Effect of Ergovaline Ingestion on Recovery of Horses Subjected to an Anaerobic Standard Exercise Test

The objective of this study was to determine whether consumption of tall fescue seed which contained high levels of ergovaline would affect post-exercise recovery of horses subjected to an anaerobic exercise test. Ten Quarter horses were separated into two groups and fed alfalfa hay, commercial sweet feed, and either endophyte-infected (E+) or endophyte-free (E−) ground tall fescue seed. Diets contained 11.8% seed, which resulted in 459 ppb of ergovaline for the E+ diet. During the first 28 days, horses in group A received E+ and group B received E−. Diets were reversed during the next 28 days (crossover design). Horses were ridden for 5 days per week. On day 14, 28 (period 1), 42, and 56 (period 2), they were subjected to a standardized exercise test (SET) that consisted of 41 turns in 4 minutes and was designed to raise the horse’s heart rate (HR) beyond the anaerobic threshold (150 bpm). There was a horse effect (P < .05) on post-SET respiration rate, HR, and post-exercise whole blood lactate level, but not rectal temperature (RT). For these variables or period effects, there was no horse × treatment, period × treatment, or period × horse interactions (P < .05). Treatment had no effect on whole blood lactate level, RT, or HR at any time measured. Respiration rate did not vary by treatment at rest or 1 minute after SET but was higher for the E+ treatment at 5 and 10 minutes after SET (P < .005). Consumption of diets that averaged 450 ppb of ergovaline caused the horses expend more respiratory effort in an attempt to recover to resting RT.     

Factors Affecting Prognosis and Conversion in Equine Atrial Fibrillation

Sixty-seven horses presented with atrial fibrillation (AF) from January 1, 1980 to August 1, 1986. All horses were evaluated for the type and severity of the underlying cardiac disease and the probable duration of the arrhythmia. Fifty-two (78%) of the horses were treated with quinidine sulfate and/or digoxin. The response to treatment was assessed in each horse. Horses were followed for periods extending from 8 months to 7 years. Standardbreds, young horses, and males predominated in the study group. There were more male horses (stallions and geldings) than mares. Most horses with AF had no evidence of other cardiac disease (56.7%). All performance horses without other cardiac disease were treated, and return to performance was significantly associated with conversion to sinus rhythm. Horses that did not convert with quinidine sulfate therapy, whose arrhythmia recurred, and that had side effects from quinidine sulfate therapy, had a longer history of poor performance. Tachycardia (heart rate greater than 60 beats/min) was significantly associated with the existence of congestive heart failure. The horses with congestive heart failure had a poor prognosis for life (7.7% survived) and a poor conversion to normal sinus rhythm (23.1%). Mitral regurgitation (19 horses) was the most common underlying cardiac disease. Tricuspid regurgitation (15 horses), aortic regurgitation (3 horses), myocardial dysfunction (3 horses), and atrial septal defect (1 horse) also were diagnosed. Congestive heart failure was common in this group of horses with underlying cardiac disease.     

DYNAMIC CT MEASUREMENT OF CONTRAST MEDIUM WASHIN KINETICS IN CANINE NASAL TUMORS

Tumor oxygenation affects the biologic behavior of a tumor and also its radiation response. Decreased tumor oxygenation has been associated with an aggressive phenotype and with decreased local tumor control following irradiation. Thus, measurement of oxygenation may be useful for pretreatment evaluation of a tumor. Many methods for assessing tumor oxygenation are available but most are invasive. There is a need for a non-invasive measure of oxygenation, or a surrogate for oxygenation. Measurement of perfusion has been suggested as a substitute for measurement of oxygenation. The use of washin kinetics of iodinated contrast medium to estimate perfusion has been shown to be related to radiation response of human carcinomas. We quantified the washin kinetics of iodinated contrast medium using dynamic CT in 9 dogs. All dogs had a malignant nasal tumor and perfusion was quantified at two sites in each tumor to evaluate intratumoral variation in perfusion. Dogs were given an intravenous bolus injection of contrast medium and arterial and tumor washin kinetics quantified using a helical CT scanner. Perfusion was estimated from these data using previously validated methods. Eight of the 9 dogs received definitive radiation therapy and perfusion was quantified a second time in these 8 dogs midway through irradiation. Pretreatment perfusion varied between dogs by a factor of 16.9. Between dog variation in perfusion was subjectively greater than within tumor variation based on comparison of two intratumoral regions. Changes in perfusion in individual dogs during irradiation were observed, but no identifiable pattern of perfusion alteration was detected. Measurement of perfusion in canine nasal tumors using dynamic CT is possible and further study of this parameter as it relates to radiation response is reasonable.     

Ex Vivo Comparison of Three Surgical Techniques to Stabilize Canine Cranial Cruciate Ligament Deficient Stifles

Objective— To quantify and compare canine stifle stability after 3 stabilization techniques. Study Design— Randomized controlled study. Sample Population— Adult canine cadaveric pelvic limbs. Methods— Total craniocaudal (CrCa) tibial translation quantified in stifles with the cranial cruciate ligament (CrCL) intact, transected, and stabilized with 1 of 3 techniques: (1) hamstring graft (HG); (2) modified retinacular imbrication (MRIT); (3) anatometric fascia lata translocation (AFLT). Tibial translation was quantified from radiographs generated during application of cranial and caudal forces to the tibia. After removal of all soft tissues except periarticular ligaments and fixation, CrCa tibial translation, as before, and medial–lateral rotation, via torsional loading, was quantified with an active motion analysis system. Total tibial translation was evaluated for effect of technique and cruciate status using mixed effect linear model with significance considered at P‐value <.05. Results— CrCa translation was not significantly different across stabilization techniques with CrCLs intact, transected, or after stabilization. Poststabilization translation was significantly less than posttransection for all techniques. Compared with the intact CrCL, CrCa translation poststabilization after HG was significantly greater whereas poststabilization after MRIT and AFLT was not significantly different. Tibial rotation exceeded instrumentation limits in 62.5% HG limbs, 20% MRIT limbs, and 60% AFLT limbs. Conclusions— All 3 stifle stabilization techniques confer comparable CrCa translational stability after CrCL disruption with that provided by the MRIT and AFLT techniques comparable to the intact CrCL. Clinical Relevance— The extra‐ and intracapsular techniques evaluated in this study reduced CrCa tibial translation in CrCL deficient stifles to varying amounts.     

QUANTITATIVE HEPATOBILIARY SCINTIGRAPHY WITH DECONVOLUTIONAL ANALYSIS FOR THE MEASUREMETN OF HEPATIC FUNCTION IN DOGS

A nuclear medicine procedure that has been used for quantification of hepatocyte function in man is applied and validated in the dog. This procedure employs deconvolutional analysis of liver and heart time activity curves obtained following peripheral intravenous injection of hepatobiliary radiopharmaceutical. The deconvolutional analysis simulates a bolus injection of the radiopharmaceutical into the afferent blood supple of the liver which permits the calculation of the hepatic extraction fraction. Hepatic extraction fraction is a measure of hepatocyte function. In this report, the deconvolutional analysis via fast Fourier transformations and subsequent calculation of hepatic extraction fraction is validated by direct afferent intravascular ijection of ^99mTc-mebrofenin. The hepatic extraction fraction determined via deconvolutional analysis was found to be the same as the first pass hepatic extraction fraction determined via deconvolutional analysis was found to be the same as the first pass hepatic extraction fraction determined by direct mesenteric (portal) vein injection. The same results can be obtained in a sedated animal, making the technique clinically applicable. Thus hepatic extraction fraction, obtained from a perlpheral intravenous injection of ^99mTc-mebrofenin, can provide a quatitative measure of hepatocyte function from a non-invasive procedure. The quantitative ability to measure hepatocyte function has potential in many clinical and research situations.     

SCINTIGRAPHIC DETECTION OF SUBCUTANEOUS METASTASIS IN A DOG WITH APPENDICULAR OSTEOSARCOMA

This report describes the detection of subclinical soft tissue metastasis of an appendicular osteosarcoma in a dog using bone scintigraphy. A 7-year-old spayed female Rottweiler was presented with a biopsy confirmed diagnosis of osteosarcoma. Initial radiographs revealed an aggressive bone lesion of the left distal radius. At presentation, there was no clinical or radiographic evidence of metastasis; however, a nuclear bone scan showed the primary bone lesion of the distal left radius and numerous soft tissue lesions consistent with diffuse soft tissue metastases. A left foreleg amputation was performed and cisplatin chemotherapy was given post-operatively. A second bone scan performed one month following initial presentation showed progression in size and number of soft tissue masses. Many of the lesions had become apparent on physical exam and survey radiographs. Excisional biopsy was performed on one of the soft tissue masses and a diagnosis of metastatic osteosarcoma was made. The dog was euthanized 2 months after initial presentation at the owners request due to deterioration of the animals physical condition.     

Preliminary investigation of the effect of treating sheep during pregnancy with a vitamin A,D, E formulation on the incidence of vaginal prolapse

ABSTRACT

Aim: To determine if vitamin D₃ treatment reduced the incidence of vaginal prolapse in pregnant sheep on a North Canterbury sheep breeding property.

Methods: Pregnant ewes from a single farm were allocated to three treatment groups in May 2018. At this time, the first group (EarlyVitADE; n?=?512) received an I/M 1?mL dose of 500,000?IU/mL vitamin D₃, 60,000?IU/mL vitamin A, and 25?mg/mL vitamin E. This was repeated in July 2018, when the second group (LateVitADE; n?=?695) also received the same treatment. The third group (n?=?737) were untreated controls. All cases of vaginal prolapse on the property were recorded from pregnancy diagnosis in June 2018 until ewes were set-stocked in August 2018. The planned start of lambing was 10 August 2018.

Results: During the period of observation, vaginal prolapses were recorded in 3/699 (0.4%) 2-year-old ewes, and the odds of vaginal prolapse were not associated with treatment group in these ewes (p?>?0.3). Amongst ewes aged ≥3 years, during the same period, there were 6/333 (1.8%), 6/443 (1.4%) and 25/469 (5.3%) cases in the EarlyVitADE, LateVitADE and control groups, respectively. Compared to control ewes, the odds of vaginal prolapse were reduced in both the EarlyVitADE (OR?=?0.37; 95% CI?=?0.15–0.92) and LateVitADE (OR?=?0.25; 95% CI?=?0.10–0.62) treatment groups.

Conclusions and clinical relevance: In this preliminary study, administration of injectable vitamins A, D₃, and E to pregnant ewes reduced the incidence of vaginal prolapse during the period from pregnancy diagnosis to set-stocking on one North Canterbury hill-country farm. Due to the restricted data collection period, this investigation should be replicated to better quantify the repeatability of the observed treatment effect over the complete lambing period.