Revised:  01/10/2013

Ask the Expert -- Nutrition

















How do I manage my broodmare on fescue?

I had some reproductive issues this past year, so I recently had fescue samples tested. Two samples were sent with an infection rate of 27% and 37%. Some pastures may contain 70% fescue and others much less. Unfortunately the fields with the greatest percentage are the ones used for the broodmares. We are not able to close down fields for extended periods of time due to our high population. Would this percentage of infestation be significant enough to cause reproduction problems?


I would not risk your babies or mares by feeding fescue. It is hard to say if that infection rate is "safe", but if you are really concerned, I would not trust it. I usually recommend that people with fescue is remove the mares when they are 30 to 90 days from foaling. I don’t know what your management situation is, but if you have a way to do this, do it - it is the best option. Removing them could be as simple as putting them in a pasture with less or no fescue, or keeping them in a barn or dry lot and supplementing their diet with hay to replace the pasture forage. The other option is to give Domperidone in their last trimester, but this is a pretty expensive option. The reproductive problems you would most likely see are retained placenta and agalactia (lack of milk production). Other problems like late term abortion or premature separation of the placenta could also arise.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



What are good grasses for a horse that has foundered?

I am wondering what combination of grasses you would suggest to reseed a pasture for horses that need low-carbohydrate, low-sugar feed due to a tendency to founder/develop laminitis?




All of the cool season grasses that would thrive in most parts of the country will accumulate fructans and sugars under certain environmental conditions. Timothy and Cocksfoot have been reported to accumulate less than ryegrass, however.


The highest sugar accumulations are after cold (< 32 degrees Fahrenheit) overnight followed by bright sunshine, just after cutting, or during droughts. As long as the temperature overnight is above freezing, the lowest content of sugars is between 4 AM - 10 AM. Also, grasses accumulate more sugars in May and late August/September.


So, restricting access to only the early morning hours during the summer, and keeping at-risk horses off pasture or a day or two after mowing, if there is a drought or after an overnight freeze would be your safest approach.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.



Can foundered horses ever eat grass again?

I have an 18-year-old Thoroughbred that foundered. She has been on the same pasture every day of her life for the last 9 years. She has been off pasture for about 6 weeks and is recovering very slowly. She is thin and I thought a good walk through the pasture once a day would not only allow her to gain a little weight but force her to walk a little more, which should promote hoof growth and recovery by maintaining the blood supply to her hoof. She is suffering from an abscess in her hoof that I pack with a poultice every day. She has egg bar shoes on with hospital plates to keep her soles clean and protected. More walking might promote better drainage of that abscess as well. What do you think?


How much walking she can tolerate really depends on how severe the rotation in her hooves is. I would consult with your veterinarian on that issue. Yes, the walking will help with circulation to the hoof, but if there is severe rotation of the pedal bone it could also cause more damage.


Very dry conditions could have led to an unusual accumulation of carbohydrates in the pasture grasses that triggered the founder. Rains and cool weather should reduce the risk, but you want to re-introduce her to pasture slowly since she has been off it for over two months. If you reintroduce her to the pasture, make sure you let her graze only in the early morning (6AM to about 11AM) when the sugar content of the grasses is lowest. If it is cloudy, you could leave her out longer than if it is sunny and warm, which stimulates the grasses to accumulate sugars. If there is an overnight freeze, do not let her graze-the grasses accumulate more sugar and have not yet converted from the previous day's production to fiber! Gradually increase the amount of time you let her out.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.



Should foundered horses be allowed to graze on pasture?

I have a 20-year-old Morgan gelding who foundered in 2003. It was not severe and there was less than .5-degree rotation in the left foot. Since then I have been careful about his diet and grazing time. He had no episodes at all in 2004. At the end of this August (during a drought period) he started to exhibit pain in the front feet so I've kept him in a deeply bedded stall since and have been giving him 2 grams of Bute a day. Now he is about 90% sound at the walk and I started letting him out to graze for 15 minutes twice a day. He is starting to get bored and anxious in the stall and I would like to turn him out for longer periods but I am worried that the grass at this time is still too potent. What is your recommendation for acclimating this type of horse to grass? Is there a way to tell when the grass is safe for him to eat? At what increment should I increase the grazing time? Would walking under saddle be a problem if he is sound? He does not do well with a grazing muzzle.


It is unfortunate that he does not tolerate a grazing muzzle, for that would be the best solution. The short walks under saddle should not be a problem. Fall is the most dangerous time of year for laminitis prone horses because the grasses are accumulating significant amounts of starch and sugar for the winter. The issue is not so much how to acclimatize him but when to let him graze. As long as there has not been an overnight freeze (which prevents the previous day's sugars from being converted to harmless fiber) the early morning hours are safest, up to about 11 AM or so. On cloudy cool days you can leave him out longer than sunny warm ones, especially if there has been plenty of rain. Grasses accumulate more sugar during a drought too! Five- to ten-minute increments should be safe, but back off under the "danger" conditions. Also make sure he gets his hay or beet pulp before turning him out so he won't be as hungry.


There isn’t enough information at this time to give more exact recommendations, so in the meantime erring on the side of caution is probably best.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.


How long do frozen pasture grasses stay high in sugars?

I have read that fall is a cautious time for grazing a sugar sensitive horse if the temperature falls below freezing overnight followed by a warm sunny day which results in a spike in sugar content. Does this hold true throughout winter, too? What if it is the middle of winter and the grass is brown? Where I live, this scenario will be common all fall-spring. Is it safe to graze a few hours per day or not at all?


No, this situation does not continue throughout the winter months. Once the grasses completely stop metabolizing (i.e. hard freeze for prolonged periods of time), they go dormant and no longer produce any sugars. Normally, grasses make sugars during the day through photosynthesis, and then use the sugars for growth and other processes at night. The most critical situation is when there is a frost overnight so grasses do not use up the sugars, followed by a thaw during the day when sugar is produced again. This is when horse owners with metabolically challenged horses need to be cautious. Be aware that dormant winter grasses store sugars and starches in the roots and bottom of the stems for re-activation in the spring. If the pasture is overgrazed to the point that horses are biting off the grass stems at the roots, some metabolically challenged horses unaccustomed to pasture access can still experience adverse reactions.


Recent research at North Carolina State University (NCSU) found that horses will actually consume more than one would think when grazed for short periods of the day (3-4 hours). Traditionally, we have assumed that if a horse grazes for 1/6 of the day that means it would consume 1/6 of the grass it would eat in an entire day. Conversely, the NCSU research suggests that if the horses know they are only outside for a short period of time, they eat more rapidly and can consume almost their entire daily allotment in just a few hours. Using a grazing muzzle and leaving horses out all day or a half day is actually better than only partial day turnout because they benefit from time outside, but are less likely to overeat grass. As an added bonus, the muzzle also prevents them from clipping off the grasses at the roots.


In the case of horses prone to metabolic problems, be aware of cold evening freezes followed by bright sunny days while the grasses are still green and active. If this is your daily pattern and your horse has Equine Metabolic Syndrome, you might be safer finding a dry lot and feeding them hay until the grass goes dormant for the year.



Are grass clippings safe to feed to horses?

I have a question regarding grass clippings - is it safe to feed them to horses? If not, why? Also, what is the difference between feeding grass clippings vs. turning a horse out onto a grass pasture in the springtime?



Usually when referring to grass clippings for horses, most people are thinking of lawn grass. Lawn clippings are generally not the best source of nutrition because the turf grasses used for lawns are not nutritionally balanced for horses. If fed as a treat in small quantities it would be okay, but it should not be used as a major part of the diet. Also, some sources of lawn grasses contain endophytes that may be toxic to horses, so it is a very good idea to know what types of turf grasses were seeded before feeding them. However, Lucerne (alfalfa), pasture grasses, and chaff are perfectly adequate forage sources for horses and are okay to be cut and fed. Just be cautious not to let the clippings sit in a pile long enough for them to mold. Feed them right away or spread them out so they will dry instead of collecting moisture and molding.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



If I graze sheep with my horse, will that increase the sugar content of the grasses?

Lore has it that grass recently grazed or cut is high in sugar content. Does this mean that the practice of grazing a few sheep with a horse to keep the grass down is not advisable? The pasture my horse is in is long and has mostly seeded. Some parts are grazed short, about a third of the one acre field. I was thinking this was quite good, as he leaves the long grass alone for the most part and grazes the smaller area of short grass. The owner of the farm wants to tidy up the field and has put five sheep on it with him, but I am anxious about this both increasing the area available for my horse to eat, and raising the sugar content in the grass grazed. As he is an easy keeper stallion who already has a stallion 'crest', I am a bit concerned but lack the data to back up the request to remove the sheep. I keep him in from 12:00 – 7:00 pm currently to keep the sugar content as low as I can?



Even though there is not much research on pastures grazed specifically by sheep, the situation would be similar to mowing the pasture regularly to keep the grass height uniform. As you suspect, the sugar content is higher in grass that has been grazed shorter or mowed. This is because the grasses are trying to grow and produce seeds, and in order to do that they need to produce sugar for energy; therefore, grass will accumulate sugar and use it for growth. Taller, more mature grasses do not put energy into growth, but once they go to seed, they also produce sugars in their seed heads. If sheep are pastured in with this horse, they will graze down the taller grasses, making the field more uniform; however, they won’t graze the fields as low as horses do. Horses can graze grasses down to less than an inch tall, which really stress the grasses. Sheep leave the grasses longer, so while they will be higher in sugar than those very tall grasses, they will not be as high in sugar as the very short grasses your horse prefers to eat.


As for the best time to graze a horse that is sensitive to sugars, research has shown that grasses accumulate sugars throughout the day to be used when the sun goes down at night. On a sunny day, the sugar content will be at its highest in the afternoon and late afternoon hours when the sun is at its highest and before it sets. Then grasses start to use the sugars in the evening, so the lowest point of sugar content (if the evening temperatures haven’t been low enough to turn to frost) will be after midnight until about 10:00 or 11:00 am. This may not be the best grazing time for management purposes, but this is why a lot of people turn their horses out at 6:00 am and bring them in by 11:00 am. Unlimited turnout on lush pasture can lead to obesity in a lot of horses. If a horse is also being fed grain concentrates, one may want to cut them back if its energy needs are being met by the pasture. Remember, forage is the base of the ration and grain concentrates are only necessary to supplement the energy not provided by forage!


You will also need to be careful in introducing sheep into a pasture with a stallion; he might become aggressive toward them.





Which is better: oats or pellets?

I am engaged in a debate over nutrition with the barn owner where I currently board. Several of the boarders, including myself, feed a pelleted feed; but the barn feeds straight oats. They have mixed some oats in with the pellets of the boarders. The barn owner insists that pellets are a low quality feed and that the ingredients used are cheap and inferior. However, my experience with my pellets has been good. The horses’ manure is always full of oats or oat hulls. My feeling is why feed something they can't totally digest when science and technology has provided a better substitute? I would appreciate your opinion of commercially available pellets and their effectiveness or nutritional value.


Pelleted feeds from the major companies, especially the premium product lines, are made from good quality ingredients and are under careful quality control. They are more balanced with respect to minerals and vitamins than straight grains like oats and tend to be more digestible.


The hulls of oats tend to be indigestible, which is why you see them in the feces. There is no real problem with that. While oat kernels are a good source of energy, they do not supply the calcium and minerals needed for proper bone development of young horses. Even with abundant good quality hay, young growing horses should be on a commercial mix (pelleted or otherwise).


Pelleted feeds got a bad reputation early on when they were first introduced in the 70's because some were made from inferior ingredients. However, the reputable companies do not include substandard ingredients in their top of the line products. Pellets are more balanced, and you can easily pick a product with the nutrient profile you need (e.g. higher fat for a hard keeper, low starch and fat, high fiber for the easy keepers, etc.) without adding supplements.


Answer provided by Sarah Ralston, VMD, Ph.D., dACVN, Rutgers Cooperative Extension.



How do I adapt my horse to pasture?

I have a 5 year old Irish Sport Horse in good health, but a little on the chunky side at 16.3hh. He is currently receiving timothy hay, 4 pounds of oats and 4 pounds of sweet feed per day. His turnout has been basically rocks and dirt for the last two years. I will be moving him soon to a new barn that has ample pasture turnout. I'm hoping you can give me some advice on how to acclimate him to his new surroundings to lower the risk of founder and colic. I have been hand grazing him a couple of hours per week at his present barn. Do you have a schedule that I can follow, or time spans that would be preferred? How long should I maintain a transition schedule?


Hopefully the barn you are moving to will help you with a bit of flexibility during your transition time. Your horse needs to adapt gradually to turnout on pasture if he has no access to it now. The hand grazing now is fine, but when you get to the new barn I would recommend about 2 hours of pasture turnout per day for the first couple of days. Then gradually increase the turnout over the course of 3 weeks until he is up to the full amount.


Assuming it is half-day turnout, you can easily increase the amount over 3 weeks to get up to 8 to 12 hours of pasture consumption. If it is a full 24 hours of pasture, you might want to extend the adaptation to 4 weeks. However, if he is a bit chunky now, I would be concerned that he will gain more weight on the pasture, so along with increasing the pasture over the course of the 3 to 4 weeks, I would recommend cutting the oats and sweet feed ration in half. Pasture has plenty of fiber, sugars, starches, and protein to make up for the decrease in the grain meal.


Answer provided by Carey Williams, Ph.D., Rutgers Cooperative Extension.



The material provided on this site is for educational purposes only and is not intended to diagnose, prevent, or treat any illness. Any recommendations are not intended to replace the advice of your veterinarian. Any products mentioned are not intended to diagnose, treat, cure, or prevent disease. Mention or display of a trademark, proprietary product, or firm in text or figures does not constitute an endorsement by the Equine Science Center or Rutgers University and does not imply approval to the exclusion of other suitable products or firms.







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