What you need to know about synchronization and vaccination injections PDF Print E-mail
El Lechero Dairy Basics - Herd Health
Written by Carlos Téllez   
Monday, 08 February 2010 12:12

Herd health management and reproductive efficiency are important components of economic success in dairy operations, so it is very important to know the difference between the shots in an A.I. synchronization protocol and the injections used in a vaccination program.

Synchronization injections (reproductive hormones) are used to work with a group of eligible cows to increase the number of animals submitted for breeding, therefore increasing the number of cows pregnant. Vaccination injections (bacterin and virus) are given to a group of eligible cows to prevent infection diseases within a herd operation.


To administer injections, restrain animals properly to reduce the risk of a potential accident. Follow the sanitation protocol established in your operation. It will reduce the risk of spreading infection from one animal to another and the chance to contaminate the product. Make sure you first select the right product; read and follow the label instructions.

When giving injections the selection of the route of administration is crucial to the effectiveness of the product. The routes of administration of the vaccines are: intranasal (IN) or into the nose, oral, intramuscular (IM) or into the muscle and subcutaneous (SC) or under the skin. The information label will state the best way to administer the product. The route of administration for the synchronization shots should be IM. Synchronization and vaccination shots (SC or IM) must be given in the neck area.

Depending on the characteristics of the vaccine, killed products can be injected SC and modified live vaccines are usually injected IM because the virus reaches the lymphatic system more easily. The hormones used in a synchronization protocol are GnRH and Prostaglandin (PF2a).

For SC administration, tent the skin and insert the needle into the fold of skin. For IM injection insert the needle directly into the muscle. Be sure to avoid mixing vaccines (this may decrease effectiveness of the vaccine) and always prepare just the right amount of vaccine that you will be using in one hour. Try not to go back in to the product bottle with the same needle. Left-over products must not be used. It will not be effective and could be contaminated.

When administering SC injections, use a 16 or 18 gauge needle ½ to ¾ inch long. For IM injections use a 16 or 18 gauge needle, 1 to 1 ½ inch long. Avoid the use of 14 gauge needles (leak-back and tissue damage).

Replace needles every five to 10 animals. Bent or broken needles must be discarded. Do not administer more than 10 cc of product per site of injection.

Finally, compliance is a key element in the success of any synch and vaccination program. One of the most important differences between synchronization and vaccination injections is the time of administration. In a synchronization program these shots must be given to the correct cow on the correct day so the animal is successfully submitted for timed artificial insemination (TAI). Failure in the administration of any of the protocol’s shots can dramatically reduce the conception risk to first TAI, therefore delaying the establishment of pregnancy. In a vaccination program, there is not an exact day but a number of days to give injections so the time frame is wider than the one you have in a synchronization program. EL

by Carlos Téllez, DVM


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