What is the purpose of purifying bovine tuberculin?

Purified bovine tuberculin—this product is prepared by inoculating bovine Mycobacterium tuberculosis into a suitable culture medium, harvesting the culture, inactivating the bacteria, removing bacterial debris through filtration, and then purifying or concentrating the resulting solution. It is used for the diagnosis of animal tuberculosis. Purified bovine tuberculin appears as a clear liquid that is colorless or slightly yellowish-brown.

What is the purpose of purifying bovine tuberculin?

1. A reaction test used for diagnosing animal tuberculosis.

2. For the diagnosis of bovine tuberculosis, the purified bovine tuberculin freeze-dried product should first be diluted with injection water (or saline solution) to a concentration of 100,000 international units per milliliter before use. Regardless of the size of the cattle, hair in the middle third of the neck should be clipped (or shaved one day in advance), disinfected with an alcohol swab, and then 0.1 milliliter should be injected intradermally. Calves under three months of age may have the test performed on the scapular region. Before injection, use calipers to measure the thickness of the skinfold at the center of the injection site and record the measurement carefully. Observe the site for 72 hours after injection to determine whether there is any inflammatory reaction, such as local warmth, pain, or swelling. Use calipers again to measure the thickness of the skin wrinkles at the injection site and record these measurements in detail. If possible, for negative and suspect animals, reobserve the injection sites at 96 and 120 hours post-injection, respectively, to avoid late-onset reactions in individual animals.

What are the criteria for purifying bovine tuberculin?

1. There is an obvious inflammatory reaction locally, with a skin thickness difference of more than 4 millimeters.

2. The suspected reaction shows mild local inflammatory response, with skin thickness ranging from 2.1 to 3.9 millimeters.

3. The negative reaction shows no inflammatory response, and the skin thickness difference is less than 2 millimeters.

4. As long as there is some inflammatory swelling, even individuals with a skin thickness difference of less than 2 millimeters should be classified as suspicious.

5. Cattle judged to have a suspicious reaction shall immediately receive a second injection of the same dose on the opposite side, followed by 72 hours of observation for any reactions.

How to store purified bovine tuberculin: Liquid-purified tuberculin has a shelf life of 2 years. Freeze-dried tuberculin tablets have a shelf life of 10 years.

Usage of Purified Bovine Tuberculin

The purified bovine tuberculin reaction solution does not require dilution. For frozen products, first dilute them with injection water (or saline) to a concentration of 10 tuberculin units per milliliter (2,000 IU per head), and then proceed with use. Regardless of the size of the cattle, always shave the hair at the one-third point in the middle of the neck (or shave the hair the day before). Disinfect the area with an alcohol swab, then inject 0.1 milliliter (1 dose) intradermally into the bloodstream. Calves under 3 months of age may have the test performed on the scapular region. Before injecting the tuberculin, measure and record the thickness of the skin fold at the center of the injection site using calipers. Evaluate the local reaction—such as heat, pain, or swelling—72 hours after injection, and measure and meticulously document the thickness of the skin fold at the injection site using calipers. If possible, re-examine any animals showing abnormal reactions or exhibiting suspicious signs at 96 and 120 hours post-injection to detect delayed-type reactions that might occur in individual animals.