Feeding supplements to horses

Megan Elphick jumping

I have heard garlic is toxic, is it safe to feed and in what quantities does it become toxic?

David Marlin – When fed at more than ~50-100g per day to a 500kg horse.

What is your view on whether to feed garlic to a horse with sweetitch or not please?

David Marlin – I don’t think it will do any harm but I have not seen any evidence that it would help. It does not keep midges away.

What is garlic used for?

David Marlin – In people there is good evidence for reducing LDL-C, total cholesterol, blood pressure and rate of illness. But this is at a rate of around 23g per day per 80kg, which would equate to 144g per day for a 500kg horse which would almost certainly be toxic and result in Heinz body aneamia.

I have been told feeding garlic can cause anemia, is this true in the quantities it is normally fed in as a supplement?

David Marlin – Possibly. The amount needed to induce Heinz body anaemia in horses is quite low.

What is your view on garlic? Especially in relation to a pony with sweetitch.

David Marlin – I have not seen any evidence that garlic can help sweetitch nor can I understand why it would be expected to. For example, garlic does not deter flies, contrary to popular belief.

Does the way you give garlic effect the results seen i.e. liquid, granules, powder?

David Marlin – I am not aware of any positive effects of garlic in horses.

Is it important to feed linseed in winter for vitamin E when there is no grass?

David Marlin – Linseed doesn’t contain very much Vitamin E. Linseed is great for the GI (gastrointestinal) tract and as a source of energy and protein. If you want to supplement due to deficiencies in preserved forage, then a general purpose balanced vitamin and mineral supplement with Vitamin E and C in would be a good choice.

What is your opinion on charcoal for gastric problems?

David Marlin – I would only use it short term in cases of poisoning or other toxicity.

If you’re currently feeding a joint supplement but would like to swap to another brand, what would be the best way to make the switch? Would it be similar to swapping feed?

David Marlin – No, it’s a small amount each day and there would be little risk in stopping one and starting another. You could taper one out and the other in over a week to be safe and reduce the risk of palatability issues.

Is an oil/liquid form of supplement, a more effective supplement for joints than a powdered one?

David Marlin – There is no evidence to suggest that oil or liquid have any advantage over powder. In fact the liquid supplements hold less active ingredients so generally likely to be less effective. Here is a complete list. Feed in Focus – Joint Supplement Comparison Table – Dr David Marlin

Dr David Marlin

You can find out more at drdavidmarlin.com, an independent information resource for all equestrians featuring unbiased science-based research, product reviews, webinars, podcasts and articles covering all aspects of the equine world.

Contact the Pure Feed Nutritional Team

For advice on feeding your horse to help them stay calm and focused when ridden, or for more information about Pure Feed contact our friendly nutritional team. You can email [email protected] or call 01458 333 333. You can also request a free diet plan for your horse. 

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