Tuesday, January 14, 2003

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 Rs 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 fillloss 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.