1. Number of experimental animals
In the experiment, for the convenience of grouping and identification, it is often necessary to number the experimental animals in advance. The commonly used numbering methods are as follows:
1. Dye labeling method
(1) Commonly used dyes: red dye: 5% neutral red or magenta liquid;
Yellow dye: 3%～5% picric acid solution;
Brown dye: 2% silver nitrate solution;
Black dye: an alcohol solution of coal tar.
(2) Marking rules: According to different coat colors of experimental animals, choose different chemicals to paint animals.
A. Marking method for rabbits, cats, dogs and other animals: Dip dye solutions of different colors with a brush and directly write numbers on the back of the animals. If you write with silver nitrate solution, you need to expose it to sunlight for 1 minute.
B. Marks for rats and mice: usually painted with colored spots on different parts of the animal to indicate different numbers. For example, the number 1～10 will be the nine areas of the left, middle and right parts of the forelimb, waist and hind limbs of the back of the mouse. From right to left, the numbers are 1～9, and the number 10 is not painted in yellow.
2. Ear-piercing method: Use a special puncher to punch holes or notches in different parts of the animal’s ears to indicate a certain number. This method is one of the commonly used labeling methods in mice.
3. Listing numbering method: This method is simple and practical, and is often used for the numbering of large animals such as dogs, monkeys, and cats. Brand the numbers on round or square metal plates, which are usually made of aluminum or stainless steel. Fix it on the animal's collar or ear before the experiment.
4. Artificial acupuncture numbering method: first remove the animal's coat, pierce the number on the animal's skin with a needle, and then paint with alcohol ink.