Sodium chloride (salt) is an essential aspect of the equine diet. Sodium plays a crucial role in many body processes such as the maintenance of body temperature, nerve function, chemical transport, regulation of pH and regulation of osmotic pressure. When sodium is deficient in the diet there can be a plethora of negative health consequences including poor performance, decreased appetite, weight loss, decreased fertility, impaired milk production etc. This is why it is crucial to ensure that we are providing our horses with adequate salt in their diet.

What does the research say?

One study that evaluated the feeding practices of active eventing horses found that most of the horses were not having their sodium and chloride requirements met. 20% of the horses did not have access to salt supplements at all and 45% of the horses had no access to salt on competition days.

Another published study that investigated salt intake found that voluntary intake from a salt block ranged from 0-62 mg per kg of body weight per day. The variation between horses was large, but the individual horses did not have large variations in salt intake day-to-day.

Lastly, when we look at the evaluation of salt intake from a block when the diet is not meeting sodium and chloride requirements it has been calculated that there is often an insufficient intake of sodium despite the animal having unlimited access. Overall, based on the published literature, it points towards a salt block not being sufficient at providing the horse with enough sodium and chloride to meet their requirements. Despite this, as a nutritionist, I still recommend that my clients give their horses free choice access to salt as many will still lick a block even with their requirements being met in their daily ration. So, which block type do you choose?

The Various Types:

There are a wide variety of salt block options for horses, but in this blog post, I am simply going to touch on the four that I come across most frequently.

1)      White Block

• The white salt licks are generally just sodium and chloride. They will also occasionally contain iodine depending on the brand.

2)      Blue Block

• The blue blocks contain cobalt. Cobalt is a trace mineral that is important in the synthesis of vitamin B12.

3)      Brown/Red Block

• The brown or red blocks contain other trace minerals. It will vary slightly from brand to brand, but they generally contain zinc, copper, selenium and iron.

4)      Himalayan Salt

• Himalayan salt has a higher concentration of iron and does contain other trace minerals. The trace minerals are present in minute quantities.

Despite some containing trace minerals, they are still primarily sodium and chloride.

Recommendations:

Prior to recommendations, I would like to highlight the personal aspect of salt block intake. An observation I have made over the 9 years of owning my mare is that she has never touched a salt block (and I’ve pretty much tried every kind!). On the other hand, a horse that lives with her will consume a salt lick in a matter of days…and they are on the same ration balancer with adequate salt provided in their daily rations. This is why it is important to work with a nutritionist that will reach this level of personalization in their recommendations.

My recommendation for salt blocks is to always give your horse free-choice access. The gold standard is to have all their nutrient requirements (specifically trace minerals) met in their daily ration and not rely on the salt block as it is hard to guarantee intake.

From there, I would choose a salt lick based on your horse. If they are going to consume it within the week, I would exercise caution around the trace mineral blocks and use a plain salt lick. However, if they do not readily consume it – they are likely not going to be consuming enough trace minerals to unbalance the diets. So, in that case the trace mineral block is likely safe.

When balancing, I always recommend a ration balancer that will meet their needs, then adding loose salt to that. From there, you can go with the plain salt lick as those are typically less expensive!

If you have any questions or would like your horse’s diet evaluated, please contact me at balancedbaynutrition@gmail.com

Written by: Madeline Boast, MSc. Equine Nutrition

About the author: Madeline Boast completed her master’s in Equine Nutrition at the University of Guelph and started an independent nutrition company known as Balanced Bay. She has worked with a variety of equids – from miniature ponies to competing thoroughbreds. Through Balanced Bay she designs customized balanced nutrition plans that prioritize equine well-being. This includes diets for optimal performance as well as solving complex nutritional issues and everything in between. For additional information see www.balancedbay.ca