Equine Health Update EHU Vol 19 Issue 3 - Page 11

EQUINE | Equine Disease Update echocardiography with the potential to provide informa- tion on aspects of cardiac function that have largely been ignored previously. Clinical highlights: Smartphone apps and echocardiogra- phy devices have become a viable option for monitoring exercise associated dysrhythmias and may provide access to echocardiography technology to more equine clini- cians. Nutrition Dr Joe Pagan addressed the influence of nutrition in the equine athlete. Recent developments include the use of feeds with moderate to high fat content. The horse, though lacking a gall bladder, has a surprising ability to utilise fat. As fat has high energy density and slowly releases of that energy, these feeds provide for an ideal alternative for nervous horses. An adaption period of 5 weeks is required for the muscles to adapt to the utilisa- tion of the new energy source. Diets low in nonstructural carbohydrate (NSC; 15–30% digestible energy [DE]) are ideal for patients with recurrent exertional rhabdomyoly- sis and polysaccharide storage myopathy. However, these diets are not suited to every horse, particularly not those doing high intensity work that require fast readily avail- able digestible energy. The primary substrate for energy production in the horse is muscle glycogen and its use is closely related to the intensity and length of exercise. During high intensity work muscle glycogen is depleted and needs to be replaced quickly for the muscle to work optimally. Diets low in NSC (<20% DE) take longer than 3 days to replenish muscle glycogen stores fully, unlike diets with medium (20–30% DE) to high (30% DE) NSC content. Another topic of interest was the effects of furosemide on the horse’s electrolyte balance and total body water. Although not legal to race on in South Africa, it is used during training. Furosemide results in a total body weight loss of approximately 40 kg in the form of isotonic urine. Loss of isotonic urine does not activate thirst receptors and thus dehydration can easily result. Administration of a hypertonic electrolyte paste post-exercise may en- courage drinking and to replace the sodium and chlo- ride lost in association with furosemide. Clinical highlights: Future equine nutritional research is focusing on nutrigenomics and nutrigenetics. Nutri- genetics is the study of the effects of nutrients on gene expression while nutrigenomics is the study of how individual differences in genes influence the body’s re- sponse to diet and nutrition. Medicine Prof Derek Knottenbelt focussed on the diagnosis and treatment of sarcoids and melanomas. Sarcoids are pro- gressive tumours and should be dealt with as early in as possible and treatment should be aggressive. Smart sur- gery, where the tumour is isolated before it is removed, may be useful. Alternatively, laser resection, cryosurgery, ligation and a variety of chemical agents [39] can be used, all with the aim of removing all cancer cells. Prof Knottenbelt commented that clinicians continue to ig- nore melanomas on the whole when they should be taking action sooner. Most, but not all, early melanomas are benign but over time will show malignant transfor- mation and micro metastasis. Prof Knottenbelt is a pro- ponent of the idea that melanomas should be removed as early as they &RFVFfVBFW"F6G&VFVG0fR&fVBVffV7FfRC"v7F6ǒfW'6VrЦr6Ɩ6vƖvG3fB&7b7W7V7B6&6G2VЦW72&&FRG&VFVB2FFVBVFFVǒVЦ26VBB&Rv&VBFG'G"7FWV( w&GGf6FVB66VFf2&6Ff'&W'V6bvB2FVvB&7F6VBBWfVFVvB&WBWVRFG'2&6VBG&FF@( "fVR2( "6WFV&W"#r(