Detailed Explanation of Energy Requirements in Fox Nutrition

Organic nutrients in feed are the energy source for foxes, and these nutrients release energy during metabolic processes within the organism. When calculating the total nutritional value of feed rations and the energy requirements of animals, metabolizable energy is usually used as the measure. The conventional unit for feed energy and nutritional value of fur-bearing animals is 418 kilojoules (100 kilocalories) of metabolizable energy. Feed energy units are expressed in kilojoules or kilocalories; 1 kilocalorie equals 4.184 kilojoules, or 1 kilojoule equals 0.239 kilocalories. The range of basal metabolic energy per kilogram of body weight per day for adult foxes is: 255-280 kilojoules (61-67 kilocalories) in June-August; 209-243 kilojoules (50-58 kilocalories) in September-October; 176-218 kilojoules (42-52 kilocalories) in November; 172-197 kilojoules (41-47 kilocalories) in December. Basal metabolic energy is the basic energy requirement for foxes to sustain life, accounting for approximately 72% of total energy, meaning the energy utilization ratio is 100:72, or 1.39. Therefore, for maintenance feeding of adult foxes, the average metabolizable energy per kilogram of body weight per day is: 389 kilojoules in July-August, which is 280 kilojoules (67 kilocalories) multiplied by 1.39; 339 kilojoules (81 kilocalories) in September-October; 301 kilojoules (72 kilocalories) in November; 272 kilojoules (65 kilocalories) in December. In summer, foxes require 19 kilojoules (4.6 kilocalories) of energy to gain 1 gram of body weight, and in autumn, 27 kilojoules (6.4 kilocalories). In winter, foxes often lose weight; female foxes lose 8-12 grams per day, and male foxes lose 15-20 grams. This range of weight loss is a normal preparation for foxes transitioning to the breeding season.