|The Bovine Respiratory Disease Complex (BRDC) results from a complex series of steps: (1.) stress, (2.) viral infection, and (3.) bacterial infection.|
Stress can be caused by routine procedures such as castration, dehorning, nutrition, weather (change of environment), congregation (co-mingling) and transportation. Stress causes the entire body to be more prone to infection. This occurs by allowing disease causing organisms easier route of entry and by disarming some of the body’s important defense mechanisms against disease.
Viruses that commonly take advantage of the situation usually include IBR and BVD. Other viruses such as BRSV and PI3 sometimes can cause problems. Although viruses may cause death, the major role they play in the BRDC is to allow the third factor-bacteria-to gain a foothold and possibly lead to death.
Mannhemia haemolytica, Pasteurella multocida, and Haemophilus somnus account for
the majority of bacterial infections of the BRDC.
This complex series of steps causing the BRDC with large economic losses with high morbidity and mortality resulted in the development of pre-conditioning.
Pre-conditioning programs vary considerably, but generally include weaning, training to eat and drink from troughs, vaccination, and treatment for internal and external parasites, castration, and dehorning. Pre-conditioning is a general term used in the beef industry to basically describe the time period and management of calves which takes place at the farm/ranch before arrival into the feedyard. Therefore, pre-conditioning can be defined as the preparation of feeder calves for the marketing and shipment to the feedyard. Pre-conditioning is intended to give the calf time to return to normal behaviors, improve feed intake, and allow time for the immune system to rebound from weaning stress and immunization. (Bartle, Steve ADM Alliance Nutrition) Don’t confuse or compare the term pre-conditioning towards backgrounding. Backgrounding is a similar approach; however, the vaccinations and other management procedures take place at a separate facility-not at the farm/ranch.
American Association of Bovine Practitioners (AABP 1968) defined the following areas in pre-conditioning:
Historically, most pre-conditioning programs supported a 21-30 day weaning period; however, more recent efforts have been directed toward increasing the number of days weaned before shipment and improving management procedures on the ranch. The Texas Ranch to Rail data shows it take at least 45 days for calves to develop independent behaviors, achieve consistent intake targets, and to develop immunity from vaccination. Therefore today, most programs require a 45-day weaning period. Several pre-conditioning programs have also been replaced by individual programs developed at the producer level and by commercial programs promoted by biological firms. (Radostits, Otto Third Edition)
The vaccination requirements also vary but most include modified live vaccines such as IBR, BVD, PI3, BRSV, Mannheimia haemolytica leukotoxoid, and clostridial bacterins. In any pre-conditioning program, it’s important to meet beef quality assurance standards and all label directions should be followed regarding injection location, dosage, needle size, and timing of vaccination including boosters.
Different alliances of which this author works with have different requirements but a general outline includes:
The nutrition and management during the pre-conditioning period is dependent upon the producer’s objective. Oklahoma State University (extension publication F-3031) list several possible objectives:
· Optimize condition and health for the pre-condition phase
· Produce added weight at low cost
· Market calves through a program requiring pre-conditioning for best market potential
· Minimize the risk of digestive upsets and disease
· Achieve a specific target weight.
Suggested Nutrient Recommendations for Stressed Calves
(Adapted from 1996 Nutrient Requirements for Beef Cattle)
Dry Matter,%------------------- 80-85
NEm, Mcal/lb------------------- 0.82-0.90
NEg, Mcal/lb-------------------- 0.46-0.56
Crude Protein,%----------------- 12.5-14.5
Vitamin A, IU/lb------------------- 2500
Vitamin E, IU/lb------------------- 50-100
Management practices that minimize weaning and arrival stress will result in fewer calves requiring health treatments. The importance about prevention of disease, particularly the BRDC, does not only affects the morbidity (health treatments) and mortality (deathloss) but data also shows the impact on average daily gain, feed efficiency and carcass merit.
Health and Performance Effects of Preweaning Management
(Reprinted from Cattle Health Tech)
How does preweaning management influence disease resistance, average daily gain, feed efficiency, quality grade, and yield grade of carcasses? This question has been addressed in various research projects over the course of several years.
1. Compared to fresh, unweaned calves, calves that were preweaned and fed for 30-45 days at the ranch had:
2. Compared to fresh, unweaned calves, calves that were limit creep fed (1-3 lb/head/day) for the last 60 days had:
3. Compared to polled steers, calves that must be castrated and/or dehorned/tipped at the feedyard generally had:
4. Compared to nonvaccinated calves, calves that were vaccinated for IBR, BVD, PI3, BRSV and Pasteurella on the ranch had:
The Texas A & M Ranch to Rail program has consistently shown an impact of health on the ability of steers to express their genetic potential and the costs associated with sick cattle beyond the cost of medicine. Healthy steers had an average of $93.20 more favorable return than sick steers in the 20003 program and an average net return over a five-year period has been $37.54 per head.
Thursday, July 1, 2004
In the feedyard, questions arise daily concerning medication programs for respiratory disease. It’s the single biggest disease problem.
When faced with a history of no response to medication, we spend very little time on the actual medications. The more important consideration is determining management procedures aimed at prevention and treatment of diseased cattle.
Following are some rules of treatment that need to be observed when evaluating a
feedyard health program. They also are good guidelines when training new personnel to pull and treat sick cattle.
Pull Sick Animals Early
The first and foremost rule of treatment is to pull sick animals early, pull appropriately and treat aggressively.
If sick animals are not pulled from the pen before respiratory disease becomes an advanced problem, medication response will generally be very poor.
Good pen riders are able to spot animals just as they are breaking with pneumonia. This corresponds to the latter stages of the incubation period of disease and is before the animal actually shows clinical signs. It takes a certain eye to be a good pen rider; some
cowboys seem to have it instinctively; others have developed it over the years.
Pull Animals Properly
Animals must be pulled for sickness appropriately. If sick animals are not pulled properly, they will not get the hospital care they need, hospital pens will become needlessly overcrowded, and the doctor crew will become overworked.
Heavy pulls do not always coincide with proper pulls. Sometimes, heavy pulls from a pen occur, leaving some sick animals and pulling some with no obvious signs of illness. If heavy pulls occur in a pen (greater than 25%), then steps should be taken toward
What does treating aggressively mean? It means that when an animal is pulled initially for respiratory disease, it is treated with strong therapeutic agents (antibiotics) that will stop pneumonia at its earliest stages, and not allow further progression of the disease
process. This will effectively decrease total treatment days, decrease the number of retreatments and, of course, prevent high death losses.
With good therapeutic agents and supportive care, sick animals will not have to be rested between treatments, if additional treatment is deemed necessary. Antibiotics are stressful on the animal’s system, so supportive measures are used to stabilize the adverse changes that occur following treatment, as well as treat the disease.
Supportive care includes such drugs as (1) B-complex vitamins, to stimulate the appetite and replenish body loss, (2) antihistamines to open swollen, narrowed airways, and
(3) electrolytes to replace body water loss as well as body electrolyte loss.
The primary objective of supportive care is to counteract the serious side effects of disease and subsequent changes referable to antibiotic usage. Supportive care also includes nutritional support in the form of fresh hay and high-energy rations, plus hospital
management aimed at prevention of overcrowding and further stress.
All drugs used in beef cattle, including antibiotics and supportive medications, have a specific purpose and use. Your consulting veterinarian is the best source of information on proper use of these drugs. The feedyard health crew must be well versed on the
proper use of drugs because a drug used improperly is sometimes worse than no medication at all.
Visual inspection of sick animals in the hospital is absolutely necessary. Occasionally feedyard personnel will look at the thermometer and forget to look at the animal.
To prevent this oversight, all animals should be given a severity code, such as severely sick, moderately sick or mildly sick. This simple system encourages the health crew to assign a uniform code to the sickness of all animals.
This coding system allows sequential assessment of sick pulls and progress through the hospital treatment program. Secondary benefits of this system allow various persons to treat the animal on subsequent days and assess response to treatment. Also, it allows assessment of sick animal pulling.
If you are using an antibiotic that requires daily administration, treatment of sick animals should be continued for at least three successive days. This can be accomplished with one shot or administration or with three successive days of treatment. In the end, this will decrease the treatments and the pen deaths following treatment.
Research and experience has shown that only one or two days of treatment has detrimental side effects. Antibiotics can be changed during these three-day periods, but not after only one day of treatment.
Alternate routes of administration or increased dosages can be used on the second day of treatment when added response is needed on this treatment day. If treatment response is inadequate after two days of therapy, then alternate treatments or increased dosages should be considered.
You never want to give up on the treatment of an animal, but you should realize the limitations of antibiotic therapy and strike a happy median between cost-benefit and continued treatment. It is very discouraging to treat an animal day after day, only to have it die after an extended treatment period.
As a general rule, treatment of a sick animal for six continuous days or three treatments will constitute adequate treatment. Continued treatment often will result in a chronically sick animal or a dead animal.
The last rule of treatment is the keeping of clear, concise and accurate records. The feedyard runs on paperwork. Because of the large numbers of cattle that any feedyard handles and many sick animals that are treated, records are absolutely essential. These records will not only provide bookkeeping services, but will allow you to assess treatment response. Records must be (a) easy to fill out, (b) supply the appropriate information, and (c) be easily compiled for further evaluation.
These rules are formulated from sound medical practice and experience. Some of them vary depending on your particular antibiotic or medication program. But they will, in most cases, result in a successful medication program.