Objective--To study whether end products of 2 pathways of anaerobic energy metabolism, lactate and purines, that accumulate in the blood after intense exercise indicate any relation to exercise performance. Design--Venous blood samples were taken within 1 and 15 minutes after a trotting race of 2,100 m. Animals--16 Clinically healthy Standardbred trotters. Procedure--Blood and plasma lactate concentrations were measured by enzymatic analyzer, and purines, uric acid and allantoin, were determined by high-performance liquid chromatography. The concentrations of metabolites were then correlated to racing time and individual performance indexes that are annually calculated from the percentage of winnings, placings, and starts rejected, average earnings per start, and the racing record. Results--Blood lactate concentration immediately and calculated cell lactate concentration immediately and 15 minutes after the race correlated positively (P < 0.05 to P < 0.01 ) with the individual performance indexes. Plasma lactate concentration was not correlated to the individual performance indexes. Uric acid concentration, immediately and 15 minutes after the race, was negatively correlated (P < 0.05) to the individual performance indexes, and a positive relation (P < 0.05) was found between the highest concentration of uric acid and the racing time. Concentration of allantoin immediately or 15 minutes after the race did not have any significant correlation to the individual performance indexes. Conclusions--Accumulation of lactate in the blood, which was greater in the superior performing horses, may prove to be an useful predictor of anaerobic capacity. The results also indicate that the loss of purine nucleotides was less in the superior performing horses, although further studies are needed to confirm this.

Improvement of the standards of energy and protein diets of young stock cattle of 1-6 month old and determination of its influence on animal productivity was realized in the conditions of the Republic of Belarus. The studied made it possible to determine that at the age of 1 month the calf diet should contain 1,02 kg of dry matter and 21,2 MJ of metabolic energy; at the age of 2 months - 1,26 kg and 23,5 MJ; at the age of 3 months - 2,2 kg and 25,6 MJ; at the age of 4 months - 2,9 kg and 31 MJ; at the age of 5 months - 3,28 kg and 34,2 MJ; at the age of 6 months - 3,76 kg and 37,6 MJ, respectively. Metabolic energy concentration per 1 kg of dry matter should not be lower than 20,7 MJ at the first month, 19 MJ - at the second month, after the third month it should lower up to 10 MJ. In course of 6 months the presented diet scheme made it possible get 832 g of average weight gain in the conditions of forage expenses of 3,52 forage units per 1 kg