Tuesday, October 27, 2009

Colic: Diet Can Reduce Enterolith Risk, Review Finds

Thehorse.com - Full Article

by: Marie Rosenthal
September 14 2009, Article # 14907

If your horse is at risk for intestinal stones or enteroliths, consider replacing an alfalfa-based diet with grass hay, said Diana M. Hassel, DVM, PhD, of Colorado State University.

Hassel and colleagues evaluated two equine diets and water supplies to see their effect on minerals and the pH of the gut. The gastrointestinal tracts of horses with stones tend to be more alkaline and have higher mineral content. Half of the study horses had undergone surgery in the past to remove intestinal stones, and the other half had no history of stones.

An enterolith inside a horse's colon, which can cause colic
Enterolith after being removed form a horse's colon

An enterolith before and after surgical removal at Washington State University. This particular one weighed 3.6 kg and measured 20 cm around. The horse survived and recovered well.

"We found that horses fed alfalfa had a higher pH (more alkaline) in their gut than those fed grass hay," she said.


Saturday, October 24, 2009

Prevent Weight Gain to Minimize Metabolic Changes in Horses

Thehorse.com - Full Article

by: Stacey Oke, DVM, MSc
October 16 2009, Article # 15041

Weight gain and obesity in horses should be avoided to prevent insulin resistance, increased insulin and leptin blood levels, and laminitis, and to maintain a healthy metabolic state.

To date, "it is unknown whether obesity is the primary cause of or contributes to metabolic abnormalities or whether these abnormalities are inherent characteristics of the animal," wrote a group of researchers from the Virginia-Maryland Regional College of Veterinary Medicine. The research team, which included authorities in the fields of equine nutrition and metabolic disorders, hypothesized that diet-induced weight gain in horses would decrease insulin sensitivity and increase blood levels of various hormones and fatty acids.

To test this hypothesis, they fed 13 Arabian or Arabian-cross geldings, ranging in age from 8 to 20 years, 200% of their maintenance energy requirements for 16 weeks.


Insulin Resistance: Variation in Blood Test Levels

Thehorse.com - Full Article

by: Marie Rosenthal
October 14 2009, Article # 15029

A blood sample is usually a key step in diagnosing a horse as insulin resistant. But a recent study showed that one sample might not give enough information because the horse’s blood sugar and insulin fluctuates daily.

"Your veterinarian should probably take at least two samples on different days," recommended Shannon E. Pratt, PhD, of North Carolina State University, who recently completed a study on the topic.

For six days, Pratt and her colleagues took blood samples from six horses that had not been fed for four hours. The researchers measured the insulin and glucose concentrations, finding "significant day-to-day variation, which means that the results from a single blood sample aren’t entirely reliable," Pratt said.


Tuesday, October 20, 2009

Clinical and biochemical abnormalities in endurance horses (a retrospective study)

Clinical and biochemical abnormalities in endurance horses eliminated from competition for medical complications and requiring emergency medical treatment: 30 cases (2005 - 2006)

C. Langdon Fielding, DVM, DACVECC; K. Gary Magdesian, DVM, DACVIM, DACVECC,
DACVCP; Diane M. Rhodes; Chloe A. Meier and Jill C. Higgins, DVM

Objective – To describe the clinical and clinicopathologic abnormalities in endurance horses eliminated from competition and requiring emergency medical treatment.

Design – Retrospective study over a 2-year period (2005–2006). Ten horses that successfully completed the ride in 2006 were included for comparison.

Setting – Temporary equine emergency field hospital.
Animals – All horses (n 5 30) that were removed from endurance competition and treated for a metabolic abnormality were studied.

Interventions – Horses were treated with IV fluids and analgesics. Monitoring included lab work (PCV, total protein, and electrolytes) and serial physical examinations.

Statistical analysis included descriptive statistics and parametric and nonparametric comparisons (ANOVA, Friedman’s test, and Kruskal-Wallis) where appropriate.

Measurements and Main Results – The clinical diagnoses identified included colic, esophageal obstruction, poor cardiovascular recovery, myopathy, and synchronous diaphragmatic flutter. As a group, these sick horses had lower plasma chloride and potassium and higher total plasma protein concentrations as compared with 10 healthy horses that successfully completed the ride (Po0.05, o0.01, and o0.05 for chloride, potassium, and total protein, respectively). Horses with colic had a lower PCV as compared with horses with poor recovery and those with synchronous diaphragmatic flutter (Po0.05). All horses, including colics, were treated medically and discharged to owners.

Conclusions – Based on the results of this study, the prognosis for horses requiring emergency veterinary treatment after being removed from endurance competition (for metabolic reasons) appears to be good if horses are withdrawn from competition under the same criteria outlined in this study. Biochemical abnormalities tend to be mild and do not necessarily aid in delineating sick horses from successfully completing horses. None of the horses with gastrointestinal disease required abdominal surgery.

Full Study - download pdf

Monday, October 12, 2009

Veterinary clinical trial at AERC event

Intraocular Pressure Measurement in Equine Athletes during Endurance Competitions

In humans, continuous strenuous exercise has been shown to decrease pressure within the eye (intraocular pressure); however, no study has evaluated the effect of exercise on intraocular pressure in horses. With extensive documentation of normal equine intraocular pressure (15-30 mm Hg) and the knowledge of intraocular pressure changes in humans during exercise, we are evaluating elite equine athletes for similar changes. The objective of this investigation is to document the intraocular pressure of equine eyes prior to, during, and immediately after endurance competitions (50 miles) to determine the normal intraocular pressure of conditioned equine athletes and to document change during exercise. A second objective is to identify intraocular pressure differences between horses who successfully complete competition and those that are removed from competition due to exhaustion to determine if intraocular pressure is predictive of exhaustion. Our hypothesis is that continuous exercise will result in reduced intraocular pressure in the eyes of horses during endurance competitions, and the magnitude of change will represent an objective measure predictive of physical exhaustion.

Tonometry is the measurement of intraocular pressure and is a routine part of both human and animal ocular examinations. In this study, intraocular pressure will be measured with a portable TonoVet® rebound tonometer. This rapid, simple, noninvasive device allows reliable measurements to be obtained from horses in a normal standing position. Most horses are amenable to intraocular pressure measurement with this device due to the small probe size (1 mm) and brief corneal contact time. Following riders’ permission, cursory eye examinations will be performed on each horse participating in the study during the pre-ride examination and baseline intraocular pressure readings will be obtained. Intraocular pressure measurements will also be acquired at the intermediate vet checkpoints and at the post-ride examination. Measurements will not add significant time to the checkpoint as intraocular pressure can be measured while a horse and rider are waiting in line or immediately afterwards, as preferred by the rider. Veterinary cards will be scanned so that pertinent data from each horse can be logged with the intraocular pressure measurements for correlation between horses who complete competition and those who do not.

This investigation will generate data regarding the intraocular pressure status of horses participating in endurance competitions. The results may also identify intraocular pressure as an easily measured, objective measure of exhaustion that could change the way horses are assessed during competition and ultimately help to reduce the number of injuries during endurance rides, therefore benefitting endurance horses and endurance horse riding.

Please do not hesitate to contact us with any questions or concerns regarding this study!

Rachel Allbaugh, DVM, MS
Board-Certified Veterinary Ophthalmologist
Assistant Professor, Kansas State University
mobile phone 785-410-5560

Susan Keil, DVM, MS,
Board-Certified Veterinary Ophthalmologist
AERC Board of Directors
mobile phone 913-233-9098
Board-Certified Veterinary Ophthalmologist