Dogs and cats, like any other living creatures, have certain nutritional needs to enable them to remain in optimal conditions. These needs are for nutrients and energy, and can be modified by many factors, both specific to the animal and the environment that surrounds it. 

Some aspects related to feeding in the different stages of the life of animals are described below.

Young animals (Junior)

Young animals have a higher metabolic rate than adult animals: their growing bodies carry out molecular synthesis reactions that lead to the formation of new tissues and body structures. This development process entails an increase in energy and nutrients which, together with a reduced ingestion capacity due to the smaller size of the young animal, requires diets for growing animals to have a higher concentration of highly digestible nutrients in a smaller volume of food.  

In general, these are the portion guidelines for young dogs and cats:

From weaning to 6 months, spit the recommended daily portion into 3-5 feeds.

From 6 months to adulthood, split the daily portion into 2 feeds.

The growing phase lasts about 10 months in small and medium-size breed dogs and cats and up to more than 2 years in large and giant-size breed dogs and cats.

Overfeeding increases growth rate, although it has been shown that an excessive growth rate is incompatible with adequate skeletal development and predisposes the animal to obesity when it reaches adulthood. For example, it has been shown that overconsumption of food accelerates the achievement of adult weight and results in an overload of still immature joints, increasing the risk of osteoarticular pathology (Dobenecker et al., 1998; Hedhammar et al., 1974).  It has also been observed that, in puppies of giant-size breeds such as the Great Dane, an excessive intake of calcium can cause alterations in bone growth and mineralization (Schoenmakers et al., 2000). Thus, it is preferable to control the growth rate. In addition, the growth rate needs to decrease gradually so the relationship between the daily portion and the weight of the animal is not linear, but the manufacturer's recommendations should be followed. 

Adult animals (Adult)

You can start to administer a maintenance diet to your animals when they reach around 90% of their expected adult weight. Adult animal diets are specifically formulated to maintain the animal at an ideal weight and in optimal physical condition. Maintenance diets in adult animals can be administered in a single or several portions per day. 

Small animals have a higher metabolic rate, in addition to a limited ingestion capacity, so their nutrient and energy needs per unit of body weight are greater. That is why the specific diets for small-size breeds have a higher nutritional and energy concentration. On the other hand, in large-sized animals, an important factor to take into account is the size of the kibble, which must be sufficient to force the animal to chew, so that the ingestion process is slower and progressive and thus avoid problems of swelling or twisting of the stomach (i.e., pathology in which the dog's stomach suffers abnormal distension, due to the accumulation of food, liquid and gas, in addition to a rotation that alters its usual anatomical position). 

Older animals (Senior)

There is no exact chronological point at which the Senior stage begins, but it depends on each individual: genetics and the racial pattern influence the appearance of diseases that can affect energy and nutrient needs. As a general criterion, the phase of advanced age generally begins from 6-8 years in large breed dogs and from10 years in small breed dogs and cats.

Normally, the older they are, the lower the maintenance energy needs since the animals in this phase are less mobile and temperamental. The optimal body condition in Senior animals is lean: restricting energy intake by 20-25% can lengthen life expectancy and delay the onset of chronic diseases, especially osteoarthritis (Lawler et al., 2008). In order to reduce the energy concentration in this type of diet, the fat content is normally reduced and the fibre content is increased. In Senior animals, it is also very important to avoid the loss of muscle mass, which is why, in Ownat products designed for older animals, highly digestible proteins are incorporated to maintain muscle mass, as well as an additional supply of chondroitin sulphate and glucosamine to help keep joints and cartilage in good condition.