This study aimed to evaluate the influence of the substitution of soybean meal (SM) by detoxified castor cake (DCC) by two alkaline products on intake, performance and on the growth curve of goat’s kids. 24 were used, Saanen goats (n=12) and Anglo Nubian (n=12), with initial body weight of 16.2±0.67 kg, initial age of 3 months and confined during the growth phase. The treatments consisted of three diets: a standard diet formulated with a traditional protein source, the soybean meal (SM); and test diets, which consisted of a protein source alternative, differing detoxification processes, on the basis of calcium hydroxide (Ca(OH)2) or sodium hydroxide (NaOH). The animals were distributed in a completely randomized design, in factorial 3 x 2 (diet SM, Ca(OH)2 DCC and NaOH DCC x Saanen and Anglo Nubian) totaling six sessions with four replicates each. The experimental period lasted 270 days. The non-linear models used were the Gompertz and Logistic. There was no effect (P < 0.05) of diets on the intake of nutrients, but there was no effect (P > 0.05) of breeds and interaction between both factors. The intake of DM during the phase of growth was greater for the goats fed with SM. There was no effect (P>0.05) of diets nor of the breeds in the ADG. Feed conversion was influenced (P < 0.05) by the diets, in which the goats fed diets with DCC presented better feed conversion. It has been observed that both models had good adjustments, with values numerically superior to 90%, however, the logistic model showed higher R2 and, at the same time, asymptotic index (AI). Despite the ADG be equal, the breeds presented absolute growth rate (AGR) vary over time, where the Saanen goats reached the peak first (181 days), with AGR of 0.14 kg day-1. However, even the goats Anglo Nubian reaching the highest peak late, the AGR was higher, around 0.16 kg day-1 higher than the Saanen. Both castor cake has the potential to replace the SM on a diet of goat’s kids during the growth phase. The mathematical model of Logistics estimates more accurately the growth of Saanen goats and Anglo Nubian, being that the rate of absolute growth is greatest in goats Anglo Nubian.