A Nine-Step Program for Herd Health

By Glenn M. Rogers, DVM, MS, DABVP, Senior Veterinarian,
Beef Veterinary Operations, Pfizer Animal Health

Editor’s note:  This paper was presented by Dr. Rogers at the
Texas Veterinary Medical Association meeting, March 2005, Austin.

A written summary of the year’s herd health activities is an excellent planning tool and reminder system to assure the right products are purchased and used at the right time. A health management calendar can be laminated and posted to be a handy reminder of scheduled activities.  

Figure 1. Click here for a Sample of a Herd Health Calendar

By including your veterinarian in this planning process, there is tremendous opportunity for improved communication and understanding of the health needs of your operation and how you schedule your working events for the herd. He or she will be better able to coordinate services such as pregnancy examination and breeding soundness examinations.  

This planning process will also point out opportunities for management improvements. Ask these questions:

• Do we work cattle at a certain time of the year to optimize animal health inputs or because of tradition?

• Could we improve reproductive performance by enhanced product selection and by moving cow vaccinations from the fall to spring, prior to the breeding season?

• If so, could we administer a springtime deworming program when we vaccinate for a more strategic approach to controlling internal parasites?

Through planning, the most cost-effective products are ordered at the best possible price and are available at the right time. Planning the entire year’s animal health needs often results in considerable cost savings.  Since you will know in advance what animal health supplies you will need to purchase, look into a yearly contractual arrangement with animal health product suppliers to lock in a lower cost.

Planning a herd health program that fits an operation is challenging. The latest Compendium of Veterinary Products shows there are more than 400 commercial beef cattle vaccines. The various combinations for single injection, and the combining of various products using multiple injections, present a mind-boggling array of possibilities.

How do we take the information on package inserts, marketing hype and the feasibility of practical application in the field to build a simple, yet comprehensive and cost-effective program? The answer is to work closely with your animal health professional and set aside time for planning and documentation.

Use these nine steps to develop a comprehensive herd health program.

Step 1. Work with your local cattle-oriented veterinarian.

In the National Animal Health Monitoring System (NAHMS) Beef ’97 Report, 60.8 percent of all producers indicated the veterinarian was a “very important” source of information for the cow-calf operation. Despite this obvious level of trust and respect, too little time is spent with veterinary practitioners specifically developing written herd health plans.

Schedule a time with your local cattle-oriented veterinarian to develop a health plan tailored to your operation. This plan may be the first step in developing a consulting relationship with your veterinarian that focuses on preventive health as opposed to crisis management.

Step 2. Determine the optimal time of the year for calving/breeding seasons for your operation.

Many times, the calving/
breeding season(s) for ranches are etched in stone. However, it’s worthwhile to re-evaluate this.

Calves begin to depend more on grass as part of their diet at about 90 days of age. One strategy is timing the birth of calves so the quantity of high-quality grazing coincides with calves’ shift towards increased grass intake (December – February calving).

Another strategy would be to have cows calve when they are naturally in the best body condition to maintain themselves in good enough condition to lactate and rebreed (April — May calving).

Another strategy would be to calve in the fall to take advantage of traditionally higher calf prices in late spring and early summer.  

All of these examples have advantages and disadvantages. Analyze the management and forage resources of your operation to schedule calving at the optimal time for your ranch.

Circumstances that favor one season over another may change over time. As an example, traditional calving times that were originally based on avoiding screwworms more than 50 years ago may need to be re-evaluated. Since everything in a herd health planning program revolves around the breeding season, it’s beneficial to consider alternatives and justify decisions.

Step 3. Determine the optimal length for your calving/breeding seasons.

The optimal length of breeding seasons is dictated by operation goals, management re­sources, forage resources, geography, breed and other factors. A short, controlled breeding season allows for improved uniformity, marketability and concentration of labor inputs.

Short breeding seasons also allow for the maximum effect of animal health inputs. The positive effect of reproductive vaccines on the whole herd is negated when the cows are vaccinated in widely varying stages of gestation or lactation.

However, consider the nutritional resources and the management capabilities of your operation before you follow a blanket recommendation for a short, controlled breeding season – 60 days in cows and 45 days in heifers.

Step 4. Learn about the specific diseases and parasites economically significant in your area.

Your local veterinarian is an excellent source for information about the diseases and parasites that are economically significant in your area. He or she can help develop disease control programs that incorporate appropriate biosecurity and health management practices.

Effective vaccination of all breeding animals against IBR, BVD, leptospirosis and campylobacter (Vibrio) should be routine in the United States. Consider other diseases based on geography, biosecurity practices and other factors.

Here are common diseases which cause reproductive losses in beef cattle. Proven vaccines are available for these diseases.

Infectious Bovine Rhinotracheitis (IBR)

Though most known for its role in bovine respiratory disease (BRD), IBR remains one of the most important causes of abortion and reproductive losses in cattle.

Abortions can occur at any time, but IBR is most commonly diagnosed during the last half of gestation. Abortions occur weeks after infection and aborted fetuses tend to decompose prior to expulsion, thus reducing accurate diagnosis of positive cases.

IBR virus has been shown to cause infertility in heifers and temporary damage to the ovary.

IBR is a herpes virus and becomes hidden (latent) in nervous tissue after the disease subsides. The virus reactivates during times of stress. Cattle latently infected with IBR exhibit no clinical signs during reactivation, but can spread the virus to susceptible animals.

Modified live virus (MLV) vaccines administered to the entire cow herd are the most effective products for IBR control. Label recommendations should be closely followed, since modified live IBR vaccines may cause abortions in pregnant animals.

Bovine Viral Diarrhea (BVD)

BVD virus can cause abortions, birth defects, stillbirths, undersized or weak calves. Additionally, this virus suppresses the immune system, allowing other infectious diseases to occur.

Cow herd production and reproduction losses from BVD are most severe when BVD-persistent infection (BVD-PI) is present in the cattle population. PI calves are created when the fetus is exposed to the most common form of BVD virus (non-cytopathic) during the first four months of pregnancy. In the first four months, fetuses have an underdeveloped immune system which is incapable of recognizing BVD virus as a foreign agent.

The BVD-PI condition remains with the animal until death. Most BVD-PI animals die during the first year of life, but a small percentage survives to reproduce and continue the cycle of herd infection.

Throughout their life, PI cattle will secrete large amounts of virus — up to 1,000-fold more virus than acutely infected animals will shed. The only way to effectively control BVD is to incorporate appropriate control measures, including vaccination, to prevent viremia (virus in blood) and keep the virus from reaching the fetus, thus preventing birth of BVD-PI calves.

This is best accomplished with an effective pre-breeding BVD (Types 1 and 2) vaccination program and by eliminating
exposure to BVD virus, particularly BVD-PI animals, during the critical first four months of pregnancy.

Campylobacter (Vibrio)

This is a common venereal disease of cattle. Infection of the female is temporary and may manifest as infertility or occasionally, abortion. Males, especially older animals, are chronically infected, possibly for life.

Very little new information has been published about vibrio in the last 20 years. Nevertheless, this organism continues to interfere with optimum reproductive rates and remains a potential source of economic loss throughout much of the United States.

Effective vaccines are available which provide good protection for both bulls and females. There are even reports with one product of clearing infection in cows and bulls by vaccinating in the face of an outbreak. The mechanism for clearing infection is poorly understood by immunologists.

Leptospirosis

Leptospirosis is a bacterial disease which affects animals and man. It can cause abortions, embryonic death, stillbirths, infertility and loss of milk production. The most common cause of leptospirosis in the United States is Lepto spira hardjo bovis. This type of hardjo is antigenically different from the hardjo-prajitno identified in Europe and used in most combination leptospirosis vaccines in the United States.

Cattle are carriers (maintenance hosts) for hardjo-bovis, which has been shown to decrease conception rates and increase the number of stillbirths and weak calves. While carriers do not always develop signs of being sick, they do continue to shed the organism. Diagnosis is often difficult because carrier animals may have low antibody titers.

The best method for diagnosis is a combination of a urine sample to identify the presence of leptospires and a blood sample to differentiate which type (serovar) is involved.

An effective hardjo-bovis vaccine became available in the United States in 2003. This vaccine prevents urinary shedding, kidney and reproductive tract colonization, provides yearlong immunity and provides protection to calves as young as four weeks. Heifers can be infected with Lepto spira hardjo bovis early in life, resulting in subsequent infertility or pregnancy loss. Vaccination of replacement heifers and bulls should be performed as early in life as possible to reduce infections and infertility.  

Step 5. Determine the best time to administer preventive measures for each disease or condition.

Before developing a simple and brief health management plan, it’s helpful to review specific recommended time periods for vaccination and parasite control.

The basic tenet of any immunization program should be to vaccinate prior to disease challenge.

Target vaccination before breeding season for heifers, cows and bulls. Immunizing against reproductive diseases before breeding allows a peak immunologic response during the breeding season.

Vaccines for a value-added calf program are most effective if administered before the calves face disease challenges during weaning and the traditional marketing environment.

In Texas, the single most important time to treat cows and calves for gastro-intestinal parasites is in May through early June, just before the summer brownout for the brown stomach worm (June — August). Products with persistent activity can be given as early as late April and achieve the same affect. If treatment is given too early before the summer brownout, animals will become reinfected.

In fluke-infested areas of Texas, August through September is the best time to treat. Treating at the end of summer ensures that most flukes infecting cattle are in the adult stage and any recently released eggs have a month of unfavorable hot and dry weather in which to die. This is also when the snail population required for transfer is estivating (buried in mud) and is unavailable as an intermediate host. Infected snails will generally die during estivation.

Failure to vaccinate or treat for parasites at the correct time may result in decreased health performance, even when the best products available are used.

Step 6. Select products with research-proven efficacy and the best data.

All animal health products are not created equal. Just because a vaccine is licensed and available does not mean it works.

USDA vaccine licensing does not require evidence of efficacy in cattle under normal farm and ranch conditions. It only requires evidence of efficacy against specific aspects of the disease.

Base your product selection on peer-reviewed research information (when available), specific label claims and proven efficacy under field conditions.

By planning in advance for yearly animal health product needs, you can avoid confusion from animal health product marketing and literally hundreds of product choices.

If a specific animal health product is determined by your animal health professional to be the best fit for your operation, then that product — and only that product — should be purchased.

Many products are delivered and used under the guise of, “It’s the same thing,” when in many cases, tremendous differences exist between products. A little planning of animal health needs will prevent you from settling for an inferior product, needed at the last minute, or for a product that does not fit your operation.  

Beware of “me, too” products, such as certain dewormers. By law, generic equivalents can have far less active ingredient than required in an original product. The U.S. beef industry is rapidly becoming more value-based and data-driven. Source verification, carcass data, growth performance information, estimated progeny differences (EPDs) and improved record system technologies are just a few examples.

Animal health products should be aligned with the changing beef industry and selected based on science, data and technical support. Total annual veterinary expenses in a cow-calf operation average approximately four percent of total per cow production costs. This four percent includes all animal health products used, as well as veterinary services. A few cents saved for a “me, too” vaccine or dewormer product without supporting data is usually a poor decision and could produce inconsistent re­sults.  

Step 7. Determine which additional health or management practices will require cattle handling. Schedule these practices into a limited number of events.

While the design and implementation of a cost-effective health program can never be perfect, every operation can improve profitability through better planning and coordination.

Combine animal health product inputs, when appropriate, with management practices such as calf working, pregnancy testing or breeding soundness examinations. Prioritize the procedures to be done and the products to be administered.

For instance, administering reproductive vaccines prior to the breeding season has the highest priority in replacement heifers. In some areas, administering fluke treatment at the appropriate time may be the highest priority.

Ultimately, product administration and other health procedures must be positioned, often competitively, with tradition, labor issues, other farm/ranch enterprises, weather and many other factors.

In a commercial cow operation, handling cows twice per year (spring and fall) is often feasible and allows for administration of an effective preventive health program. This would also apply
to calves unless they are being marketed in a value-added calf program that includes weaning and two additional rounds of respiratory vaccines. Replacement heifers may require an additional handling to facilitate adequate pre-breeding immunization.  

Step 8. Put it all together in a one-page summary calendar.

Figure 1 is an example of a herd health calendar. This sample is not specific, nor is it a standardized recommendation.

In fact, avoid standardized protocols. Every operation is unique and requires a specific, tailored protocol. A better approach is to design protocols based on your unique answers to standardized questions.

Effective beef herd health planning ultimately is a series of optimal compromises that weaves immunology, management and economics into a simple, cost-effective program.

Step 9: Provide periodic updates.

Modify recommendations as management changes occur and when improved products become available to provide a proper fit for each operation. Any change in events, such as pre-breeding heifer vaccinations, time period for vaccinating nursing calves or alterations in breeding season, could create a domino effect and require other changes in the overall health management program.

Post a yearly reminder

Develop a short, written summary in a calendar format as a reminder of the proper timing for animal health inputs during key events. This calendar will improve communication with ranch employees, veterinarians and others and will help you develop a list of yearly animal health needs.

Update the health calendar regularly to include new and improved products and to adjust to improved management opportunities.