Journal of Equine Veterinary Science最新文献

This study aimed to evaluate changes in body temperature in athletic horses during two different road transport distances. Six Italian Saddle horses were subjected to a 100 and 300 km transport during different times of day (am and pm). Rectal and cutaneous temperatures were recorded before (T0), immediately (following 5 min- T1) and 1 hour (T2) after transport by means of a rectal digital thermometer and a thermal infrared camera (FLIR T440) respectively, for the evaluation of left and right side of four body regions: jugular, shoulder, croup and inner thigh. There were no differences between left and right sides, inner thigh or rectal temperatures when comparing the transport distance, time points or time of day. At T0, jugular (P < 0.0001), shoulder (P < 0.01) and croup (P < 0.01) average temperatures were higher in the pm compared to those in the am in both journeys. At T1, jugular (P < 0.01) and croup (P < 0.01) temperatures were lower in the pm compared to am following the 300 km journey. Jugular temperature (P < 0.0001) was higher following the 300 km compared to the 100 km journey at each time point (T1 and T2) at both times of day (am and pm). Shoulder (P < 0.0001) and croup temperatures (P < 0.0001) were higher at T2 after the 300 km journey than at T2 after the 100 km journey). The current results suggested a difference between the two distances and the time of day appeared to have as great effect on ocular temperature as road transport distance

Intracytoplasmic sperm injection (ICSI) in horses is currently employed for clinical and commercial uses, but the protocol could be optimized to improve its efficiency. We have hypothesized that destabilization of plasma and acrosomal membranes prior to injection would positively impact the developmental potential of equine zygotes generated by ICSI. This study evaluated effects of the sperm treatment with lysolecithin on plasma and acrosomal membranes and on oocyte activation ability, initially following heterologous ICSI on bovine oocytes and subsequently employing equine oocytes. The effects of the lysolecithin -treatment on the efficiency of conventional and piezo-assisted equine ICSI were evaluated. To do this, the equine sperm were treated with different concentrations of lysolecithin and the sperm plasma membrane, acrosome and DNA integrity were evaluated by flow cytometry. The results showed that a lysolecithin concentration of 0.08 % destabilized the membranes of all sperm and affected DNA integrity within the range described for the species (8–30 %). In addition, the heterologous ICSI assay showed that lysolecithin treatment was detrimental to the sperm's ability to activate the oocyte, therefore, chemical oocyte activation was used after equine ICSI after injection with lysolecithin -treated sperm. This group showed similar developmental rate to the control group with and without exogenous activation. In conclusion, lysolecithin pre-treatment is not necessary when using ICSI to produce equine embryos in vitro. The results from the current study provide additional insight regarding the factors impacting ICSI in horses.

Rhodococcus equi (R. equi), a gram-positive facultative intracellular pathogen, is a common cause of pneumonia in foals and represents a major cause of disease and death. The aim of the present study was to investigate the time-depended changes in White Blood Cells (WBC), basophils (Baso), neutrophils (Neu), lymphocytes (Lymf), monocytes (Mon), eosinophils (Eos), platelet (PLT) counts, fibrinogen (Fbg) concentration, interferon (IFN-α, IFN-γ) and interleukins (IL-2 and IL-10) in foals with clinical R. equi pneumonia. The main treatment was with azithromycin-rifampicin for 14 days. Blood was sampled prior to, 7 and 14 days after starting therapy. Treatment was associated with significantly decreased counts of WBC, (25.6 ± 6.7 and 14.2 ± 2,7 × 10³/ml), Neu (18.6 ±6.2 and 10.7 ± 3.1 × 10³/ml), Mon (1.5 ± 0.5 and 0.9 ± 0.2 × 10³/ml) and Fbg (539 ± 124 and 287 ± 26 g/dl) between day 0 and day 14. IL-2 and IL-10 concentrations were significantly increased (P = 0.028, P = 0.013, respectively) after treatment, whereas IFN-α and IFN-γ concentrations were not. The diagnostic potentials of INF-α, INF-γ, IL-2 and IL-10 per se seems not very high, however, the study suggests that the activity change of selected interleukins in the course of the disease may be associated with amelioration. We concluded that patterns of serum concentration changes of INF-α, INF-γ, IL-2 and IL-10 may help in the study of the innate immune response in foals during infection and treatment of R. equi pneumonia.

A Quarter horse filly was evaluated for a two-week old wound of the right hind cannon bone after the mare stepped on her. A sequestrum was noted radiographically and was surgically debrided. After continued follow-up a left hind varus deformity was noted and was corrected with a lateral transphyseal screw in the distal left tibia. After the varus deformity was improved, a lateromedial radiograph was taken of the distal left tibia and tarsus and talocalcaneal subluxation was seen. The same view was taken of the right tarsus and the same deformity was noted. After finding no case reports on the condition with information on treatment or surgical correction, humane euthanasia was elected. A few months later, the same owner brought a two-month-old colt out of the same mare to the hospital for an elective procedure. Tarsal radiographs were taken due to the owner's previous experience, although the colt had no clinical history or any traumatic incidents. A lateromedial view of the right tarsus revealed talocalcaneal subluxation.

The Polo Argentino (PA) horse is a recognized breed, developed originally by mixing crossbred and Thoroughbred (TB) horses to play polo. Early PA selection is difficult due to unreliable performance estimations. This study investigated the usefulness of genomic markers previously linked to morphological and functional traits as a tool for the early selection of PA. To this, we genotyped 520 PA and 30 TB horses using the Equine GGPArray (Illumina, n = 71,778 SNPs). Analyses included a genetic characterization of six genetic markers associated with behavioral (DRD4), muscular development (MSTN), and body size (LCORL, HMGA6, ZFAT, and LASP1) genes. Genetic differences in the DRD4, MSTN, and LCORL SNP were found between the two breeds, in the last two F_ST index between breeds was 0.13 and 0.6, respectively (p < 0.01). In DRD4, G allele was the more prevalent in PA (0.56 vs 0.45 in TB, p < 0.05), but no differences were observed between the genotypes associated with phenotypes. In MSTN, heterozygous genotypes were the most common in PA (48 %), with a significant decrease in AA (Hardy-Weinberg p < 0.05), suggesting a negative selection against it in polo horses. In body size, HMGA2 was monomorphic in all horses, while ZFAT and LASP1 SNP showed higher variability. Interestingly, 99 % of PA showed a TT genotype in LCORL (only 66 % in TB), demonstrating selection for smaller horses. Our results suggest that empirical selection in PA has generated an incipient genomic differentiation in discrete traits which could be used as a marker-assisted selection tool for early selection of polo horses.

The motor development of 14 healthy foals was observed using continuous video-recording from birth to 24 h of age. An ethogram was made of behaviours of interest with behaviour quantification using CowLog software. Behaviours were divided into six main classes: main activities, attempts to get up or lie down, nursing, playing and other skills, being helped by a human, and the foal not being visible. First-time behaviours (mean, range) of early motor development after birth included going into sternal position (5.4 min, 0-34.5 min), attempting to get up (7.6 min, 0.5-34.6 min), successfully getting up (56.4 min, 27.7 min - 1 h 43.3 min), walking (1 h 1.9 min, 28.1 min - 1 h 43.4 min), nursing (1 h 49.1 min, 1 h 10.3 min - 2 h 29.7 min), shaking (31.9 min, 0.2 min - 2 h 32.7 min), running (2 h 55.6 min, 1h 33.2 min - 6 h 12.1 min), walking backwards (4 h 12.8 min, 56.9 min - 12 h 50.6 min), frolicking (4 h 52.5 min, 2 h 3 min - 15 h 18.8 min), and autogrooming (7 h 30.3 min, 43.3 min - 14 h 40.1 min). All foals made several attempts before they were able to get up for the first time (61.9, 14-103). During the first 24 h the overall duration of lying down was highest, followed by standing and walking. This information adds to the basic information for assessing normal motor development in these animals, with the potential to identify delayed development.

Ultrasonographic imaging of the diaphragm is a non-invasive alternative for respiratory function evaluation in horses. This study aimed to measure diaphragm thickness, thickening (change in thickness with contraction) and thickening fraction in healthy adult horses during tidal breathing and forced vital capacity. Correlation between body weight (≤400 kg and >400 kg) and diaphragm thickness was investigated. To that purpose, 20 adult horses, weight 409±50 kg, height 1.47±0.05 m, and age 16±6 years were included in the study. Diaphragm thickness was measured at end-inspiration and end-expiration using B-mode and M-mode. The transducer was placed in the 10th, 11th and 12th intercostal spaces of both hemithoraces. Measurements obtained at end inspiration using M-mode during forced vital capacity were greater than for tidal breathing for diaphragm thickness (P=0.006), diaphragm thickening (P<0.001) and thickening fraction (P<0.001). The same was found for thickening (P<0.001) and thickening fraction (P<0.001). Diaphragm thickness at end-inspiration was greater in horses weighing >400kg than those ≤400kg at the inspiration (0.93±0.2 cm and 0.74±0 0.02 cm, P<0.001) and at the end of expiration (0.77±0.02 cm and 0.63±0, 02 cm, P<0.001). There was no difference in thickening fraction between horses weighing ≤400kg and >400kg (tidal breathing: 18±2 % and 16±2 %, P=0.609; forced vital capacity: 39±6 % and 31±5 %, P=0.301). Diaphragm assessment in horses is possible using both B-mode and M-mode. Breathing workload has a positive correlation between breathing workload and diaphragm contraction. Due to the relationship demonstrated between diaphragm thickness and weight, it is recommended that diaphragm thickening fraction is used to compare diaphragm measurements between horses.

The reproductive features of equine leptospirosis are often neglected. Equine genital leptospirosis is characterized as a silent chronic syndrome, and besides abortions, leads to placental abnormalities, stillbirths, and birth of weak foals. This study aimed to study the occurrence of placental abnormalities associated with Leptospira interrogans infection in naturally infected mares under field conditions. The studied herd had a high occurrence of placentitis and abortions. Ten pregnant mares, eight with placental abnormalities on ultrasonography and were selected. Serum and cervicovaginal mucus (CVM) samples were collected for serology and PCR, respectively. Positive samples in lipL32-PCR were submitted to the sequencing of the secY gene. In lipL32-PCR of CVM, five out of 10 (50%) mares were positive and all were characterized as Leptospira interrogans. Our results highlight the presence of placental abnormalities in the reproductive subclinical leptospirosis syndrome. We encourage field veterinarians to include leptospirosis testing in their reproductive management.

Anise has demonstrated equine palatability but its olfactory effect is underexplored. The objective was to investigate the effect of the aroma of anise on consumptive behavior. Stock-type horses (n = 8) were used in a crossover 6-day preference test. Palatability stocks were utilized. Bowls containing oats were situated on plates holding gauze soaked with 0.375 ml of anise or corn oil (control). Variables included first diet sniffed (FS), first consumed (FC), first action (FA), and amount consumed (AC). Each trial was video-recorded. Behavior data were analyzed using chi square and Kruskal-Wallis tests. FS and FC were elevated for anise treatment (P = 0.02; P = 0.04). For FA, sniffing was more frequent versus consuming (P < 0.01). AC for anise was twice the daily average of control (P < 0.01). Data represents an important relationship between olfactory stimuli and feeding in horses. To determine thresholds, more work is needed.