Influence of body size in animals on health and disease

Abstract

A great many properties of animals vary in a consistent way with bodyweight (W), for example, rates of production and consumption vary with W 3/4 and the time-spans of biological processes vary with W 1/4. These quite robust principles enable prediction of many aspects of an animal's biology and are established as important practical tools in the fields of nutrition and selection for growth efficiency. They are perhaps underused in the fields of pharmacology, toxicology and anaesthesiology and their implications on pathogenesis, rate of immune response and healing have received very little consideration.

Antibiotic therapeutics in laboratory animals

“…This formula is described and illustrated by Kirkwood (1983). The constant b has been found for many parameters to be approximately 0.75 (Kirkwood 1983, Calabrese 1991.…”

“…The constant b has been found for many parameters to be approximately 0.75 (Kirkwood 1983, Calabrese 1991. The constant a fixes the value of P when W = 1 kg (Kirkwood 1983, Mordenti 1986). …”

“…An example is the difficulty in measuring surface area in an Table 5. Many chronological parameters, such as life span, number of heartbeats per minute and gestation period also are related by the basic allometric equation described above, but in this case the constant b averages approximately 0.25 (Kirkwood 1983). This means that as body size decreases these parameters greatly increase and this is well illustrated in Fig 2. The implication of this is that instead of raising the dose rate in proportion to the dose, the dose frequency can be increased with timeO.…”

“…7s basis 1a mixture of 125 mg/ml of each drug, total 250 mg/ml active agents. Data adapted from Kirkwood (1983) Body surface area, calculated using the allometric equation:-Surface area = 11.7 x Weighto. 66 was used to extrapolate doses of antibiotics from man to rhesus monkeys (Kelly et al 1992).…”

MEDETOMIDINE HYDROCHLORIDE EFFICIENCY AND SAFETY IN GUINEA PIG (Cavia porcellus), IN DOSES ESTIMATED THROUGH ALLOMETRIC EXTRAPOLATION

“…Such diversity creates a problem for the clinician, who must attempt estimate dosages of drugs from an animal to another (KIRKWOOD, 1983;BRITO, 2001;PACHALY, 2006). More than any other area of the veterinary medicine, the treatment with drugs in wild animals presents a high potential for wrongly calculated dosages, resulting in sub-dosage (inefficacy) or excessive dosages (toxicity) (PACHALY; BRITO 2001, PACHALY 2006.…”