I have used Purina Equine Senior for over 20 years with no problems. In fact, my oldest horse died of natural causes at the age of 42.

 I have a 26 year old black thoroughbred mare that had been losing weight, even though she had her teeth floated recently and was on Equine Senior. I have been out of state for 8 months and the caretaker took the mare to an equine dentist and had her teeth floated aagain. The previous floatation was done by a regular vet and apparently not done very well. The caretaker's friend who also has been in the horse business for many years has contacted me BEGGING me to take the mare off Equine Senior and put her on "oat groats" 3 x per day instead. She said senior feeds and most pelleted feeds have a secret ingredient the government doesn't require to be put on label....ARSENIC!  She said arsenic "works" for horses because it causes weight gain. The only feeds that don't have it are the organic ones which are hard to come by and VERY expensive. She said the simple solution is oat groats...they have like 5 % fat! no hull...100 digestible.  The reason oats has been a centuries long stand by is the shelf life is long...it most closely resembles the wild grass seed heads in the wild in nutritional make up.  The groats (looks just like the oatmeal you buy at the store!) for the old horses with decreased ability to chew and slower working GI tract...She said it naturally soothes inflammation in the stomach...has good fat content and is 100 % digestible with no waste.  She beleives the molasses in sweet and senior feeds is death to the hooves. She said corn and wheat is also very bad...but she can't remember why.

I've always thought that plain old oats are about as nutritious as popcorn is to a human. I would think that a company like Purina with over 100 years of science/research in animal feed would know exactly what formula works best for a senior horse. I can't imagine oats being the answer to an old horse's feeding strategy. I'd love to hear pros and cons from anyone that reads this. I need to make a decision fairly soon on what to do. Thanks folks!
 

I would seriously doubt this.  My question is, if all of these feeds have arsenic in them, why haven't we heard about it elsewhere?  I've never heard that before.

Oats are not necessarily easier to chew.  Many horses can have trouble chewing oats.  Senior feed, on the other hand, is specifically designed to break apart so that older horses can chew it.  Oats are not very nutritious; for a younger horse who only needs to be maintained, you could certainly get by with just oats and high-quality hay, but a senior horse needs the nutritional support that is not provided by oats.  Oats are also usually high in sugar, which will make a horse hot (every heard the term that a horse is "feeling his oats?"  That's why).

The other thing is, if your mare eventually gets to where she doesn't have many teeth, you can just soak some senior feed for her and make a mash and she'll be able to eat it.

Although it is true that oats have good fat content and are relatively easy to digest, I think that the good outweighs any bad in the senior feed.

 What the heck?  I think your friend might be a little off their rocker with that one.  No, there are NO "secret government ingredients."  And I don't even feed Purina, so I have no ulterior motive in saying that.  Also, arsenic is a naturally occurring chemical found in, for example, apples.  However, that is organic arsenic, which is non-toxic.  The inorganic form can be toxic once it reaches a certain level, but your horse is not being poisoned by its Senior feed!

There is naturally occurring arsenic in many things ---- including ground water but don't take my word for it.

http://toxics.usgs.gov/highlights/arsenic_gw/

I have been feeding rice bran to four horses for more than four years.  Because two of them have metabolic issues, which were BEFORE the rice bran, everyone gets physicals twice yearly.

They are all healthy, their winter coats glisten in the sun and everyone's hooves have a beautiful natural shine to them -- as soon as I brush the mud off. 

The bottom line is we would probably all be in shock if we knew precisely what we are eating, drinking and feeding our animals

I agree with others. Senior Feed is especially important. I only have two other comments, and I have no connection with feed companies but am a physician. I noticed that in one week 3 horses in our boarding barn choked on Purina Senior. All were even being wetted! I noticed that after 30 minutes you could put your hand in bucket and still feel BB's of rock hard pellets and feed expanded 3-4 TIMES the volume with water! I contacted Purina because I wanted to understand if they pellet their beep pulp and later combine with other pellets, which would be a logical cost efficient method but might result in settling of beet pulp pellets to bottom or top of bag and contribute to choking. Vet staff was curt and unbelievably nasty to a logical question from a medical professional that wasn't "accusing" them of any wrongdoing. Same question posed to Triple Crown Senior got me a 45 minute scientific consultation which was a blast of intellectual info and no bull either. I switched feed to Triple Crown Senior, and Horse Journal had a wonderful article about the thought and "locked formula" and why that is especially important in a senior horse. It smells AWESOME. It makes a wonderful warm mash in 5 minutes on cold days. It has taken a 23 year TB to look many years younger! He's shiny and happy again. Then vet mentioned he is getting very good results with Platinum Performance supplement. I added it to mine and I swear that senior TB got his first thick winter coat EVER and people thought he had died and I got a new horse! I am VERRRRY skeptical on vitamins in humans and animal supplements but Platinum Performance truly has made a huge difference in my senior horses! Just thought my experience might help others with feed issues in senior horses.

I've never heard anything about the arsenic and I'm sure that if it were true we would all hear a lot of controversy about it.  That being said, I think you should stick to the senior feed.  If it's a sweet feed, I might suggest switching to a pelletted version.  The added sugar in the sweet feed can cause a lot of metabolic problems with your horse.  If your horse has problems chewing, soaking the pelletts could help make them easier to digest.  I would also suggest feeding a lot of hay and making it available throughout the entire day.  This allows for the most natural diet and can help keep weight on.  Also make sure that your horse's teeth are done regularly (1-2 times a year) and that you are blanketing adequately so that the horse doesn't expel extra energy trying to stay warm.