The alternative crossbreeding programs initiated in 1940 by Dr. Antonio Teixeira Viana had the objective of obtaining first, crossbreeds 5/8 Charolais and 3/8 Zebu and second, 3/8 Charolais x 5/8 Zebu, to evaluate which of the two was the most successful. The total number of Zebu cows utilized to produce the half-breeds was 368, of which 292 were Indubrasil, 44 Guzerá and 32 Nelore. All the animals produced were reared exclusively on the range. Control of parasites was done every 15 days and the animals were weighed at birth and monthly. The females were weighed up to 30 months and the males up to 40 months.