Concentration of Serum Prealbumin (Pr) Protein in Sick Horses and Its Correlation to Blood Leucocyte Count and Albumin Content in Serum

Studies of Pr protein concentrations in sera of sick horses were carried out using Mancini et al.’s (1965) immunodiffusion technique. Relative values against a chosen standard of 100 % were determined for a total of 102 horses. Horses with acute infections had Pr protein values significantly above the normal. The highest individual Pr protein value recorded in this group was 202. Horses suffering from acute laminitis and malignant tumours also had increased Pr protein values.There was a positive correlation between the Pr protein value and the blood leucocyte count and a negative correlation between the Pr protein value and the albumin content in serum.     

Serum IgM concentrations in normal,fit horses and horses with lymphoma or other medical conditions

The purposes of this study were to (1) prospectively establish serum IgM and IgG concentrations in normal, fit, adult horses over time and (2) determine the accuracy of serum IgM concentrations for diagnosing lymphoma. Serial IgM and IgG concentrations were measured with a radial immunodiffusion assay in 25 regularly exercised horses at 6-week intervals. Horses had serum IgM concentrations ranging from 50 to 242 mg/dL over 5 months, with 20% of horses having IgM < or = 60 mg/dL. The normal range for IgM in fit horses should be considered 103 +/- 40 mg/dL and a cut-point for an IgM deficiency, < or = 23 mg/dL. IgG concentrations ranged from 1,372 to 3,032 mg/dL. Retrospectively, medical records of adult horses (n = 103) admitted to the Cornell University Hospital for Animals for which serum IgM was measured were examined. Horses were categorized as "lymphoma negative" (n = 34) or "lymphoma positive" (n = 18). The sensitivity and specificity of a serum IgM concentration (< or = 60 mg/dL) for detecting equine lymphoma was 50 and 35%, respectively. At the new cut-point (< or = 23 mg/dL), the sensitivity was low at 28% and the specificity improved to 88%. The negative predictive values at various population prevalences indicate that a horse with a high serum IgM (> 23 mg/dL) is unlikely to have lymphoma, whereas the positive predictive value (70%) does not allow for reliable determination of lymphoma in a horse with serum IgM < or = 23 mg/dL. Therefore, serum IgM concentrations should not be used as a screening test for equine lymphoma.     

Serum gamma glutamyl transferase activity in horses with right or left dorsal displacements of the large colon

The purpose of this study was to test the hypothesis that horses with right dorsal displacement of the large colon (RDDLC) have elevations in serum gamma glutamyl transferase (GGT) activity when compared with horses with left dorsal displacement of the large colon (LDDLC). Medical records from 37 horses with RDDLC and 48 horses with LDDLC were reviewed. Horses were included for study if the RDDLC or LDDLC was confirmed by exploratory laparotomy or postmortem examination and if a serum GGT measurement was obtained within 24 hours before surgery. The proportion of horses with GGT activity within or above the reference range was determined. Of 37 horses, 18 (49%; exact binomial 95% confidence interval, 32-66%) with RDDLC and, of 48 horses, 1 (2%; 95% CI, 0-11%) with LDDLC had GGT above the reference range. Horses with RDDLC had higher serum GGT than did horses with LDDLC. Of 37 horses, 36 (97%) with RDDLC were discharged with a good prognosis and none returned as a result of hepatic disease. Evaluation of surgical and postmortem examinations revealed that positioning of the colon in horses with RDDLC results in compression of the bile duct, which can cause extrahepatic bile duct obstruction and a subsequent elevation in serum GGT activity.     

Vertical Frontlimb Ground Reaction Forces of Sound and Lame Warmbloods Differ From Those in Quarter Horses

Lameness is a highly prevalent condition in horses and is the principal cause of removal from athletic activity in this species. In evidence-based veterinary medicine studies to evaluate non-setoidal anti-inflammatory drug (NSAID) therapies, force plates are commonly used to objectively assess improvement of lameness. The objective of this study was to determine whether breed differences would influence force plate measurements in sound and lame riding horses. Force plate measurements of lame (n = 20) and sound (n = 18) Warmblood and lame (n = 15) and sound (n = 8) Quarter Horses were compared. Lameness was visually scored using the grade 0–5 American Association of Equine Practitioners (AAEP) lameness scale. Trotting sound Warmbloods loaded their frontlimbs with 118% body weight (BW) and their hindlimbs with 96% BW, whereas Quarter Horses only used 101% BW in the front and 92% BW in the hindlimbs (P < .05). Furthermore, it appeared and was estimated that, at trot, front-limb-lame Warmblood horses showed higher peak vertical force (PVF) values (grade 2: 89% BW; grade 3: 69% BW), than front-limb-lame Quarter Horses with similar lameness scores (grade 2: 78% BW; grade 3: 66% BW). In conclusion, peak vertical forces (PVF expressed in % BW) of either lame or sound horses seem to be influenced by breed differences between Warmblood and Quarter Horse riding horses. Possible conformation and gait differences enabled trotting Quarter Horses to demonstrate lower absolute PVF values than Warmbloods, whereas trotting lame Warmbloods showed a relatively larger decrease in frontlimb loading and thus in PVF than lame Quarter Horses at a trot. Thus, in studies in which objective lameness observations are recorded, breed differences should be taken into account when specific grades of lameness of a group of horses are to be objectively compared with another group.     

Serum Protein Concentrations in Horses With Severe Liver Disease: A Retrospective Study and Review of the Literature

The present retrospective study was undertaken to determine the frequency of hypoproteinemia and hypoalbuminemia in horses with natural occurring severe liver disease. The study represents a review of case records and laboratory data of 84 horses presented with acute or chronic liver disease to the University of California Veterinary Medical Teaching Hospital between 1973 and 1991. Forty horses (48%) had serum protein concentrations above the maximum reference value (7.7 g/dL). The increase in serum protein concentration was associated with hyperglobulinemia ( P = .00005, R ² = .80). Only 13% (11/84) of the horses had serum albumin concentrations below the minimum reference range (2.5 g/dL), and hypoproteinemia was found in only 1 of these horses. Of these, 18% (9/51) of the horses with chronic liver disease and 6% (2/33) of the horses with acute liver disease had albumin concentrations below the minimum reference value. Globulin concentrations in 64% of the horses (54/84) were above the maximum reference value (4.0 g/dL). The present study indicates that hypoproteinemia and hypoalbuminemia are not common features in horses with severe liver disease.     

Effect of aspirin on ex vivo generation of thromboxane in healthy horses

Different dosages of aspirin were administered (by nasogastric tube) to 3 groups of 5 healthy adult horses to determine the minimal effective dosage needed to decrease serum thromboxane B2 (TxB2) concentrations and to determine the duration of this decrease. When compared with their base-line serum TxB2 concentrations, horses in group 1 (given 5 mg/kg) had a 71% decrease in TxB2 concentrations at 24 hours after aspirin was given and a 86% decrease at 48 hours; serum TxB2 concentrations were back to base-line values by 120 hours. Horses in group 2 (given 10 mg/kg) had a 60% decrease in TxB2 concentrations at 24 hours after aspirin was given, an 84% decrease at 48 hours, a 48% decrease at 96 hours, and an 18% decrease at 6 days. Horses in group 3 (given 20 mg/kg) had a 68% decrease in TxB2 concentrations at 24 hours, a 93% decrease at 72 hours, an 87% decrease at 96 hours, and a 70% decrease at 6 days after aspirin treatment was given. All groups had a statistically significant decrease in TxB2 concentrations (P less than 0.05) by 12 hours after aspirin was given, which persisted 96 hours for group 1 and throughout the study for groups 2 and 3. The maximal TxB2 decrease was similar among the 3 groups (90% decrease from base line), and there were no significant differences among the TxB2 concentrations between 24 and 72 hours after treatment was given.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of age and sex on serum osteocalcin concentrations in horses at weaning and during physical conditioning

Three experiments were conducted to evaluate serum osteocalcin concentrations in normal weanling and yearling Quarter Horses. In Experiment 1, jugular blood samples were taken at 3 hr intervals for 24 hr to evaluate diurnal changes in serum osteocalcin concentration of foals (n=3) and yearlings (n=5). In Experiment 2, twelve Quarter Horse foals were weaned at 4 months of age to determine the influence of sex, weaning and method of weaning of serum osteocalcin concentration. The third experiment utilized fifteen yearling Quarter Horses (7 geldings, 8 fillies) in a two-phase trial to evaluate normal peripheral osteocalcin concentration in sedentary and exercising horses. In Experiment 1, there was no detectable variation (P>.05) in serum osteocalcin concentration during the 24 hr sample period in either age group. In Experiment 2, colts had greater (P<.05) osteocalcin concentrations than fillies at weaning. Method of weaning did not alter mean serum osteocalcin concentration (P>.1). Serum osteocalcin concentrations declined (P<.05) in all horses following weaning but returned to preweaning levels within one week. In Experiment 3, sedentary horses had similar (P>.1) osteocalcin concentrations on d 0, 45 and 90. Serum osteocalcin concentrations of sedentary horses were not affected by sex (P>.1). During exercise, fillies had greater (P<.05) osteocalcin concentrations than geldings. Serum osteocalcin concentrations of all horses declined linearly (P<.0001) during the 90 d exercise period. Osteocalcin may be useful as a tool to assess bone metabolism during growth and physical conditioning in horses. However, variability in serum osteocalcin concentrations due to age, sex and level of activity suggest that these factors must also be considered.     

Arterial blood gas analysis in 53 racehorses with a diagnosis of Small Airway Inflammatory Disease (SAID)

In 53 racehorses with a mean age of 4.5 years old presented for poor performance, Small Airway Inflammatory Disease (SAID) was diagnosed by bronchoalveolar lavage (BAL). Thirty of these horses (58.5%) had arterial pCO₂ above normal range (> 46 mmHg), while pO₂ was within normal range (> 80 mmHg) in both hypercapnic (group A) and normocapnic (group B) horses although pO₂ was significantly lower in group A horses. The horses were subsequently subdivided into two groups according to the duration of symptoms (group 1: less than 4 weeks; group 2: longer than 4 weeks). Horses from group 2 had significantly higher values of pCO₂ (p < 0.01) , HCO₃- (p < 0.01) and TCO₂ (p < 0.05) when compared to horses from group 1. It was concluded that the duration of the inflammatory process may play a role in the alteration of blood/alveolar gas exchanges and acid-base status in SAID affected racehorses.     

Effects of pre-shipping marbofloxacin administration on fever and blood properties in healthy Thoroughbreds transported a long distance

The present study evaluated the effects of single-dose marbofloxacin in protecting horses against fever associated with transportation using 48 healthy Thoroughbreds. All horses were premedicated with interferon-α (0.5 U/kg, sublingually, every 24 hr) for 2 days before transportation and on the day of transportation. Horses were randomly assigned to receive marbofloxacin (2 mg/kg, IV, once; MRFX group), enrofloxacin (5 mg/kg, IV, once; ERFX group) or saline (0.9% NaCl) solution (10 ml, IV, once; control group) ≤1 hr before being transportation. Each group contained 16 horses (8 males, 8 females). Horses were transported 1,210 km using commercial vans over the course of approximately 26 hr. Clinical examinations and hematologic analyses were performed on all horses both before and after transportation. Post-transportation neutrophil to lymphocyte ratios were significantly lower in horses in the MRFX group compared with the control horses. The serum amyloid A levels were significantly lower in horses in the MRFX group and ERFX group compared with the control horses. Regarding the post-transportation rectal temperatures, fever was detected in 0 horses and 1 horse in the MRFX and ERFX groups, respectively, whereas fevers exceeding 39.1°C were detected in 2 horses in the control group. Additionally, the number of essential post-transportation treatments provided by veterinarians was reduced 3-fold in the MRFX and ERFX groups compared with the saline group. MRFX provided ERFX-like protection against fever associated with long-distance transportation, yielding significantly better protection than saline. Administration of MRFX just before transportation deserves a further study for efficacy in preventing horse fever associated with transportation.     

Effect of airway disease on blood gas exchange in racehorses

Inflammatory Airway Disease (IAD), exercise-induced pulmonary hemorrhage (EIPH), and upper airway obstruction (UAO) are common respiratory tract diseases that can decrease performance. The purpose of this retrospective study was to compare bronchoalveolar lavage fluid cytology and arterial blood gas analysis during a treadmill test by poorly performing racehorses presented to Purdue University. One hundred thirty-two horses with a history of poor performance were included in this study. Ten horses with no history or diagnosis of EIPH, IAD, or UAO served as controls. Horses were evaluated by rhinolaryngoscopy for upper airway abnormalities and underwent a standardized treadmill test, and samples were collected for blood gas analysis. Horses with IAD or EIPH had a more severe exercise-induced hypoxemia, (mean+/-SD; 84.8+/-1.5 and 86.0+/-1.7 mm Hg average Pao2, respectively), than horses in the control group (92.8+/-2.1 mm Hg). The average Pao2 of horses with only UAO (88.3+/-3.3 mm Hg) was not significantly different from control horses. Gas exchanges were the most severely impaired in horses affected with both EIPH and UAO because they exhibited the lowest Pao2 and highest Paco2 values (66.5+/-15.2 and 52.2+/-6.3 mm Hg, respectively).     

Comparison of post-operative inflammatory response in horses undergoing elective castration treated preoperatively with ceftiofur crystalline free acid or procaine penicillin G

Castration is among the most common surgical procedures performed in the horse (Equus Caballus) and a variety of post-operative complications can occur. This study aims to determine if a single dose of long-acting ceftiofur crystalline free acid (CCFA) used as a preoperative antimicrobial in equine field castrations offers any reduction in post-operative inflammatory markers when compared to procaine penicillin G (PPG). Sixty-five horses aged 8 months to 2 years were randomly assigned to the CCFA (n = 33) or PPG (n = 32) treatment groups. Horses were castrated under general anaesthesia using a closed castration technique with removal of the median raphe. Quantitative and qualitative inflammatory markers were measured and short-term complications were recorded post-operatively on Days 3, 8 and 14. No clinically significant difference in any post-operative inflammatory markers between the CCFA and PPG group was detected. In the CCFA group, 48% of horses experienced short-term post-operative complications compared to 31% in the PPG group. Regardless of the preoperative treatment, castration induced significant elevation in serum amyloid A (P<0.0001), preputial oedema (P<0.0001) and scrotal oedema (P<0.0001) at Day 3. These values returned to baseline levels by Day 8. Horses with grade 3 or above preputial oedema had elevated serum amyloid A values (P<0.001). The data from this study indicate CCFA used as a preoperative antibiotic for routine castration offers no advantages over PPG. The difference in complication rate between groups is likely of minimal clinical importance, as all complications were mild and self-limiting.     

Ionized calcium concentration in horses with surgically managed gastrointestinal disease: 147 cases (1988-1990).

Packed cell volume, total plasma protein, serum sodium, potassium, and ionized Ca2+ concentrations, and blood pH were determined at the time of admission and following surgery in 147 horses with acute abdominal crisis. Horses were allotted to 3 categories on the basis of the surgical lesion: (1) nonstrangulating obstruction of the ascending or descending colon (category A, n = 76), (2) strangulating and nonstrangulating infarction of the cecum or ascending colon (category B, n = 37), and (3) strangulating and nonstrangulating infarction of the small intestine (category C, n = 25). Horses with low serum ionized Ca2+ concentration following surgery were given 23% calcium gluconate (100 to 300 ml) IV to effect, and ionized Ca2+ concentration was determined following treatment. The serum ionized Ca2+ concentrations of horses in categories A, B, and C before and after surgery were lower than our normal laboratory reference range. Prior to surgery, serum ionized Ca2+ concentration measured from horses in category B and C was lower than that in horses in category A. There was no difference in ionized Ca2+ concentration in serum samples obtained before surgery in horses from category B and C, and in serum samples obtained following surgery. There was a decrease in ionized Ca2+ concentration during surgery in horses in category A. There was no change between preoperative and postoperative ionized Ca2+ concentration in the samples obtained from horses in category B and C. After calcium gluconate administration, all horses with low serum ionized Ca2+ after surgery had concentrations within our normal range. Measurement of serum ionized Ca2+ in horses with an acute abdominal crisis is recommended.(ABSTRACT TRUNCATED AT 250 WORDS)     

Postmortem diagnosis of potassium poisoning

Serum potassium concentrations in horses euthanatized by intravenous injection of potassium chloride (KC1) were determined and compared to potassium concentrations in control horses euthanatized by injection of sodium pentobarbital. Horses euthanatized with 50 (n=7) or 100 (n=5) mg KCl/kg body weight had significantly higher (P<0.05) serum potassium concentrations compared to control horses, (11.3±0.8 meq/1 or 16.0±4.7 meq/1 versus 7.6±2.2 meq/1, respectively) at 2 hours after death. Both test groups sustained elevated serum potassium concentrations from 15 to 120 minutes postmortem. Whole blood potassium and serum chloride concentrations were of little diagnostic value.     

Quantitative Comparisons of Acidic Prealbumin (Pr) Phenotypes in Horses

Comparisons of Pr protein amounts in horse sera have been performed using Mancini et al.’s (1965) immunodiffusion technique. Relative values against a chosen standard of 100 % were determined for a total of 435 horses.There was considerable variation between horses, the highest Pr value being 125 % and the lowest 50 % of the standard. In animals of the same Pr phenotype the mean Pr values were significantly higher (P < 0.001) in foals than in mares. In Norwegian Trotter horses the Pr value of Pr NN animals was significantly higher than that of Pr SS phenotypes, whereas the mean Pr values of Pr SS was significantly higher than that of Pr UU Warmblood Trotter horses, the Pr value of Pr SS being 90 % and the Pr-UU 80 % of that of Pr NN.No difference between sexes with regard to Pr values was found.     

Traumatic brain injury in horses: 34 cases (1994-2004)

OBJECTIVE: To investigate the clinical, clinicopathologic, and diagnostic characteristics; treatment; and outcome associated with acute traumatic brain injury (TBI) in horses and assess risk factors for nonsurvival in TBI-affected horses. DESIGN: Retrospective case series. ANIMALS: 34 horses with TBI. Procedures-Medical records of horses that had sustained trauma to the head and developed neurologic signs were reviewed. Data that included signalment, clinicopathologic findings, diagnosis, treatment, and outcome were analyzed. Clinicopathologic variables among horses in survivor and nonsurvivor groups were compared, and risk factors for nonsurvival were determined. RESULTS: Median age of affected horses was 12 months. Findings of conventional survey radiography of the head alone failed to identify all horses with fractures of the calvarium. Horses with basilar bone fractures were 7.5 times as likely not to survive as horses without this type of fracture. Depending on clinical signs, horses received supportive care, osmotic or diuretic treatments, antimicrobials, anti-inflammatory drugs, analgesics, or anticonvulsants. Twenty-one (62%) horses survived to discharge from the hospital. In the nonsurvivor group, mean PCV was significantly higher, compared with the value in the survivor group (40% vs 33%). Risk factors associated with nonsurvival included recumbency of more than 4 hours' duration after initial evaluation (odds ratio, 18) and fracture of the basilar bone (odds ratio, 7.5). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that prognosis for survival in horses with acute TBI may be more favorable than previously reported. Among horses with TBI, persistent recumbency and fractures involving the basilar bones were associated with a poor prognosis.     

Efficacy of Hyperimmunized Plasma in the Treatment of Horses with Acute Colitis

Colitis in the adult horse is a life-threatening clinical condition that can be caused by any of several enteric pathogens. This study was conducted to determine whether treating horses with plasma obtained from donors that were hyperimmunized against the common equine diarrheal pathogens Clostridium difficile, Clostridium perfringens, and Salmonella sp shortens the duration of diarrhea in acute colitis. To evaluate the efficacy of plasma treatment, 42 horses with acute onset of diarrhea were studied. Horses were enrolled if they were of age >1 year, duration of diarrhea at presentation was <72 hours, and they had not received equine plasma within the last 3 months. In addition, the serum cortisol concentrations of horses with acute diarrhea were studied.Horses were randomized to receive hyperimmunized plasma, control plasma (collected from nonimmunized horses), or no plasma therapy. Clinical parameters and fecal consistency were observed until resolution, discharge, or death, and complete blood counts (CBCs) and biochemical profiles were collected throughout the study. A total of 38 horses completed the study. The mean duration of diarrhea was 40.7 ± 9.8 (mean ± SEM) hours, 119.2 ± 56.1 hours, and 72.0 ± 24.5 hours for the hyperimmunized plasma, normal plasma (NP), and control groups, respectively. Using survival analysis techniques, this difference did not achieve statistical significance (P = .374). Serum cortisol was found to be increased in all horses at presentation and to decrease with time in all treatment groups. There was no difference in cortisol concentrations between the three treatment groups studied (P = .237).     

Characteristics and risk factors for failure of horses with acute diarrhea to survive: 122 cases (1990-1996)

OBJECTIVE: To characterize horses with acute diarrhea and determine risk factors for failure to survive. DESIGN: Retrospective study. ANIMALS: 122 adult horses admitted for acute diarrhea at the teaching hospital between Jan 1, 1990 and Dec 31, 1996. PROCEDURE: Medical records of horses with acute diarrhea were reviewed to abstract information regarding signalment, history, physical examination, clinicopathologic testing, treatment, and outcome. RESULTS: 91 of 122 (74.6%) horses lived and were discharged from the hospital. Horses with history of administration of antimicrobials for a problem preceding diarrhea were approximately 4.5 times less likely to survive. The following variables that had been determined at the time of admission were significantly associated with failure to survive: administration of antimicrobial drugs for another illness, serum creatinine concentration > 2.0 mg/dl, PCV > 45%, tachycardia (heart rate > 60 beats/min), and low serum total protein concentration. Prevalence of laminitis was 11.5%. CLINICAL IMPLICATIONS: Diarrheic horses that are azotemic and have clinicopathologic findings consistent with hemoconcentration and hypoproteinemia have a poor prognosis for survival. Antimicrobial administration may induce diarrhea, and antimicrobial-associated diarrhea may have a worse prognosis than other types of acute diarrhea.     

Serum insulin concentrations in horses with equine Cushing's syndrome: response to a cortisol inhibitor and prognostic value

REASONS FOR PERFORMING STUDY: Serum insulin concentration and its use as a prognostic indicator in horses with equine Cushing's syndrome (ECS) have been poorly documented. OBJECTIVES: To examine daily insulin variations in horses with ECS and the effect of treatment using trilostane, a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. Further, we aimed to examine the relationship between baseline serum insulin concentration and survival in horses with ECS. METHODS: Basal serum insulin concentrations were measured in 20 confirmed ECS cases by taking blood at regular 4 h intervals for 24 h (1200, 1600, 2000, 2400, 0400 and 0800 h) before treatment (Day 0) and 10 days, and 30 days and 1-2 years after the onset of trilostane therapy. The temporal pattern of insulin was analysed using a linear mixed model approach, and the prognostic value of measurements on Day 0 assessed using receiver-operating characteristic analysis. RESULTS: Horses with ECS showed a diurnal pattern of serum insulin concentration, highest value at 1200 h, and this pattern was not altered by treatment with trilostane. Furthermore, despite a mild increase of serum insulin concentrations after 10 days of trilostane therapy, insulin concentration was unaffected in the long-term. Low serum insulin concentrations at the beginning of the trial were significantly associated with improved survival to 1-2 years. The 1200 h sampling before treatment had the highest prognostic value for prediction of survival with a sensitivity and specificity of at least 90% for serum insulin at < 62 and > 188 microu/ml to predict survival and nonsurvival, respectively. CONCLUSIONS AND POTENTIAL RELEVANCE: Insulin is a useful prognostic indicator for ECS, but potentially large variations can occur throughout a 24 h period, indicating a single sample may not be representative. Serum insulin concentration did not increase over 1-2 years in horses receiving trilostane therapy.