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Feeding Chart
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Active Dog - At least 30 minutes of vigorous exercise daily
Working Dog - More than two hours of vigorous exercise daily
This is only a guide. Please consult your veterinarian to determine the perfect feeding amount for your dog.
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Product Overview

Ideal nutrition for horses fed alfalfa

Mega-Mag™ (Pellet) is a well-balanced multi-vitamin and mineral supplement formulated to coincide with current NRC (National Research Council) recommended daily requirements, to accommodate feeding programs consisting of alfalfa hay/grain based diets. The addition of live, stabilized direct-fed microbials, live cell yeast culture, and amino-acid content, sourced from alfalfa meal, rice bran, and soybean meal makes Mega-Mag™ an excellent choice to support growth, stamina, conditioning and maximum performance for all disciplines.

Note: To accommodate feeding programs consisting of grass-type hays (timothy, coastal, Bermuda, native grass)/grain, choose Mega-Cell™.

  • Comprehensive selection of vitamins & minerals plus probiotics, yeast & amino acids
  • Formulated to coincide with current NRC (National Research Council) recommended daily requirements

Learn More

Key Ingredients


Supplement Facts

Ingredient Name Amount Per Serving
Ingredient Name Amount Per Pound

Ingredient Details


Weight Recommended Amount Loading Amount

How the Ingredients Work


Supporting Success

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    We take the guesswork out of serving sizes, ensuring your horse gets the right amount, every time. SmartPaks have airtight seals to ensure that your horse always has the freshest supplements available. Your horse is unique and his supplements should be too. Choose from over 230 supplements to get everything he needs, nothing he doesn't. We print your horse's name on every Pak so there are no mix-ups, making feeding time fast, accurate and easy! Unlike most buckets, SmartPaks are made from recycled plastic and can be recycled again! We'll send your SmartPaks on time so you never run out, with total flexibility and no commitment. Plus all SmartPaks over $40 receive free ground shipping.


The reviews provided on this website represent the experience of the individual posting the review. We do not adopt, edit, or endorse any of the submissions posted within the reviews section. Rather, the reviews are part of an online community of animal owners that desire to share their particular experience with other individuals. These reviews are not a substitute for discussing the health of your animal with a veterinarian.

SmartPak customers are some of the most conscientious animal owners around. We encourage you to share your experience with the products we sell to help fellow customers to make informed choices for their animals. We do not edit these reviews in any way - they are direct customer-to-customer communication. We do monitor reviews for positive and negative feedback, and use this feedback to improve our selection as well as sharing feedback with product manufacturers to help them improve their products. Please note that we recommend consulting your vet with serious health issues.

Mega-Mag™ is rated 4.7 out of 5 by 60.
Rated 3 out of 5 by from Great Ingredients, But Made My Horse Aggressive I really liked how well-rounded this vitamin was, but after about a month of use, my horse's entire demeanor changed. He became very aggressive and 'hot,' and after speaking to stable hand about another horse who'd been on it and became aggressive, I began to consider weaning him off. I then spoke to the trainer and the vet, we agreed to wean him off of it and see if it helped. He's been without it for about a week and a half, and his demeanor is back to normal. I think perhaps it's too high of a concentration of nutrients for some horses, mine being one of them. He's on high quality hay, so I think it was perhapps causing a nutrient buildup of sorts. However, your horse is on lesser quality hay, I think this would be great inclusion to their diet.
Date published: 2022-04-19
Rated 5 out of 5 by from PICKY EATER APROVED! Horse was Diagnosed with Headshaking Syndrome back in June '21. After lots of research, I decided to try this product out. Seams to be doing a great job with my gelding. One major decision on this supplement was that is was picky eater approved and in pelleted form. I would for sure give this a try.
Date published: 2021-08-12
Rated 5 out of 5 by from a good vitamin supplement I got this product because I was already feeding a vitamin supplement AND a magnesium supplement separately. It was more cost effective to feed this ONE supplement instead of two. Plus its pelleted; which is way easier to feed than powders. I havent seen any changes in my horses and that's a good thing! The extra magnesium was having a calming effect on my "over reactive" geldings. This supplement has the same amount of magnesium and seems to be doing the job. However, I recently noticed that it is more for horses on alfalfa, and mine are on grass, so I will be switching to the Mega cell on my next purchase. Same amount of magnesium, but formulated for grass hay and pasture.
Date published: 2021-07-12
Rated 5 out of 5 by from Relaxes muscles This helps my older horse with a stiff back. When she is on magnesium she warms up more quickly.
Date published: 2020-10-05
Rated 5 out of 5 by from Great for OTTB! 3-4 year old OTTB mare who is on 50/50 alfalfa and grass hay diet responded BEAUTIFULLY to this--especially her weight and topline, the "dip" between her neck and withers disappeared! Feet look great, coat is blooming. She will stay on it!
Date published: 2020-07-21
Rated 5 out of 5 by from Great vitamin supplement Very palatable, and has everything the horses need.
Date published: 2018-09-10
Rated 3 out of 5 by from Horse spit it out Bought this because of the desired ingredients. Gave my horse a scoop by hand and he spit it out ... two days in a row. Doesn't smell very appealing. Because he will leave his entire grain ration with his meds in it, I don't dare use this.
Date published: 2018-08-19
Rated 5 out of 5 by from I bought this for my mini mare that was in need of a good vitamin. Love the pelleted form and she had no problem eating it all up !
Date published: 2017-10-19
Rated 5 out of 5 by from Great product! 30days in and we have had a very noticeable difference in our mare who has tons of anxiety and little focus when off the farm
Date published: 2017-06-28
Rated 4 out of 5 by from Multi-Vitamin I really like this product--I love the pelleted format, and I am confident that the product is supplying the correct amounts of vitamins and minerals to complement his alfalfa-based diet. However, this is the first supplement I have encountered where no scoop is included for measuring. Typically a scoop is included by the manufacturer for accurate measuring, and I was disappointed to find that there was nothing included in this bag of supplement. While I think it's a great product and my horse eats it with no problem, I am unsure that he is getting the exact amount required.
Date published: 2017-02-21
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