Energy and Nutrients
The body composition of the canine is similar to that of its mammalian prey, thus they are “nutritionally exchangeable” such that the carnivore should not necessarily “suffer specific nutrient deficiencies if they consume entire carcasses of prey” (Mech and Boitani, 2003). The body composition of a domestic dog, closely related to the dingo especially due to many occurrences of dingo-dog interbreeding, can function as an example of what nutrients are needed for physical maintenance. An adult dog’s body composition is on average 50% water, 16% protein, 23% fat, 5% minerals, and 1.7% carbohydrates, while the skeleton is roughly 12-20% of the body weight.
The wild canine's diet is very digestible, approximately 90% so, with fat as the most thoroughly digested component of the diet at 97%, then protein at 93%. However, digestibility decreases with an increase in food intake relative to their weight (Mech, 2003).
The wild canine also requires less accessible parts of the prey to meet its nutrient intake requirement, thus it usually needs to ingest the entire prey, save for the plants present in the herbivorous prey’s digestive system. The prey’s liver is incredibly important to eat since it provides a large number of vitamins and minerals, such as those in table 4.3 (Mech, 2003).
As a canine, the dingo can use beta-carotene as a form of Vitamin A. Wolves, and by extension dingoes, are known to synthesize vitamins such as Vitamin C if the requirement is not met in the diet. The bones are also a major source of calcium and phosphorous which aids the canine in the maintenance of its own skeletal structure. This is why a lone dingo can scavenge bones from carcasses to maintain its nutrient requirements before its next kill. If the bone is fresh, even better, since it will contain in the marrow up to 20% protein and 20% fat (Mech, 2003).
The brain tissue of the prey, accessed by breaking the skull, contains high amounts of polyunsaturated fatty acids needed for body maintenance. As well, the mucous membranes of the gastrointestinal systems provide essential fatty acids, while muscle tissue has 1% of its maximum metabolizable energy in the form of isomeric d-essential fatty acids, the heart contains 4%, liver 5%, and the brain over 11% (Rivers and Frankel 1980).
Quantitative Energy Requirements
The basal metabolic rate of the dingo can be estimated by similar calculations done with wolves by Mech and Boitani (2003). The wolf’s energy requirements in kcal/day is measured when the animal is in a thermoneutral zone, fasting, and at rest. Relative to body mass (W) in kg, the equation is BMR= 70W^0.75. For a 35 kg dingo, the BMR would be 1007 kcal/day or 175.4 kJ/hr. An adult wolf falls close to that number, and the average energy of a prey caracass is 7.7kJ/g, thus the wild canine would need to ingest 0.55 kg prey/day. However, since there is energy lost during ingestion, digestion, and excretion it is more likely that food at a level of 93% digestibility and accounting for 10% energy loss in urine, would lead a canine to ingest 0.65 kg prey/day to maintain its basal metabolic rate. The field metabolic rate (FMR) of a wolf, otherwise known as the daily energy requirement (DEE) is estimated by Glowacinski and Profus (1997) to be 21,300 kJ/day for a 35 kg wolf, assuming it ingests 2.8 kg of food/day, if the prey has an energy content 7.7 kJ/g.
However in a recent publication, Glen and Dickman (2014) provide the following quantitative energy value for the dingo:
Wolves, like dingoes, often maintain their water requirements from consuming prey tissue and chemical oxidation of this food. In fact, 55-75% of fresh meat is water, and various organs such as the heart, kidney, lung, and liver contain even higher percentages of water. Metabolic water produced as a by-product of digestion yields 107 g of water per 100 g of fat tissue, while 100 g of protein yields 40 g of water. (Randall et al. 1997). The wolf (and by extension the dingo) produces dry feces from which much of the water content has been extracted, to a low level of 29% during the winter. While free water intake may be helpful when the canine is in a heat-stressed state (desert landscape or after hunting difficult-to-catch prey) it is not as necessary as one may expect (Mech, 2003).
Lactating females establish dens as close to water sources as possible since after reproduction, lactation requires greater water intake proportional to food intake which in itself is usually two-to-threefold normal intake (Oftedal and Gittleman, 1989). For a domestic canine, a female lactates 1.2 litres of milk per day with a litter of five or so pups (1989).