IgE-bearing cells in bronchoalveolar lavage fluid and allergen-specific IgE levels in sera from RAO-affected horses

Recurrent airway obstruction (RAO) is a common condition in stabled horses characterized by small airway inflammation, airway neutrophilia and obstruction following exposure of susceptible horses to mouldy hay and straw and is thus regarded as a hypersensitivity reaction to mould spores. However, the role of immunoglobulin E antibodies (IgE) in the pathogenesis of RAO is unclear. We hypothesized that the number of cells with receptor-bound IgE in bronchoalveolar lavage fluid (BALF) and IgE levels in serum would be higher in RAO-affected than in healthy horses living in the same environment. Therefore, IgE-positive (+) cells were identified by immunocytochemistry on cytospins from BALF and counted. IgE levels against the mould extracts Aspergillus fumigatus (Asp. f.) and Alternaria alternata (Alt. a.) and the recombinant mould allergen Aspergillus fumigatus 8 (rAsp f 8) were measured by enzyme-linked immunosorbent assay (ELISA) in the sera of seven RAO-affected and 22 clinically healthy mature horses housed in the same conventional stable environment. After correcting for the number of neutrophils, there were no significant differences in IgE+ cells on cytospins from BALF between both groups of horses (5% versus 7%, P > 0.1). Serum IgE levels against the mould extracts were significantly higher in RAO-affected than in clinically healthy horses [median = 119 versus 66 relative ELISA units (REU), P < 0.05]. Furthermore, significantly more RAO-affected than healthy horses had detectable serum IgE against the recombinant allergen rAsp f 8 (4/7 and 3/22, respectively, P < 0.05). Age had no significant effect on BALF cell ratios or on specific serum IgE levels. These results show that high IgE levels against mould antigens are associated with RAO under controlled environmental conditions but ranges of mould-specific serum IgE levels overlapped too much between diseased and clinically healthy animals to be of any diagnostic value. Further studies are needed to assess whether IgE-mediated reactions contribute to the pathogenesis of RAO.     

The presence of precipitating antibodies in the sera of horses with chronic obstructive pulmonary disease (COPD).

The sera of horses affected and not affected with chronic obstructive pulmonary disease (COPD) were examined for precipitins to Micropolyspora faeni and Aspergillus fumigatus. Precipitins to both antigens were not restricted to COPD cases but occurred more frequently in animals affected with COPD. Many animals without detectable precipitins responded clinically to inhalation challenge with these antigens.     

Chronic obstructive pulmonary disease in the horse. 2: Therapy

The therapy of equine chronic obstructive pulmonary disease (COPD) essentially entails minimising the horse's exposure to the aetiological antigens which are predominantly thermophilic actinomycetes and moulds occurring in hay and straw. This can be achieved, for example, by keeping affected horses permanently out of doors, or when stabled, using shredded paper, wood shavings or peat moss as bedding and feeding a complete cubed diet. There should be no supplementary hay feeding apart from dust-free vacuum-packed hay. Applying such measures generally allows horses to become asymptomatic in seven to 14 days. Bronchodilators and corticosteroids bring about a marked, but temporary, improvement and can be of value in the treatment of acute attacks. The use of oral bronchodilators in combination with environmental control measures may hasten the remission of clinical signs in affected horse. Inhaled sodium cromoglycate can be used prophylactically in asymptomatic horses to prevent the onset of COPD when unavoidable antigen exposure is anticipated.     

The bovine immune response to Brucella abortus IV. Studies with a double immunodiffusion test for antibody against A2.

A double immunodiffusion test for precipitins against Brucella antigen A2 was developed and applied to a variety of samples. The A2 precipitins were produced by a heifer infected with B. abortus strain 2308, cattle vaccinated with killed B. melitensis strain H38 or live B. abortus strain 19 and by a dog infected with B. canis. Precipitins were also detected in the second International Standard for anti-Brucella abortus serum, in several anti-B. canis sera and at low levels in one anti-B. ovis serum tested. Antisera produced in calves against Yersinia enterocolitica serotype 0:9 had no anti-A2 activity despite titers greater than or equal to 1/1024 and greater than or equal to 1/80 in standard Brucella agglutination and CF tests, respectively. The test for A2 precipitins lacked specificity as weak reactions were obtained with five of 295 sera from brucellosis-free herds. This test was relatively insensitive, detecting precipitins in only 16 of 24 sera from infected cattle and 27 of 54 sera positive by complement fixation and enzyme labelled antiglobulin tests performed with whole cell and smooth lipopolysaccharide antigens, respectively. The A2 precipitins were detected in nine sera from five cattle, in two infected herds, which were negative by agglutination and complement fixation tests.     

Results of allergen-specific immunotherapy in 117 dogs with atopic dermatitis

The success of the treatment of 117 dogs with atopic dermatitis with allergen-specific immunotherapy for up to 48 months was assessed. An excellent response (remission with exclusive immunotherapy) was recorded in 18 of the dogs, a good response (more than 50 per cent reduction in medication and improvement of clinical signs) was recorded in 57, a moderate response was recorded in 24 and a poor response in 18. The mould antigens in the allergen extract were stored in a separate vial before administration and the success rate of the immunotherapy including mould antigens was much higher than in an earlier study in which mould and pollen antigens had been stored in one vial. The success rate was not affected significantly by the age of the dogs when the disease developed, or by their age or the period for which they had shown clinical signs when the treatment began; it was also unaffected by whether pollens, moulds or dust mites were used as antigens, or by whether the offending allergens had been identified by intradermal testing or by serum testing for allergen-specific immunoglobulin E.     

Allergen-specific IgE levels against crude mould and storage mite extracts and recombinant mould allergens in sera from horses affected with chronic bronchitis

Immunoglobulin E antibody (IgE) levels against four recombinant (r) mould allergens (r-Aspergillus fumigatus [rAsp f] 7, 8 and 9; r-Alternaria alternata 1 [rAlta1]) and crude mould (Aspergillus fumigatus, Alternaria alternata, Penicillium notatum) and storage mite extracts were determined by ELISA in sera from 24 pulmonary sound control horses and 26 horses suffering from chronic bronchitis/bronchiolitis (CB), also called chronic obstructive pulmonary disease (COPD). Serum IgG and IgA titres were also determined against Aspergillus fumigatus extract and rAsp f 8.IgE against the crude extracts could be measured in all sera, but there was no significant difference between CB-affected and control horses. In contrast, only 8-30% of the horses, depending on the r-allergen tested, had detectable IgE levels in serum against the r-allergens. Horses with CB had significantly more often detectable IgE levels than controls against rAlt a 1 (10/26 and 3/24, respectively, p=0. 054), rAsp f 7 (13/26 and 2/24, respectively, p<0.01) and rAsp f 8 (11/26 and 1/24, respectively, p<0.01). Only four horses (three CB-affected and one healthy, p0.05) had detectable IgE levels against rAsp f 9. Furthermore, CB-affected horses were often sensitised against two or more r-allergens (13/26 of the CB-affected horses) while only one of the 24 healthy horses had positive IgE levels against more than one r-allergens. Similarly to IgE levels, no significant differences between CB-affected and healthy horses were found for IgG titres against the Aspergillus fumigatus extract. However, horses with CB had significantly higher serum IgG titres against rAsp f 8 than healthy controls (median=28 versus 10 relative ELISA units [REU], p<0.01). Additionally, horses with detectable IgE titres against rAsp f 8 had significantly higher IgG titres against this r-allergen than horses with undetectable IgE titres (median IgG titres=46 and 13 REU, respectively; p<0.01). For serum IgA titres, neither differences between healthy and CB-affected animals nor correlations between IgA and IgG or IgE titres could be found.These results show that horses suffering from CB are more often sensitised to some Aspergillus fumigatus and Alternaria alternata allergens than control horses and that they are partly sensitised to the same fungal proteins as mould-allergic human patients. Furthermore, this study shows that r-allergens allow a much more sensitive determination of specific serum antibody levels by ELISA than crude mould extracts.     

Gastrointestinal Parasites of Stabled and Grazing Horses in Central and Northern Greece

The aim of this investigation was to compare parasites found in feces from stabled and grazing horses in Greece. For this, a total of 223 fecal samples were collected from horses from various parts of Central and Northern Greece. One hundred fifty were stabled and 73 were grazing horses, used for riding, working, or breeding. One hundred came from seven riding clubs, 73 from one breeding farm, and 50 were work horses from five farms. Parasitologic investigation was performed by applying three fecal examination techniques (Teleman's, zinc flotation, and stained smears) to detect ova, larvae, and oocysts of parasites. It was found that 77 the 223 horses (34.5%) in the study were infected with one or more parasite species. In the stabled horses, the most common parasites detected were eggs of strongyles, Strongyloides spp, Anoplocephala spp, Habronema spp, and Parascaris equorum and oocysts of Eimeria spp and Cryptosporidium spp; in the grazing horses, Anoplocephala spp. Strongyles were significantly more prevalent in the group of stabled horses than in the other group (P < .05). The results of the current study demonstrate that parasite infection is highly prevalent in horses in Greece.     

Chronic obstructive pulmonary disease (COPD): factors influencing the occurrence.

Breed, age, weight, type of work performed, seasonal onset, poor ventilation and exposure to moulds in the habitat were investigated in relation to the occurrence of chronic obstructive pulmonary disease (COPD). COPD was most commonly detected in showjumping and hacking horses. The older a horse, the more likely it was to become affected although most were 6 to 10 years of age. Of the horses in this sample of the population, which was not a random one, thoroughbred horses were affected least and ponies most often. The high incidence in ponies was related to their more frequent exposure to poor quality fodder and bedding. Most horses are exposed to the hazard of moulds, but more affected horses were so exposed than those not affected with COPD. Poor ventilation of the stable increased the chance of a horse becoming affected. Sex, body weight and season of onset of coughing had no influence on the occurrence of the disease.     

"Haysickness" in Icelandic horses: precipitin tests and other studies

Blood samples were taken from 18 healthy horses (Group A), 15 horses clinically diagnosed to have "haysickness" ("farmer's lung") (Group B), 10 closely related horses (Group C) and 14 inbred horses (Group D). Precipitins in sera were measured by double gel diffusion test against Micropolyspora faeni, Thermoactinomyces vulgaris, Aspergillus fumigatus, Alternaria, Penicillium and Rhizopus species. In Group A, all the horses were precipitin negative except one with a faint reaction to Rhizopus species. In Group B all had precipitin against M faeni. One horse also had precipitins against Rhizopus species and another against A fumigatus. In Group C, seven of the 10 horses had precipitins against M faeni. Of these, five had a history of respiratory signs, but two horses with a faint reaction had no such history. In Group D, four out of 14 horses had positive precipitin tests against M faeni. Of these four horses, three also had a faint reaction to A fumigatus and one a faint reaction to Alternaria species. All were asymptomatic. These results indicate that "farmer's lung" in man and "haysickness" in horses are of the same origin. However, further studies are necessary to substantiate the diagnostic or prognostic value of these precipitin tests in equine practice. The question of whether hereditary factors play a role in causing this disease also warrants further studies.     

Evaluation of a rapid agglutination method for detection of equine red cell surface antigens (Ca and Aa) as part of pretransfusion testing

BACKGROUND: Blood typing before transfusion minimizes the risk of transfusion reactions and prevents immunization of the recipient against incompatible RBC antigens. The major RBC antigens that warrant identification before packed RBC or whole blood transfusions in horses are Ca and Aa. Standard blood-typing protocols are time-consuming (2.5-3.0 hours) and impractical in emergency settings. OBJECTIVES: The purpose of this study was to determine whether equine RBCs could be typed for Ca and Aa antigens using sera from horses with RBC antibodies in a modified rapid (15 minute) blood-typing protocol. METHODS: Serum was obtained from a horse with anti-Ca antibodies and from another horse with anti-Aa antibodies. The presence of agglutinating antibodies was confirmed with antibody screening. Venous blood samples, collected in citrate-phosphate-dextrose, were obtained from 21 horses of various breeds. Samples were blood typed in the Veterinary Medical Teaching Hospital Hematology Laboratory using standard methodology. Washed RBCs from each of the 21 horses were incubated individually with anti-Ca and anti-Aa sera at dilutions of 1:4, 1:8, and 1:16 for 15 and 30 minutes at room temperature and 37 degrees C. RESULTS: Of the 21 horses, 13 were identified as Aa+/Ca+, four were Aa+/Ca-, two were Aa-/Ca+, and two were Aa-/Ca-. All 17 Aa-positive horses had a positive agglutination reaction at all dilutions of anti-Aa serum, incubation times, and temperatures, while all Aa-negative horses were negative. Each Ca-positive horse had a positive agglutination reaction at all incubation time points and temperatures up to the 1:16 dilution of the anti-Ca serum. All Ca-negative horses were negative at all times, temperatures, and dilutions of anti-Ca serum. Use of the modified protocol on 26 hospitalized horses resulted in accurate typing, based on complete antibody screens. CONCLUSIONS: These results support the hypothesis that equine RBCs can be blood typed using a rapid (15 minute) protocol, at room temperature, for the presence of Ca and Aa antigens using equine-derived antisera. This technique may be beneficial for pretransfusion testing of equine patients in an emergency setting.     

Rapid and specific serodiagnosis of western equine encephalitis virus infection in horses

Paired sera from 28 nonvaccinated horses with serologically confirmed western equine encephalitis (WEE) virus infections were evaluated for immunoglobulin (Ig)M and IgG directed against WEE virus, by use of enzyme immunoassay. Twenty-one of the horses developed greater than or equal to 4-fold increases or decreases in serum IgM titers in paired serum samples, confirming the diagnosis of WEE in these horses. Of the remaining 7 horses, 1 had stable IgM titers, 1 had a 2-fold increase in IgM titer between paired sera, 2 had 2-fold decreases in IgM titer, and for 3 horses adequate volumes were not available for both sera of the pair. Twenty-nine of 56 blood samples collected from these 28 horses had been collected within the first 3 days after clinical disease was recognized; all 28 horses and 48 of 53 available serum samples had IgM antibody to WEE virus. Immunoglobulin M also was detected in sera of 27 of 45 other nonvaccinated horses that had illnesses clinically compatible with WEE. Sera with IgM did not have cross-reacting IgM against eastern equine encephalitis virus. Therefore, the sensitivity, specificity, and lack of persistence of IgM was useful in the rapid diagnosis of WEE virus infections in horses.     

Endotoxin concentrations within the breathing zone of horses are higher in stables than on pasture

Inflammatory airway disease is common in stabled horses, with a prevalence of 17.3% in Michigan pleasure horses. Stable dust is rich in endotoxin, which may induce neutrophilic airway inflammation. Climatological conditions (ambient temperature and relative humidity) may influence endotoxin concentrations in pastures. The aim of this project was to determine if endotoxin levels in the breathing zone of horses in stables were higher than of horses on pasture, and if the endotoxin on pasture was associated with climatological conditions. Endotoxin exposure of six horses that were stabled or on pasture was determined by a Limulus amebocyte lysate assay. Climatological data were obtained from the US National Climatic Data Center. Endotoxin exposure was significantly higher (about 8-fold) in stables than on pasture. On pasture, endotoxin varied widely, despite constant climatological conditions. It was concluded that stabled horses are exposed to higher endotoxin concentrations than horses on pastures. Local endotoxin concentrations may be more important than ambient climatological conditions in determining endotoxin exposure of individual horses.     

Association between serum cytotoxicity and selected clinical variables in 240 horses admitted to a veterinary hospital.

A total of 378 serum samples from 240 hospitalized horses and 47 sera from healthy control horses were assayed for growth effects on actinomycin D-treated L929 cells. On average, patient and control sera stimulated cell growth; however, mean percentage of the relative growth index (RGI) of sera from clinical cases was significantly (P less than 0.001) lower than that of control sera. Approximately 35% of patient sera and 6% of control sera had tumor necrosis factor-like cytotoxic activity for L929 cells (ie, RGI less than 100%). Sera from horses with either peritoneal leakage of gastrointestinal tract contents or any bacterial infection were significantly (P less than 0.05) more cytotoxic than sera from horses that did not have these clinical factors. A clear tendency was evident for horses that had the highest serum cytotoxicity (RGI less than 75%) to also have clinical profiles suggestive of endotoxemia. Fever, leukopenia, diarrhea, and gastrointestinal tract leakage were significantly (P less than 0.05) overrepresented among these horses, compared with horses without serum cytotoxicity. Bacterial infections and abdominal surgeries were also increased in this group, but not significantly. Of the 14 horses with serum RGI less than 75%, 13 had some form of gastrointestinal tract disease and the other had gram-negative septicemia. Survival to discharge was significantly (P less than 0.05) lower among horses in the high-cytotoxicity group than among horses without serum cytotoxicity. Diarrhea and bacterial infections were the only clinical factors found more frequently in horses with low serum cytotoxicity than in horses without serum cytotoxicity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of immune complexes and collagen type-specific antibodies in sera and synovial fluids of horses with secondary osteoarthritis

Thirty-one horses with secondary osteoarthritis as a sequel of trauma (chip fractures) or osteochondritis dissecans were screened for immune complexes (IC) and anticollagen antibodies. Eighty-two percent of horses with joint disease had circulating C1q-binding IC; 77% of those horses had IC in synovial fluids of affected joints. Although only a few horses had anticollagen type-II antibodies, anticollagen type-I antibodies were found in sera of 25% of the horses and in 41% of their synovial fluids. This correlated well with the clinical data and suggested that antibodies might have been elicited by antigens derived from detached intra-articular osteochondral fragments. Immunologic reactivity is a new concept in equine secondary osteoarthritis and might be involved in the mechanisms of chronic inflammation and progressive collagen destruction in degenerative joint disease.     

IgE ELISA using antisera derived from epsilon chain antigenic peptides detects allergen-specific IgE in allergic horses

Equine disease with an allergic etiology is common. Environmental antigens most often implicated as allergens in horses include molds, dusty hay, grass pollen, hay dust mites, and insect saliva. Although intradermal testing with allergen is a useful diagnostic tool for some species, skin testing frequently produces false positive results in horses. Allergen deprivation as a diagnostic tool is often impossible and at best it is ineffective at diagnosing the specific allergic reactivity. Synthesis of IgE after exposure to allergen is the instigator of the allergic process. While IgE exerts its effect after binding strongly to mast cell Fc receptors, the presence of free IgE in the serum can be used to quantify and determine the allergen specificity of the allergic disease. A lack of widely available reagents for detection of equine IgE has limited this approach in horses. We have used the nucleotide sequence of equine IgE to prepare a peptide-based immunogen to elicit equine epsilon chain-specific antisera. Selection of peptides was based on antigenic attributes of the deduced amino acid sequence of the equine epsilon chain. Six peptides were selected for conjugation to carrier molecules and rabbit immunization. Of these, one peptide elicited antisera that was successfully used in enzyme linked immunosorbant assay (ELISA) to screen horse serum from 64 allergic horses for allergen-specific IgE. Twenty-four of the 64 horses showed positive reactivity to one or more of the following allergens: grass, grain mill dust, mosquito, and horsefly. This study demonstrates the usefulness of peptide-based immunogens for development of antisera to rare or difficult to purify antigens such as IgE. Resultant antisera has great usefulness in diagnostic assays for equine allergy and as a research tool.     

泰氏锥虫抗原制备及实验室诊断研究

应用体外培养的泰氏锥虫制备可溶性抗原Ⅰ、抗原Ⅱ和代谢抗原.经测定,其蛋白含量每毫升分别为6.5mg、7.4mg和7.1mg.薄层等电聚焦电泳测定结果表明,抗原Ⅰ出现22条区带,抗原Ⅱ21条区带,代谢抗原28条区带,对照的伊氏锥虫琼脂免疫扩散抗原14条区带.经分析,泰氏锥虫抗原和伊氏锥虫抗原有4条区带在同一迁移率上.琼脂免疫扩散反应中,3种泰氏锥虫抗原均与相应免疫兔血清发生沉淀反应,抗原Ⅰ出现1条致密沉淀线,抗原Ⅱ和代谢抗原出现2～3条沉淀线,抗原效价为1:4～16.免疫电泳显示了类似的结果,抗原Ⅰ与免疫兔血清出现1条弧形沉淀线,抗原Ⅱ和代谢抗原与免疫兔血清出现了3条弧形沉淀线.间接血凝试验结果表明,泰氏锥虫自然感染牛血清效价为1:20～40,免疫兔血清为1:1280～5120.所制泰氏锥虫抗原对伊氏锥虫和媾疫锥虫血清也能很好地发生交叉反应,3份伊氏锥虫病马血清和3份伊氏锥虫人工感染兔血清血凝效价分别为1:10～40和1:8～1024;5份媾疫马血清有4份血凝效价为1:20～320.4份环形泰勒虫病牛血清均为阴性.     

The use of chosen serological diagnostic methods in Lyme disease in horses. Part II. Western blot

In this investigation the Western blot test was treated as a method verifying results of the IFA, commercial ELISA and standardized ELISA tests (described in Part I). The verifying investigations were performed on 82 serum samples, which in the commercial ELISA were positive in 36 cases, dubious in 31 cases and negative in 15 cases as well as on 5 serum samples obtained from horses infected with Leptospira spp., which in the ELISA commercial were dubious (total of 87 sera samples). The antigens, against which the immunological response in horses was directed, were also established. The Milenia--Blot--Borrelia IgG test (MIDBO IgG-Kit 30 Tests: DPC Bierman GmbH) was used in the investigation. In view of species differences, rabbit anti-horse IgG (whole molecule) alkaline phosphatase conjugate, no A6063 SIGMA-ALDRICH was used interchangeably. Also the control sera were substituted with the horse control sera. It was demonstrated that the Western blot test is the most reliable in the serological diagnosis of B. burgdorferi infection in horses. The commercial ELISA and standardized ELISA tests represent a lower diagnostic value than the Western blot test, although similar to each other, while the value of the IFA is minimal. In the Western blot test antigens were established against which the immunological response in horses in mostly directed. In the sera evaluated in this test as positive the presence of antibodies, mainly against antigens with the following molecular weights: 41 kDa, 62/60 kDa, 93 kDa, 72 kDa, 34 kDa (OspB), 66 kDa was noted. At the same time, antibodies contained in the sera accepted as negative, in 55.5% cases also reacted with the antigen of 41 kDa. It points to its minimal specificity. On the basis of the results obtained it is recommended that serological examination of horses should be with the ELISA and that positive or dubious results should be verified with the Western blot test.     

Serum level of cartilage oligomeric matrix protein (COMP) in equine osteoarthritis

This study was designed to assay and compare cartilage oligomeric matrix protein (COMP) in horse sera, in samples from normal and joint diseased horses, and to investigate the relationships between COMP in sera and synovial fluids (SF) with keratan sulphate (KS) data. Sera from 38 horses free of any joint pathology (controls) and from horses with aseptic joint disease (AJD horses, n = 40) were assayed for COMP and KS concentrations. Of the 78 horses in the study, 53 were also assayed for COMP and KS concentrations in SF. COMP and KS were measured by inhibition ELISA, using monoclonal antibodies 12C4 and 5D4, respectively. The COMP concentration in sera from AJD horses (mean +/- s.d. 10.7 +/- 7.4 microg/ml) was significantly (P<0.02) lower than in control sera (14.8 +/- 7.8 microg/ml). The joint disease sera also had significantly lower (P<0.01) KS levels (180.5 +/- 61.8 ng/ml) than controls (237.1 +/- 116.1 ng/ml). A significant correlation (r = 0.52, n = 53, P<0.001) was seen between serum and SF in COMP levels; no such relationship was seen in KS levels. It is possible that serum COMP concentration could be a more specific marker of equine joint disease than any other described to date.     

Assessment of an immunoturbidimetric method for measuring equine serum haptoglobin concentrations.

Serum haptoglobin was measured by immunoturbidity in Thoroughbreds stabled in three Newmarket yards for nine months. The mean serum haptoglobin value for horses housed in Stable 1 was 1.43 +/- 0.68 g/litre, similar to values in grazing adult ponies. The mean monthly haptoglobin values remained constant. For horses in Stable 2 there was an increase in serum haptoglobin values in June and July whereas, in Stable 3, the increases early in the training season were associated with an increase in serum viral titres. In equine serum, haptoglobin values estimated in g/litre by immunoturbidimetry were twice the haemoglobin binding capacity (HbBC). The correlation coefficient, between the methods, exceeded 0.96. Surgical interference caused a 2- to 3-fold increase in serum haptoglobin, with levels peaking between three and five days post surgery. The concomitant presence of haematomata following surgical interference (castration) resulted in the disappearance of haptoglobin from the circulation. There was no significant increase in serum haptoglobin levels following vaccination of Thoroughbreds against influenza and tetanus. However inhalation of influenza virus by vaccinated and non-vaccinated ponies resulted in a 2- to 3-fold increase in both groups of ponies, peaking seven to 10 days post infection. Serum haptoglobin proved to be a useful indicator of infection/inflammation and haemolytic disease in the horse and could be used to monitor the health status of stabled Thoroughbreds.     

Clinical, biochemical, and hygiene assessment of stabled horses provided continuous or intermittent access to drinking water

OBJECTIVE: To compare health, hydration status, and management of stabled pregnant mares provided drinking water continuously or via 1 of 3 intermittent delivery systems. ANIMALS: 22 Quarter Horse (QH) or QH-crossbred mares and 18 Belgian or Belgian-crossbred mares (study 1); 24 QH or QH-crossbred mares and 18 Belgian or Belgian-crossbred mares (study 2). PROCEDURE: Stabled horses were provided water continuously or via 1 of 3 intermittent water delivery systems in 2 study periods during a 2-year period. Body temperature, attitude, appetite, water intake, and urine output were recorded daily. Hygiene of each horse and the stable were assessed weekly. Clinical and biochemical measures of hydration were determined 3 times during each study. Clinical measures of hydration included skin turgor, gum moisture, capillary refill time, and fecal consistency. Biochemical measures of hydration included PCV, plasma total protein concentration, serum osmolality, plasma vasopressin concentration, urine specific gravity, and urine osmolality. RESULTS: All horses remained healthy. Stable hygiene was worse when horses had continuous access to water. Clinical and biochemical measures of hydration did not differ among water delivery systems. CONCLUSIONS AND CLINICAL RELEVANCE: Various continuous and intermittent water delivery systems provided adequate amounts of water to stabled horses to maintain health and hydration status. Providing intermittent access to water may be preferable on the basis of stable hygiene.