by Casie Bazay

How to Reduce the Post-Weaning Stress Response in Foals

How to Reduce the Post-Weaning Stress Response in Foals

There’s no doubt about it – weaning is a stressful time for foals. In fact, new research shows that weaning is one of the most stressful periods in a horse’s life. 

During this process, the foal is taken away from its mother in order to transition from milk to concentrated feeds and forages. This is usually done when the foal is between 4-6 months of age, but in some cases, weaning may be done as late as 8 months of age. 

The weaning process is stressful not only because there is a physical separation from the mother, but multiple changes taking place at once, including a change of diet, acclimation to a new social group, a change in housing, as well as changes in management routines. 

In the past, researchers mainly focused on the short-term stress response of foals directly after weaning. However, they are learning that foals actually continue to experience stress for a much longer period of time. 

The good news is that there are some things owners can do to improve the long-term welfare of their foal both during and after the weaning process.

Signs of Weaning Foal Stress

When animals or humans experience stress of any kind, it leads to activation of the hypothalamic-pituitary axis. The pituitary gland secretes ACTH, which then releases cortisol, commonly referred to as the “stress hormone.” 

Cortisol can be found in many bodily fluids, including plasma, feces, saliva, and urine. All of these can then be analyzed for an animal’s stress response in particular situations.

Cortisol impacts multiple organ systems and lowers plasma calcium levels. It also causes an increase in bone resorption as well as a reduction in the synthesis of collagen. This can lead to disruption of length growth of bones– a definite concern for growing horses. 

Every foal is different, but many will show obvious signs of stress during the weaning process, such as:

  • Increased frequency of vocalizations
  • Altered feeding and sleeping patterns
  • Irritability and anxiousness
  • Aggressive behavior
  • Suspension of normal play behavior
  • Weight loss
  • Decreased immunity/higher risk of infectious diseases
  • Development of stereotypical behavior such as cribbing

One recent study showed that, when compared to their behavior before weaning, foals are less active and tend to spend more time resting

The researchers noticed that foals would often stand still or lie in the sternal position (upright, with their chest on the ground) more than normal. 

How Stress Affects a Foal’s Gut Health

In studied foals, cortisol concentrations from fecal samples indicated a notable stress response to weaning. In fact, on day one, cortisol concentrations were about twice the level they were two days before weaning. 

Cortisol levels continued to increase during the course of the first week and then slowly declined over the three-week study period. However, most of the foals in the study never fully returned to their pre-weaning stress levels within that time frame. 

Studies also show that circulating stress hormones can negatively impact a foal’s gastrointestinal tract. The hormones can alter the intestinal microbiome and possibly allow for overgrowth of harmful organisms such as E coli

It’s clear that separation from their mothers at weaning shifts a foal’s gut microbiota. The stress may kill beneficial gut bacteria and also cause proliferation of pathogenic (bad) bacteria. 

Researchers found the most substantial shift occurring at day three post-weaning

Long-term foal stress can lead to weight loss and disturbance in growth. It can also weaken the immune system and affect the central nervous system by increasing appetite, decreasing REM sleep, and affecting excitability, mood, and behavior. 

Because of this, it is in the best interest of the horse to decrease risk of long-term stress that can result from weaning. 

How to Decrease Stress in Weaned Foals

There are two different approaches for weaning foals: the first uses abrupt and total separation between mare and foal, while the second takes a more gradual approach, separating mares and foals for short periods at first and then longer periods over time. This is usually done in a way where the mare and foal can still see each other. The gradual weaning approach is more aligned with how foals are weaned in the wild and is believed to cause less stress on them. 

Researchers also believe that weaning foals in groups rather than alone or in pairs may be beneficial. Another method that appears to decrease stress is weaning in pastures as opposed to stalls.

More tips for decreasing foal stress during weaning include:

  1. Plan ahead: Aside from deciding which weaning method you will use, formulate a plan for implementing this strategy. 

  2. Provide plenty of human interaction: Weaning is an ideal time to halter break and handle foals as much as possible in order to build trust as well as provide companionship. 

  3. Practice safety first: Mares and foals may panic upon being separated, so ensure that your fences are up to par and the environment where both mare and foal will be housed is free of potentially-dangerous objects that they could injure themselves on. 

  4. Avoid additional stressors: The weaning process is stressful enough in and of itself. Therefore, do not combine vet or farrier visits, vaccinations, or deworming protocols with weaning. Also avoid weaning during extreme weather. 

  5. Feed for success: Gradual feed changes, as well as high-quality supplements (more below), can help protect the foals’ gut health during the transition and beyond.

How Probiotics Can Help

No matter how a foal is weaned, there will still be a certain amount of stress involved in the process. Because of this, it’s recommended that owners support the foal’s digestive system and gut microbiome by feeding a foal after weaning with high-quality probiotics such as Fullbucket’s Probiotic Pellets – a yeast-based formula that naturally supports gut health and optimal immune function. 

FullBucket Probiotic Pellets contain:

  • 25 Billion CFU’s of Saccharomyces boulardii (a strain that can be used effectively with antibiotics)
  • Probiotics to support a healthy immune system
  • L-Glutamine to help maintain a healthy intestinal tract
  • Prebiotics for supporting a healthy microflora

By placing both the mare and foal’s welfare first, planning ahead, and supplementing with good-quality probiotics before, during, and after the separation, we can give foals the best shot at getting through the difficult transition time and on their way toward a healthy adulthood.

Read More:

Behavioral and Hormonal Assessment of Stress in Foals (Equus caballus) Throughout the Weaning Process

The Effects of Weaning Methods on Gut Microbiota Composition and Horse Physiology

Photo by Romualdo Olazábal on Unsplash

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