Vaccinations for Dairy Goats.

 By Michelle Buckley, DVM, MS - Post Doctoral Associate, Iowa State University.

 Vaccinations are one of the best tools in our arsenal for preventing disease, along with nutrition, housing, husbandry, and biosecurity. However, not all vaccines are equally effective and not every herd needs to be protected from the same diseases. Creating a herd-specific vaccine program is best done with the guidance of a veterinarian who is familiar with your animals and the challenges that your herd faces. It is important to note that there are very few vaccinations developed and labeled for goats in the United States due to the relatively small market share this species holds. Extra-label vaccine use in goats is common practice but can lead to adverse effects not noted in those species that the product has been tested and approved for. Vaccine administration should always be performed according to the labeled route or per your veterinarian’s recommendation and an appropriate meat and milk withdrawal time must be observed when utilizing these products, just as with any other medication.

CDT
CDT protects against Clostridium perfringens types C and D (enterotoxemia) as well as Clostridium tetani (tetanus). This vaccine is almost universally recommended across US goat herds. There are two approaches to vaccination for these diseases: it is preferred that previously vaccinated does receive a booster approximately 4 weeks before their due date in order to allow antibodies – which are not affected by proper pasteurization techniques – to pass into colostrum and provide immunity to kids for a few weeks after birth. This protection begins to lose strength around 6 weeks of age so kids should receive their first dose of vaccine at this time with at least one booster given three weeks later. After this period, the minimum recommendation is revaccinating all animals in the herd annually though some herds may require more frequent boosters if they have a known problem with these diseases.

The second option is for kids who do not receive colostrum from recently vaccinated dams. This includes herds that feed colostrum replacer, do not vaccinate dams 4 weeks before due dates, or who can’t ensure that kids receive colostrum within 12 hours of birth. In this system, kids should be vaccinated at 2 weeks of age (potentially sooner, depending on herd-specific scenarios), with at least two additional boosters given 3 weeks apart. Revaccination of adults should still continue on an annual basis at minimum. In both scenarios, a booster dose should also be administered if an animal sustains a cut or undergoes surgery and has not had a dose of vaccine in the prior 6 months.

Rabies
Herds that are part of a with a high rate of human exposure or those located in high-risk areas may wish to vaccinate animals against rabies. These vaccines are highly effective at preventing disease and, while there is no labeled product for goats, the sheep-approved vaccine appears to provide adequate protection.

Respiratory Diseases
Use of bovine respiratory vaccines is becoming increasingly common in small ruminants, especially before times of high stress (i.e. travel, shows, etc). A few considerations are warranted before adding one of these products to a caprine vaccination protocol. Pathogen strains found in approved respiratory vaccines are common to cattle but differ from those known to cause disease in goats. The amount of known cross-protection is generally minimal between cattle and goat strains. Additionally, modified live vaccines consist of pathogens that have been “injured” but are not dead. Because these vaccines were developed for cattle, they do not cause disease but do induce a strong immune response in this species. However, there is no safety or efficacy data on the effects that these vaccines have on other species. That means that these pathogens may induce a wide range of effects on goats including no effect, decreased milk production, and potentially even clinical respiratory disease and anecdotal reports of use vary widely on this spectrum. Some researchers suggest that intranasal vaccines may stimulate localized inflammation that primes the respiratory immune system to fight off infection if administered shortly before times of high infection risk.

Caseous Lymphadenitis (CL)
While this disease has become quite prevalent within commercial herds and unsightly abscesses are the bane of any show herd’s existence, vaccination for CL is not necessarily the optimal method of preventing the disease from entering a herd. Currently, there is a commercially available vaccine for sheep which is commonly used in goats, despite manufacturer suggestions to avoid this practice. Administration of this product has been associated with short-term decreases in milk production and feed intake in some herds and administration during the dry period is commonly recommended in order to mitigate these problems. Though vaccination does not prevent all abscesses or cure already infected animals, it can be useful in decreasing external abscesses which, in turn, can help to decrease disease spread. Thus, it can be a useful tool in decreasing spread of CL in an already infected herd. For herds that are clear of this disease, proper biosecurity (especially for shows, exhibitions, and breeding practices) are far more effective at preventing infection.

Infectious Abortions – Chlamydophila & Campylobacter
Vaccination against Campylobacter (also known as Vibrio) may be indicated for preventing pregnancy loss in herds with a confirmed outbreak, especially due to widespread resistance of currently circulating Campylobacter strains to antibiotics, especially tetracyclines (the traditional treatment for this disease). There is currently only one vaccine product on the market for this disease and its extra-label use in goats has proven effective in some outbreaks.

The bacteria Chlamydophila is one of the top three causes of infectious abortions in both sheep and goats in the United States and a vaccine labeled for use in sheep is. Vaccination can help to prevent abortions in infected animals and minimize shedding (and spreading) as animals tend to remain infected for life though abortion rates generally drop after initial infection. Efficacy of vaccination for this disease is more variable than others, most likely due to variations in bacterial strains between farms. Diagnostic testing can help to determine whether a commercially available vaccine will be beneficial for an individual herd.

Mastitis
Recently, a vaccine has entered the US market with a label for decreasing signs of mastitis and bacterial counts of Staphylococcus aureus and coagulase negative staphylococci (CNS) in goats. While similar vaccine products have been available in international markets, data on efficacy against pathogen strains common to US dairy goat herds is still forthcoming. This product is certainly exciting for producers facing the challenges of CNS bacteria which appear to be more prominent and cause more significant production losses in goats than in cattle.
The importance of proper biosecurity, housing ventilation, nutrition, and husbandry protocols can not be overstated in preventing disease, especially in high-producing dairy goats and those that have a high rate of exposure to other animals or the general public. However, vaccination can also be a useful tool for preventing disease and mitigating spread of some common diseases. Tailoring a vaccine protocol to your herd’s specific risk factors and weighing the costs of labor, product, and (in some cases) short-term production decreases are best done with your management team, including your herd veterinarian.