Effects of Starch Overload and Cecal Buffering on Fecal Microbiota of Horses.

Starch overload in horses causes gastrointestinal and metabolic disorders that are associated with microbiota changes. Therefore, we identified the fecal microbiota and hypothesized that intracecal injection of alkaline solution (buffer; Mg(OH)2 + Al(OH)3) could stabilize these microbiota and clinical changes in horses submitted to corn starch overload. Ten crossbred horses (females and geldings) were allocated to group I (water−saline and starch−buffer treatments) and group II (water−buffer and starch−saline treatments). Clinical signs, gross analysis of the feces, and fecal microbiota were evaluated through 72 h (T0; T8; T12; T24; T48; T72). Corn starch or water were administrated by nasogastric tube at T0, and the buffer injected into the cecum at T8 in starch−buffer and water−buffer treatments. Starch overload reduced the richness (p < 0.001) and diversity (p = 0.001) of the fecal microbiota. However, the starch−buffer treatment showed greater increase in amylolytic bacteria (Bifidobacterium 0.0% to 5.6%; Lactobacillus 0.1% to 7.4%; p < 0.05) and decrease in fibrolytic bacteria (Lachnospiraceae 10.2% to 5.0%; Ruminococcaceae 11.7% to 4.2%; p < 0.05) than starch−saline treatment. Additionally, animals that received starch−buffer treatment showed more signs of abdominal discomfort and lameness associated with dysbiosis (amylolytic r > 0.5; fribolytic r < 0.1; p < 0.05), showing that cecal infusion of buffer did not prevent, but intensified intestinal disturbances and the risk of laminitis.

Facial Expressions of Horses Using Weighted Multivariate Statistics for Assessment of Subtle Local Pain Induced by Polylactide-Based Polymers Implanted Subcutaneously.

Facial-expression-based analysis has been widely applied as a pain coding system in horses. Herein, we aimed to identify pain in horses undergoing subcutaneously polylactide-based polymer implantation. The sham group was submitted only to surgical incision. The horses were filmed before and 24 and 48 h after implantation. Five statistical methods for evaluating their facial expressions (FEs) were tested. Primarily, three levels of scores (0, 1, and 2) were applied to the seven FEs (ear movements, eyebrow tension, orbicularis tension, dilated nostrils, eye opening, muzzle tension, and masticatory muscles tension). Subsequently, the scores of the seven FEs were added (SUM). Afterwards, principal component analysis (PCoA) was performed using the scores of the seven FEs obtained using the first method. Subsequently, weights were created for each FE, based on each variable's contribution variability obtained from the PCoA (SUM.W). Lastly, we applied a general score (GFS) to the animal's face (0 = without pain; 1 = moderate pain; 2 = severe pain). The mechanical nociceptive threshold (MNT) and cutaneous temperature (CT) values were collected at the same moments. The results show no intra- or intergroup differences, when evaluating each FE separately or in the GFS. In the intragroup comparison and 48 h after implantation, the control group showed higher values for SUM, PCoA, and SUM.W, although the horses implanted with polymers displayed more obvious alterations in the CT and MNT. Our findings show that the five statistical strategies used to analyze the faces of the horses were not able to detect low-grade inflammatory pain.

Needle Arthroscopy of the Scapulohumeral Joint and Bicipital BURSA in Horses: An Ex Vivo Study.

To evaluate the feasibility of performing needle arthroscopy of the scapulohumeral joint and bicipital bursa in standing horses by using the thoracic limbs of euthanized horses. To that purpose, this experimental study was designed. Ten thoracic limbs, five left and five right from euthanized horses were retained in an upright position to simulate a standing horse. The craniolateral and lateral scapulohumeral arthroscopic portals were used to access the articular structures. A third (caudal) portal was also identified and described. The degree of difficulty in accessing the articular space and the optic maneuverability within the joint were compared between portals. The needle arthroscopy image lacks in quality, but the procedure was considered useful as a diagnostic aid for examination of the scapulohumeral joint of horses. Needle arthroscopy of the bicipital bursa was not possible. Needle arthroscopy has a great diagnostic potential for lesions in the scapulohumeral joint of horses. A new access (caudal) to the scapulohumeral joint of horses has been identified.

The role of vanilloid receptor type 1 (TRPV1) in hyperalgesia related to bovine digital dermatitis.

Bovine digital dermatitis is a contagious and chronic disease affecting the digits of dairy cattle worldwide. Tissue degradation may alter ionic channels and further activate vanilloid channels, more specifically the vanilloid receptor type 1 (TRPV1) that can generate and modulate hyperalgesia in cows affected with bovine digital dermatitis. The aim of this pilot study was to identify and quantify TRPV1 channels in dairy cows presenting with different stages of bovine digital dermatitis and compare these data according to the disease evolution and degree of hyperalgesia described in previous studies. Biopsies were taken from 15 lactating Holstein cows (23 lesions), and immunochemistry was performed to identify the number of TRPV1 fibers in the 4 M-stages of digital dermatitis and the control group. This pilot study had 5 experimental groups, M1 (5 samples), M2 (5 samples), M3 (4 samples), M4 (4 samples), and the control group (5 samples), with inclusion criteria was the presence of a bovine digital dermatitis lesion in at least one digit. The pilot results demonstrate an increase in expression of TRPV1 receptors in group M4 in comparison with the other groups. Bovine digital dermatitis may cause an increase in expression of TRPV1 receptors in the chronic stages of the disease, possibly contributing to the hyperalgesia described in affected animals; nevertheless, further research is needed to define this relation.

Intra-abdominal Pressure Screening of Horses With Colic.

The objective of this study was to evaluate changes in intra-abdominal pressure (IAP) in horses with colic by associating the underlying etiologies with directly acquired IAP values and survival rate. This is a 2-year cohort study (2014-2016). Horses with clinical signs of colic were admitted to the veterinary teaching hospital during the period 2014-2016. Twenty-eight horses, of different breeds, males (stallions and geldings) and females, aged between 2 and 20 years, and weighing from 300 to 450 kg presenting with clinical signs of colic, were included in the study. IAP was directly acquired at the right flank (standing under sedation) and at the linea alba (supine position under general anesthesia). Twenty IAP measurements were recorded at end expiration for each recording site. IAP values >0.0 mmHg, obtained at the upper right flank in the standing position, were associated with surgical treatment (P < .05). In these cases, signs of colic were associated with strangulated obstructions of the large colon, and a greater likelihood of death as a result of colic (P < .001). Intra-abdominal pressure varied considerably in horses with colic, even for the same underlying etiologies. Horses with colic related to strangulating obstructions of the large intestine had IAP >.0 mmHg, at the upper right flank. These horses were also considerably more likely to require surgical intervention (P < .05) and death/euthanasia was more likely in this group of horses (P < .001).

Intrabladder pressure as predictor of intra-abdominal pressure in horses.

OBJECTIVES: To investigate effects of postural changes and bladder distention on intrabladder pressure whilst estimating intra-abdominal pressure in horses. DESIGN: Two-year cohort study. Patients admitted for elective surgical procedures unrelated to gastrointestinal or genitourinary tract. SETTING: School of Agricultural and Veterinarian Sciences, Jaboticabal, SP, Brazil. ANIMALS: 20 adult horses, 11 males (stallions and geldings) and 9 females; between 3.5 and 12 years, weighing 350 to 500 kg. INTERVENTIONS: Intra-abdominal pressure was directly-recorded through abdominocentesis at the ventral midline with a fluid-filled system. Intrabladder pressure was obtained from a bladder catheter with the fluid-filled system zeroed at the level of the tuber ischia with patients in dorsal recumbency or pubic symphysis if in lateral recumbency. MEASUREMENTS AND MAIN RESULTS: Body position directly influenced intra-abdominal pressure. In dorsal recumbency, intra-abdominal pressure differed (p < 0.05) from intrabladder pressure at end-inspiration and end-expiration regardless of whether the bladder was empty or distended. There was no correlation nor association between the two pressures in this body position. In lateral recumbency a difference (p <0.05) between intra-abdominal pressure and intrabladder pressure was recorded at end-inspiration with the bladder distended with 25 ml, and at end-expiration for distension volumes of 25 ml and 50 ml. There was a strong correlation between both pressures for left and right lateral recumbency, regardless of the distension volume. Ordinary least product (OLP) regression analysis showed no fixed or proportional bias between both pressures for distension volume of 50 ml, at both end-inspiration and end-expiration. CONCLUSIONS: Indirect assessment of equine intra-abdominal pressure cannot be made in dorsal recumbency. For that purpose, patients should be in left lateral recumbency with the bladder distended with 50 ml. Values can be recorded at end-inspiration or end-expiration. RESTRICTION: Occlusion of the catheter tip by the bladder wall when minimally distended.

Experimentally Induced Open Pneumothorax in Horses.

The objective of this study was to evaluate clinical and cardiovascular parameters and pleural and intra-abdominal pressures of horses after experimentally induced unilateral open pneumothorax. Prospective, experimental study-animals: seven healthy adult horses, 4 females and 3 males. Left hemithorax thoracotomy was carried out to create an open pneumothorax for 60 minutes. Pleural pressure (Ppl) was directly obtained at the midpoint of the left eighth intercostal space before thoracotomy. Esophageal pressure (Pes), arterial blood gas analysis, left ventricular function, and ultrasonographic assessment of pneumothorax extent/resolution were performed at the baseline, and 5, 10, 15, 30, 45, and 60 minutes after thoracotomy, and on the first, second, third, fifth, and seventh days postoperatively. Intra-abdominal pressure was only recorded while the pneumothorax was present. There was moderate correlation (Spearman's rs = 0.404; R2 = 0.8; P < .00001; Bland-Altman bias = -2.59; s.d. = 2.11) between Pes and Ppl. Esophageal pressure increased (P < .05) after open pneumothorax until the fifth day postoperatively. Partial pressure of oxygen in arterial blood reduced (P < .05) until the third day postoperatively when it returned to the baseline. No significant variations in PaCO2, pH in arterial blood, and in left ventricular function were appreciated. The extent of the pneumothorax was assessed by thoracic ultrasonography. Esophageal pressure, in association with blood gas analysis and thoracic ultrasonography, could be used to aid diagnosis of pneumothorax in horses. Horses tolerate open pneumothorax, with minimum cardiovascular impairment, even without aspiration of free air from within pleural space to restore thoracic wall integrity.

Hyoscine-N-butylbromide premedication on cardiovascular variables of horses sedated with medetomidine.

OBJECTIVE: To evaluate the effects of intravenous (IV) or intramuscular (IM) hyoscine premedication on physiologic variables following IV administration of medetomidine in horses. STUDY DESIGN: Randomized, crossover experimental study. ANIMALS: Eight healthy crossbred horses weighing 330 ± 39 kg and aged 7 ± 4 years. METHODS: Baseline measurements of heart rate (HR), cardiac index (CI), respiratory rate, systemic vascular resistance (SVR), percentage of patients with second degree atrioventricular (2(o) AV) block, mean arterial pressure (MAP), pH, and arterial partial pressures of carbon dioxide (PaCO2 ) and oxygen (PaO2 ) were obtained 5 minutes before administration of IV hyoscine (0.14 mg kg(-1) ; group HIV), IM hyoscine (0.3 mg kg(-1) ; group HIM), or an equal volume of physiologic saline IV (group C). Five minutes later, medetomidine (7.5 µg kg(-1) ) was administered IV and measurements were recorded at various time points for 130 minutes. RESULTS: Medetomidine induced bradycardia, 2(o) AV blocks and increased SVR immediately after administration, without significant changes in CI or MAP in C. Hyoscine administration induced tachycardia and hypertension, and decreased the percentage of 2(o) AV blocks induced by medetomidine. Peak HR and MAP were higher in HIV than HIM at 88 ± 18 beats minute(-1) and 241 ± 37 mmHg versus 65 ± 16 beats minute(-1) and 192 ± 38 mmHg, respectively. CI was increased significantly in HIV (p ≤ 0.05). Respiratory rate decreased significantly in all groups during the recording period. pH, PaCO2 and PaO2 were not significantly changed by administration of medetomidine with or without hyoscine. CONCLUSION AND CLINICAL RELEVANCE: Hyoscine administered IV or IM before medetomidine in horses resulted in tachycardia and hypertension under the conditions of this study. The significance of these changes, and responses to other dose rates, requires further investigation.