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Goals and strategies for a first rate vaccination program
By Guy Jodarski, DVM
Added July 21, 2008. Vaccination of organic livestock is a topic that receives a lot of attention. The enormous number of vaccines available is confusing. Wide ranging claims (both positive and negative) about vaccine effectiveness and safety leave many producers wondering if they should vaccinate and if so how often and with what products?
The first thing to consider is the fact that vaccination does not equal immunization. This means that just giving a vaccine does not guarantee a proper immune response to the organism being vaccinated for. To immunize an animal is the process of inoculating a vaccine into an animal that responds with a detectable immune response. This implies a level of protection against the pathogen being vaccinated for. To vaccinate on the other hand is the process of inoculating a vaccine into an animal, whether or not an immune response has occurred. Failure to immunize an individual or group can occur for many reasons; poor timing of vaccination, immune suppression (stress), wrong vaccine used, failure to give a booster and many others.
This article will outline some ideas and strategies for the vaccination (and hopefully immunization) of organic livestock with an emphasis on dairy cattle. Please remember to work with a local veterinarian to develop a specific vaccination program for your herd. There is no one ideal vaccination schedule that works in every situation. Disease challenges by infectious organisms (viruses, bacteria and parasites) vary with climate and local conditions. Dr. Ron Schultz at the University of Wisconsin Veterinary School said it well; “The first decision in the process of designing a vaccination program is choosing the correct vaccine(s). One must understand that there are not now, nor will there be in the future, vaccines to prevent all infectious diseases.”
In my opinion, the goals of a vaccination program should be to:
The last point is important to consider. It makes little sense to vaccinate for diseases that do not generally occur in the area where the herd is kept. On the other hand, diseases common in the population that cause serious losses when they occur should be vaccinated for on a regular basis. Bovine Virus Diarrhea (BVD) virus and Leptospira bacteria are two pathogens that are common in cattle herds and wildlife populations. These two organisms cause millions of dollars in damage to the dairy and beef cattle industries. It is my belief that most if not all cattle producers should vaccinate for BVD and lepto. Likewise, sheep and goat producers should seriously consider vaccinating their herds and flocks for Clostridium (overeating and tetnus) with a CD/T vaccine on a regular basis. Some organic cattle producers also use a different combination vaccine for Clostridium because blackleg is common in their area.
The large number of vaccines available is often a point of confusion for livestock producers. Let’s start by breaking it down into types of vaccine – one way to classify vaccines is whether or not they contain living organisms. Modified Live Vaccines (MLV) contain living disease organisms that have been changed from their wild form to a form that is less likely to cause disease. An example of an MLV is the intranasal vaccine for cattle that contains the IBR and PI3 viruses. This vaccine has been altered so that it will not grow in temperatures above 85 degrees Fahrenheit. The viruses in this vaccine multiply on the surfaces of the nasal passages but can’t grow inside the body (and cause lung infection) because of its’ higher temperature.
Killed vaccines on the other hand, contain disease causing organisms that are not alive. Heat or other methods are used to kill the viruses, bacteria or parasites present in the vaccine. Some vaccines like Lepto. and Clostridium containing products are only available in the killed form.
MLVs stimulate a more complete and lasting immunity than do the killed vaccines. Vaccination with an MLV provides a wider spectrum of coverage for a given pathogen. BVD for example, is a large family containing many different strains of the virus, and MLVs for BVD will provide immunity to more strains than a killed vaccine will. MLVs do not require multiple doses for good immunity to develop whereas killed vaccines require a booster (2 to 4 weeks after the first dose) to be effective. MLVs stimulate both antibodies (humoral immunity) and T-cell lymphocyte responses (cellular immunity) killed vaccines stimulate only antibodies for the most part. MLVs contain less antigen load than their killed counterparts and therefore cause less vaccine reactions such as fever, off feed animals and decreased milk production following vaccination.
A potential downside to MLVs is that they can cause disease in an immune compromised individual. The MLVs should also not be used in pregnant animals as they can cause abortion. Farmers and Veterinarians that remember the first MLVs to be marketed are reluctant to use them because the early versions did cause problems such as abortion in cattle that were kept close to vaccinated cows. The old vaccine was not very “tame” and could pass from an open cow that was recently vaccinated to one of her pregnant neighbors and cause an abortion in a cow that wasn’t even vaccinated. Fortunately, modern MLVs have been altered sufficiently or “attenuated” so that this is not a problem. Still, one should not use an MLV on cows or heifers within 3 weeks of their breeding date.
The table above summarizes the important differences of vaccine types – MLV vs. Killed
In general, MLVs provide better immunity than killed vaccines but some vaccines like Lepto., Clostridium, and mastitis vaccines are only available in a killed form. Some producers prefer the convenience of killed vaccines because an entire herd can be vaccinated at once and open bottles can be kept in a refrigerator for later use.
This is a critical part of a successful program. Times of stress should be avoided. Dairy cows have three well known stress periods – at dry off, precalving and just recently fresh. Cortisol levels will be high in cows at these times, cortisol is a natural stress hormone that decreases immune system function. Avoid vaccinating cows until they have been dry at least 10-14 days and also do not vaccinate cows from 2 weeks precalving to 4-6 weeks fresh. Calves should probably not be vaccinated until they are 4 to 6 months old as antibody received from colostrum can interfere with vaccination in younger calves.
In order to optimize the immune response to vaccination it is better to limit the number of antigens given to an animal at any one time. Combinations of more than one vaccine containing multiple antigens should be avoided. Vaccines that are derived from gram negative bacteria (E. coli, Salmonella, Leptospira, etc.) contain small amounts of endotoxin. Endotoxin is very stressful to all animals and one should not vaccinate with combination vaccines containing more than one (gram negative) endotoxin source. Use as few antigens as possible when vaccinating. It is better to give a second vaccine at a later time than to overload the immune system with multiple antigens.
Avoid vaccinating the whole herd at once with killed vaccine. It is more convenient to vaccinate all cows at once but this approach results in all of the cows experiencing vaccine stress at the same time. Use MLVs on open animals only or better yet, do a good job of vaccinating heifers with MLVs before they enter the milking herd.
Many herds can stop vaccinating cows for the viral diseases (IBR, BVD, PI3 and BRSV) if they do a good job with MLVs in the youngstock. Cows will still need to be vaccinated with Lepto., as it is a killed vaccine that requires periodic boosters – probably twice per year in cattle.
What about pregnancy losses (abortions) after vaccination?
One should never use vaccines containing live virus to vaccinate pregnant animals. Killed vaccines are considered “safe” but contain more antigen and also materials called adjuvants. My personal belief is that the “loading” of killed vaccines with adjuvants and increased amount of antigen leads to vaccine reactions (fever, off feed, abortion) more often than occur with modified live vaccines. For these reasons I recommend giving MLVs to open cows instead. If one must vaccinate pregnant cows, limit the number of vaccines and antigens to as few as possible.
One should always consult with a local Veterinarian and design a vaccination program specific for your operation. The following is a basic program for a dairy herd that I recommend as a starting point. This is not a “one size fits all” program that every dairy ought to use but rather a simple program that should provide coverage against the most common and sometimes devastating infectious diseases of dairy cattle.
Calves at ~6 months of age (4-8 mos.) – One dose of live (MLV) 4-way virus vaccine (IBR, BVD, PI3 and BRSV) Examples include; Bovi-Shield 4, Bovi-Shield Gold 5, Express 5, Pyramid 5 Titanium 5 and Vista 5
Heifers at 10-12 months of age (Pre-breeding) - One dose of live 4-way (as above) plus 5-way lepto (killed) Examples include; Bovi-Shield Gold FP5+L5, Express 10, Pyramid 10, Titanium 5 + L5, Vista 5 L5 SQ
Repeat 5-way Lepto 2 to 4 weeks after the dose listed immediately above. Examples include; Leptoferm-5, Lepto Shield 5
Cows – Booster 5-way Lepto twice per year, can give to all cows as this is a killed vaccine. A booster dose given at the time of pregnancy check boosts immunity to help protect the calf at the most common time of abortion caused by Lepto.
Optional Vaccines for Cattle – Clostridium 7 or 8-way (includes Blackleg and overeating disease), Intranasal IBR + PI3 (Nasalgen or TSV-2), E coli or endotoxin – J-5, J-Vac or
Enodovac-bovi BVD (w/IBR, etc.) for cows, Scours vaccines (rota- and corona-virus, E coli) Leptospira Hardjo-bovis, Salmonella (SRP)
Not Recommended – Haemophilus, Pasteurella, Mannheimia, Pinkeye, Hairy Heel Wart (Serpens species bacterin)
The topic of homeopathic nosode use for immunization is controversial. Some feel that all conventional vaccines are bad and they prefer to use nosodes instead of vaccines.
Conventional vaccines work at the molecular and cellular levels and produce responses that can be measured with laboratory tests such as antibody titre (humoral response) or white blood cell assays (cellular response). Homeopathic nosodes work at an energetic level. The activity of homeopathic nosodes does not produce immunologic responses that can be measured in a laboratory. My personal preference is to use nosodes at the time a herd or individual is challenged by a pathogen but not as a preventative measure to immunize animals. Homeopathic nosodes for herpes, mastitis and ringworm are examples of preparations that producers have had good success with in the face of a disease outbreak. In my experience the use of homeopathic nosodes to immunize cattle against respiratory viruses (and bacteria such as Lepto.) has produced mixed results. Some producers report problems with pneumonia and abortions after using homeopathic nosodes to immunize their animals that resolve after they return to using conventional vaccines. Others feel satisfied that they have achieved good results using homeopathic nosodes exclusively in place of conventional vaccination.
Please keep in mind that vaccines are not a cure-all. Many people have overly optimistic expectations of vaccination as an aid to animal health. Vaccines are sometimes used as a crutch to avoid making management changes. The first line of defense against infectious diseases is to have a healthy immune system. Organic production methods emphasize disease prevention by providing excellent nutrition, good sanitation and an environment that minimizes stress. Taking care of these basic needs will promote excellent natural immunity and decrease the incidence of sick animals. However, vaccination can be a useful addition to overall herd management by helping to prevent and limit the severity of disease. The National Organic Program both allows and encourages the judicious use of vaccines as a livestock health aid.
Guy Jodarski, DVM, is an independent veterinary consultant based in Neillsville, WI. He works in an organic and sustainable livestock practice with an emphasis in dairy cattle herd health. Phone: 715-743-4703. Email: email@example.com