Ask Horse Journal: 01/06

Arthritic Cushing’s Horse
I recently inquired to various companies regarding joint supplements for my 17-year-old gelding, who seems to be developing some mild creakiness/arthritic symptoms.

One of the companies sent me several Horse Journal reports from various years, including product comparisons similar to what I have seen in your magazine previously. I am still stymied as to what the best product for my horse would be, because I am dealing with a possibly insulin-resistant horse and have heard that some ingredients may not be safe for these horses.

The safety of various joint supplement ingredients in horses hasn’t been studied, so no definitive warnings can be made. One thing you need to watch out for is sweet, sugary bases in liquid products, or even powders.

There are anecdotal reports from owners of insulin-resistant horses that products containing glucosamine were thought to have triggered a laminitis attack, although it’s also true that there are insulin-resistant horses on glucosamine-containing joint supplements that do just fine with it. It’s true that intravenous glucosamine can induce or worsen insulin resistance, but so far no studies have found that to be the case with oral glucosamine. Many insulin-resisistant-horse owners choose to avoid it “just in case,” rather than risk finding out the hard way their horse may not tolerate it. In other species, yucca has been found to induce insulin resistance, so that is probably something you should avoid until we know if the same is true in horses or not. There are no known contraindications to using hyaluronic acid or chondroitin sulfate.??

It’s also important to realize that low-grade laminitis pain is commonly mistaken for arthritis, and horses that are trying to protect tender feet will overload the joints in the hind legs. Any insulin-resistant horse that seems to be showing signs of new or worsening arthritis, especially in the hocks, should have the front feet blocked by a veterinarian to make sure the real problem isn’t actually the feet. More often than not, the arthritis symptoms will immediately disappear.


Pregnancy And Pain
My mare has been in foal about 90 days.?? Because of a missed diagnosis, I now know she is permanently lame (collapsed pastern joint, ringbone) from an injury that started with tendon damage and a sesamoid fracture.?? I give her Recovery EQ and a combination glucosamine, chondroitin sulfate, HA supplement.?? I know I cannot give her??bute and devil’s claw. Is there anything safe to use for pain relief in pregnant mares’?? ??

You’ll probably get better control of the pain with nondrug/supplement approaches. First, find a hoof angle that is most comfortable for her and results in even loading of the pastern joint. She needs frequent trims to make sure her foot is meticulously balanced and she has easy breakover. Assuming this is articular ringbone (close to the joint), it is the pastern joint’s effort to fuse, which will eventually make her much more comfortable since there is not much natural movement to that joint anyway. In the meantime, you may find that a magnetic wrap or, better yet, electromagnetic therapy provides her with pain relief. You can lease an electromagnetic therapy boot from (, 203-481-2810). We suggest an hour/day of the electromagnetic treatment, with an ice pack over the pastern during treatment. This is a Velcro-secured leg wrap so you don’t have to actually be standing there the whole time, just crosstie her.


Rusty Water
I have a situation that is troubling and I can’t find much information to help. My water in the barn has had a little iron in it for years. The buckets will have a rusty color develop after months of use. Now the rust/iron content seems to be increasing. I have a 19-year-old mare who is becoming hard to keep weight on, and I know this could be age, but I am wondering how long term iron in the water may be affecting her and the other younger horses. She has been drinking this water for 14 years. Now that it is increasing I feel I need to find out more about it as soon as possible.

Iron is a potentially toxic mineral when present in excess, but iron overload has not been studied in horses beyond one short-term feeding study. In horses, all we know for sure is that foals are easily poisoned, even killed, by iron (true for the young of all species) and that high iron even over short periods results in zinc deficiency. What hasn’t been studied is the potential consequences of long-term high intake. In other species, iron loading causes joint pain/arthritis, fatigue, insulin resistance, eventually liver and heart muscle damage. Whether your horses are at risk from the water, though, depends both on how much iron is in it and how much iron is in the rest of their diet. You can have them tested for iron overload by asking your vet to submit blood for serum iron, transferrin saturation and ferritin to the Comparative Hematology Laboratory at Kansas State,

Click on “iron panel request form.” If you don’t have web access, call them at 785-532-4424. There are special instructions for handling of the sample so it’s a good idea to have your vet talk to them beforehand to make sure she/he understands what’s required. KSU is the only place that can do this panel. Any other lab offering it is sending it to KSU anyway, which means more opportunity for the sample not to arrive in good condition.


Vitamin A
How many IUs per pound is a concern when it comes to vitamin A intake’ I don’t want my mare to get into a toxic state, and I’m not sure how to even know she’s having problems. She gets about two pounds of carrots per week, and I recently started her on a vitamin supplement that gives her 25,000 IUs per day.

Increased intracranial pressure is likely to manifest itself as a headache, certainly a tough diagnosis to make in a horse where signs would be nonspecific (depression, irritability, mildly elevated pulse and respirtator rate indicating pain). Edema of the optic nerve may be found on an opthamologic exam. The bone pain will likely present as a shifting lameness.

We sympathize with your predicament. Many readers share your concern. Let manufacturers know about it. In the meantime, pick and choose your supplements carefully.

The cautions about supplementing vitamin A refer to A in the form of retinols, which are biologically active. On a supplement or feed label, this will usually appear as “Vitamin A,” although you will sometimes see the terms “trans-retinyl palmitate” or “trans-retinyl acetate” instead. Retinols are not found naturally in plants or grains. The form of vitamin A the horse would normally consume is provitamin A, also called carotenes. This is a safer form since carotenes have no direct vitamin A activity. They have to be converted to retinol in the intestine. This process is not very rapid and can probably be regulated by control of the converting enzyme. This is nature’s way of protecting the horse from excessive vitamin A.

For example, alfalfa contains extremely high amounts of provitamin A, but vitamin A poisoning does not occur even in horses on 100% alfalfa hay. Carrots are also a rich source of vitamin A. Two pounds of carrots has the potential to produce about 25,000 IU of vitamin A, by conversion of carotene to retinol. The amount of retinol in your mare’s supplement is equivalent to 83% of the optimal intake of 30,000 IU/day. These figures are for an 1,100-Ib. horse. Your mare may not be this heavy, so the percentages in her case would be higher. This level is probably safe, as long as you are not feeding any other sources of preformed vitamin A but also likely unnecessarily high. Be sure to check your feed bag labels too. Vitamin A is commonly added at between 3000 and 6000 IU/lb. To help you with your totals:

Bare minimum daily requirement is about 20 IU/kg of body weight/day. A kg is 2.2 Ibs.

Optimal daily intake estimated to be 60 IU/kg of body weight/day.

Estimated upper safe intake limit 320 IU/kg of body weight/day.

Carrots contain about 12,500 IU/lb (as provitamin A – carotene).

Timothy hay less than 6 months old, average about 18,000 IU/kg (as provitamin A – carotene) Legume hays less than 6 months old, 20,000+ IU/kg (as provitamin A – carotene).

Hays over 2 years old – all activity lost (progressive decline from 6 months).

Straws and bleached hays average around 1000 IU/kg.


How Much FlaxSeed
I really liked your article hoof-care article in the October issue, but how much flaxseed do I feed’

Feed two to four ounces of whole or ground flaxseed per day.


Biting Gelding
I have a mare and a gelding. We bought the mare in April and she replaced another mare that died. The first mare was the gelding’s best friend. Now, I’m wondering if I have to replace the second mare.

My gelding bites the new mare like crazy. I can’t separate them either, due to a lack of space. My veterinarian said the gelding is probably depressed at the loss of his friend. What can I do’

We agree with your veterinarian that your gelding misses his old buddy. He is also probably trying to establish himself as the boss with the new mare. Replacing her might not work. Some horses simply just don’t adapt well to another horse.

New horses must be introduced slowly. When it is possible to do, keep them separated at first, with no contact beyond sniffing. This will help minimize fighting when they’re actually together. Obviously, your gelding now knows this mare, but backing up a bit might help.

Also, his attitude might change if he thinks he’s going to lose her, too. Try to find a way to separate them even for a few hours, such as putting her in a trailer or taking her out alone, then gradually reintroduce them. In addition, make it clear to the gelding that the behavior is unacceptable.


Winter Door Tips
We keep a sweat scraper and hoof pick at the door of the barn during winter, so we can scrape snow/ice off our horses’ backs before we bring them in the barn. We also pick out their hooves right at the door to avoid any slipping from snowballs in the hooves. The Oster sweat scraper and hoof pick are excellent for these tasks, with a heavy-duty feel and good grips ( 800-830-3678). And don’t forget to put some kitty litter or sand on top of snowy/icy pathways to add traction and reduce slipping.


Simple Horse Toys
If horses in stalls become bored and start to develop annoying vices like pawing, chewing, stall walking or weaving in their efforts to have something to do, it may help to give them a toy to occupy their minds and their time. A durable rubber ball (get the ones made for horses, which he won’t be able to gnaw through) may divert him; he can chew it, paw it, root it around or pick it up with his teeth, to entertain himself.

Some horses enjoy hanging toys. Well-washed plastic jugs (clean old milk jugs, bleach or vegetable oil bottles) can be hung from the ceiling or high on the stall wall (using doubled baling twine) for the horse to play with. You can fill some with small pebbles or rice to create a rattling toy. If a horse gets bored with one type of toy you can give him a new one.


Keep Birds Out Of The Barn
If birds are a problem in your barn, try installing a revolving amber light in the loft, or up near the rafters. Birds are deterred by the moving light. The light can be purchased at an auto-supply store.


Fast Fence Repair
To make quick repairs to fences, keep your equipment at the fence line. Use a five-gallon empty plastic supplement pail with a secure top and store all the tools in it you would need to restore the integrity of your fence. Place it near a gate.

Put nails and staples in an old coffee can or plastic peanut butter jar and set them in the pail. Add a hammer???cheap at most garage sales???insulators, a voltage meter, short lengths of wire or electric fence tape, and fencing pliers, if necessary. Place a substantial rock on top the lid, and the kit can sit there year around.

Instead of walking all the way back to the barn and assembling everything you need, or even possibly letting the job slip your mind, you can make immediate repairs, hopefully preventing escape and/or injury. Just don’t forget to replace your inventory a couple times a year.