capsule 1 is applicable to ruminants of different species ages and weights according to the different variants envisaged and provide an answer to the current problems by which it is impossible to identify young animals with a small bolus that is subsequently retained when these animals grow and reach adult age wherein they may have increased their weight by between 10 and 20 times since birth more specifically the invention is applicable although not in an exclusive way to domestic ruminants cows sheep and goats whether stabled or in pasture and to wild ruminants or farmed for hunting deer roe deer fallow deer mouflons mountain goats whether wandering freely or in captivity in order to obtain their identification and control at an early age and in a way that is compatible with good animal welfare and management practice the capsule 1 described has been tried out on ruminants of various ages and sizes and no cases with problems of hypersensitivity ulceration or alterations of the animal 39 s behaviour have been detected said capsule 1 has been applied to animals only a few days old and neither swallowing problems nor losses during the animal 39 s life have been observed thus allowing for a more accurate control thereof from the first days of life which if extrapolated to the entire stock of a cattle farm or grazing farm significantly improves their control and management from the available data and that obtained in several complementary trials carried out by the authors of the present patent some of the laws which list the dimensions of the boluses and their retention in calves for fattening up have been determined therefore the retention of the identification devices rid can be explained by means of equations obtained from non.