Erythrocyte Osmotic Fragility and Hematological Responses of Horses Administered Ascorbic Acid and Exposed to Road Transportation

The experiment was performed to evaluate the ameliorative effect of ascorbic acid (AA) on some hematological parameters and erythrocyte osmotic fragility (EOF) in horses transported by road. A total of 14 horses, consisting of seven experimental and seven control horses, were used for the experiment. Before the transportation, blood samples were obtained by jugular venipuncture from all the horses. Experimental horses were administered with AA (200 mg/kg dissolved in 20 mL of distilled water per os), whereas the control horses were given 20 mL of distilled water per os. Thereafter, the animals were transported for 6 hours and blood samples collected after transportation. Packed cell volume and hemoglobin concentration were higher (P < .05) in experimental than the control group, whereas total leukocytes reduced significantly (P < .05) in experimental in comparison with the control horses. Lymphocyte, neutrophil counts, neutrophil/lymphocyte ratio, and total protein decreased in experimental horses in comparison with control, but they were not significant (P > .05). Erythrocyte osmotic fragility was lower in experimental than the control at 0.3% NaCl concentration (P < .05). The result of the present study revealed that AA ameliorated changes in hematological parameters and EOF induced by road transport stress, partly because of its antioxidant properties.     

Heart rate variability parameters as markers of the adaptation to a sealed environment (a hypoxic normobaric chamber) in the horse

Simulated hypoxic normobaric devices have been used in human beings in order to enhance endurance capacity. These devices are sealed chambers where the athletes are supposed to stay for at least 6–8 hr daily. The current research assesses the changes in time‐domain, spectral and non‐geometrical heart rate variability (HRV) parameters in 6 horses subjected to progressive duration periods inside of a hermetically sealed chamber. It was pursued, firstly to evaluate the intensity of the stress experienced by the animals and secondly to elucidate whether the horses might require an acclimation period before implementation of hypoxic conditions. HRV parameters were monitored for 6 days: day 0 (6‐hr duration; in paddocks; basal conditions), and days 1, 2, 3, 4 and 5 (1, 2, 3, 4 and 6 hr inside the chamber every day respectively). During day 1 and during the first hours of days 2 and 3, compared to day 0, horses presented increased HR and SDHR values and decreased RR interval duration. SD1 values decreased on some hours of days 2 and 3, but differences with day 0 were not found on day 1. Increased SDNN, RMSSD, SD1 and SD2 values were observed on days 4 and 5. These results showed an activation of the sympathetic activity together with an attenuation of the parasympathetic activity during the days 1 to 3. Increased parasympathetic activity was found only during the first hours of days 4 and 5. Spectral parameters experienced minor variations, with increased LF_peak and LF% during some hours of days 4 and 5. In conclusion, at least 3 days are needed to adapt the horse to a sealed environment before starting to subject the animals to hypoxic conditions. When the horses were acclimatized, however, a minor stress was detected with they spent more than 4 hr inside of the chamber.     

The Influence of Stable Management and Feeding Practices on the Abnormal Behaviors Among Stabled Horses in Malaysia

The present study aimed to provide preliminary data on the prevalence of oral stereotypic, locomotory stereotypic, and redirected behaviors as well as their associations with stable management and feeding practices. In this cross-sectional study, a total of 207 working horses used for leisure riding, equestrian sport, polo, endurance, and patrolling were selected from seven equine facilities. Data on the stable management and feeding practices were obtained through the stable records, interviews, and on-site monitoring visits, whereas the prevalence of abnormal behaviors in the studied population was determined using the instantaneous scan sampling method. Most horses in the present study worked for more than 8 hours per week (n = 93). In addition, more horses were fed three times per day (n = 65) with different amounts of hay, concentrate, and chaff. Among the study population, oral stereotypic behaviors had the highest prevalence (n = 281; 54%), followed by redirected behavior (n = 181; 34%), and locomotory stereotypic behaviors had the lowest prevalence (n = 63; 12%). The oral stereotypic behavior was found to be significantly influenced (P < .05) by the working hours, amount of hay, and amount of concentrate. Both locomotory stereotypic and redirected behaviors were found to be influenced (P < .05) by the number of feedings per day and the amount of hay. In summary, the present study has proven that the stable management and feeding practices could influence the prevalence of different abnormal behaviors in the majority of working horses, with oral stereotypy being the most common abnormal behavior in this country.     

Trimming and Re-shoeing Results in More Steps per Day and More Time Spent Lying per Day

To examine the impact of trimming and re-shoeing on behavior, light horse geldings (3–21 year-old Quarter Horse, Dutch Warmblood, or Thoroughbred) were fitted with three-axis accelerometers (IceTag, Ice Robotics, Edinburgh, Scotland) on the left rear limb. Boots were placed under the accelerometer, and both were removed daily for approximately 1 hour while horses were stalled for morning feeding to examine the horses’ limb. After a two-day adaptation period and five days of activity tracking, horses were treated by having shoes removed, feet trimmed, and new shoes fitted (re-shod; n = 3) or being handled but not trimmed or fitted with new shoes (sham; n = 4). Horse activity was monitored for five days after treatment. Steps per day, time spent lying per day, and the number of lying bouts were tested for effects of treatment, time (before or after treatment), and interaction of treatment by time using procedures for repeated measures with JMP Software (version 7, SAS Inst. Inc, Cary, NC). Means separation was performed using the Student’s t-test. There was a treatment by time interaction on time spent lying per day (P = .0447) and steps per day (P = .0501). Re-shod spent more time lying after treatment than before (121.4 ± 22.8 vs 66.8 ± 22.8 minutes per day, respectively). After treatment, re-shod also took more steps than sham (3499 ± 527 vs 3056 ± 456 steps per day, respectively). These results may indicate increased mental and physical comfort following trimming and re-shoeing in horses.     

A Proton-Pump Inhibitor Modifies the Concentration of Digestion Biomarkers in Healthy Horses

To determine the concentration of various blood biomarkers associated with digestion in healthy horses treated with different doses of omeprazole (OMPZ), four Arabian horses without gastric ulcers were selected and distributed in one factorial with four oral treatments (Control; OMPZ^BOLUS; OMPZ^4mg/kg; OMPZ^1mg/kg). Control did not receive any treatment. OMPZ^BOLUS were given 4 mg/kg of omeprazole in a single dose on the day before blood sampling. In the OMPZ^4mg/kg and OMPZ^1mg/kg treatments, horses were treated over 11 days. All treatments were performed 16 hours before morning feeding. The “washout” period was 21 days between rounds. After an overnight fasting period, blood samples were collected from all animals (T1), after which the animals received supplementation, and blood samples were collected after 30 minutes (T2), 1.0 hours (T3), 1.5 hours (T4), 2.0 hours (T5), 3.0 hours (T6), 4.0 hours (T7), 5.0 hours (T8), 6.0 hours (T9), and 7.0 hours (T10). Blood samples were analyzed for total plasma protein (TPP), glucose, urea, creatinine, uric acid, cholesterol, triglycerides, calcium, phosphorus, and magnesium. The results showed differences between treatments for urea, cholesterol, uric acid; between phases for glucose; and between phase and treatment for creatinine, triglycerides, phosphorus, and magnesium; however, there was no difference for TPP and calcium between treatment and between phases. Oral administration of OMPZ in healthy equines interfered with the metabolism of digestion biomarkers of lipid, mineral, and protein metabolism, although the animals were treated for a maximum of 11 days. Horses treated with a proton-pump inhibitor need to be evaluated regularly to avoid significant modification in their metabolic parameters.     

Horses Could Perceive Riding Differently Depending on the Way They Express Poor Welfare in the Stable

This study investigated the relationships between four behavioral and postural indicators of a compromised welfare state in loose boxes (stereotypies, aggressive behaviors toward humans, withdrawn posture reflecting unresponsiveness to the environment, and alert posture indicating hypervigilance) and the way horses perceived riding. This perception was inferred using a survey completed by the usual riding instructor and during a standardized riding session (assessment of behaviors and postures, qualitative behavior assessment (QBA) and characterization of the horses’ locomotion using an inertial measurement unit). In accordance with ear and tail positions and the QBA, stereotypic and the most hypervigilant horses in loose boxes seemed to experience a more negative affective state during the riding session compared with nonstereotypic and less hypervigilant animals (P < .02 in all cases). Horses which were aggressive toward humans in loose boxes had higher scores regarding the occurrence of discomfort and defensive behaviors on the survey than nonaggressive horses (P = .03). They also presented higher dorsoventral accelerations at a canter during the riding session (P = .03), requiring the rider to increase his spinal movement (P = .005). These results suggest that aggressive horses may be harder to ride than nonaggressive animals. The expression of unresponsiveness to the environment in loose boxes was related to more reluctance to move forward, as assessed in the survey (P = .006). This study suggests that a compromised welfare state in the stable is related to horses having a more negative perception of riding. This perception could vary depending on the expression of poor welfare.     

Effects of different positions during transport on physiological and behavioral changes of horses

The aim of this study was to evaluate the effect of different transport positions on some physiological parameters in racehorses and their behavior patterns during and after the journey. Twelve horses made 3-hour journeys of 200 km on the same route, with the same driver, and in 3 different positions: facing forward, backward, and sideways in relation to the direction of travel. Physiological and behavioral parameters were registered before, during, and after the journey. Horses were checked at 5 different times: at rest (T0), at loading (T1), at unloading (T2), and at 2 (T3) and 4 (T4) hours after return from the journey. At each check, heart rate, respiratory rate, and rectal temperature were measured and blood samples were collected by jugular vein puncture to assess cortisol, packed cell volume, total protein, albumin, glucose, creatinine, triglycerides, cholesterol, urea, creatine kinase, lactate dehydrogenase, alanine transaminase, aspartate transaminase, alkaline phosphatase, calcium, phosphorus, and chlorine. Loading and unloading were filmed. Behavioral patterns were recorded by direct observation, during the travel, 2 and 4 hours after arrival in a new stall. The same parameters were recorded at the same times (excluding loading and unloading) in a control group that did not travel. All data were analyzed using a repeated-measures analysis (analysis of variance). Loading produced an increase of heart rate and packed cell volume in comparison with rest values. Horses facing in the direction of travel during journey made fewer forward, backward, and sideways movements than others, whereas horses traveling sideways lost their balance and touched the stall rails less frequently. Highest serum cortisol concentration value was recorded soon after unloading horses that had faced in the direction of travel (P < 0.01). Two hours after return, horses that had traveled sideways revealed an increase of creatine kinase (P < 0.01). The traveling position in the vehicle did not appear to affect postjourney behavior. In comparison with the control group, the horses that had traveled consumed concentrate faster, spent more time eating hay, and drank more frequently in the first 2 hours after return from the journey. Front-facing position led to an increase in serum cortisol concentration, whereas the sideways position caused some muscular tension, which disappeared 4 hours after the journey. Although facing backward was the travel position that provoked the greatest number of horses’ movements, it did not have a negative effect on physiological and behavioral parameters during and after the journey. We concluded that for Standardbred trotters accustomed to travel, the latter may be the less stressful position during a 200-km transport.     

Sex differences in the response of yearling horses to handling by unfamiliar humans

In adult horses, pronounced sex differences in behavior exist, and many riders prefer male horses to mares. In the present study, we tested the hypothesis that sex differences in the response of horses to handling emerge before puberty, that is, in sexually immature animals. Warm-blooded yearling horses (6 males and 9 females) were exposed to a stationary human test (exposure to an unfamiliar person for 5 minutes) and a tolerance test (haltering and direct contact with the horse) on 5 consecutive days. The horses' behavior and heart rate were recorded. Male yearling horses displayed significantly less exploratory behavior than females during the stationary human test on days 1 and 2 (P < 0.05). Latency to halter and ease with which horses could be haltered were significantly affected by day (P < 0.05), and a significant interaction of day and sex was detected (P < 0.05; e.g., time for haltering: females, day 1: 23.8 ± 7.8 seconds [±standard error of the mean] and day 5: 21.1 ± 1.7 seconds; males, day 1: 53.6 ± 10.4 seconds and day 5: 19.4 ± 2.2 seconds). Heart rate of the horses in response to the test situations was significantly affected by day (P < 0.01) but not by sex. In conclusion, sex differences in behavior do not only exist in adult horses but are already present in young horses before puberty. When exposed to unfamiliar humans for the first time, male yearling horses display more caution than females.     

Serum Amyloid A (SAA) Concentration after Vaccination in Horses and Mules

Serum amyloid A (SAA) is a sensitive acute-phase response (APR) marker in equids. Prominent APRs with elevations of SAA concentrations ([SAA]) have been reported after vaccination. The authors hypothesized that vaccination with an inactivated EHV-1/-4 vaccine would cause increase in [SAA] and antibody responses and that higher [SAA] would be positively correlated with the antibody titer in both equids. Twelve Haflinger horses and 12 mules were included in this longitudinal prospective study. All horses and mules were vaccinated with a commercially available EHV-1/-4 vaccine. Blood was sampled before and after vaccination to measure [SAA] and virus-neutralizing response (VN-T). In horses and mules, significantly higher [SAA] were measured on days 1, 3, and 5 after EHV-1/-4 vaccination; [SAA] on day 1 after vaccination were only measured in animals that developed fever, where mean [SAA] were significantly higher in horses than in mules (horses: 1,365.75 ± 87.64 mg/L, mules: 615.5 ± 153.444 mg/L) (P > .05). Four horses and 2 mules developed fever after vaccination, lasting for ≤24 hours. Increased antibody responses (VN-T) on days 7 and 14 after vaccination were observed in all animals, whereas mules showed higher overall antibody responses. Nevertheless, [SAA] did not correlate with the intensity of the antibody responses (VN-T) stimulated by the vaccine (P < .05). EHV-1/-4 vaccination caused a prominent APR, higher in horses than in mules, but [SAA] did not correlate with antibody responses. Measuring [SAA] after vaccination could help identify severe APRs that may require longer resting intervals before training or competition.     

Effects of Flunixin Meglumine,Firocoxib, and Meloxicam in Equines After Castration

This study is “aimed” to evaluate and compare the efficacy of flunixin meglumine (FM), firocoxib (FX), and meloxicam (MX) after castration of horses. Thirty horses were submitted to open castration and divided into three groups (n = 10) depending on the anti-inflammatory drug administered: group I (GI) (FM, 1.1 mg kg¹, IV, once a day [SID], 5 days); group II (GII) (FX, 0.1 mg kg¹, IV, SID, 5 days), and group III (GIII) (MX, 0.6 mg kg¹, IV, SID, 5 days). Clinical, behavioral, and hematological parameters and the peritoneal fluid (PF) were evaluated before (day [D] 0) and 1, 2, 3, 5, and 7 days afterward. In the postoperative, scores of limb rigidity and prepuce edema of animals of GII and GIII were greater than those of GI. Tachycardia was observed in the horses of GII and GIII and hyperthermia in GIII. An increase in the number of leukocytes, neutrophils, and monocytes without exceeding the reference values and hyperfibrinogenemia was observed in the animals of GI (D7), GII (D1-D7), and GIII (D7). There was reduction in serum protein after castration, together with an increase of this in the PF of the animals of the three groups. The PF on D0 was straw yellow and limpid, became reddish and cloudy on D1, and then gradually moved toward its normal color on the ensuing days, but without returning to normal on D7 in any of the groups. The results showed that castration triggers significant clinical and laboratory changes and that FM, FX, and MX are equally effective in controlling pain and inflammation in horses after castration; however, FM was more advantageous.     

An owner survey of toys,activities, and behavior problems in indoor cats

The objective of this study was to survey the owners regarding the frequency and duration of their daily interactions with their indoor cats, the provision of toys and activities by the cat owners, and the prevalence of 6 selected behavior problems (aggression to owner, aggression to visitors, periuria, inappropriate defecation, inter-household cat aggression, and intercat aggression to outdoor cats). The sample population was 277 clients from 5 veterinary practices who presented their domestic cat for anything except a behavior problem. The average number of toys and activities reported by owners per cat was 7, and the most common toys/activities used by owners in this survey were furry mice (64%), catnip toys (62%), and balls with bells (62%). A total of 78% of the owners reported that they leave the cat's toy(s) available all the time. All owners reported playing with their cat, whereas most owners (64%) played with their cat more than 2 times per day and reported play bout durations of 5 (33%) or 10 minutes (25%). Owners who reported play bout time of 5 minutes or more reported fewer behavioral problems than those with play bouts of 1 minute (P < 0.05). A total of 61% of the owners reported that their cat engaged in 1 or more of the 6 selected behavior problem(s), but only 54% of the owners who reported behavior problems in their cats reported that they had talked to their veterinarian about the problem. The 2 most frequently reported behavior problems were aggression to the owners (36%) and periuria (24%). Female cats were 50% less likely to be reported to have 1 or more behavior problems than males despite an equal sex distribution in the survey population (P < 0.05). The relationship between individual behavior problems and individual toys and activities was evaluated by use of a logistic stepwise regression. These findings are discussed as they relate to the understanding of behavioral needs of indoor-housed cats and the potential role of environmental enrichment in the home setting.     

The Effect of Hay Net Design on Rate of Forage Consumption When Feeding Adult Horses

Modern horse management systems tend to limit a horse's opportunity to forage. The objective of this experiment was to investigate the effect of hay net design on the rate of forage consumption when feeding horses. Eight adult horses were fed in individual stalls in a replicated Latin square design, with two horses per treatment per week. Horses were fed hay off the stall floor (control), or from one of three hay nets: large (15.2 cm openings), medium (4.4 cm openings), and small (3.2 cm openings). Horses had access to hay for two 4-hour periods each day. When horses could not consume all forage from the medium and small hay nets in 4 hours, a second study using a crossover design gave horses an unlimited amount of time to feed from the hay nets. Stopwatches were used to calculate time to consumption and dry matter intake rates (DMIR). Mean time to consumption was 3.1 and 3.4 hours for the control and large hay net, respectively, in study 1, and 5.1 and 6.5 hours for the medium and small hay nets, respectively, in study 2. Mean DMIR during the 4-hour feeding period were 1.5, 1.3, 1.1, and 0.9 kg/hr for the control, large, medium, and small hay nets, respectively; all treatments were different (P < .0001). These results demonstrate that hay nets were effective at decreasing the rate of forage consumption when feeding adult horses. Long-term studies are warranted to determine if horses will adapt to feeding from hay nets.     

Seroprevalence of Sarcocystis neurona and Its Association With Neurologic Disorders in Argentinean Horses

Equine protozoal myeloencephalitis (EPM) is generally caused by Sarcocystis neurona and can produce substantial economic losses on equine production in America. The aims of the present study were to evaluate the seroprevalence of S. neurona in the main horse-production area of Argentina and associate it with the occurrence of neurologic disorders. Serum samples were collected from 640 horses in nine Argentinean provinces. Most of the samples correspond to animals ≥1.5-year-old from different breeds (n = 628); 12 samples were from younger horses. Further seroprevalence comparison was conducted from the older animals grouped with (n = 148) or without neurologic signs (n = 480). Immunoblot: proteins from 2 × 10⁷S. neurona merozoites were used as antigen on each membrane. Reactivity to antigens with relative mobility of 7, 10, and 16 kDa was considered specific for antibodies against S. neurona; reactivity at 30 kDa was recorded separately. The overall seroprevalence for S. neurona was 26.1% (167/640), and all the provinces had positive horses. Seroprevalence of animals with neurologic signs was greater (P < .001) than what was observed in normal horses (39.2% vs. 22.1%), with an odds ratio of 2.27. Reactivity at 30 kDa was detected in 71% of all samples. This study identified a wide distribution of S. neurona–positive animals in Argentina and horses with neurologic signs having a greater seroprevalence than normal horses. Sarcocystis neurona infection should be considered for early differential diagnosis and treatment of animals with neurologic disorders to decrease the economic impact of EPM in Argentina.     

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.     

A prospective study on fitness,workload and reasons for premature training ends and temporary training breaks in two groups of riding horses

Little is known about wastage in riding horses and the factors like fitness and workload that may reduce injuries and maximise welfare. To evaluate fitness, workload and reasons for premature training ends (PTEs) and temporary training breaks (TTBs) during a nine week training period, two groups of riding horses were used: Group A consisting of 58 horses used for student equitation courses (32 with training prior to admission and 26 without) and Group B consisting of 26 horses owned by two riding schools (school-I and school-II). To assess fitness, all horses performed a standardised exercise test (SET) at the start (SET-I) and end of the training period (SET-II) measuring heart rate (HR bpm) and speed (m/s). In addition, all horses were monitored daily during the training period for their health and workload.In Group A, trained horses had significantly lower HRs in SET-I (P = 0.05) compared to untrained horses and in SET-II, trained horses tended to have lower HRs than untrained horses, though this was not statistically significant (P = 0.057). During the training period all horses received an identical workload. A total of 19.0% of Group A horses ended the training period prematurely for veterinary reasons (PTEV); of those untrained horses had earlier a PTEV in the training period (after 2.8 ± 1.3 weeks) than trained horses (after 4.1 ± 1.5 weeks, P = 0.030).In Group B, school-I and school-II horses did not differ significantly in fitness level nor in workload. More school-II horses ended the training period prematurely for veterinary reasons (n = 7; 70%) compared to school-I horses (n = 4; 25%, P = 0.032), although seven (63.6%) of these horses were still continuously used in riding lessons. In both groups (A and B), small injuries (without a temporary training break) were significantly associated with premature training ends for veterinary reasons later on: in Group A small injuries preceded 27.3% of the PTEVs (P = 0.005) and in Group B small injuries preceded 54.5% of the PTEVs (P = 0.030).In conclusion, as all horses in each subgroup had the same workload, the occurrence of PTEV seemed not associated with the workload. In Group A horses, level of fitness seems to be an important factor for the point in time injuries will occur during the training period. In all horses, injuries were more likely when a temporary training break was not taken following seemingly minor injuries. Since a lot of injured Group B horses were used in riding lessons against veterinary advice, this may indicate that riding school owners have different perception on welfare and if true this may cause serious welfare problems.     

Seroprevalence of Leishmania sp. Infection in Healthy Horses Housed in Endemic Areas in Tuscany

This study carried out an epidemiological survey of seroprevalence of positive immunofluorescence antibody test (IFAT) results for Leishmania infantum in horses living in Tuscany, where the disease in the dog is endemic and no cases of equine leishmaniasis were observed. Inclusion criteria were (1) horses housed for more than 2 years in endemic areas; (2) horses grazing 24 hours a day outside; and (3) horses living on farms where affected dogs were housed. Two blood samples each were collected from 277 horses from June to October 2011 (T1) and from December 2011 to February 2012 (T2), and IFAT was performed for L. infantum. A dermatologic examination was performed to detect the presence of skin lesions. No animals had skin abnormalities. At T1, 18 of 277 horses had positive results for IFAT, while at the second sampling (T2) 277 of 277 samples were negative. In conclusion, our seroprevalence is lower than that in Spain but higher than that in Greece. Our results suggest the presence of a transient humoral response to L. infantum in horses.     

The Effect of a Seaweed-Derived Calcium Supplement on Gastric Juice pH in the Horse

Low gastric pH for extended periods of time can increase the risk of gastric ulceration in horses. Therefore, nutritional interventions that buffer stomach acid may be helpful to decrease ulcer risk. The objective of this trial was to evaluate whether the incorporation of calcified Lithothamnion corallioides and Phymatolithon calcareum (Calmin; Celtic Sea Minerals, Cork, Ireland) into an equine ration would buffer equine gastric juice. Nine mature, Thoroughbred-cross horses, including 6 geldings and 3 mares (524 ± 49 kg) were housed in stalls and fed 2 kg/day of a texturized concentrate (Purina Omolene 100) and 1.5% BW grass hay/day. On testing days 0, 7, and 14, the horses received one of three pelleted dietary treatments (CON, MIN1 ×, MIN2 ×) in a randomized, crossover design. CON contained no added Calmin, MIN1 × provided Calmin at a 1 × concentration, and MIN2 × provided a 2 × dose. All horses underwent gastroscopy (Karl Storz, El Segundo, CA) prior to feeding the treatments, and at 2 and 4 hours postfeeding. Gastric juice was aspirated and pH measured using a benchtop pH meter (ThermoOrion pH Meter Model 410A). Overall, there was a significant time effect (P < .0001) with an increase in gastric juice pH from time 0 (2.31 ± 0.58) to 2 hours (5.52 ± 0.48) and 4 hours (3.59 ± 0.48). Gastric juice pH at 2 hours was higher (P = .0122) in MIN1 × (5.92 ± 0.58) and MIN2 × (5.92 ± 0.57) than CON (5.08 ± 0.58). These results demonstrate that adding Calmin to a meal increases buffering capacity at 2 hours postfeeding.     

The Effect of Feeding Two or Three Meals Per Day of Either Low or High Nonstructural Carbohydrate Concentrates on Postprandial Glucose and Insulin Concentrations in Horses

Eight mature idle gelding horses (mean body weight [BW], 558 ± 45 kg) were used in a replicated 2 × 2 Latin square design study. Horses received either two or three meals per day (MPD) for 7 days, of either a high (H; 43%; 215 g/100 kg BW) or low (L; 18%; 90 g/100 kg BW) nonstructural carbohydrate (NSC) concentrate feed to achieve four treatment groups: low NSC in two MPD (L2), low NSC in three MPD (L3), high NSC in two MPD (H2), and high NSC in three MPD (H3). On day 7 of the treatments, blood was collected before (baseline) and for 5 hours after feeding the morning meal (10, 20, 30, 40, 50, 60, 90, 120, 150, 180, 210, 240, 270, and 300 minutes after feeding). Baseline insulin concentrations tended (P = .093) to be higher for horses fed high NSC than low NSC, and horses fed two MPD tended (P = .092) to have higher baseline insulin concentrations than horses fed three MPD. In addition, baseline glucose-to-insulin ratio (GIR) was higher in horses fed high NSC compared with low NSC (P < .001). Horses fed high NSC had higher area under the curve of insulin and higher peak insulin after feeding than those fed low NSC. These findings suggest that NSC content of a concentrate feed has an impact on baseline insulin and GIRs and on postprandial insulin concentrations. Meanwhile, the number (and therefore size) of MPD had fewer impacts on glucose metabolism.