Categories: Articles, Livestock and gamePublished On: 4th April 2024

Preserving tradition, enhancing efficiency: The science behind Dry Ice’s freeze-branding technique

By 3 min read

Dry ice image 1

Although the idea of freeze branding is not new to South African agriculture, dairy farmers have only recently begun to use it more regularly to make herd management simpler.

Cattle and horses can be freeze-branded using dry ice. Freeze branding, as opposed to hot branding, necessitates the submersion of branding irons in dry ice (-79 °C) until the irons reach a temperature at which their application to the hide would result in a permanent imprint on the animal. The extremely cold iron destroys the pigment follicles beneath the animal’s hair, which results in the imprint. White hair replaces the natural hair coat in the branded area of cattle that have been branded with extremely cold irons and dry ice.

Hair under the freeze brand site will regrow in a noticeable white colour in animals carrying the white hair colour gene. The coolant lowers the iron’s temperature so that it can be used on shaved skin. This changes the colour of the hair follicles forever. The extreme cold destroys the animal’s hair follicles’ pigmentation, so any new hair that grows in will not be coloured. This leaves a strong, long-lasting mark in the shape of the branding iron’s head. The loss of hair leaves a spot of skin without hair in the shape of the brand.

Benefits of freeze branding

For permanent identification, freeze branding with dry ice is becoming more common because it leaves a clean, attractive white mark that can be used for either owner identification or animal identification.

The benefits of freeze branding are:

  • Cattle and livestock can be permanently tracked.
  • Freeze brand identification marks won’t wear or fade over time.
  • The identifying marks are perfect for use in the milking room and are required for accurate milk accounting.
  • The brands are conspicuously legible, even from far away.
  • Freeze branding is more ideal than ear tags, which can be misplaced or become unreadable over time.
  • It eliminates the skin cells that give the hair its colour.
  • Using a cold iron is less uncomfortable for animals than using a hot one.
  • Freeze branding is rather mild and less invasive.
  • Freeze branding allows for year round visibility, making it simple to track down lost livestock.

Freeze branding process

In 30 to 60 days, the iron used to freeze brand cattle make the hair lose its colour and turn white. Because they are so much colder and work better, dry ice and isopropyl alcohol will leave the best and most readable marks. Also, the timing is very important because it changes based on the age, weight, and health of the cows. When you compare freeze branding irons to hot irons, you can tell them apart because the metal on freeze branding irons isn’t cracked in key places, which lets extra heat escape. With these, the handles are usually shorter, and the branding area is usually bigger. Copper alloy is often used to make freeze branding irons. Even though irons made of brass, stainless steel, or metal can be used, copper irons have always worked best because they conduct heat better.

In conclusion, to submerge irons, a mix of 1:1 of dry ice and isopropyl alcohol (99% alcohol) works well. To determine how much isopropyl alcohol and dry ice you need, use 400 ml of isopropyl alcohol and 400 g of dry ice for every animal that needs to be marked.

For more information, visit the Dry Ice International website at

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