Abstract

Among the factors influencing the productivity and profitability of livestock, animal diseases deserve special attention because they diminish the capacity of the animal to achieve its inherent potential level of production, for any given feeding and management regimen. Evidence concerning the nature of the various effects of disease is reviewed, and a hierarchy of effects is defined. The major effects are on protein metabolism and secondarily on energy metabolism. Effects on feed intake are also common, but even diseases which severely ravage the wall of the gastrointestinal tract do not appear as a general rule to significantly reduce feed digestibility. The primary effects of disease on nutrient metabolism flow through to various consequential effects on the productivity of the individual animal, and hence on herd replacement patterns and herd improvement. At least some diseases can continue to affect productivity even after the disease has been cured by treatment. Consequently, the adage that prevention is better than cure has a sound scientific basis. Analyses have shown exceptionally high economic returns from disease prevention, commonly 500 to 1500% return on invested funds. This is much higher than from curative methods in most cases. As veterinary science evolves from a curative approach towards an economically grounded health management approach, veterinarians will make use of evaluation aids through which the economic and practical implications of alternative actions are compared, so that the action most advantageous to the livestock enterprise can be taken.

TC, Reid, RMW Sumner, and LD Wilson

Proceedings of the New Zealand Society of Animal Production, Volume 48, , 91-94, 1988