Estimation of Saliva Production in Crib-Biting and Normal Horses

Increasing saliva flow to buffer the stomach has been hypothesized as a basis for crib-biting in horses. Saliva amounts in seven cribbing and seven noncribbing (control) horses were compared either pre- and post-cribbing or at pre- and post-5-minute intervals for controls. A pre-weighed cellulose sponge was used to collect saliva at the exit of the submandibular gland for 30 seconds, then reweighed. Data were analyzed as repeated measures. Mean saliva weight overall was similar between cribbing and control horses (1.2 and 1.5 g, respectively, SE = 0.2). However, mean saliva weight for pre- and post-samples (1.5 and 1.2 g, respectively, SE = 0.06) for all horses was significantly lower (P < .05) in the post-sample, indicating a drying effect of the sponge. Because of a strong tendency (P < .06) for a treatment-by-sampling time interaction, data were analyzed by sampling time and cribbing status. Mean saliva weights in the pre-sample were 0.43 g higher (P < .03) in control than cribbing horses. Control horses showed a 0.38 g decrease (P < .01) in saliva weight between pre- and post-samples, which was not evident in cribbing horses. To determine whether cribbing offset the saliva decrease seen in control horses, nine cribbing horses were sampled as before but prevented from cribbing between samples. A similar reduction (0.39 g, P < .01) in saliva weights between samples with cribbing allowed versus cribbing prevented was seen in these horses as was seen in control horses in the initial study. Because cribbing does produce saliva, gastrointestinal irritation could be a motivating cause for cribbing.     

A Randomized Blinded Crossover Clinical Trial to Determine the Effect of an Oral Joint Supplement on Equine Limb Kinematics,Orthopedic, Physiotherapy,and Handler Evaluation Scores

Despite the range of oral joint supplements available, there has been very limited research into their efficacy. The study aimed to determine the effect of an oral joint supplement on limb kinematics, orthopedic, physiotherapy, and handler evaluation in horses. Supplement S or placebo P was fed to 24 horses for 21 days each in a random order. Horses were evaluated at days 0 (baseline), 21 (after first treatment), and 42 (after second treatment). Assessments included the following: clinical orthopedic evaluation for straight line/lunging circle in walk and trot; high-speed motion capture determined hindlimb kinematics for straight-line trotting; grading of limb range of motion (ROM) and muscle tone based on standardized physiotherapy criteria; handler grading of specific criteria during pasture, groundwork, and ridden exercise. Effect of treatment, sequence, limb, and interactions were investigated using linear-mixed models. S was associated with significantly lower lameness grade in a straight line (P = .001) and circle (P = .010), with individual horses improving up to 2/10 grades over P/baseline. S was associated with significantly improved ROM and muscle tone. Ridden/groundwork scores were significantly higher with S compared to P/baseline. With S, horses were graded significantly higher for “ease of movement” at pasture compared with P/baseline. For horses with hindlimb lameness, S was associated with significantly greater tarsal flexion than baseline (4.2% greater, P < .020) or P (2.7% greater, P < .037). S was associated with less lameness and improved physiotherapy scores, ridden/groundwork scores, and pasture “ease of movement.” Increased midstance tarsal flexion of lame limbs may indicate improved mobility/comfort during peak loading, supporting a positive effect of S.     

Endoparasite infection and Cryptosporidium/Giardia in feral horses on public lands

Two populations of feral horses and one population of domestic horses located in portions of eastern California and western Nevada (Inyo National Forest) were examined for the occurrence of endoparasite infection and the protozoans, Cryptosporidium parvum and Giardia duodenalis. The two groups of feral horses consisted of 24 sedentary horses and 29 nomadic horses; there were a total of 11 domestic horses. The sedentary and nomadic horses were tracked and observed for one to three days, respectively. Fresh fecal samples were collected from the respective groups and examined for parasite eggs using the Cornell-Wisconsin Centrifugal Flotation Technique. A total of 58 fecal samples were collected from the three groups (sedentary, n=16; nomadic, n=31; domestic, n=11). Data (eggs·g⁻¹) were initially analyzed using the Kruskal-Wallis nonparametric statistical method. Mean separation was accomplished by using the Mann-Whitney U-test following an observed significant effect of group (p<0.0001) with the Kruskal-Wallis test. The median numbers of eggs·g⁻¹ for the sedentary, nomadic and domestic groups were 803.0, 69.0 and 321.0, respectively. The interquartile range along with the 25th and 75th percentile for the respective groups were 776.0 (332.0–1108.0), 136.5 (32.0–168.5) and 486.0 (198.0–684.0). The eggs·g⁻¹ for the nomadic group were less than the sedentary horses (p<0.0001) and less than the domestic horses (p<0.02); however, there were no observed differences between the sedentary and domestic groups (p=0.13). The lower number of eggs·g⁻¹ observed for the nomadic group is most likely due to the reduced time spent on the collection site relative to their movement pattern. Separate aliquots of the fecal samples were also analyzed for Cryptosporidium parvum and Giardia duodenalis. All fecal samples were negative for these two organisms.     

Investigation of Myofascial Trigger Points in Equine Pectoral Muscles and Girth-Aversion Behavior

Horses displaying aversion to fastening of the girth may be expressing pain from myofascial trigger points (MTrPs). The location of MTrPs in the pectoral region of horses has not been previously described. The objectives of this study were as follows: (1) to locate and map MTrPs in the transverse and ascending pectoral muscles; (2) to score the severity of the MTrPs by behavioral reaction to palpation; and (3) to look for associations between these findings and girth-aversion behavior. Thirty-eight horses were recruited in a cross-sectional clinical study. Taut bands were identified on palpation of horses undergoing physiotherapy assessment and then scored for behavioral reaction to palpation as normal (0), mild (1), moderate (2), or severe (3) and mapped. Owner-reported history of girth-aversion behavior was compared with the severity score using chi-squared analysis. Myofascial trigger points were identified in all horses (average severity: mild n = 6, moderate n = 24, and severe n = 8) with the most common regions of ascending pectoral muscles being the axillary and along the region usually covered by the girth. Horses with an owner-reported history of girth-aversion behavior (n = 13) had higher severity scores than horses without a history of girth-aversion behavior (n = 25; P = .014). Knowledge of the presence and location of MTrPs could assist in the development of prevention and management strategies to improve comfort, optimize performance, and reduce girth-aversion behavior.     

Platelet‐Activating Factor and Evidence of Oxidative Stress in the Bronchoalveolar Fluid of Thoroughbred Colts during Race Training

Background: Inflammatory airway disease (IAD) is prevalent in young racehorses during training, being the 2nd most commonly diagnosed ailment interrupting training of 2‐year‐old Thoroughbred racehorses. Hypothesis: That stabling and exercise cause oxidative stress, release of platelet‐activating factor (PAF) and inflammation in airways of Thoroughbred colts. Animals: Colts in breeding farms (NC, n = 45), stabled for 30 days (EC, n = 40), and race trained (EX, n = 34). Methods: Cytological profile and parameters of bronchoalveolar lavage fluid (BALF) related to oxidative stress, bioactivity of the proinflammatory mediator PAF, catalase activity, and alveolar macrophage function. Results: Percentages of neutrophils and eosinophils in the BALF of the EX group were higher (5.4 ± 6.4% versus 0.9 ± 1.2%) than the upper limits for normal horses (3–5%). BALF from the EX group (45.6 ± 2.8 cells/μL of BALF) also displayed significantly (P= .017) higher total nucleated cell count. PAF bioactivity and the total protein concentration in the BALF were higher in the EX group (0.0683 ± 0.076 versus 0.0056 ± 0.007 340 : 380 nm ratio P= .0039, 0.36 ± 0.30 versus 0.14 ± 0.15 mg of proteins/mL of BALF P < .001). Concentration of BALF hydroperoxides was higher in the EC group (104.7 ± 80.0 versus 35.2 ± 28.0 nmol/mg of proteins, P= .013) and catalase activity was higher in the EX group (0.24 ± 0.16 versus 0.06 ± 0.02 μmol H₂O₂/min/mg of proteins, P= .0021). Alveolar macrophage phagocytosis (P= .048) as well as production of superoxide anion (P= .0014) and hydrogen peroxide (P= .0011) were significantly lower in EX group. Conclusions and Clinical Importance: Further studies should be performed to elucidate the role of PAF in the pathophysiology of IAD. Its presence in bronchoalveolar fluid of young athletic horses makes it a potential therapeutic target to be investigated.     

Profiling the New Zealand Thoroughbred racing industry. 2. Conditions interfering with training and racing

AIM: To describe and enumerate conditions that interrupted training and racing in a population of Thoroughbred racehorses in New Zealand.

METHODS: A longitudinal study design was used to collect data on horses training under the care of 20 licensed racehorse trainers from venues in the mid to lower regions of the North Island between October 1997 and July 2000. Incidence rates were reported for first and second occurrences for different categories of musculoskeletal injury (MSI), and first occurrences of upper and lower respiratory tract disease, using training days as time-at-risk. The proportion of horses that retired or died due to MSI, respiratory tract or miscellaneous conditions was used to estimate risk of exit for each type of event. Duration of training preparation, starts per 100 training days, and proportion of starts that ended in first, second or third place, were calculated for horses at risk for first MSI, and all subsequent MSIs. In training preparations that had at least one start and that ended in MSI, the cumulative percentage of MSIs by day of diagnosis was reported for 0–21 days after the last start in the preparation.

RESULTS: Horses (n=1,571) were followed during 3,333 training preparations and 392,290 training days. Events associated with the end of a training preparation or spell period included MSI (n=834), respiratory event (RE; n=165), miscellaneous event (ME; n=58), and voluntary retirements (n=360). Causes of MSI included lameness (n=400), shin soreness (n=207), tendon and ligament conditions (n=98), injury or laceration (n=56), fractures (n=55), and back disorders (n=18). MSIs involved the limbs in 97% of cases, and the lower limbs up to the carpus or hock in the fore- and hindlimbs, respectively, in 81% of cases. Most (93%) lower limb conditions involved a forelimb while 70% of MSIs that involved structures above the carpus or hock involved a hindlimb. Incidence rates (IRs) are reported for each age group for first and second occurrences of MSI, and first occurrence of upper and lower respiratory tract disease. The risk of MSI was higher in horses that had incurred one previous MSI (RR 1.4, 95% CI=1.2–1.7; p>0.001) than in horses without any previous MSI. The proportion of horses that exited due to death or retirement varied with the type of injury, and the highest proportion was associated with recurrent fractures, and tendon and ligament injuries (46.2 and 44.4%, respectively). The overall IR of horses exiting the study due to retirement or death increased with increasing age, and was higher in females than males for horses aged 2, 3, 4, and ≥5 years. A reduction in the number of starts per 100 training days was observed in horses aged ≥5 years when returning to training after an initial MSI (p=0.004). Male horses of all age groups and females younger than 4 years had shorter median training preparations (p>0.05) when returning to training after an initial MSI compared with preparations at risk for a first occurrence of MSI. Between 27 and 62% of cases of MSI that occurred in training preparations after at least one start were reported on the day of the last start, and the remainder were reported in the days to weeks following the last start of that preparation.

CONCLUSION: Incidence rates, and proportions of affected horses that retired or died as a result of injury or disorder varied with type of injury and age of horse. Horses returning to training after an initial MSI were at higher risk of subsequent MSIs and showed changes in duration of training preparations, but little change in starts per 100 training days or probability of placing in each start. MSIs in racing horses were less likely to be reported on the day of a race than at other times in the training preparation for all ages except 2-year-olds.     

Repeated handling of pigs during rearing. I. Refusal of contact by the handler and reactivity to familiar and unfamiliar humans

Pigs housed in groups received different handling treatments for 40 d until slaughter age. Pigs of the human interaction (HI) and refusal of contact (RC) groups were individually introduced into a pen each day, where they remained for 3 min in the presence of a squatted handler. The handler tried to increase progressively physical reciprocal interactions with the HI pigs using eye and body contact and voice. The handler remained immobile and avoided eye contact and use of voice with RC pigs. These pigs were pushed away when they touched the handler. Control pigs remained in their home pens. Over sessions, HI pigs progressively increased physical interactions with the handler, up to 35% of their time. The RC pigs were motivated to interact with the handler as they tried to establish physical contact with the handler throughout the experiment. They increased levels of locomotion, rubbing, immobility, and snout contact with the wall, suggesting that they were frustrated by the refusal of contact. At the end of the experimental period, all pigs were subjected to three human exposure tests, where pigs were exposed to the handler and two other persons, one of which was unfamiliar, in a Latin square design. During this test, behavior of the humans was the same as for the RC treatment. The HI pigs discriminated between the handler and the other persons as indicated by their increased approach behavior towards the handler. Part of the prior handling experience was generalized to other humans as indicated by higher levels of proximity of HI and RC pigs with the different persons compared with controls. Physical contact with the human was associated with increased heart rates. Two possibilities are that these two characteristics are part of a general behavioral/physiological reactive profile, or that contact with humans provokes an arousal or emotional response. Despite this, behavioral data show that pigs are motivated to be in physical contact with a handler, even when the handler consistently refuses contact.     

Preliminary Examination of Farriery and Hoof Care Practices and Owner-Reported Injuries in Sport Horses in New Zealand

Retrospective management and owner-reported injury data, and measurement of forelimb hoof conformation, were collected via a cross-sectional survey from a convenience sample of 96 registered show jumping (n = 67) and dressage (n = 29) horses. Most of the horses were medium- to upper-level performers, aged 9 (interquartile range [IQR] 7–12) years, and in the current rider's ownership for 28 (IQR 12–60) months. The horses were trained 45 (IQR 35–60) minutes, 6 days per week, on a sand or sand mix arena. Failure to train for ≥7 days was reported in 26 of 96 horses, generally associated with lameness diagnosed by a veterinarian (16/29), with a median time-off of 26 (IQR 14–93) days. During the preceding 12 months, 33% of the riders had been working with the farrier on hoof-related issues, 30% of which had involved ≤2 issues. This remedial work often involved a veterinarian (14/30) or allied health practitioner (6/30). Most horses were hot shod (67/89) with conventional fullered shoes. Uneven feet were identified in 16 of 89 horses but were not positively associated with inability to train, possibly reflecting the minor variation between feet. Uneven feet were associated with variation in heel length and angle measurements and a greater sole length and reduced sole width, rather than smaller and boxy. Multiple correspondence plots identified an association of uneven feet with the dressage horses rather than show jumping horses.     

Endoscopic findings of the stomach in pleasure horses in Poland

Background

This study was performed to determine the prevalence of ulcers in the gastric squamous and glandular mucosa in Polish pleasure horses.

Study design

Medical records from gastroscopic examinations of 108 pleasure horses of different breeds were reviewed. The study population consisted of two groups; group I (n = 48) with horses that expressed mild clinical signs of gastric ulcer syndrome (EGUS) including poor appetite, slight weight loss or poor body condition, and group II (n = 60) with horses that had no signs of gastrointestinal problems. The age range was 4–10 years, including 5 males, 34 castrated males (geldings) and 69 mares. The prevalence, distribution and severity of gastric ulcers were recorded. Lesions involving the squamous mucosa and the glandular mucosa of the antrum and pylorus were graded and compared between groups.

Results

Significant difference was found in the presence and severity of gastric ulcers between the two groups of horses. The overall prevalence of gastric ulcers in the first group of horses (n = 48) was 59% while in the group of clinically healthy horses (n = 60) the prevalence of gastric lesion was 40% (P = 0.004). Almost 19% of horses from group I had between 6–10 lesions (EGUS score III) and nearly 19% had either >10 localized lesions or very large diffuse lesions (EGUS number score IV). The number of ulcerations in affected horses were significantly lower in group II compared to group I (P = 0.016) as 10% of horses had 6–10 lesions (EGUS number score III) and nearly 14% had either >10 localized lesions or very large diffuse lesions (EGUS number score IV). Gastroscopy revealed that nearly 32% of horses from the second group had an ulceration EGUS score ≥ II.

Discussion and conclusions

This study confirms that gastric ulcerations can be prevalent in apparently clinically normal pleasure horses and a complete gastroscopic examination including the examination of the pylorus is advisable to evaluate this syndrome.     

Effect of Mineral Block Supplementation on In Vivo Digestibility and In Vitro Gas Production With Equine Fecal Bacteria

The effects of a mineral block for horses on in vivo digestibility and in vitro fermentability with equine fecal inoculum were evaluated. Fifty healthy horses from three groups (lactating mares n = 19, working horses n = 18, and maintenance horses n = 13) were randomly assigned to two treatment groups (with or without the mineral block; Ca 10.0%, P 12.0%, Zn 12.1 mg/kg, Cu 2,050 mg/kg, Mn 4,050 mg/kg, Se 30 mg/kg, and I 105 mg/kg). Dry matter digestibility was estimated with an internal marker. Samples of diet were incubated with equine fecal bacteria with varying amounts of mineral block (0, 1.1, 3.6, and 6.2 mg/g dry matter [DM]) to record gas production and to estimate in vitro DM digestibility. The results showed that mineral supplementation with the blocks increased in vivo DM digestibility (P < .01) in all groups, but there was an interaction (P < .01) with a greater response in the maintenance horses (55.5% vs. 78.0%) compared to lactating mares (62.8% vs. 79.6%) and working (70.3% vs. 75.1%). Block consumption was lowest in the lactating mares (12.8 g/d), intermediate in the working horses (44.6 g/d), and highest in the maintenance horses (74.2 g/d). The mineral supplementation did not affect the kinetics of gas production but tended (P = .10) to improve the in vitro DM digestibility (37.01% vs. 38.34%). Mineral block supplementation increased dry matter digestibility in horses. The unsupplemented control diet was deficient in several minerals, and block intake was not proportional to the mineral requirements.     

Horses Seropositive for Neospora spp.: Immunoglobulins,Cytokines, and C-Reactive Protein Levels

Neosporosis is a disease known to cause reproductive problems in cattle. In horses, the disease is caused by the protozoa Neospora caninum and/or Neospora hughesi, but little is known about this infection in this species. Therefore, the aim of this study was to quantify the levels of immunoglobulins (Igs), cytokines, and acute phase protein in seropositive horses for Neospora spp. (n = 23) comparing with seronegative horses (n = 20). There was no significant difference (P > .05) between IgG levels; however, IgM levels were significantly higher in sera samples from positive animals (P < .01). Similarly, proinflammatory cytokines (tumor necrosis factor, interferon gamma, interleukins [IL-1, IL-4, and IL-6]) and C-reactive protein levels were also significantly higher (P < .01) in horses seropositive for Neospora spp. On the other hand, the IL-10 levels (anti-inflammatory cytokine) were lower in horses seropositive for neosporosis (P < .01). Therefore, we conclude that horses naturally infected by Neospora spp., even without clinical disease, are able to activate their immune systems to control the infection, which may lead to disease chronicity.     

Prevalence of Ocular Disorders in an Indian Population of Horses

The objective of this clinical study was to report the prevalence of ocular disorders in a large population of horses from the Indian army. Both eyes of 500 horses were examined using a direct ophthalmoscope and by a transillumination procedure. Intraocular pressures were measured in several study horses. Fluorescein dye, Schirmer tear test, and menace testing were performed when indicated. Corneal culture swabs were collected from horses affected with corneal ulcers found on ophthalmoscopic examination. A total of 100 horses were found to be affected with some form of ocular disorder. The eye problems recorded were congenital eye lid disorders (2%) and included a subcutaneous cyst in the lower eye lid and slit in upper eye lid; conjunctivitis (12%); chronic interstitial keratitis (30%); a parasite in the anterior chamber (1%), which was however not removed for genus and species identification; phthisis bulbi (1%); uveitis (24%); glaucoma (13%); cataracts (3%); unilateral retinal hemorrhage (1%); luxation of cataractous lens (3%); posterior synechia (2%); and corneal ulceration (8%). Pseudomonas spp was the most common bacteria identified in horses affected with corneal ulceration. Vision-threatening ocular disorders are high in Indian army horses; this is a cause of major concern for the rider and the horse and, therefore, it is important to include ocular examination in horses as part of a routine and complete physical examination.     

Alveolar macrophage graded hemosiderin score from bronchoalveolar lavage in horses with exercise-induced pulmonary hemorrhage and controls

The objective of this study was to determine if a quantitative scoring system for evaluation of hemosiderin content of alveolar macrophages obtained by bronchoalevolar lavage provides a more sensitive test for the detection of exercise-induced pulmonary hemorrhage (EIPH) in horses than does endoscopy of the lower airways. A sample population composed of 74 Standardbred racehorses aged 2-5 years was used. Horses were grouped as either control (EIPH-negative) or EIPH-positive based on history and repeated postexertional endoscopic evaluation of the bronchial airways. Bronchoalveolar lavage was performed and cytocentrifuge slides were stained with Perl's Prussian blue. Alveolar macrophages were scored for hemosiderin content by a method described by Golde and associates to obtain the total hemosiderin score (THS). Test performance criteria were determined with a contingency table. All subjects had some degree of hemosiderin in the alveolar macrophages, regardless of group. The distribution of cells among the different grades followed a significantly different pattern for the control group versus horses with EIPH (P < .05). When using a THS of 75 as a cutoff point, the THS test was found to have a sensitivity of 94% and a specificity of 88%. The level of agreement beyond chance, between the EIPH status and the THS test result was very good (Cohen's kappa = 74%). The conclusion was made that careful assessment and scoring of alveolar macrophages for hemosiderin by means of the Golde scoring system shows promise as a more sensitive approach than repeated postexertional endoscopy alone to detect EIPH.     

Conflict Behavior in Show Jumping Horses: A Field Study

The study objective was to determine if there was a relationship between behavioral and physiological stress measures in sport horses and their performance. Nineteen horses competed in show jumping events (6 housed at the center and 13 transported), while 5 horses at home training served as controls. The competition horses were assigned to “light” (obstacles ≤100 cm) and “difficult” class (obstacles >100 cm). The conflict behaviors (CBs/min) in two rounds were calculated. Total faults were classified as “less faults” (≤one fault) or “more faults” (>one fault). Salivary cortisol concentration (SCC) before the first round (SCC-SP1), 20 minutes (SCC-SP2), and 60 minutes after the second round (SCC-SP3) was measured. The increase (SCC-in) and decrease (SCC-dec) in SCC were calculated. No effect of competition was found. Horses that waited longer for the second round had greater CB (P < .05). Conflict behavior was more frequent in horses from the “more faults” (P = .05) and “difficult” (a tendency; P = .06) classes. No correlation of CB with SCC was found. SCC-SP2 was greater in “more faults” (P < .01) and “transported” (P < .01) horses. Competition increased the SCC (P < .05), whereas SCC-SP2 was greater in less successful horses (P < .05). Transported horses and horses with more faults had the greatest SCC-SP2 and SCC-dec (P < .05). Our results suggest that horses which presented stress response were also less successful in competition. The adoption of effective methods to reduce transport and competition stress could enhance welfare and performance of sport horses during competition.     

Comparison of Caudal Epidural Anesthesia with Lidocaine-distilled Water and Lidocaine-MgSO4 Mixture in Horses

This study was performed to compare the onset and duration of analgesia produced by either a lidocaine−MgSO₄ or lidocaine−distilled water combination administration in the caudal epidural space of horse. Seven healthy adult horses, aged 11.7 ± 1.4 years (mean ± SD), body weight (kg) 567 ± 32.5 (mean ± SD), were selected for this study. Caudal epidural anesthesia was produced in all horses by administering 2% lidocaine (0.22 mg/kg) diluted in 1 mL distilled water and repeated with 2% lidocaine (0.22 mg/kg) diluted in 1 mL 10% MgSO₄ 2 weeks later. Time to onset (minutes), duration (minutes), and cranial spread of epidural analgesia were recorded. Heart rate (HR), respiratory rate (RR), and body temperature (°C) were recorded. Measurements were taken at 0 (as a baseline value before epidural administrations) and at 5, 10, 15, 30, 60, and 75 minutes after the epidural administrations of each treatment. Statistical analyses included paired Student t test and analysis of variance (computer program SPSS, Analytical Software, version 15.00). Statistical significance was set at P < .05. Onset of analgesia was significantly different (P < .001) between lidocaine-distilled water (2.38 ± 0.47 minutes) and lidocaine−MgSO₄ (4.62 ± 0.54 minutes). Duration of analgesia after lidocaine−MgSO₄ (186.0 ± 7.0 minutes) was longer than lidocaine-distilled water (54.5 ± 7.3 minutes). No significant differences were recorded for HR, RR, and body temperature in comparison with baseline values for each group. Using the lidocaine−MgSO₄ combination for obstetric and surgical procedures could commence relatively soon after epidural injection and could be completed without readministration of anesthetic agent.     

A survey of feeding,management and faecal pH of Thoroughbred racehorses in the North Island of New Zealand

AIM: To identify feeding and management variables associated with variation in faecal pH within a population of intensively managed Thoroughbred racehorses in New Zealand.

METHODS: A cross-sectional survey was conducted of 16 racehorse trainers in the North Island of New Zealand. Interviews were conducted at the trainers' stables to obtain information on feeding and management of horses, and faecal samples were collected and faecal pH measured.

RESULTS: Ninety-seven percent of the horses surveyed were confined in an area ≤5 × 5 m for ≥12 h/day. Trainer's age, number of years they had trained horses, age and gender of horses, weeks in race training, racing class, frequency of feeding, bedding type, and exercise workload had no effect on mean faecal pH. Acidic faecal pH (pH ≤6.32) was associated with stables with ≤12 horses, and trainers at stables with ≤12 horses offered more concentrate feed than those at stables with >12 horses. Acidic faecal pH was associated with trainers who offered 4 kg of grain as the only form of concentrate fed, or offered ≤2.25 kg hay/day. Horses that displayed stable vices had less acidic faecal pH than horses that did not display stable vices, viz pH 6.70 (standard error of the mean (SEM) 0.135) vs 6.43 (SEM 0.029) (p=0.04).

CONCLUSIONS AND CLINICAL RELEVANCE: Racehorse management in New Zealand is similar to that observed in other major racing countries. Trainers with ≤12 horses fed more concentrates and their horses had lower faecal pH than those of trainers with >12 horses. Irrespective of management system, it appears important to provide at least 2.25 kg of hay/day ad libitum, to buffer hindgut acidosis associated with diets high in soluble carbohydrate.     

Enhanced or Reduced Fetal Growth Induced by Embryo Transfer Into Smaller or Larger Breeds Alters Postnatal Growth and Metabolism in Weaned Horses

Embryo transfer between breeds of different sizes impacts fetal growth in horses. We have shown that it elicits various postnatal adaptations in terms of growth and glucose metabolism until weaning. Postweaning effects remain to be described. Pony (P), saddlebred (S), and draft (D) horses were used. Control Pony-in-Pony (P-P; n = 21) and Saddlebred-in-Saddlebred (S-S; n = 28) pregnancies were obtained by artificial insemination. Enhanced and restricted pregnancies were obtained by transferring P or S embryos into D mares (Pony-in-Draft [P-D], n = 6 and Saddlebred-in-Draft [S-D], n = 8) and S embryos into P mares (Saddlebred-in-Pony [S-P], n = 6), respectively. Control and experimental foals were raised by their dams and recipient mothers, respectively and weaned on day 180. Weight gain, growth hormones, and glucose metabolism were investigated in foals between days 180 and 540. Pony-in-Draft (P-D) remained heavier than P-P on days 180, 360, and 540, with lower glucose and higher non-esterified fatty-acids on days 180, 360, and 540 and higher T₃ on day 180. Insulin sensitivity was similar between pony groups on days 200 and 540. S-P were lighter than S-D on day 180 but caught up by day 540. S-P had higher glucose than S-D on days 180, 360, and 540, as well as lower non-esterified fatty-acids and higher T₃ on day 180. Insulin sensitivity was higher in S-P than in S-D on day 200. No difference was observed between saddlebred groups thereafter. In conclusion, in horses, fetal growth is determinant for postnatal metabolism, especially for energy availability.     

Dry Matter Intake,Body Weight,and Body Condition Scores of Blanketed and Nonblanketed Horses in the Upper Midwest

Thermoregulation is an energy-expensive process, which can be mitigated by blanketing horses in cold climates, potentially preventing weight loss or leading to decreased feed intake. The objective of this study was to evaluate feed intake, body weight (BW), and body condition scores (BCSs) in blanketed and nonblanketed horses. In October 2019, 16 mature adult horses were blocked by breed and BCS and randomly assigned to a blanketed (n = 8) or nonblanketed (n = 8) treatment; blankets were placed. Data were collected in December 2019 and January 2020 in River Falls, Wisconsin. During the study, horses were housed in dry lots and fed grass-legume mixed round bales. At the start of each trial period, BW and BCSs of horses were taken, hay cores were taken for nutritive analysis, and hay bales were weighed. Hay waste was collected daily, and when hay could no longer be consumed ad libitum, the remaining hay was removed from both pens (orts) and new bales were fed. Hay waste and orts were dried and daily dry matter intake was estimated as the difference between hay provided minus hay waste and orts during the trial period divided by the total BW of the pen. The average bale weight, forage nutritive value, BW, and BCS did not differ across treatment groups (P ≥ .05). However, the daily dry matter intake differed (P ≤ .05) at 2.31% BW for blanketed horses and 2.51% BW for nonblanketed horses. These results suggest blanketed horses conserve energy leading to decreased feed intake.     

Aminophylline Affects Glycemia Control and Increases Anaerobic Glycolysis in Horses during Incremental Exercise

A study was conducted on the effects of acute administration of aminophylline on physiological variables in purebred Arabian horses submitted to incremental exercise test. Twelve horses were submitted to two physical tests separated by a 10-day interval in a crossover study. These horses were divided into two groups: control (C, n = 12) and aminophylline (AM, n = 12). The drug at 10 mg/kg body weight or saline was given intravenously, 30 minutes before the incremental exercise test. The treadmill exercise test consisted of an initial warmup followed by gradually increasing physical exigency. Blood samples were assayed for lactic acid, glucose, and insulin. Maximal lactic acidemia was greater (P = .0238) in the AM group. Both V₂ and V₄ (velocities at which lactate concentrations were 2 and 4 mmol/L, respectively) were reduced in the AM group by 15.85% (P = .0402) and 17.76% (P = .0109), respectively. At rest as well as at 4 minutes, insulinemia was greater in the AM group (P = .0417 and .0393). Glycemia was statistically lower in the AM group at times 8 (P = .0138) and 10 minutes (P = .0432). Use of aminophylline in horses during incremental exercise does not seem to be beneficial, because this drug has a tendency to cause hypoglycemia and to increase dependence on anaerobic glucose metabolism.     

Prevalence of Surra among camels and horses in Jordan

The prevalence of Trypanosoma evansi infection among camels and horses in Jordan was studied using thick blood smears and inoculation techniques with mice and rats. A total of 437 camels and 83 horses from four climatic zones were surveyed. In addition, 40 donkeys, 32 cattle and 35 goats in contact with infected camels and horses were also tested in the same way. Clinical disease was evident in 8.2% of the camels (36 out of 437) and in 9.6% of the horses (8 out of 83). Infection was limited only to the Sweama area on the Dead Sea (within the warm desert-climatic zone), with prevalence of 30.5% and 33.3%, respectively, for camels and horses. Donkeys, cattle and goats examined were all free from T. evansi. Clinically affected camels were positive by both, thick blood smear and mouse and rat inoculations. Rat and mouse inoculations revealed (X²=3.2, df=1, exact p=0.07) greater number of positive cases in horses than those revealed by thick blood smears. T. evansi-infected camels and horses showed all the clinical signs known for Surra. In addition, it was observed that 100% of infected camels stared at the sun.