Brand Marks - a Pain in the Butt6 August 2007
Farmers need a method of permanently identifying their cattle. In fact it is compulsory in many countries and branding has been the tradition method of use for centuries. Ear tags are too easily lost and, like tattoos, can only be read at close quarters. Branding provides a quick, cheap and very permanent mark that is easy to read at a distance. But, whilst branding helps the farmer, it certainly does not help the leather which is left with scars and grain disfigurement.
There are two commonly used types of branding; hot iron branding and freeze branding. It is hot branding that causes the most damage to hides. Hot branding Hot brands are applied with an iron or steel pre-formed shape that has been heated in either a propane burner or open fire. Electrically heated irons are also available. The hot iron is held against the skin of the animal for up to five seconds, during which time it is essential that the animal is tightly restrained to avoid mis-marking as the animal struggles to escape. The heat of the iron and dwell time should be sufficient to destroy the upper part of the skin (the grain layer) which contains the hair follicles, but should not be sufficient to burn through to the corium layer beneath. Once the burn has healed, the hair does not grow back and the identifying mark is left permanently hairless. Unfortunately for the tanner (and the animal) hot brands frequently do burn well into the hide structure and can be clearly visible on the underside of the leather. In countries where cattle roam over vast distances, eg Australia, cattle are often herded by means of helicopter. Consequently, branding on the side of the animal is useless since it cannot be seen from above. Therefore, brands are placed on the back of the animal which is the prime area on the hide of course. This renders the leather useless for many purposes, but modern finishing techniques, particularly in the upholstery sector, are surprisingly good at disguising them. Freeze branding Freeze brands are applied using copper or bronze pre-formed shaped irons that have been super-cooled in either liquid nitrogen or a slush of dry ice in alcohol. The temperature of the irons will vary between -70-180°C. It is important that there is direct contact of the cold iron with the skin, so it is necessary to clip the hair first and then wet the skin with an alcohol solution before applying the cooled iron. The cold iron is held against the skin for between 15 and 60 seconds depending on the age and breed of the animal and the refrigerant used (liquid nitrogen is colder than dry ice). The freezing of the skin kills the cells that produce pigment. Consequently, the hair grows back white instead of coloured. For this reason, it is only possible to use this technique successfully on animals that have areas of dark hair. However, it can be used on pale coloured animals if the cold iron is held against the skin for longer which kills the hair follicles completely. The area then remains hairless like a hot brand. By studying behaviour, monitoring heart rates and levels of stress hormones in the bloodstream, veterinarians have shown that freeze branding causes less pain and stress to the animal than hot branding1. Also, unlike hot branding, freeze branding causes only superficial damage to the grain surface of the leather and, therefore, it is easier to conceal. For this reason it is the method that tanners and those concerned with animal welfare would prefer farmers to use. Alternatives to branding In European countries where farms are relatively small and easily accessible, freeze branding has become the norm. But elsewhere, hot branding is still the preferred method and farmers have perfectly legitimate reasons for not using freeze branding; it is more expensive than hot branding, it is not easy to store and transport refrigerants in remote areas and it takes much longer to freeze brand cattle than it does to hot brand them. If you own a herd of many hundred cattle that are spread over a large remote area, freeze branding is, unfortunately, just not practical. Numbered ear tags have been around for many years, but there is a risk of them being lost. Tattoos inside the ear of the animal have also proved less effective because they are difficult to read and they also tend to fade with time. But we are in the digital era now and there is microchip technology available that could prove beneficial. These are small electronic transmitters that can be attached to the animal via rumen boluses (a pellet that remains inside the stomach), electronic ear tags or injectable transponders (a microchip embedded under the skin). Electronic ear tags are the most cost effective of the three, but are likely to suffer the same fate as their non-electronic predecessors and get lost. Subcutaneous microchips are read by a hand-held device next to the skin. They have found great popularity in small pets, eg cats and dogs, but are impractical for larger animals due to difficulties in restraining the animals to enable the chips to be read. The location of the implanted chip also needs to be taken into consideration for animals intended for consumption. The rumen bolus does show some promise since it can be read from a significant distance by means of a battery powered handheld device. The use of Global Positioning Systems (GPS) have even been considered. This technology has the added advantage of being able to remotely monitor the animal's health by means of monitors that measure body temperature etc2. If the cost of this technology can be brought down to an affordable level, we could see some real benefits in terms of hide quality. We are frequently asked if brand marks are an area of weakness in leather. Probably not is the answer. Scar tissue comprises of very densely packed collagen fibres and another fibrous protein, elastin. Both impart strength. In fact, the veterinary profession have for many years used deliberately induced scar tissue to strengthen weak tendons in racehorses.