Cow Magnets | SDM Magnetics Co., Ltd.

Ι What Are Cow Magnets?

Cow magnets, also known as cattle magnets or rumen magnets, are veterinary devices used to help prevent hardware disease in cattle. These cylindrical cow magnets are given orally and settle in the rumen or reticulum, where they attract and hold metal objects such as nails, staples, and wire that cows may swallow while grazing. Because they stay inside the cow’s stomach area, cow magnets are sometimes called cow stomach magnets or cattle stomach magnets, and they are widely trusted by farmers and veterinarians.

Once in place, cow magnets usually remain for the cow’s lifetime, continuously trapping metal debris before it can pierce the stomach wall or cause infection. This simple, non-invasive approach protects cattle health and reduces the risk of costly treatments. By lowering the chance of hardware disease, cow magnets help keep herds healthier and support long-term farm productivity with a one-time, reliable solution.

What Is Hardware Disease in Cattle?

Hardware disease, also known as bovine traumatic reticuloperitonitis, happens when cattle swallow sharp metal objects such as nails, staples, or wire while grazing. Because cows do not use their lips to sort feed and often swallow before fully chewing, they are more likely to take in harmful debris—especially in pastures near human activity where metal scraps or broken fencing may be present. Once swallowed, these objects can lodge in the reticulum and may pierce the stomach wall, leading to pain, infection, and in severe cases death. Common signs include reduced appetite, lower milk yield, weight loss, and slow movement, all of which can seriously affect farm productivity.

Cow magnets help prevent hardware disease by attracting and holding metal pieces in the stomach before they cause injury. Without prevention or treatment, hardware disease can result in major complications, expensive veterinary intervention, or livestock loss. Using cow magnets is a simple and reliable way to protect cattle in debris-prone environments, reducing both health risks and financial impact for farmers.

What Is Hardware Disease in Cattle-Cow Magnets

How Cow Magnets Protect Cattle and Their Benefits

Cow magnets work by attracting and holding metal objects—such as nails, staples, or wire—that cows may swallow while grazing, especially in pastures near human activity. Because cattle do not use their lips to sort what they eat and often swallow feed without fully chewing, they can easily ingest sharp debris. A cow magnet is given orally with a bolus gun, then settles in the rumen or reticulum, where it captures these metal pieces before they can puncture the stomach and cause hardware disease. This is a simple, one-time preventive method that does not require surgery or ongoing maintenance, making it practical for herds in higher-risk areas.

Beyond disease prevention, cow magnets help farmers protect productivity. Healthier cattle mean fewer interruptions to milk or meat production, lower veterinary costs, and less risk of losing animals to avoidable injuries. As a reliable, long-term safeguard, cow magnets support efficient herd management and add steady value on farms where metal debris is hard to fully eliminate.

Specifications of Cow Magnets

Cow magnets are made in specific shapes and materials to stay effective and durable inside cattle. Traditional cow magnets are smooth, rod-shaped AlNiCo magnets. Many modern cow magnets use several ring-shaped ferrite magnets stacked on a stainless-steel or plastic core, keeping the same cylindrical form. This structure helps cow magnets resist corrosion and wear in the rumen while reliably attracting metal debris.

Newer cow magnet designs improve holding ability with added features. Some models use a plastic cage or sleeve around the magnet, which helps trap and secure sharp metal pieces once they are captured. Others place high-strength Neodymium magnets inside a stainless-steel body, keeping the classic rod shape but delivering stronger magnetic force. With these different options, cow magnets remain reliable, long-lasting tools that can match various farm conditions and herd management needs.

Model A

Product Name: AlNiCo Cow Magnets

Material: Cast AlNiCo magnets

Dimensions:

Diameter: 12.7 mm (0.50 in)
Length: 76.2 mm (3.00 in)

Finish: Polished

Weight: ~70 g

As the earliest commercially available permanent magnet material, AlNiCo has been used for cow magnets for decades. Most AlNiCo cattle magnets use the AlNiCo 5 grade and are axially magnetized.

Model B

Product Name: Ferrite Cow Magnets

Material: Ferrite magnets

Dimensions:

Length: 65.0 mm (2.53 in)
Width: 16.0 mm (0.63 in)
Thickness: 13.0mm (0.51 in)

Finish: Black

Weight: ~73 g

These block-shaped rumen magnets are a unique type of cow magnet. Made from ferrite and protected with a tough nylon coating, they use multipole magnetization to improve metal capture and cattle protection.

Model C

Product Name: Ringed Ferrite Cow Magnets

Material: Ferrite magnets with stainless steel

Dimensions:

Diameter: 18.5 mm (0.75 in)
Length: 79.0mm (3.375 in)

Finish: Black and silver

Weight: ~117 g

These cattle stomach magnets use several ferrite ring magnets combined with stainless steel parts. The steel pole pieces are designed with the same magnetic polarity on both sides, which concentrates the magnetic flux and produces a strong holding force for reliable metal capture in the rumen. Rounded stainless steel ends improve corrosion resistance and help protect the cow’s stomach from sharp contact. A stainless steel rod runs through the center to reinforce the structure and ensure long-term durability in service.

Model D

Product Name: Plastic Caged Cow Magnets

Material: Ferrite magnets with plastic

Dimensions:

Diameter: 35.0 mm (1.37 in)
Length: 100.0mm (4.00 in)

Finish: Green plastic, customizable

Weight: ~117 g

These cattle magnets use ferrite block magnets enclosed in a durable plastic cage. The cage has molded grooves that help lock sharp metal pieces in place after they are attracted, preventing the debris from shifting and reducing the risk of injury in the reticulum or rumen. The plastic housing is tough and resistant to stomach acids, supporting reliable long-term use.

With its rounded shape, the cage also helps shield the rumen by keeping trapped metal contained and away from the stomach wall. The internal magnet layout provides strong attraction, giving cattle steady, lasting protection against hardware disease while keeping performance consistent after placement.

Model E

Product Name: Neodymium Cow Magnets

Material: Neodymium magnets with stainless steel casing

Dimensions:

Diameter: 12.7 mm (0.50 in)
Length: 76.2 mm (3.00 in)

Finish: Polished

Weight: ~80 g

These stomach magnets use an internal magnetic circuit made from Neodymium magnets and steel pole pieces, all sealed inside a polished stainless steel casing. This structure delivers very strong magnetic force, and the rod shape helps concentrate that force to pull metal debris from the cow’s reticulum or rumen. The stainless steel shell provides excellent corrosion resistance and a smooth, durable surface, allowing safe, long-term use inside cattle.

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