BRD Complex Viral Conditions, ETC

BVD Infection of Feedyard Cattle    If you ever want to start an argument in a feedyard about vaccination programs, mention BVD (bovine virus diarrhea). The folklore, myths and half-truths concerning this virus are many. BVD does play a key role in feedlot respiratory disease, but we are unsure of its exact role and even more unsure of possible control methods.    BVD was first described in 1946 as a severe and often fatal disease of dairy cattle. Early researchers named this disorder “mucosal disease” and many people still call the severe digestive form of BVD by this name. We now know that BVD can affect other organs, including the respiratory and immune systems. Because of the complexity of this disease, we do not completely understand all the effects of BVD virus on cattle.    BVD in the feedyard can mimic many other diseases or show no obvious signs at all. Common clinical signs include depression, off-feed, discharge from the eyes and nose, coughing and rapid respiration. These signs may or may not progress to a severe watery diarrhea with ulcers in the mouth and entire digestive system. This set of signs could account for any of a number of diseases seen in feedlot cattle and explains why it is important to avoid a diagnosis of BVD from clinical signs alone.    In order to put this viral disease in perspective, let’s look at the effects of BVD on the respiratory system and the Bovine Respiratory Disease complex.    BVD has two prime effects on the respiratory system. First is a direct negative effect on the local disease fighting mechanisms of the lungs and upper respiratory tract. Second, BVD virus can cause a severe disruption in the body’s immune system.    The end result is that the BVD infected animal is more susceptible to any infection, but most importantly bacterial pneumonia such as Pasteurella haemolytica(Mannheimia haemolytica), Pasteurella multocida and Hemophilus somnus. Mycoplasma bovis may also play a role.    In order to have a problem with BVD in a feedyard, you must have two factors present: (1) a susceptible animal and (2) a virus capable of causing disease.    Of course, salebarn cattle and freshly weaned calves are more susceptible to any disease challenge. Also, some strains of virus are capable of causing disease to greater extent than other strains.    If you take a highly susceptible calf that has been freshly weaned and expose it to an extremely hot virus in the feedyard, the outcome usually is death. Conversely, if the cattle are protected against BVD or non-stressed, the same virus may have little to no effect on them. Control of BVD    There are three schools of thought concerning BVD vaccination:    1. First, all cattle must be vaccinated with a modified live virus (MLV). This procedure has one serious drawback. Any MLV vaccination on stressed calves is potentially harmful, but the effects of MLV BVD vaccines can be even more harmful than most by causing immunosuppression of an already compromised animal. There are good MLV BVD vaccines that confer adequate protection to feedlot cattle with minimal side effects, but the potential for this adverse reaction is present with many MLV BVD vaccines.    2. The second school of thought says vaccinate for BVD with a killed product. Killed products have been much improved over the last few years and offer good protection without causing adverse reactions. Opponents of these vaccines agree that protection is adequate, but rather slow in appearing.    3. The third school of thought is that BVD vaccination has no effect on respiratory disease in a feedlot.    In our practice, recommendations on BVD vaccination are based upon the type of cattle fed, past health history and confirmed presence of BVD problems through diagnostic techniques.    In summary, BVD has the potential to cause serious problems in feedlot cattle. The key to control lies in proper diagnosis and sound preventative measures. Respiratory Syncytial Virus Vaccine    Currently, two modified live vaccines and one killed respiratory syncytial virus vaccines are available for use in beef cattle. In order to understand the potential use of these products, let us examine this virus, its clinical manifestations and application of vaccination to a feedlot health program.    Bovine Respiratory Syncytial Virus (BRSV) is named because of its ability to form syncytia in infected cells. Syncytia are simply an aggregation of cells that clump together in a large mass with an indistinct internal structure.    This virus was first seen in Europe and Japan. Reports of outbreaks in the U.S. were first seen in Nebraska and Colorado. A human counterpart has been recognized that has many similarities to the virus seen in cattle.    When BRSV is exposed to susceptible cattle, an incubation period of 2 to 10 days can be expected.    Clinical signs during an outbreak are of rapid onset and include increased respiratory rate, depression and discharges from the eyes and nose. Salivation or slobbering is common and may be blood-tinged as can the discharge seen coming from the nose. Coughing is usually marked and seems to persist throughout the course of infection. Swelling may occur around the eyes but is usually pronounced in the throat region. Body temperatures are increased and range from 104° to 108° F. Abortions usually are not seen but some have been reported.    The disease outbreak can affect all ages of cattle, but is usually most pronounced in freshly weaned calves. Infections can range from mild to marked and affects a large number of cattle, but usually with a low death loss. As with any virus infection, bacterial pneumonia can be a secondary invader.    The clinical picture of BRSV can resemble other viral infections such as IBR, PI3 or BVD, except that the disease is usually mild and the marked swelling in the throat latch is rather unique.    Other viral infections such as those mentioned can cause much higher death losses; but early in the outbreak there has been confusion as to the actual agent involved. Many times BRSV has not been identified until other common viral agents have been eliminated as the causative agent.    As yet, in our feedyard experiences, the problems with BRSV have been minimal. That is, we have not recognized this condition in the pure form. This is not to say that BRSV has not been involved in certain respiratory problems. As with other viral agents, over- growth of Mannheimia haemolytica or Pasteurella multocida may actually mask the true initiator of the problem. BRSV can cause severe damage to the trachea and lung, which would then allow for bacterial pneumonia to occur.    In order to diagnose BRSV as a problem, you must attempt to isolate the virus from the lung, trachea or nasal secretions. The affected lung must also be examined under the microscope for the syncytial formation so characteristic of this disease. These two procedures may prove very unfruitful in the feedlot environment.    Blood samples and serology taken at the time of respiratory outbreak and repeated 2 to 4 weeks postoutbreak are the most beneficial method of positive diagnosis currently. Continued development of more accurate and effective diagnostic techniques is     under way.        In summary, Bovine Respiratory Syncytial Virus is usually a mild viral infection which can be relatively severe under some circumstances. This disease is usually a problem in freshly weaned calves, but can be a problem in any age of cattle. Other Respiratory Diseases    Many times when we talk about respiratory disease, infectious bronchopneumonia or Bovine Respiratory Disease Complex (BRDC) is the focal point.    In the feedyard, other forms of respiratory disorders exist. Diphtheria and “hardbreathers” or “honkers” can be problems, although not as common as BRDC. Diphtheria    Diphtheria is an infectious disorder of the upper airways. A focal point of damage usually occurs to the larynx or voice box and allows for opportunistic invasion of the damaged airway lining by bacteria. The bacteria that invades the airway is the same organism that causes foot rot in cattle.    Symptoms of the calf affected with diphtheria may include difficulty in breathing, excessive salivation, swelling around the throatlatch and increased body temperature. Often the most obvious clinical sign is the foul smelling breath that occurs. Because of the bacterial invasion of airway tissues and the particular pathogenic organisms involved, dead tissue is formed at the site of infection causing the fetid odor.    Diphtheria in a feedyard may often be an uncommon occurrence, but may occur secondary to feeding coarse feedstuffs, in the form of hay or finished feed. Other outbreaks of widespread diphtheria have not been attributed to any known factors.    Treatment for the condition is generally quite satisfactory, if treated symptomatically with a broad spectrum antibiotic. Treatment should also include therapeutic agents to decrease swelling and increase the overall airway opening. Swelling in the voice box or larynx area can lead to a greatly decreased airway capacity. Hardbreathers    Hardbreathers or honkers are frequently seen in the feedyard. A hardbreather is an animal that usually has 45 to 60 days or more on feed. It generally is seen in a pen of cattle having difficulty breathing. Depending on the severity, a “honk” may be heard as air is expelled.    Hardbreathers are not caused by a single condition, but by several possible conditions. These conditions may include (1) IBR, (2) acute spread of a low level pneumonia, (3) allergic tracheitis, (4) atypical interstitial pneumonia, or (5) respiratory syncytial virus.    It is difficult, if not impossible, to tell which of these conditions the animal has when it is pulled. Laboratory tests and response to treatment are necessary to separate these five causes of a hardbreather. And it is important to know the causes before proper treatment can be instituted. Acute IBR    Acute IBR infection is seen as a single condition in cattle with greater than 45 to 60 days on feed. Cattle often have severe respiratory difficulty and a high body temperature (in excess of 105°F). A blood tinged nasal discharge may also be present.    Animals with low grade pneumonia which previous therapy failed to completely resolve the condition, often are triggered by the IBR virus into an active, more severe respiratory condition.    As the animal becomes closer to finish and fatter, the digestive tract is pushed forward into the diaphragm causing pressure on the previously compromised lung thus causing less total function air space and many times death. Allergic Tracheitis    Allergic tracheitis and atypical interstitial pneumonia are actually an acute response to chronic exposure to allergy – causing moldy feed or other airborne allergenic particles. These animals appear very suddenly with no previous indication that there was a problem.    Such cases may occur when the animals are moved longer distances, as might occur to reimplant. Airway space was adequate when in the pen, but the exertion of movement caused the animal to become decompensated and thus suffer an acute lack of necessary oxygen. Respiratory Syncytial Virus    Respiratory Syncytial Virus (RSV) has been reported by some to be a cause of allergic tracheitis and atypical interstitial pneumonia. It is unclear at this time as to the significance of this condition in fat cattle pneumonia.    Therapeutic goals for these conditions are relatively simple: (1) avoid any procedure at the time of treatment that would increase the animal’s need for additional oxygen; (2) supply therapy to open narrowed airways; (3) reduce swelling and possible allergic reaction; and (4) treat with a short withdrawal antibiotic.    Animals treated may respond favorably at first only to relapse soon after treatment is completed. Therefore, you should keep the option of early slaughter open should treatment response be unsuccessful.    Even though the incidence of fat cattle respiratory conditions is much less than BRDC in newly arrived cattle, the economic losses incurred are much greater per animal affected. For example, an animal lost soon after arrival will realize an economic loss that is roughly two-thirds that of an animal that is near finish. Therefore, it is easy to see that keeping the animal healthy throughout the feeding period is important for efficient economic returns. More information may be received through Beef Production Medicine which can be purchased in the publication section of this web site.

Respiratory Disease of Feeder Cattle

Respiratory disease of cattle is known by various names – pasteurella pneumonia, shipping fever or Bovine Respiratory Disease complex.

No matter what it is called, this disease accounts for huge economic losses every year. So it is important for cattlemen to be familiar with recognition, treatment and prevention of this disease.

There are several types of respiratory disease, but the one of most concern is the infectious form. We all are familiar with the calf that has pneumonia. This sick calf will be depressed, drawn, gaunt and unwilling to move. It will cough, breathe rapidly, have a yellowish

discharge from the eyes and nose, and have a fever of 103° to 106° F.

The first thing we often do when we see these signs is reach for a bottle of antibiotic. Rather than reach for a bottle of antibiotic, let’s look at the factors that interact to cause pneumonia. Once we better understand these factors, we can work toward more effective prevention and treatment programs.

Pneumonia results from a complex series of steps that are only partly understood. Research has shown that three factors must be present for a calf to get sick with pneumonia: (1) stress, (2) viral infection and (3) bacterial infection. Stress can be caused by routine

procedures such as castrating and dehorning. Also, new situations – nutrition, weather, congregation and transportation – can induce stress.

When a calf is stressed, its body reacts by secreting hormones that positively and negatively affect bodily functions. On the negative side, stress causes the entire body to be more prone to infection. This occurs by allowing disease causing organisms easier routes of entry and by disarming some of the body’s important defense mechanisms against disease.

So the first step toward pneumonia occurs following a stressful event.

The second step takes place when the body’s defenses are down and viruses invade the nose and other parts of the respiratory system. Viruses that commonly take advantage of this situation usually include IBR and BVD. Other viruses such as BRSV and PI3 sometimes cause problems.

Virus infection in cattle could be compared to the common cold or flu in humans, which rarely cause death. Although viruses may cause death, the major role they play in pneumonia is to allow the third factor of this disease – bacteria – to gain a foothold and possibly lead to death.

Pasteurella haemolytica (Mannheimia haemolytica) and Pasteurella multocida and Hemophilus somnus account for the majority of bacterial infections of pneumonia.

These bacteria gain entry via infected nasal secretions (much like virus particles may), or they may be stimulated to grow from normally low populations in the throat. Either way, without proper recognition and antibiotic treatment, these organisms can cause death

rather quickly in affected animals.

Since antibiotics kill or inhibit growth of bacteria, these are the organisms that we are trying to eliminate when we use drugs such as an antibiotic.

Respiratory Viral Disease

Respiratory viral disease can be devastating to animal health. It continues to be poorly understood and treated with mediocre results.

Viruses are not actually alive but are particles of genetic material that must infect the animal’s own living cells before they can reproduce and cause damage. The use of antibiotics will not directly fight a viral infection; but in most instances, antibiotics are indicated to treat the coinciding bacterial disease.

Viruses are spread from one animal to another via (a) direct nose-to-nose contact,
(b) contact with nasal secretions or other bodily exudates from an infected animal, or

(c) through aerosol particle transfer between animals. Exposure to viruses is unavoidable

in a feedyard, so we must concentrate our efforts on prevention and control-mainly with timely vaccination- preferably before exposure to the disease causing virus.

The four most common respiratory viruses are IBR, PI3, BVD and BRSV.

IBR (infectious bovine rhinotracheitis) has also been called “rednose.” It causes a reddened, tender nasal surface that crusts over and peels, as well as sore and runny eyes. Internally, the animal’s trachea or windpipe becomes very inflamed and may fill up with

a thick exudate. IBR has also been implicated in genital infections in cows, as well as in central nervoussystem disorders.

PI3 (parainfluenza 3) has long been recognized as a respiratory pathogen in cattle, especially lightweight calves. Its most harmful characteristics is that it destroys the cilia (hairlike projections) in the trachea, which prevent foreign matter and bacteria from

entering the lungs.

BVD (bovine virus diarrhea) has long been recognized to cause problems in the digestive tract, but in recent years has been implicated as a respiratory agent. BVD is very immunosuppressive; it weakens the animal’s immune system and thereby lessens its

ability to fight disease. Some cattle have been proven to be chronic carriers of one type of BVD and develop severe digestive and respiratory disease when exposed to another strain. Unfortunately, there is no practical and quick way to identify these animals, and we have

no accurate estimate of the extent of this problem.

An Ounce of Prevention: Feedyard Receiving Programs

Computerization has helped us evaluate the costs of disease and the savings through prevention. As a result, our focuses in feedyard health programs have evolved away from antibiotic treatment and mass medication. The new focus is towards vaccination, stress management and immune competence. The objective is to block or minimize the processes that amplify disease susceptibility. Feedyard veterinarians face a unique challenge. No other food animal production is as variable and non-integrated as the beef industry. Repeated transportation, resulting in environmental and nutritional changes, is the norm rather than the exception. Thus, the types and degrees of stress must be identified and addressed. A strategic receiving program should be designed and executed with the same organization and detail as a processing or treatment program. The Three “Rs” Many of the needs of stressed cattle are summed by the three R’s of a receiving program: rest, rehydration, and rumen. Transported cattle become physically fatigued from standing especially if hauled long distances over 12 to 24 hours. Additionally, mental stress can be a factor due to loading, unloading and commingling with unfamiliar cattle. We recommend that a spacious, dry (or bedded) pen be provided during receiving. Specific parameters include 150 to 200 square feet of pen space per head and 12 to 16 inches of feedbunk space per head. If bedding is used, be sure it is removed when it becomes wet or soiled. If left in place, it becomes a seedbed for contamination and infection. Before stressed cattle are processed, a rest of at least 12 to 24 hours is suggested. Research test after test shows how stress compromises current immune function, as well as further development of immunity. A rest period simply allows the animal to regain some of the immunocompetence that transportation and marketing stressors have disfavored. So rested cattle respond better to the vaccines administered during processing. Practical observations have suggested that a 1/2% to 1% increase in morbidity is seen for each 24 hour delay in processing after arrival. Of course, short-haul, healthy country cattle experience minimal stress and immediate processing can be performed as a matter of convenience. Also, highly stressed sick cattle may need immediate handling if they merit mass or individual treatment. If this is the case, recognize that prevention has given way to treatment and results rarely are optimal. Keen observers learn through practice and experience how to differentiate between sick cattle and stressed cattle. The veterinarian may check white blood cells counts, plus serum glucose levels and fibrinogen, to aid in this differentiation. Rehydration of transported or water-deprived cattle is crucial. Weight loss or shrink during transport or other handling procedures consists of “fill” loss and tissue losses. Fill consists of digestive tract contents and bladder contents at initial weigh-up. Tissue losses are made up of evaporative, urinary and even fecal losses at some point when fill is gone. Tissue losses result in some degree of dehydration as well as disruption of extracellular and intracellular fluid components. Experience and recent research show that in shrinks greater than 7%, stress is significant. And in long-haul cattle it can be significant when shrink is less than 4%. Unreasonably low shrinks may indicate a high degree of previous loss before initial weigh-up. Rehydration is more critical initially than feed consumption. The old industry practice of holding cattle off water to make them consume feed is unsound. Free choice, clean, fresh water should be available at all times. We avoid water medication whenever possible, as it may alter palatability and water intake. (One exception has been a commercial vitamin E additive that actually seemed attractive to cattle.) Do not assume that cattle are drinking just because water is available. Electric current, unpalatable or toxic contents, ice and ignorance of location may deter or prevent water intake. Water troughs in receiving pens should be checked and cleaned daily. The final R (for rumen) is representative of a large array of nutritional needs. Highly available energy is critical to restore energy balance in the food-deprived animal. But beware of over-consumption, which can lead to metabolic and/or clinical acidosis. The energy-depleted animal may be in a catabolic state, breaking down muscle and other proteins for energy sources. Protein supplementation provides readily available amino acids to aid in slowing and reversing the catabolic process. Non-protein nitrogen should be avoided, however, due to both palatability and toxicity problems. Recently, much attention has been given to vitamins and trace minerals, especially in relation to immune development and protection of tissues. Particular focus has been on vitamins A, C and E, plus the micro-elements zinc, copper and selenium. Research results show this to be promising. Remember, however, it is critical that a physiological balance be maintained on these compounds and elements. Over-supplementation is at best inefficient, and it can be toxic. Roughage, the Natural Foodstuff Roughage provides early fill in the deprived rumen and acts as a substrate for microflora. Reestablishment begins with forage (hay), the natural foodstuff of the ruminant. Native long-stem high quality grass hay is preferable. It can attract cattle to a bunk, and it can deter them from walking fencelines. Starter ration recommendations vary greatly, though a general consensus suggests the following: Energy is provided in a medium level concentrate (about 55%). This is based on a 500 pound calf; and for every 100-pound decrease in body weight, a 10% increase in concentrate is recommended. High levels of protein (13% to 14%) should be provided from a natural protein source. Vitamins and trace minerals should be assessed for need based upon other ration components and cattle source and condition. Health and performance are very dependent on the job done in the receiving period. Before any thought is given to processing and treatment programs, a detailed and effective receiving program should be implemented.

Biosecurity-An Extension of Herd Health Management and Emergency Preparedness

Biosecurity-An Extension of Herd Health Management and Emergency Preparedness Terrorism is defined as an act of terrorizing or state of being terrorized by intimidation. Those weapons available to terrorists for intimidation include chemicals, biological, radiological, nuclear and explosive. Biological terrorism involves the use of microorganisms or toxins derived from living organisms to induce death or disease in human beings, animals or plants. A microorganism to be pathogenic and effective in biological terrorism against animal agriculture must be highly infectious and contagious, have the ability to survive in the environment, have predictable clinical disease pattern (including morbidity and mortality), be pathogenic to livestock and poultry, easy to acquire or produce, attributable to as if it was caused by a natural outbreak, not harmful to person causing the infection and easily spread. Foot and Mouth Disease (FMD) is one example that meets these criteria and also poses the greatest potential threat to the cattle industry. Biosecurity is defined as a comprehensive management program to avoid introduction of virulent (FMD) and zoonotic (a disease of animals that can be transmitted to humans-Anthrax) disease causing pathogens into a livestock herd, non-confinement and confinement, and to prevent the movement of these pathogens within the herd. Biosecurity, as an international, worldwide practice of protecting animals from infectious diseases, has become a major concern with the worldwide threat of Foot and Mouth disease (FMD) and Bovine Spongiform Encephalopathy (BSE). A high percentage of beef operations are managed with an open herd policy that allows entry or re-entry of animals or animal products. During calving season, foster calves may be grafted onto cows. Feedyards and stocker operations commingle cattle routinely. Seedstock operations use artificial insemination or embryo transplants throughout the breeding season. All these management practices, which have been discussed in the management section of this book, place beef operations, cow-calf, stocker, and feedlot operations at risk of disease. To plan an effective Biosecurity Herd Health Management Program (BHHMP), a risk analysis should be conducted.      1. Risk assessment          Identify the level of any infectious diseases already existing, identify and prioritize     those diseases targeted for control and identify the diseases not present and you wish to continue to exclude. i.e.-Bovine Respiratory Disease Complex and Foot & Mouth Disease      2. Risk management          Formulate a comprehensive prevention health program and implement.      3. Risk communication          Explain the plan to management, personnel, suppliers and customers to ensure buy-in and implementation.      4. Collate and analysis results frequently. The first step is to know the complete condition of your operation- herd health, nutrition and facilities. Be aware of potential diseases, how they are contacted and the risks. Biosecurity can be broken down into external and internal components.      External Biosecurity: The rules and procedures implemented to avoid contamination of the herd from outside sources.      Internal Biosecurity: The rules and procedures implemented to avoid any spread of disease within the herd. Many of the components of a Biosecurity Herd Health Management Program are just good common sense. Biosecurity Herd Health Management Programs (BHHMP) programs should include all management, prevention and treatment procedures. See Chart #1.      External and Internal    1. An awareness of diseases-both domestic and foreign. See Chart #2     2. Disease management-prevention, incubation, treatment and risks.     3. An accurate evaluation of health and nutrition of herd.     4. Strict herd health and vaccination programs     5. Health, vaccination and production records of purchased animals      Internal     1. Where possible quarantine program and separate facilities for new animals      2. Isolation, hospital pen for sick animals      3. Clean, sanitary cattle equipment, facilities and lots      External     1. Ability to control human traffic-control access to property, provide disposable protective clothing and provide disinfectant for incoming visitors.      2. Ability to control herd contacts/purchases.      3. Regular veterinary inspection and consultation. Biological security measures are becoming standard in many agricultural sectors. The USDA has implemented three levels for its personnel to follow to minimize the risk of disease introduction. For more detailed information go to www.aphis.usda.gov/oa/fmdbiose.html. Biosecurity Levels Routine levels of biosecurity measures are described below. When in doubt as to which level of biosecurity is needed, choose the higher level. These steps should be repeated for each premises that is visited. Level 1- Visits to farms or ranches that entail office or home visits only.         No contact with livestock or their housing (including pet horse or work dog).         Use the minimum measures such as:         Minimum Biosecurity Measures         1. Avoid livestock areas, pens, barns, etc., unless it is necessary to complete the goal of the visit.         2. Park your vehicle on paved or concrete areas, away from production sites on farm, to avoid contact with dirt, mud or manure. If not possible, be certain that tires are free of dirt and debris by hosing the tires and wheel wells before leaving the premises. If this does not clean the tires adequately, take the vehicle to a nearby pressure car wash.         3. Wash hands with soap and water or an antibacterial gel before entering and after leaving the premises to avoid transmitting disease agents from person to person. Level 2- Visits to farms or ranches where minimal contact with livestock or their housing (barns, pens, hutches, etc) is unavoidable to attain the goal of the visit,  i.e. property appraisals, tour of production facilities. Contact constitutes walking through animal housing or pastures where the animals are not within reach.         1. Apply minimum biosecurity measures plus:         2. Immediately put on clean rubber or new plastic boots upon exiting the vehicle.         3. After returning to your vehicle, clean and disinfect any equipment used with a brush and approved EPA disinfectant solution (see listed supplies- Chart 3).         4. Clean rubber boots with an approved EPA disinfectant diluted with water.             Scrub the bottoms of the boots with a brush to remove all dirt or debris.         5.  Dispose of disinfectant solution according to the label. Unused       disinfectant solution should not be discarded on ground.         6. If wearing plastic boots, place them in a plastic bag that should be left on the premises for the owner/producer for disposal or place in a designated dirty' area of your vehicle.        Level 3- Visits to farms/ranches where there will be close contact livestock. This includes contact such as walking through narrowly confined pens/ lots where animals are within reach or actually handling/inspecting the animals.         1. Apply measures used in Levels 1 & 2 plus:         2. Pre-plan the needed supplies and clothing for daily visits.         3. Use a pair of clean coveralls for each premises.         4. Designate a 'dirty' area in your vehicle for clothing and equipment that        has been used on the farm.         5.  Put on clean coveralls and rubber boots immediately upon exiting the        vehicle.         6. After returning to your vehicle, clean and disinfect all equipment used        (including eyewear) and place all disposable supplies in a plastic bag to         leave with the owner/producer for disposal. If not possible, place plastic        bag in the 'dirty' area of the vehicle and dispose of in a manner that        prevents exposure to other livestock.         7. Clean rubber boots with an approved EPA disinfectant diluted with water.         8. Scrub the bottoms of the boots with a brush to remove all dirt or debris.         9. Dispose of disinfectant solution according to the label. Unused disinfectant        solution should not be discarded on ground.         10. Remove coveralls so that they are inside out and place in a garbage bag.         11. Place the clean equipment and boots in the designated 'clean' area of the        vehicle.         12. If the vehicle was not parked on a paved surface, wash vehicle tires and        wheel wells to remove dirt and debris at a nearby pressure car wash.         13. At the end of the day, dispose of all plastic bags that contain dirty supplies in a manner that prevents exposure to other livestock. Launder all coveralls.         14. Personal hygiene should include shampooing hair and cleaning under fingernails. Gempler’s, Inc describes a biosecurity program as an insurance policy for the health and productivity of the herd. It will not be free. Producers must make decisions about their "risk tolerance level" based on the chances of a disease occurring and the expected economic losses from the disease. There must be planning, commitment and education of all personnel throughout the operation to attain the goals set for an effective Biosecurity Herd Health Management Program (BHHMP). The components of a biosecurity program are all good management practices that will optimize beef production, increase the profitability and ensure a safe food supply. The ultimate fate of our industry is on the line, and collective anti-terrorism actions must be a top objective for all in the industry. Resources for biosecurity information can be assessed at: http://www.biosecuritycenter.org/. Purdue University. This site offers a list of peer-reviewed biosecurity references, disinfectant information, and state regulations involving dead animal disposal, reportable diseases and nutrient management. www.gemplers.com/biosecurity.htm Gempler’s Inc http://www.humanitarian.net/biodefense Humanitarian Resource Instiute http://www.beef.org/ National Cattleman’s Beef Association http://www.drovers.com/ The Drovers http://www.usda.gov/ Department of Agriculture www.aphis.usda.gov/vs/ Veterinary Services www.avma.org/vmat/default.asp American Veterinary Medical Association http://www.firstgov.gov/ For government information

Preshipment Programs for Beef Cattle

Preshipment Programs for Beef Cattle Tradition and economics form the basis for current methods of marketing beef cattle. The present marketing system has somewhat divided the industry, resulting in limited communication between the calf-producing segment and the feedyards. However, several attempts have been made to change the system with various alliance programs. The system of marketing cattle impacts the veterinarian’s work, because of increased diseases that occur when cattle are congregated, stressed and transported to feedyards. The greatest health problem—bovine respiratory disease complex—is estimated to cost the beef industry $250 million to $750 million annually. Cow-calf producers, order buyers, salebarn owners, back-grounders and feedyard operators strive to maximize production and minimize expenses and disease loss. Now they are giving a renewed attention to the maximization of animal health through procedures performed before the animal reaches the feedyard. Various programs have been used for several years that are specifically intended to prepare an animal for shipment. Some are designed for a particular feedyard or grazing operation. Programs also have been formulated that allow cattle to progress through the marketing system with a minimum of health-related disorders at the gathering point before shipment to the feedyard. Collectively, these programs are referred to as preshipment programs. Preshipment preparation is thus defined as those procedures performed before or during shipment that better prepare the animal for subsequent grazing or feeding at a particular operation. Preshipment programs are similar to preconditioning programs in that both are designed to increase cost-effectiveness during the first few weeks at the final destination. Preconditioning programs (before a calf leaves its original home) have been slow in coming, because ranchers feel they don’t get paid for the additional trouble and cost. The costs of preconditioning involve labor, feed health products and veterinary services. Preshipment programs use only procedures that give direct cost benefits to the buyer. Eliminated are the questionably cost effective procedures of extended feeding, parasite control, giving commercial implants and surgery. The cost of these programs is fully borne by the buyer of the cattle. The goal of preshipment programs is not to fully process cattle at the point of origin but rather to meet immediate medical, immunologic and nutritional needs in order to (1) better enable these animals to face the stresses of transport and commingling, and (2) minimize the physiologic disruption that occurs at this time. Programs are divided into (a) those for use at the ranch (before exposure to respiratory pathogens) and (b) those for use at the order buyer’s facility or salebarn. The programs outlined here are intended to be examples. As with other animal health programs, input and guidance from the veterinarian is essential in forming a program that meets the needs of the cattle involved. Ranch Program In Texas Panhandle feedyards, numerous calves are received from large ranches; especially some located in New Mexico and Arizona. Most of the cattle are received during the fall, are freshly weaned and are native-type British or British crossbreeds. These calves come from isolated environments with little or no exposure to the common respiratory pathogens they will face in the feedyard. Rarely do they have previous vaccination and they appear to be immunologically naive on arrival at the feedyard. Initially, these calves experience acceptable health and performance (less than 0.5% mortality) until approximately days 21 to 28 on feed. At this time, a sharp decrease in feed consumption is observed, followed by a dramatic increase in cattle requiring treatment for respiratory disease. In five to seven days, morbidity peaks (25 to 35 days on feed) at approximately 25%; while overall morbidity for the feeding period can approach 50%. Mortality rates for cattle involved in the outbreak average 2% to 4%. Diagnostic information gained from these out-breaks and from subsequent study of the herd environment demonstrated that calves become sick and die because of mixed viral and bacterial bronchopneumonia. Bovine viral diarrhea (BVD), Pasteurella haemolytica (Mannheimia) and Hemophilus somnus often are cultured in the laboratory. Increased susceptibility apparently stems from the lack of exposure at the ranch and the immunologic naive of calves on arrival at the salebarn or the feedyard. Feedlot practitioners have found that low level of selenium or copper increase health problems. However, there is no data to support these claims. The problem present in these calves also occurs in other calves that originate in the western United States and in Florida. Preshipment programs involving calf vaccination have helped. The calves are inoculated at least 21 days before shipment to the feedyard. Studies show that calves vaccinated then do have an adequate period in which to develop primary immunity by the time they are shipped to the feedyard. Weight loss incurred in handling the cattle at this time normally is not a problem for the seller. Inoculation is aimed at controlling viral and bacterial agents known to be associated with bovine respiratory disease complex. If the calves are still nursing at this time and there is concern about the use of a modified live virus and shedding by pregnant cows, alternatives are a temperature-sensitive intranasal IBR-PI3 or a killed virus product. The nutritional status of calves should be addressed if history shows that it is difficult to start them on feed. Creep feeding can be implemented approximately 21 days before shipment. Thus, the calves become accustomed to a concentrate ration and to eating from a bunk. Studies have demonstrated that limited creep feeding is cost-effective at the ranch, improves later feedlot performance, and provides health advantages. But, weaning before shipment has had variable effects on weight gain at the ranch. Therefore, preweaning is not specifically recommended in this program. Order Buyer Program Historically, the order buyer has functioned as the intermediary between the cattle seller and the feedyard or stocker operator. Order buyers draw from large geographic areas in order to supply a buyer with a specified type of cattle, a process that can takes normally five to seven days; however, it may take as long as two or three weeks. During this time, health problems can be encountered that are not fully realized until receipt at the buyer’s locale. Inadequate nutrition and management can predispose to respiratory and digestive disorders. Cattle purchased from salebarns can have pre-existing health problems and serve as sources of infection for other susceptible animals. Cattle held or sorted at the order buyer’s facility can become sick as they are subjected to the stresses of commingling, crowding and a contaminated environment. Most order buyers do their best to supply healthy, high-quality cattle, but they are faced with a difficult task because of the volume of cattle they handle and the cost of preventive and therapeutic procedures. Many order buyers are willing to cooperate on a preshipment program prescribed by the feedyard veterinarian. Identifying problems seen on and shortly after arrival at the feedyard is the key to program design. The preshipment program at the level of the order buyer should focus on (a) proper nutrition, (b) correcting bacterial infectious processes, and (c) stimulating effective active immunity for respiratory pathogens. On arrival or when gathered at the order buyer’s facility, the cattle are vaccinated with an intranasal modified live IBR-PI3. This establishes a relatively rapid onset of upper-airway secretory immunoglobulin A immunity and stimulates the release of interferon. Interferon provides some cross-protection against other viruses, such as adenovirus and rhinovirus. Respiratory and digestive diseases can be combated by giving antibiotic therapy just before shipment. The question often arises: Should antibiotics be included in the feed to deal with disease problems? Because feed consumption is highly variable among individual animals, especially those that are sick, injectable antibiotics would be more therapeutic and cost-effective. Although attention to nutrition at the order buyer’s facility may be inconvenient, it is cost-effective and benefits health and performance. A 55% concentrate diet, plus free-choice native grass hay is the optimum preshipment diet for stressed cattle. However, when grain exceeds 55% of the total ration, there is an increase in morbidity. Cattle fed this type of preshipment diet have health and performance advantages that extend to the first few weeks at the feedyard. Salebarn Program Many stocker cattle and feeder cattle are bought at auction markets. The risk of infection from exposure to pathogenic organisms is limited if cattle spend minimal time in the market environment. If the cattle are traded by a middleman or hauled from sale to sale with the idea of making a modest immediate profit, health problems will be intensified. Disease—primarily respiratory and digestive disease—will occur as a result of poor nutrition, repeated stresses of transport, water and food deprivation, and commingling. Because cattle normally are not kept at salebarns for extended periods, a one-time preshipment program focusing on treatment of existing disease and establishment of quick upper-airway immunity has been beneficial. Market veterinarians are knowledgeable about the antibiotic sensitivity pattern of a particular salebarn and can be helpful in implementing a program. Nutritional support can be difficult at salebarns, because of the high turnover rate of cattle as well as the lack of direct cattle ownership by the salebarn operator. At least, cattle should have fresh, clean water and hay available in the holding pens. Ideally, a 55% concentrate ration also would be available, but labor and expense usually make this cost-prohibitive. Failure to provide adequate nutritional support can cause die off of normal ruminal microflora and can result in decreased fermentative and digestive capacity of the rumen. Probiotics have become popular in treating ruminal malfunction; they are quick and easy to give. The easier and more economical that preshipment procedures are to perform, the more likely you will get cooperation in carrying out these procedures at the point of origin. Ongoing communication with the people who execute the program is necessary to ensure results. Generally, the impetus for initiating a preshipment program starts with the buyer. The veterinarian involved in the salebarn or with the order buyer also can initiate cost-effective programs that will benefit the client and the health of the cattle care.

New & Old Antibiotic Selection Concerns

Introduction: The cattle feeding industry is a highly specialized, efficient means of beef production; however, because the industry transports cattle over great distances, congregates them in confined areas, and exposes them to a concentrated energy ration, we see a complicated bovine respiratory disease syndrome. Despite the knowledge of the veterinarian, know-how and skill of pen riders and hospital crews, bovine respiratory disease complex (BRDC) remains the cattle- feeding industry’s number-one disease challenge. 1.) Preventative Medicine a.) Pre-Arrival b.) Arrival 2.) Nutrition 3.) Environmental Management 4.) Personnel Management 5.) Hospital Management a.) Therapeutic Management b.) Records Management The objective of the receiving program is to ensure that incoming cattle acclimate to the finishing period as efficiently and atraumatically as possible. The typical feedlot handles cattle from extremely divergent backgrounds with widely varied nutritional experience and immunologic status. A small management error in this starting/receiving period can be greatly magnified. The management of BRDC is not as simple as we would like or expect it to be. Clinical evaluation upon on arrival will alert feedlot personnel to potential problems. Subjective data should include origin, weight, type of cattle, length of transport, season of the year and ambient weather conditions. Objective data would include per-cent shrink, classical respiratory signs and number of visibly sick animals. Cattle are routinely classified into risk categories: 1.) High Risk-exposed No history of vaccination, sale barn/auction market origin and usually considered "put-togethers" com-mingled. Morbidity normally occurs first week following arrival. 2.) High Risk-unexposed No history of vaccination; however, usually one source origin. Morbidity usually occurs after typical 7-10 day incubation period and normally sees an 18-21 day break. These can be difficult and require a re-vaccination. 3.) Low Risk History of vaccination for BRDC and weaned for minimum of 30 days. Low risk vaccination program which is usually only a booster. The processing of cattle includes those procedures and medications deemed necessary to maximize performance and minimize health-related losses. The actual act of processing most commonly occurs upon arrival; however, in order to circumvent some of the shortcomings processing after exposure to disease causing factors; alternative approaches need to be examined. Clostridia diseases, internal and external parasites, and BRDC account for a majority of the monetary losses due to high morbidity, high medication, poor performance or death. Choosing an appropriate treatment program and its success depends equally upon the management of both healthy and sick cattle and the choice of medicines. Antibiotics are used both from a treatment and preventative standpoint in processing programs. Antibiotics can be utilized effectively in the preventative area but four common mistakes can be encountered. First, timing of antibiotic administration may be too early (bacterial infection not occurring) or too late (extreme damage already present to internal organs) to effect a response. Secondly, the amount of antibiotics given is not enough to ensure significant bacterial control. Thirdly, improper administration of an effective product may also result in inadequate response. Lastly, combinations or "cocktails" of antibiotics can render the ingredients inactive and cause other quality assurance residue concerns. The goal for each animal entering the hospital for treatment should be a lasting cure (minimum repull per cent). Achieving that means accurate and specific identification of the disease; proper evaluation and treatment; and re-evaluation prior to leaving the sick pen. When data from feedyards is summarized, 7.2 percent of cattle received treatments for various reasons of which 83 percent during seasonal peaks of this total morbidity is attributed to BRDC.The key to successfully manage BRDC is the feedlot’s management health team, headed by the veterinarian, ability to formulate a comprehensive health program, which consists of: Majority of pen the riders are capable to spot animals just as they are breaking with pneumonia. Animals’ exhibiting signs such as: The first and foremost rule of a hospital and therapeutic program is to pull early, pull appropriately, and treat aggressively (easier said than done). If sick animals are not pulled from the pen before respiratory disease has become an advanced problem; medication response will generally be very poor. This corresponds to the latter stages of the incubation period of disease and is before the animal actually shows classical clinical signs of disease. -Depression/lethargy, -Loss of appetite, -Stiff gait/soreness when walking, -Crusty muzzle, -Salivation, -Mild diarrhea, -Rapid, shallow breathing, -Moist cough, or a combination of these signs or symptoms should be pulled for evaluation and treatment. Acutely affected animals respond best to treatment, and animals treated earlier in the course of the disease have a better chance of recovering -Eye and/or nasal discharge,. Animals must be pulled for sickness appropriately. If sick animals are not managed properly then these animals will not get the hospital care they need, hospital pens will become overcrowded, and the hospital crew will needlessly become overwhelmed. Heavy pulls don’t always coincide with proper pulls. To treat aggressively in the feedyard means that when an animal is pulled initially for BRDC he is treated with an antibiotic program based on input from the feedyard’s veterinarian that will stop pnemoumia at its earliest stage of development, and not allow further progression of the disease process. These will effectively decreases total treatment days, decrease the number of retreatments, and prevent high death losses. Antibiotic selection can be done by antemortem testing, postmortem testing, clinical response evaluation, and with properly designed field studies. Clinical response rate evaluation is best tool for treatment of BRDC. If using an antibiotic that requires daily administration, treatment of sick animals should be continued for at least three successive days. Depending upon the antibiotic, this can be accomplished with one injection or administration or with three successive days of treatment. This rule is important in order to decrease total number of treatment days, number of treatments, and the number of pen deaths after treatment. Treatment should include antibiotics as well as other medications that are supportive in nature. Supportive care includes such drugs as B-complex vitamins to stimulate an appetite and replenish body loss, antihistamines to open swollen, narrowed airways, and electrolytes to replace body fluid loss as well as electrolyte loss. All drugs used in beef cattle have a specific purpose and use. It is important that the feedyard health crew be well versed on the proper use of drugs used in the treatment of sick animals. A drug used improperly is sometimes worse than no medication at all. Hospital treatment records are essential for calculating: First Therapy Response Relapse Rate Case Fatality Rate Chronic Rate 5.) Weight Gain/Loss According to the University of Nebraska’s Great Plains Veterinary Education Center, sick calves gaining more than 5 percent of their body weight while in the hospital pen had a repull rate of only 3 percent; whereas, those losing weight had a repull rate of 34 percent. Cost of Treatment When evaluating records and treatment response risk classification, age of animals, morbidity patterns and season of the year must be considered. Achieving a lasting cure involves teamwork from everyone on the feedlot’s health team. From a pen rider’s ability to identify sick calves, to a hospital crew’s evaluation and treatment decisions, with the knowledge and skill of the feedlot’s veterinarian and capability to communicate with the feedlot personnel will have a tremendous impact on the bottom line. The more informed and capable its members, the better equipped they’ll be to make accurate, profitable care decisions and the more likely sick animals will achieve a lasting cure. The last rule of treatment is keeping of clear and accurate records. These records should not only provide bookkeeping services but also allow to adequately assessing treatment response.