Extension Logo
Extension Logo
University of Minnesota Extension

Horse weight loss: hay nets and limit-fed diets

Quick facts

Using a slow-feed hay net with a restricted diet can reduce weight and maintain a more moderate blood and hormone pattern in overweight adult horses. 

Modern feed and care practices, such as meal feeding and stalling horses for a long time, may contribute to obesity in horses. How you feed and care for your horse can impact your horse's blood profile and hormones. 

Increasing the amount of time a horse takes to eat decreases their rate of intake. Here's a look at how slow-feed hay nets extend foraging and promote weight loss in overweight horses when used with a restricted diet. 

Testing slow-feed hay nets with restricted diets

Our objectives were to determine if a limit-fed diet used with show-feed hay nets would affect body measurements and blood and hormone patterns in overweight adult horses. 

  • We looked at eight adult Quarter horses with an average body weight of 1,241 pounds and a body condition score (BCS) of 7.2.
  • Each horse ate hay either off the stall floor or from a slow-feed hay net.
  • We fed horses in individual stalls and provided them about 60 percent of their maintenance energy needs, split evenly between two meals (morning and afternoon). 

We recorded body weight, BCS, neck and girth circumference and Cresty neck score on days 0 and 28. We also took 24-hour blood samples on days 0 and 28 to analyze glucose, insulin, cortisol and leptin content. Blood samples were taken every 30 minutes for three hours after feeding, with hourly samples taken between feedings. 

What did we find?

measuring girth circumference
Measuring girth circumference

Reduced rates of intake

Hay nets decreased the horses' rates of intake. Horses finished their hay meal in 2.0 hours when feeding off the stall floor and 3.2 hours when feeding from the hay nets. 

Hay nets can be useful to horse owners managing stalled horses or when feeding a limit-fed diet. Increasing the time it takes a horse to finish a meal promotes gut health and has been shown to reduce unwanted behaviors and incidence of colic. 

Weight loss

Each horse lost body weight over the 28-day period. The average weight loss across all horses was 79 pounds. However, we didn't find a difference in weight loss between horses fed from the stall floor and horses fed form the nets.

We know a sustained, moderate-energy deficient diet results in fat and lean body mass loss. We designed our limit-fed diets to be at 60 percent of the energy needs for adult horses at maintenance to reduce one BCS unit in one month. We didn't find a difference in BCS, neck and girth circumference or Cresty neck score between day 0 and 28. 

We may not have seen a difference due to the BCS system itself. BCS evaluates fat deposits in the following six areas: 

  • Withers
  • Ribs
  • Behind the shoulder
  • Along the neck
  • The crease of the back
  • Tail head
Blood sampling
Blood sampling

Most of the horses had clear visual losses of adipose tissue in their lower abdominal area. BCS doesn't consider this region.

Blood profiles and hormone changes

Horses fed from the hay nets had lower peak insulin and cortisol values compared to horses feeding from the stall floors. Horses feeding form the stall floors had greater peak insulin because they took less time to eat their hay meal.

These results also show that horses feeding from the stall floor had higher stress levels likely from spending less time eating. Days affected the horses' average glucose, insulin, cortisol and leptin. Glucose and insulin values increased while cortisol and leptin levels declined throughout the 28-day period.

Funding for this research was provided by Cargill.

Authors: Krishona Martinson, Extension equine specialist; Marcia Hathaway, professor of animal science, College of Food, Agriculture and Natural Resource Sciences; and Emily Glunk

Reviewed in 2024

Page survey

© 2024 Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer.