body weight | Horse Racing Free Tips

Winter Feeding: Keeping Horses In Good Weight

Shivering helps horses maintain their core body temperature in winter, yet the metabolic price is high, considering temperature regulation requires significant calories. Additional calories will likely be needed to maintain an appropriate body condition score (BCS) during cold snaps. Exactly how much more feed does your horse need to consume when the mercury drops?

According to Dr. Kathleen Crandell, a nutritionist for Kentucky Equine Research, some horses won't require any additional calories, whereas others may need to consume up to 25 percent more calories each day to maintain condition.

For example, if a horse typically consumes approximately 2 percent of its body weight in forage per day (equivalent to 20 pounds of dry forage for an average 1,000-pound horse), then this horse could require almost 30 pounds of dry forage per day in cold weather. Rather than simply feeding more of the same forage to offer additional calories, horses can be fed concentrates, fat (either as oil or high-fat supplements such as rice bran), or energy-dense forages such as alfalfa or clover mixed with their regular hay.

“Healthy horses living in regions that typically have milder winters, are maintained indoors, or are blanketed when outdoors for limited periods of time can be fed a diet similar to that fed in warmer months,” Crandell advised. Horses that may require additional feed to maintain an appropriate BCS include:

Horses that fall into the senior classification,
Horses with an underlying disease;
Horses asked to perform their regular work throughout the cold season;
Horses that reside primarily outdoors in regions with harsher winters; or
Horses that are not routinely blanketed but do have access to shelter.

Horses maintain their core body temperatures by diverting blood flow from the skin to their internal organs, shivering, growing a thick coat, altering metabolic pathways to produce heat, and fermenting forage.

One of the key factors in determining whether or not your horse requires more feed involves frequent and precise assessment of BCS. While some owners may struggle with this process on the best of days, often underestimating their horse's true condition and therefore overfeeding, the longer, thicker coats and use of blankets can make estimating BCS even more challenging. Nonetheless, this skill is imperative to ensure a healthy horse.

[Story Continues Below]

“Be certain to use your hands to feel for fat cover rather than simply glancing at these regions to assess BCS,” advised Crandell.

Looking for a specific product to maintain an appropriate BCS in the winter? Kentucky Equine Research's feed manufacturing partners offer high-calorie concentrates that will suit your horse's dietary needs.

Obese Horses More Likely To Move Unevenly

In an effort to determine how added weight affects equine fitness and performance, Dr. Anna Jansson and a research team from the Swedish University of Agricultural Sciences and Hólar University published a study in Physiological Reports in which horses were fed controlled diets to add or restrict weight gain. The scientists used nine Icelandic horses that they split into two groups. Changes in body weight and fat were induced in the group being fed a high-energy diet for 36 days.

During the last seven days of the study period, researchers recorded body condition score and weight, and percentage of body fat was estimated with an ultrasound. Each horse was then given an exercise test on a treadmill and a field test that mimicked a competition, which was scored by judges. Blood samples were taken, as well as heart rate, temperature and respiratory rate.

[Story Continues Below]

On the treadmill test, the horses that had gained weight had a higher heart rate and temperature, and heavier respiration. Blood tests showed that heavier horses had lower physiological fitness.

The team also found that overweight horses showed a marked gait asymmetry compared with leaner horses, as was shown both by sensors placed on the horses while they moved. The heavier horses moved most asymmetrically on the day after their field test.

Judges overseeing the field test also scored heavier horses lower than their leaner counterparts, suggesting that weight affects performance.

The authors conclude that higher body fat and body weight lowers equine performance, made horses move more unevenly, and delayed their recovery from exercise.

Read the full study here.

Study: Withholding Feed Affects Water Intake In Horses

Horses sometimes refuse to drink following competition. One study shows that decreased water intake may result from decreased feed consumption.*

Horses primarily drink water after eating. This behavior appears to be prompted by the large volumes of water that move into the large colon after a meal, drawing it out of circulation. As a result, horses feel dehydrated, essentially spiking thirst and driving them to drink.

“Owners withhold feed from their horses for a variety of reasons: before transport, prior to competition, or even by feeding 'meals' twice a day rather than allowing horses more continual access to feed,” advised Catherine Whitehouse, M.S., a Kentucky Equine Research nutrition advisor.

Feeding patterns and behaviors could therefore have a profound effect on a horse's water intake and overall hydration status, performance, and health.

To better understand patterns of voluntary water intake, the amount of water consumed by eight fed and fasted horses was measured for four days. When fed, horses were offered high-grain diets consisting of 4.5 pounds (2 kg) grain and 18 pounds (8 kg) Bermudagrass hay per day divided into two meals. All horses had access to 40 liters of fresh water throughout the study period. Various physical and laboratory data were collected and analyzed during the study.

Key findings included:

Feed deprivation did not cause any changes in vital signs or physical examination findings;
Horses remained alert and responsive to their environments. They did not have any behavior changes, such as eating bedding or splashing in the water;
Assessment of mucous membranes revealed no indication of dehydration;
Horses lost 7.2 percent of their body weight during the four-day study period;
Voluntary water intake was significantly lower when feed was deprived;
The decrease in water intake began within 12 hours of withholding feed;
Fecal and urine output appeared to decline based on direct observation;
Sodium was significantly reduced during the feed deprivation; and
Although still within normal limits, blood urea nitrogen and creatinine levels were significantly higher in feed-deprived horses, consistent with mild dehydration.

“Feed deprivation resulted in an immediate and consistent reduction in voluntary water consumption. Horses appeared to only become mildly dehydrated, likely because horses can draw water from their large colon to preserve water balance for a short period of time,” explained Whitehouse.

In sum, these results confirm that even short-term withdrawal of feed results in a substantial decrease in voluntary water consumption. Therefore, feed interruptions for horses being transported for competition, for example, can potentially negatively affect performance due to inadequate hydration levels.

“Horses with decreased feed consumption, either due to reduced appetite or management strategies, may be at risk for chronic mild or low-grade dehydration. This may be particularly salient for horses actively involved in competition. An electrolyte supplement offered with water in conjunction with a small meal may help tempt voluntary water intake,” advised Whitehouse.

*Freeman, D.E., A. Mooney, S. Giguère, J. Claire, C. Evetts, and P. Diskant. 2021. Effect of feed deprivation on daily water consumption in healthy horses. Equine Veterinary Journal. 53(1):117-124.