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.
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
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.
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.
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).
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.
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