The following is an edited transcript of Nicole Erwin's interview with Dr. Amanda Adams, an associate professor at the Gluck Equine Research Center at the University of Kentucky. Click below to hear the full audio:

Nicole:         Senior horses make up a large majority of the hobby horse population. Like humans, they have special dietary requirements for the support of healthy aging. How should you feed your senior horse? I'm talking with Dr. Amanda Adams, an associate professor at the Gluck Equine Research Center at the University of Kentucky. Welcome.

Amanda:       Thank you. It's great to be joining you here.

Nicole:         With more than 10 years of experience in the equine health industry, you focus on the immune system of the geriatric horse. Can you talk to me a little bit about what moved you in that direction?

Amanda:       Yeah, sure. I guess from an early age, I had an interest in and studied the immune function or immune system of the horse. In my Ph.D. program, my focus was the impact of old age on these immune responses. After the Ph.D. program, I stayed on for a post-doctorate and continued my research program with the geriatric horse and kind of expounded upon that.

                    We don't just look at how age affects immune responses in these horses, but we're also investigating how senior horses are affected by endocrine diseases and, then, how we can modulate both of these through nutrition. How can we support the immune system through nutrition, and how can we regulate some of these endocrine diseases that aged horses are suffering from? I was born and raised with horses and always had an interest in horses. I think it was a natural movement to go on and make them a career, or part of my career, instead of a hobby.

Nicole:         At what age does a horse enter into the geriatric bracket, or is it different for every horse?

Amanda:       That's a good question. How do we define age? We can define age chronologically by the number of years that the animal may be — 15, 16, 17, 18 years of age. But more so, we're interested in the biological age of the animal. A 30-year-old may be healthier in some circumstances compared to a 25-year-old. It's really about the biological age or what's going on physiologically with that animal; it's not just a number by chronological years.

                    Now, we sort of classified senior horses as being over the age of 15, or in a lot of our work that we do, we consider them to be senior over the age of 20. We see a lot of those physiological changes occurring at the age 20. I tell people, "Don't forget about your 15-to-20-year-old horses.” Over in Europe and Australia, they consider senior horses to be over the age of 15.

Nicole:         Why is that?

Amanda:       It’s just a different population of animals, and I'm not sure actually why they chose 15 as their cut-off. But, when you look at the epidemiological studies that are trying to get demographics around how many old horses are out there, they set their cut-off at 15 years of age and older to determine the percentage of old horses in their populations.

Nicole:         Easier to group things.

Amanda:       Yeah, probably. That's where you start to see maybe some of the horses not being reproductively active, and sort of coming out of being sport or show horses, breeding, et cetera. But it's really not uncommon nowadays to hear of horses in their 20s still performing and breeding. [American Thoroughbred and sire] Northern Afleet is 25 years of age and still standing as a stallion. [Editor’s note: Northern Afleet was euthanized in June 2018, following an illness.] At [Kentucky-based Thoroughbred breeding farm] Taylor Made Farms, you have these Olympic horses still competing at the age of 20.

Nicole:         Wow. It just varies.

Amanda:       It just varies. Yeah.

Nicole:         The overall health of any animal is somewhat of a holistic endeavor: colostrum — the first milk that a mare feeds her foal — to everything that can come after potentially affects the health of the animal. How much can mindful nutrition in the early stages of life prevent issues later?

Amanda:       I think that's a really good question. I think there's more interest in studying that area. There has not been a lot of research in the equine industry to understand the impact of maternal influence on the health and the outcome of the foal itself as the foal ages. I can't really give you an answer to that. I would say what happens early in life may not have an overlapping effect later in life because of the way the immune system essentially develops. There's just very little research done to be able to answer that.

Nicole:         What are some warning signs that a horse's immune system has started to degrade?

Amanda:       If you look at the immune function in a population of senior horses over the age of 20 to 35 years of age, you see varying immune responses. It's not just this continual linear decline over time. In some horses, you may see increased sinusitis issues, abscess, hoof infections and dental abscess problems. It varies. There may not be a warning sign.

                    It's really good to stay up-to-date with your horse's routine vaccination schedule and routine check of fecal egg counts. The gold hallmark is that, across the board, age affects immune responses, whether we're talking about humans, dogs, cats or horses. The number one thing that happens, or the hallmark characteristic of age impacting immune responses, is a failure to respond very well to vaccination.

                    We've done a lot of work in that area and continue to do so to see if perhaps an aged horse might respond better to a different type or platform of vaccines. We still try to make everyone aware — especially if you're still competing, showing, trail riding — that, even though they have a reduced immune response to vaccination, that doesn't mean to just forget about vaccinating them. That just means to maintain a good vaccination schedule.

Nicole:         Is that the larger portion of preventive health for horses, with vaccinations?

Amanda:       Oh, absolutely. It's part of the program, for sure, along with getting an annual or biannual exam, having a dental exam, a body condition scoring and lameness evaluation. I think the biggest area that I am trying to generate more awareness of is having your horse's endocrine status evaluated.

                    As your senior horse starts to develop early signs of equine Cushing’s disease or Pituitary Pars Intermedia Dysfunction (PPID), or if they become insulin-dysregulated, it’s really important to look at early on in the senior years so that you know how to nutritionally manage them throughout their golden years, as we say. It’s very important in making some of those decisions.

Nicole:         Do some of these indicators show that it's time to move toward a more geriatric approach to nutrition? What is that approach?

Amanda:       There's not a one-size-fits-all approach. That’s kind of what I talked about today at the [ONE: The Alltech Ideas] Conference]. The “old gray mare” is not just the old gray mare. In my opinion, and having the herd of geriatric horses at the University of Kentucky, we see six different types of senior horses. It's a broad spectrum, from the hard keeper to the easy keeper, to the endocrine-diseased horse, to the horse that is susceptible to develop laminitis because they're insulin-dysregulated.

                    It's not a one-size-fits-all dietary program to support the geriatric horse. You really need to work with your vet to understand if your horse has been affected by any of these endocrine diseases and make sure there aren’t dental problems, then work backwards from there to design a nutritional foundation for those horses.

Nicole:         Are certain breeds more likely to have endocrine issues?

Amanda:       Absolutely. Especially, if we're talking about insulin dysregulation, we know that certain breeds are more predisposed, such as your Morgans, your Walkers and warmbloods. When we talk about equine Cushing's disease, that can affect any breed.

Nicole:         But having that kind of knowledge as an owner can help you prepare a bit?

Amanda:       Oh, absolutely. Certain breeds are predisposed to being more insulin-dysregulated or not.

Nicole:         Does being able to provide the right nutrition for an aged horse increase cost significantly for owners?

Amanda:       Not necessarily. It doesn't mean that, just because you have a senior horse, you need to feed them a complete feed. If the horse is maintaining body weight and doing well on an all-forage diet and, like I said, maintaining body weight, then there's really, essentially, nothing that you need to change. Just ensure you're feeding a good quality forage. If not, make sure you're balancing it with a ration balancer pellet.

                    If the older horse is having trouble maintaining body weight or are, on the other side of the spectrum, “thrifty,” then you might have to get into some programs that might require more costs, because more calories may equal more cost. It just depends; it's just not a one-size-fit-all approach. I think that's the message: it needs to be a very individualized, tailored program for senior horses.

Nicole:         Some of your work is aimed at improving the function in redox state of the immune system. What does that involve?

Amanda:       We're looking at both applied and basic science questions. Looking at the cellular level, how does age impact immune responses? How well do the immune cells proliferate in response to a pathogen? That capability is reduced with age. There's a new phenomenon called inflammaging, which is a low-grade chronic inflammatory response that occurs as we age — as cats, dogs age — and we've shown that happens in horses.

                    It's a low-grade inflammatory response that we see systemically. That might go hand-in-hand with the oxidative status of the animal. We're still doing quite a bit of research in that area to fully understand what that means for the aged horse.

                    In humans, we know that this inflammaging process contributes to a lot of our age-related diseases: osteoarthritis, maybe even Parkinson's disease, et cetera. But for the old horse, we just don't quite know yet what all of this means. We know that these things are happening, but exactly how that affects their performance and physiological status — we're still unraveling all of that.

Nicole:         Is this a new area of research then?

Amanda:       It really is. I think in human medicine, it's not. As we're all living longer, and our horses are living longer, there's more interest in understanding how increased longevity is impacting these responses. Then can we modulate these responses to help animals live a more successful, healthy life into their golden years.

Nicole:         You're also investigating models of stress for horses. What pushed you in that direction?

Amanda:       Being an immunologist is great because so many different factors impact immune responses, from old age to obesity, and the third arm of my program is investigating the impact of stress on immune responses.

                    It really began by looking at how weaning stress impacts immune responses in horses. Then, that has taken me down the road of looking at the impact of transportation stress and how that may impact the immune response of horses and particularly, older horses that are still going out there and showing and competing. You already have an immune-compromised animal, but then you're adding layers of stress to that. What does that do to the physiological state of the animal? I think it was sort of a natural migration to have a look at that.

Nicole:         What are your hopes for owners’ understanding in geriatric horse care?

Amanda:       Just don't forget about the old horse and assume that, just because you've been vaccinating them year after year after year, that they don't need to be maintained on a vaccination schedule. Definitely maintain a proper vaccination schedule and work with your vet to do that. Make sure to check fecal egg counts on older horses. We've shown that senior horses have higher fecal egg counts and may be higher shedders than younger horses. Keep them on a proper vaccination schedule based on fecal egg counts.

                    Then, don't over-estimate the power that nutrition may have. Basically, we are enhancing or supporting immune function with age in geriatric horses. We've done some work looking at that and showing that nutrition can actually improve immune responses to vaccination in older horses and reduce inflammation or the inflammaging response. I think those are important factors.

                    Also, understand what the endocrine status is of your senior horse — work with your vet on that. Make sure that you have a full understanding of whether they are affected by early-stage equine Cushing's disease or late-stage PPID, if they're insulin-dysregulated or not — that’s really going to help properly design nutritional foundations for them and, then, support them in their later years. Keep up with yearly exams. Looking at all of that is going to support healthy, successful years for the senior horse.

Nicole:         What should owners look for in ingredients to help support vaccinations?

Amanda:       In a couple of big studies that we did with a big feed company — we'd like to investigate a variety of different parameters, but research is costly, so we had narrowed it down to looking at certain components — and some of that work was based on what has been found in human studies as having an impact on immune responses to vaccination. We looked at omega fatty acids and then we looked at prebiotic and probiotic supplementation.

                    We did a couple of big trials, and we were quite surprised to see that it was prebiotic formulation that enhanced some of the immune responses that we saw and measured in some senior horses. I think it just opened the door for more studies to come that show that nutrition is quite powerful and could potentially have an impact on improving immune responses in horses.

Nicole:         Dr. Amanda Adams is an associate professor at the Gluck Equine Research Center at the University of Kentucky. Thank you.

Amanda:       Thank you for having me.

I want to learn more about proper nutrition for senior horses. 

Internal parasites often thrive in grazing areas and can easily afflict your horses. Some of the most commonly found equine parasites are large and small strongyles, roundworms, tapeworms, pinworms and bots. They can have debilitating effects, including, but not limited to, weight loss, diarrhea, anemia, coughing and liver damage. But there is hope. By establishing a regular, targeted deworming schedule designed to significantly decrease the numbers of these harmful pests, you can help your horse — and potentially other horses on the property — achieve better health.

You may be wondering how you could possibly help other horses. Some horses have a higher immune status than others and may not be as susceptible to the harmful effects of parasites. These horses may be chronic shedders, meaning that while they might not exhibit clinical signs of parasitism, they could be carrying a lot of adult worms, which are producing eggs that are then inadvertently spread to the shedder’s pasture mates. You may need to deworm chronic shedders more often than others in an effort to keep everyone healthier.

An effective deworming program needs to take several factors into consideration, including:

• Age: Foals and other young horses are more susceptible to certain types of parasites (large and small strongyles, roundworms, pinworms, tapeworms and potentially threadworms).

• Location: Different kinds of parasites are more common in different areas or climates.

• Season: Some parasites, like bot flies, are only active during specific times of the year.

• Travel: Horses that travel to shows may be exposed to infected horses and parasites they might not otherwise be exposed to at home.

• Pasture: Many horses grazing in a given area may increase parasite exposure. Other animals may also shed parasites that could infect your horse.

The importance of fecal egg counts

The best way to determine your horse’s specific deworming needs is to have your veterinarian perform a routine fecal examination, also known as a fecal egg count (FEC), during which the feces are inspected for the presence of worm eggs and the eggs are then counted. From there, you can work together to evaluate the numbers and types of parasites and decide on a course of action.                                                                               

If possible, I recommend having a second FEC performed 10 to 14 days after deworming. This is known as a “fecal egg count reduction test” and will tell you if deworming was effective. Resistance to commonly used dewormers is becoming more prevalent, so it’s important to make sure there are fewer eggs in your horse’s manure after deworming.

Management tips

You may also aid in keeping parasite numbers down with good management practices:

• Clean pastures regularly: Remove and dispose of manure at least twice weekly.

• Rotate pastures: Move horses between pastures to naturally break parasitic life cycles.

• Use elevated feeders: Lift grain and hay off the ground, where parasites thrive.

Lastly, I should clarify that your horse will — unfortunately — never be 100 percent parasite-free. All horses will always carry some worms due to the cycle of pasture grazing and fecal contamination. However, with some precautionary steps and targeted treatment, you can help your horse build a better defense against these would-be internal invaders.

I would like to learn more about horse health.

Warmer weather means it’s time to pull in the pasture ponies and take the rugs off your show horses. At long last, riding season has arrived! Sadly, this also means the return of the horses’ constant and most pesky companion: the fly.

And, while flies may seem like nothing more than an ever-present annoyance, they can carry serious implications for your equine counterparts. Flies are well-known for spreading disease, feeding off of the equine blood supply and causing potential digestive upset. And, unfortunately, even the most encompassing of fly turnouts — think fly mask with ears, fly sheet with belly guard and fly leggings, essentially making your horse resemble some strangely armored creature — can’t keep them completely at bay.

More than a simple pest

House flies may seem like the least of a horse owner’s worries, but they can carry disease and transmit parasites. They can also irritate a horse’s eyes, where they feed off of moist secretions. These flies breed during the summer and feed on muck, so proper stable management is imperative to reducing their numbers.

Horse and deer flies are known for being ruthless biters. Thankfully, they are only active during the day. And, as luck would have it, these flies do not normally enter structures. It is best to have barn or stable access available for pasture horses if you notice these flies becoming particularly bothersome.

Stable flies are probably the biggest equine nuisance of all. They live in barns and breed in organic, fermenting matter, such as manure, decaying straw or spilled, moist feed. They typically feed on horses’ legs and flanks and can cause significant blood loss, transmit swamp fever and cause summer sores — weeping wounds that are challenging to heal. Horses may also stomp incessantly in an attempt to rid themselves of these pests, only to cause hoof and leg issues.

Shoo, fly: Sanitation and stable management tips

It should come as no surprise that proper sanitation and stable management are among the best methods of fly control. House flies and barn flies require breeding material, ideal moisture and adequate warmth to develop. Therefore, elimination of breeding sites is the key to a successful fly control program. Barns and paddocks should be thoroughly cleaned once per week to assist in breaking fly life cycles. Insecticides should only be considered as a supplement to fly control.

Below are some tips to help with your fly management program:

• Keep manure picked up and pile at a good distance from facilities, waterers and paddocks.

• Make sure all garbage cans have tight-fitting lids and are cleaned out regularly.

• Keep waterers in good condition and place them away from areas where horses are fed.

• Consider screening windows in feed and tack rooms, as well as box stalls.

• Fans that direct a downward and outward airflow will help to keep flies from entering barns.

• Fly traps and sticky paper are an effective way to capture flies. They may also be useful in documenting fly numbers over time. A notable increase in catch from one week to the next could be a warning to check on sanitation measures and increase your fly control measures.

Last, but not least, keep this in mind: Large numbers of flies mean there are a great deal of breeding sites in your area. There are many insecticide options (e.g., residuals, sprays, fogs, mists, etc.), but they will only provide temporary relief and should generally be used sparingly. Your best option is to keep a tidy stable and yard — both you and your horses will be grateful for the extra effort!

Looking to add fly control to your horse’s nutrition program? CRYSTALYX^®, SWEETLIX^®, ULTRALYX^® and STOCKADE^® brands offer several options in pressed and mineral blocks.

I would like to learn more about horse health.

Excess weight may cause or predispose horses to problems like joint pain, laminitis and insulin resistance, or it may indicate an existing metabolic disorder. Nutritional management of the overweight horse is key – and not quite as simple as some may think.

At what weight is a horse overweight?

Assigning a specific weight to define obesity in horses is impossible due to differing bone structure and muscling. Instead, evaluating fat deposition over the horse’s body is a better method to estimate body condition. Body condition scoring (BCS) systems have been developed to apply a numerical score to the horse’s condition based on fat coverage over target areas of the body. While BCS systems are subjective, they do provide a systematic method for evaluating body condition. One of the most widely accepted scoring systems is the 1 to 9 Henneke scale, where 1 is extremely emaciated and 9 is very obese. Horses scoring above a 7 on this scale are considered overweight. For more information specific to body condition scoring, you may visit McCauley's dedicated page.

Why is the horse overweight?

Determining why the horse is overweight can be helpful. Sometimes the answer is as simple as the horse receiving feed when little or no feed is required. Unfortunately, the answer is often much more complicated. Metabolic disorders such as Cushing’s disease, insulin resistance and equine metabolic syndrome (EMS) may predispose the horse to obesity. Some horses carry extra weight simply because they are very efficient at converting dietary energy (calories) to fat.

Nutritional management of obese horses

Feed should be adjusted according to body condition and season. One of the primary keys to achieving desired body condition is to balance the number of calories consumed with the number of calories used. The number of calories used changes with age, climate and activity level. As a result, the calorie consumption will likely need to change throughout the year to maintain a healthy body condition. Warmer weather means less energy is used to maintain body temperature, and as pastures grow lush and calorie-rich, winter feeding quantities need to be decreased to maintain a healthy weight.  

If reducing or eliminating feed does not accomplish the desired weight loss, grazing on lush pastures should also be limited. This may be accomplished by splitting time between pasture and stall, using a grazing muzzle or placing the horse in a dry lot and feeding hay.

Pastures are often deficient in many trace minerals. A typical trace mineral salt block will not meet the horse’s mineral requirements. If the amount of feed provided is below the minimum requirement, then supplemental vitamins and minerals will be needed. In such cases, vitamin and mineral supplements should be fed daily rather than fed free-choice.

When feeding hay to overweight horses, choose mature grass hay. The more mature the hay at harvesting, the lower the digestible calories. Sugar and starch concentrations are usually lower as well. Many metabolic disorders require avoidance of sugars and starches, making mature grass hay the best choice for reducing calorie intake.

Horses on a hay-only diet should receive a minimum of approximately 1.5 to 2 percent of their body weight per day. Feeding hay at this rate is essential to maintain normal, healthy gut function and to avoid the development of vices like wood chewing. As always, the hay should be free of dust, mold and other contaminants.

Summary

• Use a body condition scoring system to evaluate the horse’s fat deposition.

• Reducing caloric intake and/or increasing caloric output is crucial to weight reduction.

• While calorie restriction is important, the other essential nutrients (e.g., protein, vitamins and minerals) cannot be ignored.

• For optimal health, the goal is to achieve and maintain the ideal body condition throughout the year. This may require fine-tuning the diet regularly to adjust for seasonality and other factors, such as changes in activity level.

Have a question or comment?

WHAT: “Racing to the Future: Using Genomics to Improve Horse Health” will reveal the latest findings in groundbreaking research that studies the genetic traits driving horse health and performance. The discussion will explore how genomic research offers a better understanding of breeds, disease resistance and treatment. Equestrians, scientists and the merely curious are invited to gain a better understanding of the equine genetics field. The lecture is free and open to the public.

WHO: Dr. Samantha Brooks, noted equine researcher, headlines this exploration of the use of genomics tools to improve horse health. Brooks currently serves as assistant professor of equine physiology in the Department of Animal Sciences at the University of Florida, and she previously oversaw the equine biology and management course at Cornell University. A lifelong horse enthusiast, Brooks followed her passion into equine research. After earning a bachelor’s degree in agricultural biotechnology from the University of Kentucky, she remained at UK to study at the Gluck Equine Research Center and earned a Ph.D. in veterinary science.

WHEN: Wednesday, April 25, 2018 | 6:00 p.m. EDT

WHERE: Mitchell Fine Arts Center, Transylvania University

MORE: This event is part of Down to a Science, a lecture series presented by Alltech and Transylvania University. The collaboration aims to make science accessible and relatable for everyone, promoting a scientific dialogue within the local community. For more information, contact Julie Martinez at jmartinez@transy.edu or (859) 281-3617. Follow the event page on Facebook.

[LEXINGTON, Ky.] – McCauley’s, Alltech and the International Alliance of Equestrian Journalists (IAEJ) are pleased to announce the winners of the 2017 McCauley’s Alltech ‘A+’ Awards for outstanding coverage of international equestrian sport.

The ‘A+’ Journalism Awards were established in 2010 by Alltech, in collaboration with the IAEJ, to reward creativity, passion and excellence in equestrian journalism. Initially the focus of the awards program was coverage of the 2010 and 2014 Alltech FEI World Equestrian Games. The theme for the 2017 contest was “Partnership.”

The winners of the 2017 McCauley’s Alltech ‘A+’ Award are:

PHOTO: Shannon Brinkman, New Orleans, Louisiana, U.S., for her photo of Laura Graves and Verdades, published in The Chronicle of the Horse, July 22, 2017.

• Jennifer Bryant received an honorable mention for her photo of para rider Katie Jackson and Royal Dancer.

ARTICLE: Suzy Jarratt, Arcadia, New South Wales, Australia, for the article "The Unusual Benefit of Horses", first published in Equestrian News & Lifestyle, December 2017.

BROADCAST: Jenni Autry, Kennett Square, Pennsylvania, U.S., for "It's The World's Biggest CCI3 Boekelo Preview Show", broadcast on EventingPodcast.com on October 2, 2017.

Each of the winners receives a McCauley’s Alltech ‘A+’ Award trophy and a $500 (U.S.) prize.

The highly competitive contest, which attracted entries from around the world, was judged by Grania Willis, FEI communications director; Alan Smith, former Daily Telegraph equestrian correspondent, and long-time Horse & Hound photographer and Silver Camera award winner, Trevor Meeks. The judges deliberated without knowing the names of the contestants.

“It is a delight to continue to honor the creative storytellers within the equestrian world,” said Susanna Elliott, head of communications at Alltech. “They captivate us with their words, mesmerize us with their photos and draw us into a deeper understanding and appreciation of the horse.”

“The IAEJ is extremely grateful to Alltech and McCauley’s for their continued recognition of the media and its contribution to equestrian sport,” said Pamela Young, IAEJ president. “The photo category was particularly hard fought this year with Jennifer Bryant’s photo of para rider Katie Jackson and Royal Dancer deserving of an honorable mention.”

If you’re in the Northern Hemisphere, with any luck, the chill of winter is finally lifting, and grass is taking on a long-awaited healthy, green glow. You and your horses are likely chomping at the bit (pun intended) to head outside and take full advantage of the free buffet. But before you turn those ponies loose, ask yourself: Are you thinking strategically about pasture management?

Why utilize rotational grazing?

If horses are allowed to graze on one pasture continuously, they can quickly eat down the quality forage, leaving behind weeds and potentially bare ground. Given the choice, horses will selectively graze on their favorite plants and grasses and may completely neglect certain areas while overgrazing others. Whenever a plant is grazed on, it needs time to regenerate leaves and restore energy to its root system. If grazed on again before roots are re-energized, the plant grows weaker. If regularly overgrazed, the plant will ultimately die. Rotational grazing is meant to stop this cycle from taking place.

By utilizing rotational grazing, you could potentially double the amount of forage produced and salvage this precious resource, thereby saving a great deal on additional hay costs. This is because rotational grazing allows portions of pasture to rest and recover, particularly the most heavily grazed plants and grasses. A pasture can be divided into several segments to allow ample time for rested areas to grow back to a reasonable grazing height.

How do I begin a rotational grazing program?

The way you divide your pasture(s) will depend on several factors, including climate, soil fertility, rainfall/irrigation, drainage, types of plants and grasses, and number of horses grazing. Removing horses from an area when the grass has reached an approximate height of 3 to 4 inches (using a color-coded grazing stick can be very helpful) can prevent overgrazing from occurring and allow you to take advantage of the underutilized sections.

If you are transitioning a paddock to its rest period, you will need to remove manure, trim to an even height to encourage grasses to regrow uniformly and allow approximately three to four weeks’ rest. You’ll need at least four paddocks (1 to 2 acres per horse, per paddock) to maintain this schedule. Using more will allow for briefer grazing periods and increased rest, which is even better. A smart strategy is to keep a dry lot available and feed hay when longer rest periods are warranted.

You may also be wondering how long you should allow horses to graze on pasture sections. This will be dependent on the number of horses, length of daily turnout and size of the area, as well as the other factors mentioned previously. A good rule of thumb is to plan for one week’s use of each section but to monitor closely. Walking the pastures, preferably daily, will allow you to ensure that areas aren’t being overgrazed and to check that fencing is working properly. Temporary electric fencing is generally most effective for this strategy as it can be adjusted at any time. It is also worth noting that you should keep horses inside or in a dry lot during wet weather to prevent pasture damage from hooves.

What about water?

One challenge associated with rotational grazing is that we are often using automatic waterers and the question of accessibility comes into play. Obviously, you won’t be able to provide easy access to the waterer in all instances, so you may have to get creative when it comes to providing adequate water. Setting up temporary troughs, checking them often and moving them around the paddock(s) periodically can help to avoid creating particularly muddy areas or soft ground, which could lead to pasture damage.

Is rotational grazing worth the hassle?

I know what you’re thinking. This sounds like a lot of extra work, and that’s because it is. But the time, effort and commitment can truly pay off in the end, with the potential to increase forage quantity and quality, improve horse health, save money (less spent on hay) and decrease both you and your horses’ environmental footprint, making rotational grazing a very worthwhile endeavor.

I would like to learn more about horse health.

Below is a transcript of Tom Martin’s interview with Dr. Karl Dawson, vice president and chief scientific officer at Alltech and co-director of the Alltech Center for Animal Nutrigenomics and Applied Animal Nutrition.

Click below to hear the full interview:

                                    Over the last 10 years, scientists at Alltech have been using nutrigenomics to define a variety of new nutritional concepts, manage product development and redefine our view of nutrition. What are the practical applications of the science, and what does it mean for the future of feeding and farming? Tom Martin talked with Dr. Karl Dawson, vice president and chief scientific officer at Alltech.

Tom:                          Let’s begin with the question: What is nutrigenomics?

Karl:                            Nutrigenomics is a system for looking to see how the environment, disease processes and nutrition influence gene expression in an animal. This is taking the basic information that comes in an animal’s genetic makeup, its DNA, and looking to see how that's used. This system allows us to look at numerous genes at a time. And in some of our studies, we would be looking at as many as 25,000 genes at a time. So, we get very precise in our measures of what the environment, or disease — or, in this case, nutrition — does to that animal.

Tom:                          In a recent panel discussion, the webinar “Farming the Future,” you said that nutrigenomics is really going to redefine things, if it hasn't already. Can you elaborate on that?

Karl:                            Yes. We’re going to be looking at nutritional processes in a totally different way. We could also look at things like diseases in a different way. The way we look at nutrition today is based on a narrow group of responses in an animal to a nutritional strategy. Nutrigenomics allows us to do that same kind of thing while looking at many, many different characteristics at once and very rapidly. We can look at changes induced by nutrition within several days instead of waiting for a whole production cycle, which may take anywhere from 42 days to two years.

Tom:                          The name of the field, nutrigenomics, might lead us to believe that it’s limited to exploring how nutrition influences the expression of individual genes, but is it more than that? Does the science also look at disease and environmental factors and how they’re related to nutrition?

Karl:                            Yes. We can look at all of those things and how they're related. “Nutrigenomics” may be a misnomer. In the science world, we call it “transcriptomics,” the idea of looking at these genes and how they're transcribed. But the word “nutrigenomics” has taken off, and it’s really being used to describe just about anything to do with gene expression and factors that influence gene expression.

Tom:                          How is this tool being used to define new feeding strategies?

Karl:                            We can talk about a couple of examples that have developed over the last seven or eight years. One of those is the feeding of young animals. We could take a chick during the first 96 hours after hatching and change its nutrition — by limiting its nutrients, we can change how that animal performs throughout its life or its nutrient requirements throughout its life. We would not have been able to know what that looked like until we had this nutrigenomics tool.

                                 We can show that the gene expression pattern changes in a young bird when you've limited its nutrients, but those changes that take place in that gene are reflected throughout the life of that bird. So, some 24 days later, that bird has a totally different environment that it is working with, and the types of nutrients it requires have changed. It's a totally different animal when it comes to its nutritional requirements.

Tom:                          And does this bring more consistency, more precision to farming?

Karl:                            Yes. It’s going to bring a lot of precision, but it actually gives you a new tool because, in some of those changes we’re seeing, we can decrease the amount of nutrients that animal is requiring. You condition it to a low nutrient value or nutrien. As it grows, it’s expecting that as it goes on through its life. So, for example, its mineral requirement may be decreased by as much as 50 percent. That’s a totally different world for that animal to grow in, and it changes the way we feed that animal to optimize its performance and health.

Tom:                          Let's say there's been a blood draw or a tissue sample taken from the herd or the flock on the farm and brought to the lab to process. How long does it take to get that information back to the farm?

Karl:                            It only takes about 48 hours for us to process a sample, but I don't want to mislead you here. We would not necessarily use this as a diagnostic tool at this point. Today, it's a research tool to show you what changes happen with a new trend. We can use it to screen new nutritional strategies or look at nutrients in the way they're influencing that animal. Eventually, you’re going to see some diagnostic tools coming from that. But today, that probably isn't a very realistic approach for this type of technology.

Tom:                          What are some new commercially useful feeding concepts that have come directly from the use of this molecular tool?

Karl:                            A couple come to mind immediately. One of them has been a rather surprising observation. Often, in the growth of that young animal and growing livestock, we’ll use enzyme supplements. The idea behind using an enzyme supplement is really to change what is happening to the food, how it's digested. Well, one of the surprising things that we found using nutrigenomics is, that is reflected not only in the digestion process, but actually the way the tissue develops in that animal. It changes the receptors for hormones. It changes the way that animal responds physiologically.

                                  That technology has moved forward and is the basis of a couple of different programs that we’re using in beef cattle today — to use enzymes to enhance their growth and performance. In some systems, we found that this can be worth as much as $15 to $20 per head when that animal reaches its final stages of growth or finishes out and goes on for beef production. So, it's a pretty substantial thing. We never would have seen that, or even thought about doing that, if it hadn't been for that nutrigenomic tool that allows us to see those changes in those animals.

Tom:                          I also recall from the webinar, “Farming the Future,” some discussion about the influence of minerals.

Karl:                            Absolutely. Minerals are very important, and that's one of the areas that probably was the hallmark of our nutrigenomics work when we started out. One mineral, specifically, is selenium. Selenium is a nutrient that's very important, but we had no idea of how much or what the ramifications of feeding selenium really were. We found all sorts of hidden traits that are influenced by selenium, all the way from reproduction to the development of brain tissue and the speed at which an animal grows.

                                    One of the most interesting traits is the way that animal generates energy. We found very early on that we could change the function of the mitochondria and the cell. This is the energy-producing organ within that cell. We can increase its efficiency by about 15 to 20 percent. That doesn't sound like a big number, but using a dairy cow for example, that means we can improve its energy efficiency by that same amount, which probably means 2 to 3 liters of milk a day from a cow.

                                 So, this is turning everything upside down. We've changed what we thought we knew about energy metabolism, and it's a totally different world now. We're going to have to go back now and redefine energy metabolism — not based on the energy content of the feed, but based on these minerals and the way they are interacting with that energy source.

Tom:                          Let's say there's a new feed supplement out there on the market and you want to determine its value as quickly as you possibly can. Can nutrigenomics do that?

Karl:                            Absolutely. That’s one of the most exciting examples I have right now. Several years ago, we were asked to come up with an alternative antioxidant to help us address the shortage of vitamin E. We took a nutrigenomics approach to that issue and developed what we thought was a new material to serve as a booster for vitamin E activity. Normally, to evaluate a new antioxidant system like that, we would have done it over a period of several years. It takes time to grow the animals, look to see what the vitamin E is doing, to harvest the meat product and evaluate the way that is responding to oxidative stress.

                                    With a nutrigenomics approach, we were able to do the same types of evaluation, but we can look at gene expression as our measure. In doing so, we could shorten that two-year period to about six weeks. We could actually evaluate what that new ingredient was doing during that very short time.

Tom:                          By applying this tool, you're gaining a lot of information, a lot of knowledge. How does that information influence the way you think about nutrient requirements?

Karl:                            We’ve changed a lot in terms of nutrient requirements. We talked about selenium a minute ago. We used to have a fairly standard idea of what selenium requirements were. Using nutrigenomics, we’ve been able to redefine that, and found that by changing the form of selenium — by putting it in the form of a selenium yeast, for example — we could decrease its requirements by about 50 percent.

                                    We’ve gone on to look at all sorts of different minerals. We know that we can cut back on a lot of the requirements we expect for copper and zinc in the diet. We can cut those by as much as 75 percent. So, we have really started to change that. Instead of asking what a mineral is doing, we look at the form of that mineral as well as how much we're providing it. Again, it’s turning things upside down. The old requirements we had for some of these minerals have really changed.

Tom:                          How is nutrigenomics being used to demonstrate the effects of maternal nutrition on the growth or development and the disease resistance of offspring?

Karl:                            This has been another very exciting area. We did some studies several years ago in pigs — looking to see what would happen to the offspring if we fed a particular carbohydrate or supplement to the sow. We fed the sows a particular carbohydrate called Actigen^®, which is a yeast product. Then, we looked to see what was happening in the piglets. To our surprise, by looking at the gene expression in those piglets, we could easily differentiate the piglets that came from the sow that was fed that material. In fact, we found some very specific genes were being changed. One of the more interesting effects was to the hormones that influenced the ability of that young pig to eat.

                                 We could stimulate intake in those young pigs, not by feeding the young pigs the material, but by feeding the sow. That changes what we think in terms of overall production, because now we have a different animal to work with. They have different gene expression patterns and, in fact, different nutrient requirements. Their resistance to specific diseases has changed.

Tom:                          Does this enhance that consistency that we were talking about earlier across generations?

Karl:                            Yes. That's the idea. We've always thought that consistency occurs, and we have evidence of it in the human population — that you are what your mother eats. Nutrigenomics actually gives us the tools to see what is changing specifically, and to program that into the production process.

Tom:                          We've been talking about animals here as though they were something separate and apart from us, but we're animals as well. Does nutrigenomics influence the way that we think about human nutrition?

Karl:                            Absolutely. We’ve really projected into the human population from what we've done in animals with nutrigenomics. One of the star programs that we have right now is a set of compounds that we've developed to provide a preventative for Alzheimer's disease. This program came directly from our observations of what was happening to gene expression. We realized that the genes that were being expressed — or not being expressed — in Alzheimer’s patients were, in fact, associated with Alzheimer’s and the development of neurological tissue. We were able to track that relationship down, and it’s in clinical studies today.

                                 We've done similar things with some of the yeast products that we’re using. We know that they influence animals. We are now doing the same types of nutrigenomic studies in humans to evaluate how these might be useful to address health issues.

Tom:                          I know from past conversations with you about the science of nutrigenomics that you feel that it holds a lot of promise. What is your take home message about this science?

Karl:                            That this is an extremely powerful tool. It probably gives us more information and more precision for feeding animals — and probably even humans — in the future. It’s going to be a very powerful tool for changing the way we develop our feeding strategies. So, my take home message is, “This thing is going to be something that will influence the way science changes our nutrition.”

Horses exude beauty and strength, and yet, large and robust as they appear to be, we equestrians know that horses are also some of the world’s most fragile and finicky creatures. Along with their penchant for finding bizarre ways to inflict bodily harm upon themselves, they are often prone to internal ailments, especially involving their digestive systems. Why is this?

Different by design

Horses are non-ruminant, monogastric (single-stomached) herbivores. The digestion of the horse is notable for several reasons. They are perhaps most well-known for their inability to vomit. But, have you ever thought much about how their digestive tract works?

When a horse eats, portions of the feed are first digested enzymatically in the foregut. Afterward, microbial fermentation of other nutrients, like cellulose, occurs in the hindgut. The equine digestive system is truly unique because the first section resembles that of other monogastrics, like humans, but the second section is more akin to that of a ruminant species, like cattle.

What is the hindgut, and what happens there?

The equine hindgut consists of the cecum, large colon, small colon and rectum. It contains billions of symbiotic bacteria, protozoa and fungi, which all help to break down and absorb fiber. Like all species, horses do not possess enzymes capable of digesting fiber, so they rely on these microbes to process fiber for useful nutrient absorption.

What if the hindgut malfunctions?

When you consider that the majority of your horse’s diet (at least 50–60%) should be made up of forage, it makes one realize just how much work the hindgut has cut out for it. So, if something is awry, it can spell big trouble in the form of hindgut acidosis (when lower pH levels lead to increased acidity), which often leads to colonic ulcers, poor body condition, colic or laminitis.

So, what’s a horse person to do?

Keeping the hindgut healthy starts with keeping your horse’s overall nutrition in order. Below are some easy rules of thumb to keep in mind when feeding your equine partner(s).

1. Feed good-quality hay.

2. Don’t let your horse go on an empty stomach. Feed smaller, more frequent meals throughout the day or consider offering free-choice hay.

3. Remember that less is usually more when it comes to grain. Grain is often high in sugar and starch, which is difficult for the hindgut to digest. This can have an adverse effect on pH and bacteria levels (see acidosis mentioned above).

4. Add healthy fats in the form of vegetable, corn, flax or another type of palatable, equine-friendly oil.

Remember also that movement is hugely beneficial for gut motility, so be sure to give horses ample turnout time and exercise. And, last but certainly not least, don’t undervalue the importance of fresh, clean, temperate water — hydration plays a key role in keeping the horse’s overall digestive system functioning at its best.

I would like to learn more about horse health.

The following is an edited transcript of Tom Martin’s interview with Dr. Kristen Brennan, a research project manager at the Alltech Center for Animal Nutrigenomics and Applied Animal Nutrition in Nicholasville, Kentucky.

Click below to listen to the podcast:

                                    Dr. Kristen Brennan is a research project manager at the Alltech Center for Animal Nutrigenomics and Applied Animal Nutrition in Nicholasville, Kentucky. In this interview with Tom Martin, Brennan helps us gain a better understanding of her field, nutrigenomics, and its role in sustainable agriculture.

Tom:                            What is the science of nutrigenomics?

Kristen:                        The easiest way to think about nutrigenomics is to break the word down into what it is: “nutri" and “genomics.” What we're aiming to study with nutrigenomics is how nutrition — whether that’s nutrients, forms of nutrients, diets, timing of diets — influences the animal's genome. So, we’re not changing the genome, but influencing the activity of all the genes of that animal’s genome.

Tom:                            Is this an outgrowth of the human genome project, or has it been around a lot longer than that?

Kristen:                        Nutrigenomics is something that's been around forever. From the time the first living organism evolved, it needed nutrients, and those nutrients had influence on the activity of the genes within that animal or cell. The thing that we've done within the last several years is to figure out how to capture that information. It's always been there, we just never had a way of measuring it before. Technologies like genome sequencing are the core foundation for measuring what we're seeing.

Tom:                            Is there a point in time when we realized that nutrients were having an impact on genetic expression?

Kristen:                        I think we’ve known for a long time the importance of nutrition. Centuries and centuries ago, they had an idea that nutrition had a vital role. I don't know if we knew at that point, really, what DNA was and what genes did, but we knew that nutrition could influence the outcome, or a phenotype of an animal — what we're seeing on the outside — and how important it was for good health.

Tom:                            What are the advantages of nutrigenomics in animal studies?

Kristen:                        What I think makes this field so exciting is that, first of all, when we’re dealing with actual sampling, we need a very small sample amount. We can do this with, for instance, a small draw of blood from an animal, or we can take a small biopsy. So, you're not having to euthanize an animal to get tissue.

                                       Even more of an advantage is the amount of information we get. If you think about most genomes, you're talking about thousands of genes. We can measure in a single snapshot how every one of those genes is behaving in response to a diet or nutrition. That is an amazing amount of information.

                                       The other advantage is that it can be really rapid. From the time we get a sample to the time we have an output of data, it can be as short as just a few days in the lab. So, a lot of information, small input and a ton (of data) in a very rapid way.

Tom:                            And are you able to understand why some animals respond differently than others to the very same nutrients?

Kristen:                        Yes. We can use this information to understand that. An example would be healthy versus diseased animals and why nutrition may play a role in how they respond to that illness. More and more, we're starting to understand how differences on a genetic level — different breeds of animals, different production states, things like that — can influence how that animal responds.

Tom:                            Are you able to dig down into it and figure out how nutrients and bioactive components in the food turn on or turn off certain genes?

Kristen:                        Yes. The biggest amount of information we get is just a simple “Do they or do they not turn genes on or off?” So, how does each individual gene activity respond to what you're feeding? As we’re understanding that more and more, we can take a step back and start to understand how they're doing it. They are what we call signaling pathways, which are like, if you set up a row of dominoes and you hit the first one, it sets everything off. It’s the same thing with gene activity. There is a series of molecules that are responsible for regulating or activating other ones. And we can start to decipher how we get from the nutrient that we’re feeding or the diet we're feeding to that endpoint, that last domino in the line.

Tom:                            You can actually target issues that call for some kind of nutritional intervention?

Kristen:                        Yes. And that's obviously one of the most exciting applications of this research. We can use this to define precision nutrition.

                                    One of the challenges with feeding animals, or people in general, is that there are so many environmental factors that influence how an animal responds to diet — things like illness and disease, but also production state, where they're living, what their basal diets are. And so, we can use this technology to get precise information on how we can use nutrition to get the best performance or best health out of that animal.

Tom:                            How do you carry out your research? What goes on in Kristen Brennan’s laboratory?

Kristen:                        It’s magic! This research is done in several steps. It’s really a team effort. The simplest study we have is between two groups of animals, and because so many things could influence gene expression, we want to make sure that those two groups of animals are as identical as possible — same breed, sex, age, production state, and they’re housed in similar environments. The only thing we want different between those two groups is the nutrient we’re interested in.

                                    For instance, if we’re looking at a form of a mineral like selenium, we might have one diet that contains selenium in the form of sodium selenite, and we might have the exact same diet for the other group that has selenium in the form of organic selenium like our Sel-Plex® product. Once we have fed these diets for a given amount of time — it just depends on what we're interested in looking at, what tissues and what nutrients we’re evaluating — then we obtain a sample. It can be as simple as just a very tiny muscle biopsy or a few milliliters of blood. We bring that to the lab, and our laboratory technicians will essentially take that tissue, rupture the cellular membranes and then the nuclear membranes and purify what we call the mRNA, or the transcripts, that are located within the nucleus. We make sure that transcript, or a total RNA, is of super high quality and purity because these assays are so precise. We have high standards for what we can use.

                                       And then we use a commercially available DNA microarray. And what that allows us to do is profile. It has probes for each gene on the animal's genome — for example in the case of a chicken, it has something like 18,000 probes — and that allows us to measure whether the mRNA, or the transcript, for each of those genes has been increased or decreased in response to the nutrient that we fed.

                                       At the end, we get a long spreadsheet that says gene A is increased, gene B unchanged, gene C is decreased.

                                       Then the tough part comes, and that is the data analysis. So, we have all of these data points — you’re talking about thousands — and it is sort of like taking one of those huge puzzles. If you took that box of puzzle pieces and threw it on the ground, you would just have a giant mess, right? When I get that Excel spreadsheet of thousands of rows and columns, that’s what it’s like, essentially. So, we need help to try to piece those puzzle pieces together. If we took one piece out, we might find a corner and that's really important. Just like if I look at that spreadsheet, I might find a gene that's very important, that's very highly increased or decreased. That's a starting point.

                                    What we really need to do to see the big picture is piece those puzzle pieces together. We use what we call bioinformatics — essentially biological statistics — and we use software programs that say, okay, these 100 genes are related, they all have a common biological function, and based on their activity, we predict that biological function to increase or decrease. And that helps us make sense of this information.

                                    So, just like piecing those puzzle pieces together, we get that big picture of what's going on inside an animal that results in what we're seeing on the outside like improved growth, or improved feed efficiency, or improved markers of health.

Tom:                            I'm under the impression that the “Holy Grail” for you would be to find and establish a link between nutritional genomics approaches and applied nutritional research. Can you explain?

Kristen:                        Sure. The ultimate goal, at least in my view, for nutrigenomics is when we do traditional nutrition studies, we take an experimental diet, we feed it to an animal and we look at a phenotypic output. So, what do we see in the whole animal? That might be body weight change, growth rates, feed efficiency — things we can measure in the whole cow or by just looking at the animal. We might look at blood markers, stuff like that. What often is lacking and what we can use nutrigenomics for is, how do we get from point A to point B? How do we get from feeding this diet to the response in the whole animal?

                                       What nutrigenomics gives us is a tool to look at a molecular reason for those changes. We can use nutrigenomics to figure out, are we affecting energy expenditure in the cell? Are we affecting protein translation in the muscle? Things like this can help us explain what we're seeing in that animal instead of just guessing on how something works.

Tom:                            Does this technology, nutrigenomics, reduce our reliance on large-scale animal studies, and is it less invasive than the traditional approach?

Kristen:                        I think so. When we do these studies, we can work with a much smaller number (of animals) per treatment. So, where you might need hundreds of animals to get, say, carcass quality measurements that are significant, we can use six or 10 animals per treatment and still get some of the same information that would explain why we see changes in a large animal. Obviously, they're complementary, but we use this technology to minimize the number of animals we need per treatment.

                                      The other advantage is the obtaining of samples. We don't need a whole kilo of skeletal muscle to do our analysis. We need a tiny amount. So, that really is noninvasive. We can use a simple blood draw that is noninvasive and get this information out of that.

Tom:                            The 21^st century farm is a changed place compared with that of the previous century. A big reason for that is the arrival of a lot of science, technology and big data. If we were to take your science, nutrigenomics, out of the laboratory and into the farm, how would producers use what you've learned?

Kristen:                        I think one of the major ways they can use it is precision nutrition — really formulating diets to meet the actual needs of an animal. And also to understand the form versus function of different nutrients. So, how do we get the best that we can get out of an animal through nutrition? Nutrigenomics gives us that tool to understand how.

Tom:                            To carry that further, beyond helping to determine what will work for an animal's genetic type, is nutrigenomics helping explain why we need to find what works for a given animal?

Kristen:                        Absolutely. And I think it really helps push the idea of precision behind nutrition. For so long, we've overfed nutrients. We haven't really paid attention to form versus function. Nutrigenomics is giving us reasons why form is so important in nutrients, and why precise levels are important. We're taking the guessing game out of animal nutrition.

                                       I think as our population grows and the need for food continues to increase, that really optimizing nutrition based on an animal’s genetic potential is going to be really, really important.

Tom:                            How can this genomic information help us better understand nutrition and nutrient science?

Kristen:                        That’s a great question. This gives us a good understanding of the hidden effects of nutrition — the things that we don't really understand; why we see the changes. Why are we seeing increased energy efficiency with different forms of selenium, for instance? If we just look at our traditional nutrition research, we have no idea. But we use nutrigenomics to say, “Okay, well, the genes that control, say, mitochondrial growth in the skeletal muscle in the animals are turned on by Sel-Plex, and that explains why we see changes in energy expenditure.”

                                       That’s the type of stuff that we can get through traditional animal nutrition research, and nutrigenomics really helps push that information ahead and gives us a better understanding of how nutrients function — things that we can't see by just looking at an animal.

Tom:                            One final question: Among the things that you're working on right now, what really interests you and excites you?

Kristen:                        Everything, as a true scientist! One of the areas that I'm completely fascinated by, and have been for years — and we've done quite a bit of work on it, but it's just something that I start to think about and almost gives me a headache — is the idea of nutritional programming. This is the concept of how early life nutrition — whether that's in a neonatal animal or even in the gestating diet, looking at offspring — how nutrition early in life influences an animal throughout its lifespan.

                                    We've done a lot of work to look at some of the things that happen, like gene expression changes that occur. When we change the diet of an animal in the first 96 hours of life, those patterns and the changes stay with that animal throughout its lifespan, and that completely fascinates me.

                                       I think that's an application that is something that can be applied through all different species of animals, whether that’s livestock or even humans. We think about how you are what you eat, but you're also what your mother ate and what her mother ate and then maybe what her dad ate. It starts to really fascinate you. So, that’s probably one the most exciting areas that we work on.

Tom:                            Dr. Kristen Brennan is a research project manager at the Alltech Center for Animal Nutrigenomics and Applied Animal Nutrition in Nicholasville, Kentucky. Thank you for joining us.

Kristen:                        Thank you.

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