additionally, it did not affect growth rate of foals. The trend for foals from treated mares to have a shorter duration of FHD may be beneficial to farm managers who spend time and money treating and cleaning foals.     

Studies of passive immunity in foals to equine viral arteritis

The capacity of colostral samples collected from mares immune to equine viral arteritis to neutralize arteritis virus was two or more times greater than that present in the dams' sera. This activity in the mammary secretions was very low or undetectable after 1 week. The capacity of sera from eight of the nine foals born to immune mares to neutralize arteritis virus was high at 1 week of age. All of the titres had declined to extinction after 2–6 months. Arteritis virus neutralization was not detected in serum collected from foals prior to nursing or in samples from non-immune mares and their foals.Foals from immune mares developed mild signs or no signs of disease when inoculated nasally with virulent arteritis virus at 6 days of age.Seven- to nine-day-old foals from non-immune mares responded to vaccinationas they had appreciable serum-virus neutralizing antibody titres 6 months after vaccination and did not develop signs of disease when inoculated nasally with virulent virus. Foals of the same ages from immune mares did not respond to the vaccine since antibody could not be detected 6 months after vaccination and they either died or experienced clinically severe disease when inoculated nasally with virulent arteritis virus.     

Occurrence of swine salmonellosis in postweaning multisystemic wasting syndrome (PMWS) affected pigs concurrently infected with porcine reproduction and respiratory syndrome virus (PRRSV)

Fourteen diseased pigs from four farms in which there had been an outbreak of salmonellosis were investigated. Granulomatous inflammation with depletion of lymphocytes was observed in the swollen lymph nodes in these pigs. Antigens to porcine circovirus type 2 (PCV2) were immunolabeled in the lesions along with detection of viral DNA as PCV2 by polymerase chain reaction (PCR). In addition, antigens to porcine reproductive respiratory syndrome virus (PRRSV) were immunodetected in the lungs and Salmonella Choleraesuis was isolated from the affected pigs. The nine salmonellosis affected pigs, five (55.6%) with salmonellosis and PMWS concurrently infected with PRRSV were much higher than those infected with salmonellosis and PMWS (22.2%) or with salmonellosis and PPPRV (22.2%).     

Induction of parturition in mares: effect on passive transfer of immunity to foals

Parturition was induced in 11 mares, using a synthetic prostaglandin. Eight mares, not treated, were used as controls. There was no significant difference between the serum immunoglobulin G (IgG) concentrations of the treated and control mares. The concentration of IgG in the colostrum of treated mares compared favorably with that reported for naturally foaling mares. Four foals from treated mares died or were euthanatized because of weakness during the 1st 24 hours after birth. The mean IgG concentration in the surviving foals from treated mares at 24 to 36 hours of age was 1,561 mg/100 ml, which was significantly (P less than 0.01) lower than the mean concentration of 2,731 mg/100 ml in foals from control mares. The mean serum IgG concentration in foals from control mares was significantly (P less than 0.01) greater than that of their dams, whereas the mean serum IgG concentration of the foals from treated mares was significantly (P less than 0.01) lower than that of their dams.     

Genetic analyses of new movement traits using detailed evaluations of warmblood foals and mares

Detailed movement evaluations of warmblood foals and mares were performed in connection with regular breeding events of the Oldenburg horse breeding societies in 2009 and 2010. Unfavourable movement characteristics considered indicative for impaired balance were noted by a special judge (SJ) and the regular judges of the breeding events (RJ) and served as the basis for definition of new movement traits. Detailed movement information on 3374 foals and 2844 mares showed that more severe findings like irregular motion pattern in hind legs or irregularity in general motion pattern occurred only sporadically (prevalences of 1-2%). Irregular tail tone or posture was documented for 4% of the foals and 5% of the mares, resulting in prevalences of the comprehensive trait indications of imbalance (IMB) of 6.2% (foals) and 5.5% (mares). Binary coding was used for all traits, and genetic parameters were estimated bivariately in linear animal models with residual maximum likelihood. Comparative analyses between judges revealed that differences between trait definitions of SJ and RJ were larger in the mares than in the foals, but justified combined use of SJ and RJ information in both age groups. Heritability estimates for the movement traits ranged on the original scale from 0.02 to 0.26 in the foals and from 0.03 to 0.12 in the mares, with heritabilities for IMB on the underlying liability scale of 0.46 (foals) and 0.22 (mares). Comparative analyses between age groups indicated that common genetic factors may be responsible for findings of impaired balance in foals and mares. The results implied that horse breeding may benefit from using the early available information on the movement of foals obtained by detailed movement evaluations, although favourable combination of foal and mare data in future genetic evaluations may require refined recording of unfavourable movement characteristics in the adult horses.     

Clinical, serological and molecular investigations of EHV-1 and EHV-4 in 15 unweaned thoroughbred foals

Fifteen unweaned thoroughbred foals, born on a stud farm to vaccinated mares, were clinically monitored during their first six months of life and repeatedly tested for equine herpesvirus type 1 (EHV-1) and equine herpesvirus type 4 (EHV-4). Nasopharyngeal swabs and blood samples were collected and screened respectively by PCR and seroneutralisation to detect the presence of the virus, explore its role as a possible cause of respiratory disease, and to assess the efficiency of the pcr for the diagnosis of this disease. The foals were divided into three groups on the basis of their clinical signs and whether they had seroconverted to EHV-1 and/or EHV-4: first, foals with no clinical signs of disease that had not seroconverted; secondly, foals with clinical signs that had seroconverted, and thirdly, foals with clinical signs that had not seroconverted. The results indicated that the viruses circulated on the stud farm despite stringent vaccination regimens against them, and confirmed their association with respiratory disease. The absence of significantly different pcr results among the three groups of foals showed that the pcr was effective in confirming the circulation of the viruses on the premises without being particularly helpful as a diagnostic tool.     

Epidemiologic survey of diarrhea in foals

Epidemiologic and etiologic data about diarrhea in foals were collected under a planned prospective recording and monitoring study. The survey and monitoring procedures included a survey to obtain an overview of current horse management practices on participating farms, a daily health record survey to obtain information on mares and their foals, and collection of feces from 19 of 144 diarrheic foals and 10 age-matched nondiarrheic foals for electron microscopy, ELISA for rotavirus, and bacteriologic culture. Coronavirus was detected in the feces of diarrheic as well as clinically normal foals. Rotavirus was detected in the feces of diarrheic foals only. With regard to agents found in the feces, there was no significant (P less than 0.05) difference between diarrheic and nondiarrheic foals. Half of the 297 foals on which data were available developed diarrhea. Most foals that developed diarrhea lacked other clinical manifestations of disease. Basic cleanliness at foaling was associated with a lower percentage of foals developing diarrhea. Prophylactic use of antibiotics and vitamins in newborn foals was associated with a higher percentage of foals developing diarrhea. A higher percentage of foals born to visiting mares developed diarrhea, compared with foals born to resident mares.     

Comparative effects and safety of ivermectin in pregnant mares

Mares (n=20) approaching 3 months of pregnancy were assigned randomly to 1 of 4 treatment groups. Treatments were (a) an IM injection of ivermectin at 600 mcg/kg, (b) various conventional anthelmintic drugs at the manufacturers' recommended dose, (c) and IM injection of the ivermectin vehicle (placebo) and (d) no anthelmintic treatment during the trial. All anthelmintic treatments were administered at 60-day intervals up to and including the date of parturition. Fecal egg counts, arginase, hemoglobin and packed cell volume values were determined at bi-weekly intervals during the trial and there were no statistically significant differences determined between the treatment groups for these parameters. None of the mares showed any adverse clinical signs during the course of this study and all 20 mares delivered live foals which remained on the research farm until they were sold as year-lings. Mares treated with ivermectin had significantly (P<0.01) lower egg per gram counts than mares in the conventional treatment group. Multiple hematological and clinical chemistry values were determined for all mares and resulting foals within 12 hours post-parturition. A one-way analysis of variance showed no clinically relevant statistically significant differences between treatment groups in either mares or foals at 12 hours post-parturition. This study suggests that ivermectin at 600 mcg/kg is safe and highly efficacious when administered to pregnant mares.