| 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.
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.
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.
Saturday, December 1, 2001
Monday, October 1, 2001
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
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.
-Loss of appetite,
-Stiff gait/soreness when walking,
-Rapid, shallow breathing,
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:
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.
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.
Monday, June 11, 2001
Infectious Diseases that Threaten the United States Beef Industry
Infectious Disease is defined as any disease caused by the entrance, growth and multiplication of bacteria, protozoon’s or viruses in the body. An infectious disease may or may not be contagious.
Contagious Disease is defined as a type of infectious disease caused by receiving living germs directly from an affected animal with the disease or by contact with a secretion or some object previously contaminated.
Many infectious diseases are not contagious, but some special method of spreading or inoculation of the germs is required.
Foot-and-Mouth Disease (FMD) is one of the most dreaded infectious diseases in the world and difficult to control. It is caused by a highly contagious aphthovirus of the family Picornaviridae and has no cure. It infects cattle but also pigs, sheep, goats, buffalo and artiodactyl wildlife species- animals with cloven hooves. FMD is characterized by fever, vesicles in the mouth and on the muzzle, teats, and feet; eventhough the mortality is low, it can cause death in young animals.
There are seven immunologically distinct types: A, O, C, Asia 1, and SAT (Southern African Territories) 1, 2, and 3. Within each serotype there is a large number of strains that exhibit a spectrum of antigenic characteristics; therefore, a number of vaccine strains for each serotype, particularly O and A, are required to cover antigenic diversity.
Transmission of FMD is generally by contact between susceptible and infected animals. Infected animals have a large amount of aerosol virus in their exhaled air, which can infect other animals via the respiratory or oral routes. All excretions and secretions from infected animal contain virus and have a remarkable capacity for remaining viable in carcassses, animal by-products, water, straw bedding and even in pastures. It is spread by direct contact, ingestion or inhalation. The virus can survive in dry fecal material for 14 days in summer, in slurry up to 6 months in winter, in urine for 39 days and on soil between 3 and 28 days.
Ruminants that have recovered from infection and vaccinated ruminants that have contact with live FMD virus can remain infected and carry the virus in the pharyngeal region for up to 2.5 years in cattle, 9 months in sheep and possibly lifelong in the African buffalo.
The primary site of infection and replication is usually the mucosa of the respiratory tract, although the virus can enter through skin abrasions or the GI tract. Replication then occurs in the local lymph node, and infection spreads via the blood stream to predilection sites in the epithelium of the mouth, muzzle, feet, and teats, and also to areas of damaged skin. Vessicles develop at these sites and rupture, usually within 48 hours. The viremia persists for at least 5 days.
The incubation period for FMD is two to fourteen days, depending upon the infecting dose, susceptibility of the host and strain of the virus. After the incubation period, a fever of up to 106°F (41°C) develops, the animal is anorectic and salivates and stamps its feet as vesicles develop on the tongue, dental pad, gums, lips, and on the coronary band and interdigital cleft of the feet. Vesicles may also develop on the teats and udder, particularly of lacting cows and sows, and on areas of skin subject to pressure and trauma, such as legs of pigs. Young calves; lambs, kids, and piglets may die before showing any vesicles because of virus-induced damage to the developing cells of the myocardium. Vesicles in the mouth, even when severe, usually heal within seven days, although recovery of the tongue papillae takes longer. Lesions on the mammary gland and feet frequently develop secondary infections, resulting in mastitis, underrunning of the sole and chronic lameness. In pigs, the complete horn of the toe may be lost. Cattle and deer may also lose one or both horns of the foot.
In cattle and pigs, the clinical signs of FMD are indistinguishable from those of vesicular stomatitis and vesicular exanthema.
Mortality is low, but the economic losses are catastrophic because of the strict quarantine and eradication programs. United States has a policy of slaughtering of all affected and in-contact susceptible animals and strict restrictions on movement of animals and vehicles around infected premises. After slaughter, the carcasses are either burned or buried on or close to the premises, and the buildings are thoroughly washed and disinfected with mild acid or alkali and by fumigation. Because of the sensitivity of the virus to acid and alkaline pH, sodium hydroxide, sodium carbonate, and citric or acetic acid are effective disinfectants.
Control is by movement restriction, quarantine of affected premises, and vaccination (last option) around the affected premises. FMD vaccine is a killed preparation and at best, affords good protection against challenge for four to six months. The antigenic diversity of strains of FMD virus within each of the serotypes is an additional complication, so it is necessary to ensure that vaccines contain strains antigenically similar to the potential outbreak strains.
Anthrax is an acute, serious infectious febrile disease of virtually all warm-blooded animals, including man and occurs naturally in animals in South Dakota, Nebraska, Arkansas, Mississippi, Louisiana, Texas, and California.
Anthrax is a disease caused by a spore-forming bacteria called Bacillus anthrasis and after the bacilli have been discharged from an infected animal or exposed to oxygen from an opened carcass, they form spores that are resistant to extremes of temperature, chemical disinfectants, and desiccation. For this reason, the carcass of an animal dead from suspected anthrax should not be necropsied.
Bacillus produces an edema toxin and a lethal toxin. Both toxins, gain entry to target cells by competitive binding with a third protein, protective antigen, that has a membrane translocation function. The toxins and the capsule are the primary virulence factors of the anthrax bacillus.
Outbreaks of anthrax commonly are associated with neutral or alkaline, calcareous soils that serve as incubator areas for the organisms. In these areas, the spores apparently revert to the vegetative form and multiply to infectious levels when environmental conditions of soil, moisture, temperature, and nutrition are optimal. Cattle, horses, sheep, and goats may readily become infected when grazing such areas.
During an epidemic, flies and other biting insects may mechanically transmit the disease from one animal to another, but this mode of transmission is of minor importance. Infection also may be caused by consumption of contaminated feedstuffs, eg, meat and bone meal. Occasionally, crops such as hay grown on contaminated soil have caused small outbreaks. Pigs, dogs, cats, mink, and wild animals in captivity have acquired the disease from consumption of contaminated meat.
The incubation period is three to seven days and the clinical course of the disease ranges from peracute to chronic. The peracute form is characterized by sudden onset and a rapidly fatal course. Staggering, dyspnea, trembling, collapse, a few convulsive movements, and death may occur in cattle, sheep, or goats without any previous evidence of illness.
In acute anthrax of cattle and sheep, there is an abrupt rise in body temperature and a period of excitement followed by depression, stupor, respiratory or cardiac distress, staggering, convulsions, and death. There may be bloody discharges from the natural body openings.
Chronic infections are characterized by localized, subcutaneous, edematous swelling that can be quite extensive. Areas most frequently involved are the ventral neck, thorax, and shoulders.
Rigor mortis is frequently absent or incomplete. Dark blood may ooze from the mouth, nostrils, and anus with marked bloating and rapid body decomposition. The blood is dark and thickened and fails to clot readily. If the carcass is inadvertently opened, septicemia lesions are seen. Hemorrhages of various sizes are common on the serosal surfaces of the abdomen and thorax as well as on the epicardium and endocardium. An enlarged, dark red or black, soft, semifluid spleen is common. The liver, kidneys, lymph nodes usually are congested and enlarged.
Anthrax must be differentiated from other conditions that cause sudden death. In cattle and sheep, clostridial infections, bloat, and lightning strike may be confused with anthrax.
A confirmatory laboratory examination should be done by collecting a small amount of blood from a superficial vessel such as the jugular vein. Before submission, the laboratory should be contacted to determine appropriate shipping procedures.
Anthrax in livestock can be controlled by annual vaccination of all grazing animals in the endemic area and by implementation of control measures during outbreaks. Vaccination should be done two to four weeks before the season when outbreaks may be expected.
Specific control procedures are necessary to contain the disease and prevent its spread. These include:
1. Notification of the appropriate regulatory officials and your veterinarian;
2. Rigid enforcement of quarantine;
3. Prompt disposal of dead animals, manure, bedding, or other contaminated material
by cremation or deep burial;
4. Isolation of sick animals and removal of well animals from the contaminated area;
5. Disinfecting of stables, pens, milking barns, and equipment used on livestock;
6. Use of insect repellents;
7. Control of scavengers that feed on animals dead from the disease;
8. Observation of general sanitary procedures by people who contact diseased animals.
Anthrax in humans is rare. Most cases develop in people whose occupation place them in close contact with livestock or the contaminated products of livestock such as wool, goatskin, and pelts. Direct human-to-human transmission of anthrax is extremely unlikely, and most experts question whether it is possible.
Three types of anthrax are seen in people: cutaneous (skin), intestinal, and inhalation. The incubation for the disease is approximately two to seven days.
In people, cutaneous anthrax accounts for about 95% of all natural infections and develops when the anthracis bacteria enter the skin through cuts or abrasions. Without antibiotic therapy, the death rate from cutaneous anthrax is approximately 20%; if appropriately treated, death is rare.
Intestinal anthrax results from consumption of contaminated and undercooked meat. Affected individuals may experience nausea, inappetence, vomiting, and fever, followed by abdominal pain, blood in the vomitus, and severe diarrhea. Mortality is estimated at 25-75%. Human intestinal anthrax has not been reported in the United States during the 20th and 21st centuries.
Inhalation anthrax may initially present as a flu-like illness. A short period of improvement may follow, after which the patient rapidly deteriorates with high fever, respiratory distress, and shock. Fatalities approach 95% if not treated within the first 48 hours.
Infection can be prevented and treated with antibiotics. Because the course of the disease is rapid, prompt administration is essential. Effective antibiotics include ciprofloxacin, doxycycline, and amoxicillin. Vaccination is effective at preventing infection in animals and people. Animal vaccines have not been approved for and should not be administered to humans. A vaccine is available for humans, but population-wide vaccination in the United States has not been recommended because risk has been considered low.
Vesicular Stomatitis (VS) is a viral disease of cattle, swine, and horses and characterized clinically by the development of vesicles of the mouth, feet, and teats. On occasion this infection occurs in man as an influenza-like disease. This sporadic, re-emerging viral disease is endemic in the warmer regions of the Western Hemisphere and in the United States it’s mostly in the Southwest.
Aside from its negative economic impact on livestock, VS is significant because of its outward signs are similar to foot-and mouth disease (FMD).
Vesicular Stomatitis is caused by two distinct rhabdoviruses designated as the New Jersey and Indiana types. The New Jersey type is the most common isolated. How VS spreads is not fully known; insect vectors, mechanical transmission and movement of animals may be responsible. Once introduced into the herd, the disease moves from animal to animal by contact or exposure to saliva or fluid from ruptured blisters.
Clinical signs include vesicular lesions on the tongue, oral mucosa, teats or coronary bands of the feet, fever, drooling or frothing at the mouth. Oral lesions can be so painful that animals refuse to eat or drink resulting in severe weight loss. Foot lesions can also result in lameness.
The only way to diagnose and differentiate VS from FMD is through laboratory tests. Suspected cases should immediately brought to the attention of state or federal authorities.
No control measures are taken eventhough there is a vaccine available in some countries of the American tropics. Since it is a self-limiting, non-fatal viral disease, treatment is also not usually undertaken. The systemic effects of the viral infection are non-responsive to therapy and the local lesions in the mouth or on the feet or udder also usually heal without any therapeutic intervention. Maintaining the affected animals in a hygienic environment is recommended to prevent secondary bacterial infection.
The Merck Veterinary Manual, Eighth Edition, CD-ROMÓ2000, Merck & Co., Inc.
Generalized Conditions; Foot and Mouth Disease; Anthrax; Vesicular Stomatitis;
USDA Web site:
Cornell Web site:
Texas Animal Health Commission:
National Cattlemen’s Beef Association:
Humanitarian Resource Institute:
American Veterinary Medical Association
Anthrax Fact Sheet 10/12-2001
Texas Cooperative Extension Service, The Texas A & M University System, College Station, Texas. Official Dept. of Defense web site for Anthrax
Centers for Disease Control
Thursday, March 1, 2001
The field of communication is on the threshold of an electronic explosion that is putting a large amount of information into our learning library.
For many years, I have written articles for veterinary and lay journals and magazines; however, due to today's mode of communication through computers and Internet, this will be my first Internet newsletter.
A quarterly newsletter will allow me to align with the seasons (Summer, Fall, Winter, Spring). Special updates will be written as needed.
Everyone has different needs and/or concerns. I do not have all the answers but will possibly know someone that can help find the answer; therefore, please e-mail me at firstname.lastname@example.org with your questions, needs and/or concerns.
Current diseases of concern for my clients and me are:
Johne's Disease and
Johne's disease was identified more than a century ago, yet remains a common and sometimes costly infectious disease of dairy cattle that has been documented in beef herds throughout the U.S.
The Beef 97 Study, a recent project by the USDA's National Animal Health Monitoring System (NAHMS), showed that 92.2 percent of beef producers were either unaware of Johne's disease or recognized the name but knew little else about it.
Johne's disease typically starts as an infection in calves, though clinical signs do not generally appear until cattle are 2 to 5 years of age. The infection is difficult to detect in its early stages and there is no cure once an animal becomes infected.
While this is a complex disease that we do not completely understand, basic information is available about the bacteria that causes the disease, how it is transmitted and how to control it.
Johne's disease results from infection with bacteria called Mycobacterium paratuberculosis. This organism grows very slowly, causes a gradually worsening disease condition, and is highly resistant to the infected animal's immune defenses. Infected animals may therefore harbor the organism for years before they test positive or develop disease signs.
The bacteria primarily infect the intestine, leading to prolonged diarrhea, poor digestion, and excessive weight loss. These bacteria are typically shed, in varying numbers, in an infected animal's feces. Once outside the animal, the bacteria no longer multiply, however they are quite hardy, living for months in water, feed, and manure. Susceptible, non-infected animals may pick up the bacteria through fecal contaminated feed or water. These newly exposed animals may develop disease and spread it within the herd.
Calves less than 6 months old are most vulnerable to infection. Under intensive housing conditions with a high level of exposure of young cattle to the organism, clinical Johne's disease can become common in cattle from one to three years of age.
Contrary to earlier notions that fecal contamination of feed and water was the sole means of transmission, infection of calves before they are born is possible. Fetal infection can occur in 20 to 40 percent of calves from infected cows showing clinical signs and about 10 percent of calves from infected cows not showing clinical signs.
DiagnosticsBoth fecal culture and blood serum antibody tests are available to producers to determine the disease status of a herd or an animal. Both tests fail to detect early infections because blood antibody development and detectable fecal shedding do not usually occur until late in the course of the infection. However, informed use of tests along with a history of clinical signs of disease in the herd can provide information to assist disease management in the individual cow and the herd.
Principles of Johne's disease control include:
Reducing exposure and infection of replacement cattle
Identifying and removing the most highly infected cattle, and
Preventing introduction of infection by screening sources of replacements.
Johne's disease control programs require a long-term commitment to prevention and must be adapted to individual herds.
Additional sources of information include
Your local veterinarian
USDA:APHIS Info Sheet August 1999(referenced for this newsletter)
Johne's Information Center on the World Wide Web at http://www.aphis.usda/vs/ceah
(For Johne's disease information, see the Center for Animal Health Monitoring then the Dairy Cattle or Beef Cow-calf pages.
Mycoplasma infections seem to be the "buzz" word or concern in my practice at this time.
Dr. Ricardo Rosenbush of Iowa State University presented a paper to the Academy of Veterinary Consultants " Should Mycoplasma Bovis Be A Concern in Feedlots" and I will be using his presentation as one of the references.
This infection, caused by Mycoplasma bovis, can have a variety of clinical signs. Pneumonia and arthritis are important clinical signs for feedyards, but we shouldn't necessarily assume that you have to have both pneumonia and arthritis to have a M. bovis infection. Many times we see pneumonia as the only presentation. In one disease outbreak at Agri Research Center, there were 21 deads from respiratory clinical signs only with Mycoplasma being isolated from 12 of the 21 head.
Outside of feedyards, mastitis is also an important disease caused by M. bovis and calves from these dairy herds may end up fed in feedyards.
Skin abscesses according to Dr. Rosenbush may also be seen.
Middle ear infections (Droopy Ear Syndrome) tend to be a significant problem in lighter calves after a high morbidity/pull rate has occurred.
What seems to be the most significant cause of concern is the lack-of response to antibiotic therapy. Different types of antibiotic therapy programs have been used with striking unresponsiveness. At necropsy multiple abscesses are noticed which tend to be distributed at the cranial aspect of the lung. (See figures 1,2, 3)
Also at necropsy, the joint capsule would be thickened but otherwise be unremarkable; however, the synovial sheaths and the areas above the joint are enlarged with both excess fluid and the presence of abscesses similar to those seen in the lung. The joint fluid is usually clear whereas with Haemophilus arthritis the joint fluid is purulent.
DiagnosticsWhen dealing with pneumonia and arthritis, the best diagnostic method is a lung-tissue submission.
As of today, in the United States it's not possible to use serology to control M. bovis outbreaks in feedyards because of all the false positives without the actual disease being present.
VaccinationThere is no licensed vaccine in the United States; however, there is activity in autogenous bacterins with sporadic to questionable results.