Treatment and preventive measures, as an integral part of veterinary supervision in the livestock industry, require close attention and regularity. Taking blood for analysis from cattle is an important preventive procedure, the technique of which determines the reliability of the study, the safety of others and the further productivity of cows.
Preparing the animal
Blood is taken from cows to study its biochemical composition, exclude infectious diseases or confirm the suspected diagnosis.Venous blood is necessary for testing for leukemia, brucellosis, and tuberculosis. To take material from a cow without causing harm to the animal’s health, it is necessary to properly prepare for the procedure. The optimal time for collection is the morning hours before the first feeding. After eating, it is not recommended to take blood for analysis within 5 hours.
The site for taking the sample is cleared of hair and, if necessary, the animal is fixed, after which the area is treated with an antiseptic. Suitable for disinfection are 70% ethyl alcohol solution, 1% alcohol solution of salicylic acid, 5% alcohol solution of iodine.
Techniques that do not require forced fixation of body position are easier to tolerate by animals. Stress from the procedure can lead to a decrease in milk yield. It is not recommended to take blood from females 3 weeks before calving and within 3 weeks after birth.
Technique for collecting blood from cattle
Blood is collected from cows from the jugular, caudal or mammary veins. Work in each zone has its own characteristics, due to the different location and speed of blood flow.
From the jugular vein
In accordance with the common and well-established method of taking blood from cows from the jugular vein, a bloodletting needle and a sterile tube are used, into which liquid is drawn along the wall. The vessel is located in the lower third of the animal's neck. The head must be fixed, which becomes a stressful factor for the cow.
Technique for collecting blood from the jugular vein:
- The animal's head is fixed in a stationary position.
- Prepare the lower third of the cervical area, removing excess hair, and disinfect the surface of the skin with an alcohol solution.
- Press the vessel with your thumb.
- The needle is inserted into the vein at an acute angle to the surface towards the head. The insertion depth is 1 centimeter.
- Collect blood in a test tube.
Material collected in this way is not sterile and liquid may splash.
From the milk vein
The milk vein is located on the cow's abdomen on both sides, on the side of the udder. It is clearly visible in adult females, but the sampling process is complicated by the high sensitivity of this part of the body and the deeper location of the vein than it seems visually.
The cow must be securely secured and held, which often requires more than one person.
Technique for collecting blood from the mammary vein:
- The animal is secured and restrained.
- Remove hair from the area adjacent to the vein.
- Treat the area with an alcohol solution.
- Feel the venous tubercle with your fingers.
- The needle is inserted into the vessel parallel to the surface of the skin.
- Collecting biomaterial.
The procedure is unpleasant for the cow and can cause a decrease in milk yield as a result of the resulting stress. This method, complex and traumatic for the animal, is rarely used in modern conditions.
From the tail vein
Taking blood from the tail vein is quick, does not require forced restraint of the animal, and is usually easily tolerated by the animal. Modern techniques are aimed at developing devices for collecting material from this particular area of the cow’s body.
Rules for taking blood from the tail vein:
- Take the cow's tail in the middle of its length with your hand and lift it up.
- Disinfect the area of 2-5 vertebrae and adjacent areas with an alcohol solution.
- Take a sterile needle or a ready-made special system in one hand, and hold the tail with the other.
- The needle is inserted perpendicular to the center of the width of the tail at a distance of about 10 centimeters from its base. The insertion depth is 0.5-1 centimeter.
- Collecting material.
The procedure eliminates human contact with biological fluids of livestock, which is considered one of the main advantages. Slow blood flow in the vessel creates difficulties during sampling, but modern vacuum systems solve this problem, making the procedure safe and effective.
Features of vacuum blood sampling
The use of modern vacuum systems for blood collection allows the KRS procedure to be carried out quickly and safely. The vacuum method works well on the tail vein. The process does not injure the cow and eliminates direct contact of humans and other animals with the biomaterial.
The system consists of a needle and a syringe container. The needle, which has an optimal diameter (usually 0.9 millimeters), is equipped with a valve that prevents fluid from leaking out, which reduces the likelihood of possible complications. The syringe, which also functions as a transport container, is made of durable plastic. You can also isolate serum or add an anticoagulant.
Advantages of the vacuum method:
- no need to restrain the animal;
- minimizing the stress factor for the cow;
- exclusion of direct human contact with the material;
- obtaining a sterile sample;
- eliminating the unforeseen risk of spreading infection;
- ease of use without transferring the sample into a transport container.
Marking of vacuum systems includes practical color coding, which allows you to sort the samples taken.
Possible mistakes
When performing the standard technique of taking blood from the jugular vein, there is a high probability of the material getting into contact with a person and surrounding objects.If an animal is infected, there is a risk of spreading the infection. The open method takes a lot of time, requires preparation and extreme care.
If the rules of asepsis and blood sampling techniques are violated, the resulting sample may not meet the requirements, and the cow may experience complications in the form of abscesses and hematomas. It is not recommended to force the collection to avoid partial hemolysis of blood cells.
