490


EQUINE VETERINARY EDUCATION / AE / SEPTEMBER 2018


mineral premix contained within such feeds usually dictates a minimum recommended daily intake of about 0.5 kg/100 kg bwt to provide sufficient micronutrients to meet minimal requirements. This is important as many horse owners remain unaware that further vitamin and mineral supplementation is required if they feed below the manufacturer’s minimum recommended intake. Balancers are complementary feeds, fed to replace


conventional complementary feeds, that provide a concentrated source of protein (providing high quality protein, delivering essential amino acids such as lysine), as well as vitamins and minerals. Typically balancers are not provided as a significant source of energy, although they will contribute some calories to the ration depending on their formulation. They are usually formulated to be fed at a much lower intake, typically 100 g/100 kg bwt. Many horses and ponies especially those in light to moderate work can be fed appropriately through forage (grass fresh or preserved) and a balancer.


‘Straight’ feeding stuffs


There are a variety of cereal grains, oil seeds, byproducts and vegetable oils often used in home-mixed rations, or to top dress an existing fortified proprietary feed. These include cereals such as oats, barley and maize, as well as oil seeds such as soya and linseed, and a variety of vegetable oils including soya or linseed oil. High fibre ingredients such as sugar beet pulp and chopped alfalfa/lucerne are also used in this context. A degree of knowledge is required to ensure the successful use of such straight feeding ingredients to provide a balanced ration. This is because most of these ingredients will only have what would be considered as a background level of trace minerals and the relative amounts of macro minerals such as calcium and phosphorus can be unbalanced. For example, cereals tend to be high in phosphorus and low in calcium, whereas sugar beet and alfalfa/lucerne is high in calcium and low in phosphorus. Whilst straight feeding ingredients potentially offer a certain amount of ration flexibility, their use can be problematic without sufficient knowledge or experience.


Supplements As we learn more about the role of optimum nutrition in health and performance, it has been suggested that traditional rations may not offer all the desired microcomponents, especially where high performance horses are concerned and that feed ‘supplements’ (classified in EU legislation. alongside more traditional feeds as complementary feeds) may be of benefit under some circumstances (Harris and Harris 2005; Harris et al. 2013; Williams 2013). Supplements, as they are used in practice i.e. as feedstuffs


that do not form more than 5% of the total ration by weight (and are not items such as carrots, apples, mints etc.) can perhaps usefully be divided according to their core purpose:


Fundamental dietary supplements These contain substances with established nutritional requirements and therefore include amino acids, vitamins, minerals and trace elements. These supplements are often used to balance the ration and thereby ensure that specific dietary goals are attained. In many cases when fed as recommended their use can be supported e.g. appropriate


© 2016 EVJ Ltd


dietary supplementation with vitamins and minerals is essential when the core diet does not provide adequate amounts. This is commonly seen when forage based or forage/cereal based diets are being fed or when the dietary intake is being restricted for specific clinical reasons (e.g. obesity, laminitis etc.). Many forage balancers would fall under this category.


Specialised dietary supplements In a review for the National Academies of Science (USA) (Anon 2009) on supplement safety the committee defined an animal dietary supplement as ‘A substance for oral consumption by horses, dogs, or cats, whether in/on feed or offered separately, intended for specific benefit to the animal by means other than provision of nutrients regarded as essential, or provision of essential nutrients for intended effect on the animal beyond normal nutritional needs, but not including legally defined drugs’. This definition would include the various nutraceuticals and other nutrients that are commonly suggested to have highly supportive effects on health, performance and behaviour. For example, supplements may contain nutrients in amounts far greater than minimal nutritional requirements, but known to provide support at these higher levels (e.g. high doses of Biotin supporting hoof quality in some individuals), or conversely other components for which there is no scientifically established dietary requirement (e.g. chromium, various herbs, chondroitin sulphate, glucosamine). The market for such supplements is vast and horse owners are constantly offered products that claim to benefit their horses and are often marketed as offering support to specific physiological systems such as the digestive system, respiratory system, joints and skeleton or muscles. Often the role of the veterinarian is to offer advice on the


suitability, safety, efficacy and especially for competing animals, legality of such products for horse owners or trainers, which can be a difficult task. Whilst the gold standard may be for a supplement to be underpinned by species-specific research to support the specific supplement formulation, this is realistically rarely available. It is, however, the responsibility of and a legal requirement (at least in Europe) for the company marketing the product to be able to provide the client or their veterinarian with evidence or justification to support any marketing claims. This may take the form of research already in the public domain regarding the main active ingredients, or peer reviewed research on the specific product formulation, or indeed in some circumstances unpublished in-house trials. There are many aspects to consider when choosing or recommending a ‘supplement’ (Harris et al. 2013), but below are some key areas that the authors believe should be considered when offering advice or recommendation regarding supplements: • Ideally is species-specific research available to support marketing claims, either on the product formulation, or on well defined and stated active ingredients? Or is research available in other species to support the supplement claim or function and can this be reasonably extrapolated to horses (absorption of active ingredients being one of the most likely barriers to transferred efficacy)?


• Are the active ingredients clearly defined together with the dose provided?


• Can the source of the active ingredient and the delivery per dose be justified by quoted supportive research? Where there is the ability to do so the active ingredient


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84