Domestic Cat Milk vs. Wild Cat Milk: How Should We Care for Wild Cats Properly?

Domestic Cat Milk vs. Wild Cat Milk: How Should We Raise Wild Cats?

By Assoc. Prof. Dr. Somphot Virakul

There are numerous reports regarding the composition of domestic cat milk, and although we cannot cover all of them, selected studies offer valuable insights. Adkins et al. (1997) studied the milk properties of domestic shorthair cats by collecting milk on days 1, 3, 7, 14, 28, and 42 postpartum. They found protein levels ranging from 6.3% to 8.6%, with high levels present in both colostrum and mature milk. Non-protein nitrogen made up about 8% of the content, with a whey-to-casein ratio of approximately 50:50. The fat content was 9.3% in early colostrum, which declined rapidly and then rose again to around 9% in later milk. Lactose content was around 4%. Calcium levels in colostrum and early milk were initially low but increased over time, starting with a calcium-to-phosphorus ratio of 0.4–0.9 and rising to 1.0:1.2.

Another study by Jacobsen et al. (2004) yielded similar results, collecting weekly samples over six weeks, reporting 8.7% protein, 12.7% fat, and 4.2% lactose. Protein levels increased over time, while fat content rose only in cats fed high-fat diets. A study by Keen et al. (1982) reported mineral content like iron, copper, zinc, and manganese was low during the first 1–2 days but increased from day 3 and dropped again by day 8. This study also found lower nutrient levels overall—protein at 4–7%, fat at 3–5%, and carbohydrates at 4%—likely depending on the nutritional intake of the mother cat during pregnancy and lactation (Jacobsen et al., 2004). These data help in selecting milk replacers for domestic kittens, and potentially for wild cats or even cheetahs.

When compared with the milk of the serval (Felis serval), Osthoff et al. (2007) reported protein levels at 158.3±44.4 g/kg milk (15.8%), fat at 152.6±62.3 g/kg (15.2%), and lactose at 68.7±31.4 g/kg (6.8%). Casein was high at 117.7±44.8 g/kg, with lower levels of whey protein at 40.6±6.7 g/kg. The fat was further broken down into saturated (313.3±18.8 g/kg) and unsaturated (338.6±11.9 g/kg) fats per kilogram of milk. Compared to domestic cats, serval milk contains significantly higher protein, fat, and lactose levels. In contrast, cheetah milk contains 9.96% protein, 6.48% fat, and 4.02% lactose (Osthoff et al., 2006). Interestingly, the serval’s unsaturated fat is lower than that in domestic cats, making it difficult to use domestic cat milk replacers for wild cats. A specialized formula matching protein, fat, and lactose levels is necessary.

Most wild cats and big cats, like tigers and leopards, have not been thoroughly studied in terms of milk composition. Available research suggests their milk contains higher levels of protein and fat than domestic cat milk. Methods for rearing wild kittens remain unclear—even among tigers, practices vary. Thus, keepers and zoo veterinarians must study the nutritional needs and customize milk formulas accordingly due to significant health risks.

Examples of such risks include food allergies, weight loss, total fur loss, cataracts, and strabismus in tiger cubs fed with inappropriate milk substitutes. These issues are likely due to lower levels of essential amino acids—such as taurine, arginine, phenylalanine, tryptophan, and histidine—compared to natural milk (Remillard et al., 1993; Osthoff et al., 2007; Lange et al., 2017).

So what recommendations exist for hand-rearing wild kittens or tiger cubs?
Past reports show that protein and fat content vary widely among wildlife species. Common substitutes include cow’s milk, goat’s milk, or formulas from other species—often unsuitable due to mismatched protein and amino acid levels. Even using a closely related species’ formula, like domestic cat milk replacer for wild cats, carries risks. Still, keepers often have no other choice (Osthoff et al., 2006; 2007).

Researchers suggest choosing milk that closely resembles the natural milk of the target species (Baines, 1981; Remillard et al., 1993; Adkins et al., 1997). The ideal formula should have high protein and fat, low lactose, and clearly listed essential amino acids. Some products already include essential amino acids, vitamins, and minerals. Alternative formulations have used cow’s milk with reduced lactose, cod liver or fish oil, vitamins A and D, and even probiotics or prebiotics (as used in dog/cat nutrition). These enhance muscle mass and weight in growing or emaciated animals.

Even when formulas provide adequate protein, studies comparing their amino acid profiles to that of wild milk (e.g., tiger milk) show all 19 essential amino acids are lower than those found in maternal milk, negatively impacting health (Lange et al., 2017). Therefore, caretakers still face significant risks due to the lack of suitable milk replacers for wild cats and tigers. This remains a challenge for researchers aiming to develop formulas that better meet natural needs.

Caretakers should use the best available data for each species when selecting or preparing milk replacers. Some domestic cat milk substitutes are modifiable for wild use. Prefer formulas high in protein and fat, rather than cow or goat milk. Options that can be adapted include Zoologic Matrix by PetAg, Specialty Milk Replacer by Exotic Nutrition, and HPW by Exotic Nutrition.

Zoologic Matrix, popular in zoos and produced by the same company as KMR, contains 30% protein and 50% fat from natural fat and whey protein, with added casein, minerals, and vitamins. It is typically given at 10–20% of body weight per day, split into 6–12 feedings depending on age, species, and growth needs.

Specialty Milk Replacer by Exotic Nutrition is also widely used, offering ≥24% protein and fat, derived from natural fat and whey protein. It includes essential amino acids like lysine, methionine, and taurine—frequently deficient in cats—plus key minerals and vitamins. It is dosed at ½–1 teaspoon per 1 oz (28.34g) of body weight, divided into 4–6 meals daily, using 1 oz (¼ cup) powder per 5.5 oz of water.

HPW by Exotic Nutrition, designed for animals beginning to eat solid food, contains a more diverse set of ingredients beyond natural fats and whey protein, such as honey, eggs, bee pollen, flaxseed oil, omega-3s, essential amino acids (lysine, methionine), minerals, and vitamins. It has at least 29.5% protein and 7.1% fat. While not suitable for newborns, it supports growth in weaning animals by enhancing muscle cell multiplication and hypertrophy.

Ultimately, formula choice depends on the animal. Some may thrive on substitutes, while others tolerate only natural maternal milk. In such cases, signs of intolerance may include indigestion, bloating, diarrhea, vomiting, weight loss, and poor immunity—frequent issues observed when using unsuitable formulas.