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Accurate estimates of body weight can be useful in the evaluations of feeding programs, nutritional status and general health, and in calculation of dose levels (such as for anesthesia)-thus providing a valuable tool for captive elephant management. We used body measurements of 75 Asian elephants (Elephas maximus) to predict body weight. Weight, heart girth, height at the withers, body length, and foot-pad circumference were measured. All possible linear regressions of weight on one, two, three, or four body measurements were calculated. The highest correlation with a single measurement was that between heart girth and weight (R2 = 0.90). The data were also divided into age groups (1-13, 18-28, 29-39, and 40-57 yr), and all possible linear regressions were calculated for each group (there were no elephants aged 14-17 yr). Adding body length or pad circumference to heart girth resulted in a slight increase in R2. We conclude that body weight in Asian elephants can be predicted from body measurements and that heart girth is the best predictor. A second body measurement might improve predictive accuracy for some age groups.

Energy balance studies using indirect calorimetry were conducted with four mature equids ranging in weight from 125 to 856 kg. Each animal was fed three different levels of intake of the same diet. The amounts of digestible and metabolizable energy required for zero energy balance were determined by calculating regression equations for energy balance against energy intake. It was concluded that the maintenance requirements of equids vary linearly with body weight. No advantage was found for the use of weight for the comparison of equids within the range studied. The digestible energy (DE) requirement for equids confined to metabolism stalls was DE (kcal/d) = 975 + 21.28 X W where W equals body weight in kg. If a factor for activity similar to that suggested by the National Research Council was included, the requirement could be calculated by the equation: DE (kcal/d) = 1,375 + 30.0 X W.

The effect of level of protein intake on growth and calcium metabolism was studied in 24 foals. Starting at four months old, the foals were fed one of three diets containing all nutrients, with the exception of protein, at levels recommended by the United States National Research Council Subcommittee on Horse Nutrition for a 12 month period. The protein levels in the three diets were 9 per cent (low protein) 14 per cent (NRC recommended level) and 20 per cent (high protein). The foals fed the low protein diet were changed to the high protein diet after 140 days when they were nine months old. There were no significant differences in the rates of growth in weight, height, cannon circumference or in hoof growth and feed utilisation of the horses fed the 14 or the 20 per cent protein diets. However, growth, feed intake and feed utilisation by the foals fed the low (9 per cent) protein diet were significantly depressed. The average daily gains for the first 140 days for the 9, 14 and 20 per cent protein treatment groups were 64, 631 and 687 g in weight, 0.57, 0.83 and 0.87 mm in height and 0.04, 0.13 and 0.14 m in forecannon circumference, respectively. The average daily feed intakes for the 140 day period for the three groups were 2.7, 4.4 and 4.7 kg, respectively. After the change to the high protein diet the foals that had been fed the low protein diet maintained a higher rate of gain in bodyweight, height and cannon circumference, and utilised feed more efficiently than the other two groups throughout the second 140 days of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

Some aspects of energy, protein and vitamin E nutrition of the performance horse are discussed. The amount, dietary source and time of ingestion of energy before exercise can influence performance. In 1989 the National Research Council (NRC) increased their estimates of energy required by racehorses. Recent studies indicate that the increase was reasonable. Many factors, however, can influence energy requirements. Therefore, the best measure would be body weight and composition of the horse. A proper balance of soluble carbohydrate, fiber, fat and protein is essential. Some guidelines are presented. The amount and type energy source given before exercise can influence level of plasma glucose and free fatty acids during exercise, but the effects of these changes in the concentration of metabolites remains to be determined. There is no evidence that increased dietary concentrations of protein are needed and, in fact, may impair performance. Supplemental histidine (to enhance carnosine levels) or carnitine appear to be of limited value for horses fed conventional diets. Dietary concentrations of vitamin E less than the 80 IU/kg recommended by NRC seem to adequately protect against exercise-induced peroxidation. The NRC value may be justified on the basis of immune response, but further studies are needed. Vitamin E has been shown to be involved with familial equine degenerative myeloencephalopathy and may be involved with equine motor neuron disease, a condition considered to be similar to amyotrophic lateral sclerosis in humans. [ABSTRACT FROM AUTHOR]