What Is the CDT Vaccine and Why Is It Important for Sheep and Goats? (2024)

With fifteen lambs born so far this year on my farm – and five more ewes left to lamb – it seems like every day brings along with it a new list of chores to do.

Of these, administering the CDT vaccine to all our new lambs is one of the most crucial.

If you raise sheep or goats, you are probably already familiar with the CDT vaccine – but if not, this article will tell you everything you need to know about why this shot is so important.

What is the CDT Vaccine?

The CDT vaccine is a management tool that all sheep and goat farmers should have in their toolbox. It protects against three diseases:

• Clostridium perfringens type C
• Clostridium perfringens type D
• Clostridium tetani (also known as tetanus)

The CDT stands for Clostridium type C, Clostridium type D, and Clostridium Tetani, the three issues this vaccine prevents.

The first two diseases, Clostridium perfringens type C and D, are often referred to as “overeating disease.” They’re generally associated with food and can lead to enterotoxemia. Clostridium tetani, or tetanus, is a soilborne pathogen that can easily enter an animal’s body through a small wound.

What Can Happen If You Don’t Give the CDT Vaccine?

There are lots of producers who wish to eschew all vaccinations, dewormers, and other “man-made” interventions on the farm. I understand the desire to do this, but would strongly recommend against it when it comes to raising sheep and goats.

The CDT vaccine is the only universally recommended vaccine by veterinarians for goats and sheep. If you don’t give this vaccination to your animals, they run the risk of getting extremely sick. Plus for the cost of this vaccine, prevention is much better and cheaper than treating animals that get sick.

The bacteria that cause enterotoxemia are found in all animals. However, this is at a very low level. The problem arises when the populations of bacteria grow quickly and proliferate due to a rapid increase or abrupt change in diet. As the bacteria accumulate, so do toxins, which can then lead to health issues and death.

Other “early” signs of enterotoxemia include:

• Colic
• Convulsions
• Acute indigestion

The “type C” bacteria that cause enterotoxemia are found all around the farm, usually in soil and manure. You can prevent them from accumulating to a certain extent, by keeping the nursing and lambing area clean. However, lambs can still come into contact with the bacteria and it can lead to severe diarrhea.

Type D is more closely related to overeating disease and, unfortunately, affects the biggest and most vigorously growing lambs. As the lambs eat more, the bacteria use the food as fuel to continue to rapidly reproduce. Lambs that experience a spike in bacteria die quickly, making it tough to detect the cause of illness.

Tetanus, the third piece of the CDT puzzle, is another dangerous type of bacteria. This one is next to impossible to prevent. Your animals can be exposed to tetanus bacteria through shearing, tail docking, castration, or even ear tagging.

Even if you avoid all those risks and do not dock, tag, or castrate your animals, what about when your sheep cuts itself on a rock while running around? Any kind of open wound can allow tetanus to enter a sheep or goat’s body. Tetanus can lead to lockjaw, paralysis, and again, death.

When to Give the CDT Vaccine

The CDT vaccine can be administered at several times in an animal’s life.

Lambs or kids should receive a total of three doses of the vaccine if they were born from vaccinated mothers. One is given “in utero”. The second is considered a booster shot, given at four to eight weeks of age. The third must be given again four weeks later.

If you are vaccinating lambs or kids that were born from mothers that were not vaccinated, administer a shot during the first week of life. Then you’ll give two boosters, each given at four-week intervals.

There’s some variability in the first shots you give your lambs or kids. As long as you give the vaccine early on, you shouldn’t have any problems. What’s important to remember is that you need to give the vaccine before you do any kind of management, like castrating or ear tagging, to prevent infection.

An annual booster is necessary for all adult animals, too. Ewes and does should be given a vaccine one month prior to lambing. This is the easiest way to “boost” your animals, since you can do it all at once, without opening multiple bottles. The CDT vaccine can be expensive, and it only has a shelf life of about a year in the refrigerator.

Don’t forget to vaccinate your rams and bucks, either. The best time to do this is prior to breeding. Not only will you already be handling your ram or buck to move him in with the ewes, but you’ll make sure he’s healthy before it’s time to breed, too.

Tips for Administering the CDT Vaccine

1. Administering the Shot

The CDT vaccine can be administered in several places:

• The armpit
• The neck
• Over the ribs
• In the flank

Administer the shot in the spot where it makes the most sense for your animals. Some people have issues with abscesses developing at the injection site. This isn’t usually a major cause for concern, but you can avoid it by injecting it in the armpit.

When you vaccinate lambs, they don’t have a lot of flesh for you to work with. To prevent pushing the needle out through the other side of the skin “tent,” administer the shot at a slight “downward” angle.

The shot must be administered subcutaneously (under the skin). Pull up a handful of the skin with your thumb and forefinger so you make a “tent,” then slide the needle into the base of the tent. Make sure you check the syringe before administering to ensure that there is no air in the syringe – this can kill an animal instantly.

2. Storing the Vaccine

All vaccines must be stored according to the manufacturer’s label. Check the label for the appropriate dose, too, which can vary depending on the weight, species, and age of the animal.

When you vaccinate, be sure to use a clean needle for each animal (although the syringes can be reused). Both 18- and 20-gauge needles are appropriate.

3. Timing the Vaccine

Remember to vaccinate ewes and does about thirty days before lambing. This will provide adequate protection to the young via colostrum.

If you purchased bottle lambs or kids and aren’t sure if they were vaccinated – or you don’t know if they received adequate colostrum – you can still vaccinate. Make sure you vaccinate by 21 days of age and then give a booster four weeks later.

Make a note in your homestead journal and calendar when you vaccinated which group, so that you can keep up with annual repeats and booster shots.

4. Other Vaccinations

There are other vaccinations you might consider using, too, but CDT is the only one all vets recommend. Some of the other optional vaccinations include:

• Caseous lymphadenitis vaccines
• Sore mouth vaccine (this is a live vaccine that should only be used if animals have a sore mouth infection, or it can infect your other animals)
• Rabies (usually only administered by veterinarians)
• Footrot and foot scald vaccines (sheep and cattle only)
• Mannheimia haemolytica and Pasteurella multocida

Ask a vet if these vaccines are necessary where you live.

If you are giving a goat any kind of vaccine, it is smart to have epinephrine on hand. Consult with your veterinarian before purchasing any (you’ll need a prescription, anyhow). It only lasts about a year, but it’s common for goats to go into anaphylactic shock from injections. It can be a smart “just-in-case” tool to have on hand.

The CDT Vaccine Can Protect Your Flock

Lambing and kidding season has arrived (or even come and gone!) in many parts of the world. If you haven’t started giving your little ones the CDT vaccine yet, it’s important that you do so soon. It will protect your animals against a variety of preventable diseases, and it’s easy to do by yourself.

CDT costs less than $0.35 per dose – there’s really no reason why you shouldn’t vaccinate your animals for these deadly diseases. Mortality rates can be as high as 40% for unvaccinated flocks – avoid the risk with these vaccinations.

So put it on your calendar right away!