When it matters most, Zesterra® Delivers

Support that works as hard as your horses — encouraging feed and water intake, buffering gastric acid, and helping maintain performance under pressure.

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Why Horse Owners Trust Zesterra®

Buffers Gastric Acid
Zesterra® works to buffer excess stomach acid and is clinically proven to support the healing of ulcers, helping reduce one of the most common causes of performance setbacks in horses.

Encourages Normal Appetite

Stress can reduce appetite in horses, leading to setbacks in performance & recovery. Zesterra® helps stimulate feed intake by improving digestive comfort & supporting a more balanced gut environment.
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Promotes Hydration
Horses under stress often stop drinking. Zesterra® helps restore natural water consumption habits by improving overall gut comfort and encouraging water intake.

All-Natural & Safe

Formulated with a blend of natural ingredients, Zesterra® is safe for horses of all ages — including foals, seniors, and lactating mares — with no withdrawal times or harsh additives.
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SUPPORT FROM THE INSIDE OUT

How Zesterra® Works

Zesterra® helps horses perform better, recover faster, and maintain gastric health by supporting the digestive system, where stress can take its greatest toll. This all-natural formula works by neutralizing excess gastric acid, promoting healthy appetite, and encouraging hydration, even during high-pressure situations.

Buffers Excess Gastric Acid

Helps protect the gut lining and reduce ulcer risk.
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Encourages Appetite

Makes horses more likely to eat, even under stress or illness.
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Improves Hydration

The palatable formula encourages drinking — critical during travel, heat, or stress.
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Boosts Nutrient Absorption

Supports healthy gut flora and better feed utilization.
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Supports Immunity

Helps reduce cortisol levels and strengthen immune response.
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Safe for All Horses

Ideal for foals, seniors, hard keepers, and lactating mares.

Real-Life Situations.
Real Support.

Zesterra® is trusted by horsemen and horsewomen everywhere — and for good reason: it works. This 100% natural formula is relied on by breeders, professional trainers, riders, and everyday horse owners alike.

✅ Travel & Hauling

✅ Training & Competition

✅ Foaling & Weaning

✅ Digestive Upset

✅ Heat, Cold & Weather Stress

✅ Ulcer Treatment & Prevention

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How To Use Zesterra®

Whether you're managing daily stress or dosing for a specific situation, the guidelines below make it easy to get started — and if you need a little extra help, our Dosing Calculators are here to guide you to the right dose for your horse.

Ulcers or Ulcer-prone Horses

When treating or preventing ulcers:
• 1 mL per 100 lbs of body weight, orally, twice daily for 14 days
• Then once daily for another 14 days

Maintenance:
• 0.5 mL per 100 lbs once daily

Colic Support

At onset of colic Symptoms:

• 30–50 mL orally at first sign of discomfort
• May increase to 100 mL if symptoms persist
• Always consult a veterinarian if symptoms worsen or don’t resolve

Travel & Hauling

Start Zesterra® the day before leaving home:

• 1 mL per 100 lbs the day before travel
• Continue daily while away from home
• Dose again upon return if needed

Older Horses & Hard Keepers

To support body condition and feed efficiency:

• 1 mL per 100 lbs daily for 10 days
• Then reduce to 0.5 mL per 100 lbs daily until ideal weight is reached

Respiratory Infections or Shipping Fever

To support recovery and immune health:

• 1 mL per 100 lbs daily while symptoms are present
• Continue for 10 days following antibiotic treatment

Environmental Stress

Before heat, cold, or weather-related stress:

• 1 mL per 100 lbs prior to the stress event
• Repeat daily during prolonged weather-related stress

Foals & Weaning

Mares:
• 1 mL per 100 lbs orally during the final month of gestation
• Continue through foaling and early lactation as needed

Foals:
• 5–10 mL orally daily during weaning transition (typically 4–7 days)
• May continue longer during stressful weaning or if appetite decreases

Zesterra® helps support appetite, gut comfort, and immune function during this critical stage.

Mares:
• 1 mL per 100 lbs orally during the final month of gestation
• Continue through foaling and early lactation as needed

Foals:
• 5–10 mL orally daily during weaning transition (typically 4–7 days)
• May continue longer during stressful weaning or if appetite decreases

Zesterra® helps support appetite, gut comfort, and immune function during this critical stage.
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What's Inside Matters

We keep Zesterra® clean, natural, and effective — with every ingredient selected to support appetite, digestion, and hydration. No medications. No artificial ingredients. Just proven support you and your horse can count on.

INGREDIENTS
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  • Colloidal Silver
  • Corn Oil
  • Orange Peel Bitters
  • Soybean Oil
  • Veg-based Fatty Acids
  • Water
  • Guar Gum
  • Onion Extract
  • Glycerin
  • Natural Apple Flavor

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Which Tub is Right for You?
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Every herd has different needs — from growth and performance to stress support and fly control. Use the chart below to find the CattlActive® tub that best matches your herd's requirements.

🪣 13% Stress Tub
✅ Safe for all cattle classes
✅ IMI Global Certified
✅ Supports rumen health
✅ Encourages feed & water intake
✅ Ideal for stressed or high-risk cattle
✅ High protein content

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🪣 20% Tub
✅ Safe for all cattle classes
✅ IMI Global Certified
✅ Supports rumen health
✅ Encourages feed & water intake
✅ High protein content