Identifying & Evaluating Your Horse’s Topline

A horse’s topline — the muscles that support the spine, from neck to hindquarters — plays an important role in how a horse performs, looks and feels.

Awareness about this topic, however, is limited. Those who do understand the need for a healthy topline have likely heard a lot of lore and conflicting information about how to achieve it. Exercise, saddle fit, genetics and age are most frequently blamed for a poor topline. Nutrition plays the most critical role, and is often overlooked as a solution to build and maintain the topline.

So What is Topline?
Topline, simply put, is the muscle groups that run along a horse’s spine. The topline of a horse stretches along the vertebral column (spine) from the end of the neck at the wither area, down the back and loin, and over the top of the hip into the croup region. Three main muscle groups surround each side of this boney column. The longissimus dorsi is attached to the pelvis, the entire thoracic vertebrae and the last four cervical vertebrae. The latissimus dorsi attaches the upper and mid back vertebrae to the lower lumbar vertebrae. The thoracic trapezius attaches the neck and mid back vertebrae to the shoulder blade. Topline can be affected to some extent by conformation, specifically as it pertains to the angle of the hip and shoulder.

Evaluating Topline
The Topline Evaluation Score (TES) allows horse owners to easily grade their horse’s topline. This evaluation system assigns a score to help determine the stages of topline development.

TES breaks the topline into three sections:
1. Withers and mid back
2. Loin
3. Croup area

Begin by visually examining the horse in these three areas. If any areas appear sunken in on the sides of the spine, improvement is needed.

Horse owners should also observe whether musculature along the spine is adequate. An ideal topline can be described as well-muscled, displaying a full and rounded athletic appearance, lacking concave or sunken-in areas, providing ability for sustained self-carriage. This region of the horse is a good visual indicator of the whole body amino acid status. Concave, or topline areas that appear “sunken-in,” are never acceptable. Flat areas may be acceptable based on breed and/or genetics, and some breeds/genetic traits may exhibit a bulging muscle around the spine.

The topline of the horse is predominately muscle. However, once a horse gets to a BCS of 8 and above (considered obese), the subcutaneous fat layer over the topline musculature becomes visible. The goal is to maximize the topline musculature without adding fat.

Hands-On Identification
While a visual examination is a good tool to evaluate topline, the addition of a hands-on evaluation is recommended. Visual examinations alone can be misleading, especially with winter hair coats.

Follow these steps to conduct a hands-on evaluation.

Step 1.
Place the palm of your hand on the side of the horse’s withers. Does it fall inward? If so, some muscle is gone. If it remains flat, depending on the breed/horse, the amount of muscle may be adequate or can still use improvement. If your hand flexes outward there is adequate muscling in that area, unless the horse is obese. When palpating, note the presence of muscle or fat (muscle will feel firm, while fat is spongy).
Step 2.
Place your fingertips on the horse’s backbone with your palm facing downward, toward the ribs. Use the same assessment above to evaluate the muscles.
Step 3.
Follow the same process for the horse’s loin and croup.

Assessing Your Horse’s Topline – Evaluation Criteria
To evaluate a horse’s topline, refer to the visual descriptions in the chart below. Then assign a grade for each area. Add up the number of areas that are adequate-to-good to determine your horse’s TES grade.

All 3 areas adequate to good = TES score of A
2 of 3 areas = B
1 of 3 areas = C
0 of 3 areas = D

Topline Score: A – Ideal
This Horse Has Ideal Muscle Development:
•The topline muscles are well developed in all three areas, the spinal processes cannot be seen, and the muscles blend smoothly into the ribs
•The wither/back and loin of the horse is full and well rounded
•The croup and hip are full and the stifle muscle is well defined

Topline Score: B
The Sides of the Wither are Concave, as is the Back Between the Vertebrae and the Top of the Ribs:
•The loin muscles are well developed and are the same height as the spinal process
•The croup and the hip muscling is adequate; pelvis to point of hip is rounded

Topline Score: C
The Wither/Back and Loin Areas, Between the Vertebrae and the Ribs, are Concave:
•The ‘spinal process’ in the loin area is higher than the muscles beside it and can easily be seen and palpated
•Muscles over the croup and hindquarters are well developed and rounded

Topline Score: D
The Entire Topline, Including the Wither/Back, Loin, and Croup Areas, are Concave:
•The croup appears pointed at the top since the vertebrae and hip bones are higher than the concave muscles in between them
•In a severely affected horse, the width of its stifle is narrower than the width of the point of hip

Next Steps in Improving Topline
One of the key ways to impact topline is with the right nutrition comprised of quality protein. Since the topline is comprised of muscle, any nutrition that influences muscle will influence the topline.

To determine what nutrition best fits your horse’s needs, take the Topline Balance assessment for a customized nutrition plan.

Information compiled by: Emily Lamprecht, Ph.D., Russell Mueller, M.S. PAS and Abby Keegan, M.S. – Cargill Animal Nutrition

Will Too Much Protein Cause Developmental Disorders in my Growing Horse?

Protein is a very important part of every horse’s diet.  Horses of all ages, developmental stages, activity levels, and reproductive status have essential amino acid requirements, amino acids being the building blocks of protein, and are what determine the quality of the protein.

Here’s an analogy:  consider amino acids as letters of the alphabet, and protein as words with structures such as muscle being the complete sentence.  Now put it all together; the combination of amino acids (letters) determines the quality or type of protein (word) that is formed.  The body is made up of many different types of proteins, all with distinct amino acid profiles.  If you have a shortage of or imbalance of the essential amino acids, the body cannot spell the words and complete the sentences, so the body can’t build and maintain quality tissues.

Consider this example:

  • 94% of a hoof is made up of amino acids (methionine for example)
  • The remaining 6% is comprised of fats, minerals and vitamins (biotin being just one of those vitamins)
  • Having protein or amino acid deficiency in the diet or feeding an unbalanced ration will compromise hoof integrity (brittle, soft, cracks, susceptibility to thrush, etc.).

cargill050aNow for the question above: Will protein cause developmental joint disease in my growing horse?

Growing horses have high nutrient requirements, with quality digestible protein (amino acids) being a very important and significant part of that nutrient requirement.

Confusion often occurs between providing nutrients and calories.  Providing a grain concentrate that is balanced for adult horses may provide too many calories (energy) and not enough of the nutrients (amino acids, minerals, fatty acids, vitamins ) the growing animal requires, for a couple reasons:

  1. Because unlike mature adult horses, youngsters cannot eat as much per meal (small stomach) and may never consume the recommended daily intake
  2. Because their hind-gut is immature (can’t digest/ferment forages very well) so they are unable to digest and absorb as many of the nutrients from forage as an adult horse does, leaving a nutrient gap in the total diet

The result is a mismatched calorie to nutrient ratio, with too many calories and not enough of the nutrients (amino acids, minerals, fatty acids, vitamins) that they need to grow and develop properly. High calories without the right amount and type of nutrients to support the rapidly growing animal can be problematic.  Resulting issues are often experienced as hay bellies, physitis, developmental joint disease (e.g. OCD), contracted tendons, etc.

Providing a diet balancer or a concentrate specifically designed to support growing horses is a great way to avoid the calorie to nutrient mismatch as well as provide digestible sources of those nutrients.  Diet balancers tend to be very dense in their protein, vitamins and mineral content, and very low in calories themselves.  This is why crude protein, for example, seems very high (e.g. CP 30%) in ration balancers and can cause concern among horse owners.  Fear not, feeding rates for these concentrated products are much lower than a traditional grain formula, providing all of the balanced nutrients needed in a volume that a small stomach can handle, without all of the extra energy.

Having too much poor quality protein in the diet will not be utilized by your horse, and may result in an amino acid deficiency, and makes for an ammonia filled barn due to excess nitrogen being excreted in the urine.  Having the right amount and combination of amino acids in the diet is key to supporting optimal growth and reducing metabolic waste.

Working with an equine nutritionist to find a horse feed that is specifically designed for growth and development and then following the manufacturer’s feeding directions should result in a practical and effective solution to ensure your youngster is getting the right balance of energy and nutrients, helping to avoid developmental issues and maximizing performance.

Around the Barn: Winter Preparations

Even though this is a horse nutrition blog, nutrition is only one piece of the puzzle when it comes to keeping your horses happy and healthy.  As we head in to cold winter months, I thought I’d share some of my favorite tips for prepping your horse and some of the gear that goes with him!

  • Blanketing:  In general, horses adapt well to decreasing temperatures by growing an insulating hair coat.  As long as they have shelter to get out of wind and precipitation, and are able to meet their increased energy (calorie) requirement, they do quite well and can tolerate sub-zero temperatures. 
    • Keep in mind, the insulating value of the hair coat is compromised if it gets wet.  As temperatures drop below the critical temperature which is around 50°F on average, horses require more energy to stay warm, which is best provided by increasing the forage in their diet, not grain. 
    • Blanketing may be a good option if:
      • There is no shelter during turn out
      • The horse’s hair coat is clipped
      • You have a very young or very old horse that might not be efficient at maintaining body temperature
      • The horse is under-conditioned or under weight
    • Finding a blanket that fits well, is waterproof, breathable, and the proper weight (light, medium, heavy fill) based on the conditions are important considerations. 
    • If you already own blankets, dig them out before you need them and check to ensure they are clean, in good repair, and still fit your horse properly. 
    • Never blanket a wet horse, or put a wet or damp blanket on a horse.
  • Don’t forget to periodically remove the blanket and assess body condition, and check for any rub marks that the blanket may be causing.
  • Winterizing the barn and trailer: Fall is a good time to prepare your barn and trailer for colder weather.  Cleaning, installing or checking insulation, replacing screens with windows, ensuring ventilation is adequate, insulating water sources, cleaning and safety-checking heaters and electrical systems, are recommended.  
    • In the barn:
      • Check the roof for structural integrity and leaks
      • Clean gutters and install snow slides if needed
      • Plan for snow removal and de-icing walkways, if applicable.
    • In the trailer
      • Check the floor, lights, brakes, and tires and replace or provide maintenance as needed. 
      • Put together an emergency kit for you and your horse in the event of a break-down in winter weather. 
      • If you are on the road frequently, consider road-side-service for equestrians in the event of an emergency. 

Good luck, stay safe, and take a moment to enjoy the site of your horse playing in the snow if you are lucky enough to see some!

Horse Nutrition Tips Heading in to Winter

Cooper and Ferris in a snowstorm

Ferris and Cooper enjoy turnout in the winter months; it keeps them fit and happy.

This is my favorite time of year!  It is a time of reflection and relaxation after the show season, when I have time to hit the trails and enjoy the fall colors without the bugs tagging along.   The leaves have changed and like it or not, Old Man Winter is right around the corner.  Shorter days and cooler temperatures are signaling our horses to grow their winter hair coats. 

With these seasonal changes, there are a few good management practices and considerations that can facilitate a smooth and stress free transition into the cooler months of the year. 

  • Salt: Make sure loose white salt along with fresh clean water is available to your horse(s) at all times.  Meeting this requirement helps keep your horse drinking, and may help prevent seasonally related colic episodes due to reduction in water consumption as the days get colder. 
    • Loose salt is preferable to a block, as horses are not partial to licking a cold block as temperatures fall, and may not consume enough to meet requirements.  However, a salt block is preferable to no salt at all.
  • Water: Provide water in an insulated or heated bucket/tub.  Research suggests that water kept between 40 – 65°F is preferable to cold water, and helps maximize consumption.  Make sure your water source is insulated or heated to prevent ice formation when temps dip down below freezing.
    • Check electrical wires and grounding to ensure everything is working properly and is safe.  All wires should be protected to prevent chewing or disconnection from the power supply.
  • Hay: Providing hay as an alternative to fresh pasture as grass goes dormant is a common practice to meet forage and increased energy requirements as it gets colder.  Stock up now!  Having a reliable source of good quality hay that will get you through the winter months is important. 
    • Long stemmed forage is the best, however hay cubes, complete feeds, hay stretchers or replacers can be good solutions if hay is scarce, too expensive, or of poor quality. 
  • Foot care: Having a chat with your farrier about your goals and your horses’ specific needs over the winter is advisable.  You may want to consider non-slip solutions or snow pads for horses that are shod, or potentially taking off shoes, and letting your horse go barefoot for a few months.  In any case, regular trimming and balancing should be continued throughout the winter months although frequency may go down due to slower rate of hoof growth during this time of year.
  • Check in with your veterinarian:  Fall is a good time to check in with your vet to make sure your horse is up to date on recommended vaccinations, dental care, and de-worming.

With a little extra preparation and effort, you and your horse can enjoy a wonderful winter together!

Changing Hay Sources for Horses

As a horse owner, I have moved quite a few horses around and recently moved my gelding to a new boarding facility, so thought this would be a good opportunity to share one aspect of my experience. 

To help maintain as much consistency in his routine as possible, I made sure that I had 2 weeks’ worth of hay to take with me to help keep his diet consistent throughout the move and to allow for a gradual transition to the new hay. 

When I told the barn managers at the new facility that I was bringing a few bales of hay over, they seemed a little surprised at this and told me not to worry about it, because they had really high quality hay.  I asked them if they would recommend a sudden change in a horse’s grain ration, and immediately they said of course not, due to colic risk. I replied, “Then why would you switch their hay cold turkey, when it makes up 60 – 70% of the horses diet?” and watched their expressions as they realized the point I was making.

As a result, along with keeping his grain ration and meal times consistent with the previous routine, a gradual transition from the previous hay to the new hay was done over a 2 week period.  For the first couple of days he received his “old” hay only, and over time we incrementally replaced a small portion of his “old hay” with the “new hay” so that at 2 weeks post-move, he was completely switched over without any problems or decline in performance. 

As horse owners, it is important to keep in mind that ANY sudden changes in diet, including fresh pasture and hay, can disrupt the environment in the gut where communities of microbes reside.  Consequently, this disruption in the microbial population and digestive process can put the horse at risk for GI upsets (e.g. excessive gas production, colic, diarrhea, discomfort, etc.). The energy and nutrient content in hay can vary drastically depending on the plant species, geography, soil conditions, plant maturity at harvest, climate conditions, baling and storage methods, etc.  Even hay that comes out of the same field from consecutive cuttings can have large differences in quality and nutrient content that should be considered. 

It takes approximately 3 weeks for the microbes in a horses gut to adapt to dietary changes, thus making slow, gradual transitions over a 2 – 3 week period important to help prevent GI upset.  When it isn’t possible to make a full two week transition, then allow for as much of a gradual transition as possible even if is only over 2 – 3 days.  Providing dietary pre- and probiotics can also help support gut microbes through dietary changes especially if they are rapid.

Activity Levels for Horse Feed Directions

When feed companies formulate horse feeds, one of the steps involved is determining how much of a particular feed a horse would need to eat. Within that, horses of different activity levels will require different amounts of feed to meet their varying calorie and nutrient needs. The video below gives a short description of each of the activity levels listed on feeding directions, to help horse owners feed their horses properly.

Feeding “George”: A Polysaccharide Storage Myopathy (PSSM) Horse

Previously, I introduced you to George, my ‘Heinz-57’ PSSM positive horse.  Though his test results came back positive for Type 1 PSSM, his diagnosis does not mean his athletic career is over. With some diligence and routine, George is able to lead a normal life as a successful working partner.

One key to managing his condition is maintaining consistency in his diet and routine. Remember, he would get sore every time the hay changed, particularly if it had alfalfa in it.  First I work to ensure that George’s total diet is properly balanced which starts with controlling the starch and sugar energy sources in his hay and grain ration.  I buy larger quantities of grass hay (no alfalfa) that will last awhile, a full year if possible. I also have my hay tested before buying it to make sure it isn’t too high in non-structural carbohydrates (12% NSC or less), and that the rest of the nutrients are within an acceptable range for good quality hay, as this is the bulk of his diet. The lower the NSC in the hay, the more room there is in the diet to add calories from fat. More on that below.

To balance his hay, he gets a controlled starch feed concentrate that is fortified with essential amino acids, complexed trace minerals, pre- and probiotics.  If I need to add calories to his diet to support higher levels of exertion during training and show season, I add a balanced fat supplement to the concentrate component of his diet.  To meet the total caloric requirement it is recommended that PSSM positive horses receive no more than 10% of the digestible energy from non-structural carbohydrates (starch and sugar), and 15-20% of the digestible energy should be supplied by fat.  Remember, this applies to the total diet, contributions from grain plus forage.  Working with a qualified equine nutritionist is a great way to figure all of this out.  In a nutshell, I control the sugars and starches in his total diet (low NSC grass hay and low calorie, controlled NSC grain) and add a nutritionally balanced fat source when extra calories are needed. The only supplement he gets is vitamin E, which helps boost his antioxidant status (helps fight oxidative stress), and supports muscle recovery after exercise.  Because his total diet is balanced for selenium, I don’t supplement this mineral to avoid potential toxicity.

Estimating his weight and doing a regular body condition score help me adjust his diet and exercise routine accordingly, so he maintains good muscle mass and avoids excess fat deposits.  In addition, I make sure to minimize stress as much as possible by keeping his routine consistent.  His daily ration is divided up into 3 meals to avoid one large grain meal and he has access to hay for most of the day.  He gets a minimum turnout of 8 hours every day with a buddy and limited access to fresh forage.  I also exercise him at least 6 days a week.  With this management routine, regular veterinary and farrier care, he has never “tied-up” on me, and continues to excel in dressage with the occasional hunter pace thrown into the mix. Providing good quality of life is a top priority, especially when it comes to managing even the most challenging horses, and I think George would agree, he is doing great!

Meet “George”: A Polysaccharide Storage Myopathy (PSSM) Horse

I’m proud to introduce you to George, a “Heinz-57” draft cross, and my current equine partner.  He is the result of a ½ Thoroughbred, ½ Percheron (dam) x ½ Hanoverian, ½ Paint horse (sire). I’ve had the privilege of knowing George since he was a weanling, and bought him as a yearling.  It wasn’t until I started him under-saddle as a three and a half year old that I started noticing behavioral changes (crankiness – not like George), non-specific muscle soreness, and a transient, almost undetectable gait abnormality, all of which happened to be associated with new hay delivery.  I won’t mention how much I’ve spent having him worked-up, imaged, adjusted, fitted and many more things to get to the bottom of what his body was trying to tell me.  We were coming up empty handed and frustrated.

It wasn’t until after I returned from an equine nutrition symposia that it occurred to me to have him tested for polysaccharide storage myopathy (PSSM). PSSM causes the horse’s muscle cells to store energy (glycogen) in excess, which can result in a variety of symptoms, the most severe of which is tying up after aerobic exercise.  Nearly all of the classic signs were there, short of a bad tying up episode.  Wouldn’t you know it, he came back positive for Type-1 PSSM a.k.a. EPSM, tying- up syndrome/exertional rhabdomyolysis/Monday morning disease, set fast or azoturia.  There is more than one version of PSSM (Type-1 is most common) and the diagnostic tests for each are unique.

Recent advances in equine genetics have made testing a blood, muscle, or hair follicle sample possible.  As it turns out, three of the four breeds that George represents have been identified as prone to carrying the genetic mutation responsible for PSSM.  Unlike some other recessive genetic diseases, PSSM is inherited as a dominant gene; in other words having just one copy of the mutated gene means the horse has the disease.  Horses lucky enough to inherit 2 copies of the gene can be more severely affected.   The good news is, with a little diligence, these horses can be managed and go on to have a good quality of life and successful athletic careers; both of which I want for George. 

Diagnostic information can be found at the University of Minnesota Neuromuscular Diagnostic lab website: http://www.cvm.umn.edu/umec/lab/home.html

Prevention and Management of EMS in Horses

There is no treatment or cure for Equine Metabolic Syndrome (EMS), so taking preventative measures though diet and exercise are the best defenses against the development of EMS.

Crinkles on Toby's neck are evidence of his 'overweight' status

Here are some great defensive strategies to help prevent your horse from developing EMS:

    • Prevent obesity by providing a forage-based nutritionally balanced diet with controlled starches and sugars.
    • Maintain an optimal body condition through regular exercise.
    • Work with an equine nutritionist or veterinarian to understand what a healthy weight and body condition is for your horse to help prevent over-feeding or dietary imbalances that can contribute to EMS.

For horses who already are dealing with EMS, follow these tips to help successfully manage their condition:

    • Prevent or reduce obesity through controlled starch and sugar in the total diet along with exercise (unless horse is painful from laminitis episodes).
    • It is recommended that these horses have very little to no access to fresh pasture to avoid the overexposure to the sugars in grass.  Use of grazing muzzles or a dry lot are good alternatives to stall confinement, as this allows the horse to exercise on its own.
    • Have a nutrient analysis done on your hay to understand the NSC content – keeping in mind that it is important to understanding to NSC content of the total diet (hay + grain, if applicable).
    • Soaking hay (15 – 30 min warm water) can help leach out some of the sugars in the hay, just be sure to feed the hay right away before it spoils, and discard the sugar waste water, so the horse does not have access to it.
    • Low calorie ration balancers are good horse feed options to balance the diet if there are vitamin and mineral deficiencies from feeding a forage only diet, and/or from soaking hay.

 

 

What is Equine Metabolic Syndrome (EMS)?

EMS is an endocrine (hormonal) disorder in horses, similar to metabolic syndrome in humans, that is characterized by obesity, insulin resistance, and regional adiposity (abnormal fat deposits), which can predispose affected horses to chronic  laminitis.

What types of horses are affected? 

First and foremost, most horses do not suffer from EMS.  Most horses tolerate dietary carbohydrates (e.g. NSC, starch, sugar, fructan) quite well, and thrive on this important and readily available source of energy.   Performance horses in particular need sufficient NSC in their diets for work and recovery after exercise.  Too little starch and sugar in the diet can actually diminish athletic performance over time in non-EMS horses.

Tess the pony indulges

That being said, EMS can occur in any breed, however ponies, Morgans, Paso Finos, and horses that tend to be “easy keepers” seem to be most vulnerable to developing EMS.  It should also be noted that not all obese (fat) horses are insulin resistant, and not all insulin resistant horses are fat.

How do I know if my horse is insulin resistant (IR)?

Veterinary diagnostic testing (blood work) is recommended to confirm IR, but here are some other classic signs of insulin resistance in horses and ponies:

  • A classic sign of IR is a “cresty neck”, of which a clear correlation between neck circumference and IR has been documented.
  • Horses with regional deposits of lumpy or dimpled fat pads (e.g. behind the shoulder, around tailhead, over the loin), are suspect of being IR.
  • Horses that seem to gain weight rapidly, or blow up easily, particularly in spring with new pasture growth, relative to other horses may indicate IR.
  • Horses that are tender footed, and/or that demonstrate rings on the hoof wall, expanded white line and blood spots on the soles of their feet,  suggests mild, chronic bouts of laminitis and IR.

EMS is easily confused with other clinical disease such as Cushing’s Disease (a.k.a. pituitary pars intermedia dysfunction) and hypothyroidism due to similar clinical signs, despite different underlying causes.  It is very important to work with a trusted vet to ensure an accurate diagnosis if any of these conditions are suspected.

A word of caution, single blood samples for the diagnosis of IR can be very unreliable and misleading as several factors unrelated to EMS influence glucose and insulin levels (time and content of horse’s last meal, type of feed horse is adapted to, time of day sample is collected, stress level of horse), leading to false conclusions.  Taking multiple blood samples over several days, or utilizing techniques such as the euglycemic insulin clamp or a combined glucose insulin tolerance test (CGIT) are more involved, but can lend more validity to the lab analysis.  In any case, early detection of EMS and other endocrine disorders is preferable.