Objective—To determine clinical and ultrasonographic abnormalities in horses with primary desmitis of the palmar or plantar annular ligament (PAL) and the response to treatment. Design—Retrospective study. Animals—25 horses. Procedure—Data collected from medical records included signalment, horse use, affected limb, severity and duration of lameness, results of diagnostic tests performed, ultrasonographic findings, treatment, and outcome. Results—All horses had a prominent swelling in the region of the affected PAL, and signs of pain were evident during palpation of the swelling. In all horses, the affected PAL was thicker than normal as determined ultrasonographically. Twenty horses had hypoechoic regions in the PAL. Four horses, including 1 horse with 3 affected limbs, were treated by means of PAL desmoplasty, 9 were treated by means of PAL desmotomy, and 12 were treated with rest. Follow-up information was available for 21 horses. All 4 horses that underwent PAL desmoplasty, 4 of 7 horses that underwent PAL desmotomy, and 7 of 10 horses treated with rest alone became sound. Conclusions and Clinical Relevance—Results suggest that primary desmitis of the PAL may be a cause of lameness in horses. Although significant differences in outcome between horses treated with rest alone versus PAL desmoplasty versus PAL desmotomy were not identified, because it is less invasive, PAL desmoplasty should be considered for treatment of horses with PAL desmitis that do not respond to conservative treatment and do not have any evidence of constriction of the digital flexor tendons. (J Am Vet Med Assoc 2005;226:83–86)

Summary: Intramural vascular patterns of the jejunum and colon were evaluated during ischemic strangulation obstruction (iso, 70 minutes) and subsequent reperfusion (60 minutes) in 7 adult anesthetized horses. Microvasculature of experimental and control segments was described by comparison of results from microangiography, light microscopy, and scanning electron microscopy of vascular replicas. Experimental and control segments with isolated vascular arcades were removed either immediately after the experimental period or after 60 minutes of reperfusion. Blood was flushed from the vascular system by use of isotonic NaCl, and the segments were divided. Half of each segment was perfused with a modified radiopaque medium for microangiographic evaluation, and half was perfused with dilute methylmethacrylate to create a vascular replica to be studied by scanning electron microscopy. Microangiographic section also were evaluated for histologic changes. Microvasculature of jejunal control segments and all colon segments was similar to described normal microvasculature of the equine jejunum and ascending colon. In jejunal iso segments, intramural perfusion was redistributed away from the mucosa. In the villi, the central arteriole was short and convoluted and the subepithelial capillaries were not filled. The submucosal vessels and crypt capillaries were congested, compared with those of controls, and the serosal vessels were not filled in the ischemic segments. Histologic grade II-III mucosal lesion was seen in jejunal iso segments. Reperfused jejunal segments had a transmural hyperemic response, and previously unfilled capillaries were observed in all intestinal layers. After reperfusion, the mucosal lesion progressed to grade III-IV and a cellular infiltrate and edema formation were observed in the serosa. The intramural vasculature of the ischemic and reperfused colon remain unchanged. Minimal histologic damage was observed in the colon after 70 minutes of iso or after 60 minutes of reperfusion.

Objectives: To determine the success of treating distal interphalangeal joint collateral ligament (DIJCL) desmopathy using magnetic resonance imaging (MRI) guided ligament injection. Methods: Medical records of 13 adult horses diagnosed with DIJCL desmopathy using low field MRI and treated by MRI guided ligament injection of mesenchymal stem cells and/or platelet rich plasma were reviewed. Information collected included signalment, MRI diagnosis, treatment type, time to resolution of lameness and level of exercise after treatment. Results: Collateral ligament inflammation was diagnosed as a cause of lameness in 13 horses. MRI was used to guide the injection of the injured DIJCL. All lameness attributed to DIJCL desmopathy resolved with the resulting level of performance at expected (10) or less than expected (3). Conclusions and Clinical Relevance: Injection of the DIJCL can be completed in horses standing in a low field magnet guided by MRI as previously demonstrated in cadaver specimens. Administration of stem cells or PRP appears useful as a treatment for DIJCL desmopathy.

Horses are transported in the United States more than any other livestock species and co-mingle at various events; therefore, they are considered to be at an increased risk for infectious disease transmission. The fragmented movement of horses combined with numerous sites of co-mingling makes tracing the potential spread of a disease outbreak a necessary part of an infection control plan, both locally and nationally. The cross-movement of personnel with horses and the persistence of endemic diseases make biosecurity implementation an ongoing challenge. Although many of the risks for infection are known, there is limited documentation about the usefulness of prospective control measures. The objective of this survey was to determine horse owners’ understanding and knowledge of biosecurity practices for preventing infectious diseases in the United States. Questions covered owner demographic information, including horse use which was divided into 10 categories as follows: Pleasure/Trail Riding, Lessons/School, Western Show, English Show, Breeding, Farm/Ranch, Retired, Racing, Driving and Other. The survey was distributed by sending requests to a list of horse owner organizations, which then sent emails to their members. The email request described the survey and provided a website link to start the survey. A total of 2413 responses were collected. Analysis of the results included cross-tabulation to identify significant differences in biosecurity knowledge and awareness by horse use. Significant differences by horse use were identified for vaccination, biosecurity planning, use of isolation, disease risk, monitoring for diseases, co-mingling of horses, sanitation, medical decision making and health record requirements for horse events. In summary, the results suggest that most owners are not highly concerned about the risk of disease or the use of biosecurity. There are several biosecurity applications and techniques which can be increased and will benefit horse health and welfare. These include reliance on temperature monitoring, isolation of new horses at facilities, risks of horse mingling, entry requirements such as vaccination and health certificates at events, and an emphasis on having biosecurity plans for facilities and events where horses co-mingle. The information from this study will be used to create tools and information that horse owners and veterinarians can use to implement appropriate biosecurity practices for different types of horse uses and events.

Objective—To quantify peripheral blood neutrophil apoptosis in equine patients with acute abdominal disease (ie, colic) caused by strangulating or nonstrangulating intestinal lesions and compare these values with values for horses undergoing elective arthroscopic surgery. Animals—20 client-owned adult horses. Procedures—Peripheral blood was collected from horses immediately prior to and 24 hours after surgery for treatment of colic (n = 10) or elective arthroscopic surgery (10), and neutrophils were counted. Following isolation by means of a bilayer colloidal silica particle gradient and culture for 24 hours, the proportion of neutrophils in apoptosis was detected by flow cytometric evaluation of cells stained with annexin V and 7-aminoactinomycin D. Values were compared between the colic and arthroscopy groups; among horses with colic, values were further compared between horses with and without strangulating intestinal lesions. Results—Percentage recovery of neutrophils was significantly smaller in preoperative samples (median, 32.5%) and in all samples combined (35.5%) for the colic group, compared with the arthroscopy group (median, 66.5% and 58.0%, respectively). No significant differences in the percentages of apoptotic neutrophils were detected between these groups. Among horses with colic, those with strangulating intestinal lesions had a significantly lower proportion of circulating apoptotic neutrophils in postoperative samples (median, 18.0%) than did those with nonstrangulating lesions (66.3%). Conclusions and Clinical Relevance—The smaller proportion of apoptotic neutrophils in horses with intestinal strangulation suggested that the inflammatory response could be greater or prolonged, compared with that of horses with nonstrangulating intestinal lesions. Further investigations are needed to better understand the relationship between neutrophil apoptosis and inflammation during intestinal injury.