Jersolanda x gir leiteiro: what is the degree of blood in the calf?

The crossbreeding strategy of the cattle farmer who uses the gir leiteiro in jersolanda cows (which combine jersey and Holstein) can result in a tricross of great genetic value. According to the zootechnician and dairy cattle specialist, Guilherme Marquez, this mating generates a “trigrau,” which aggregates the rusticity of the zebu and maintains the milk production of the taurine. The composition of the calf is easily calculated, being crucial for genetic planning. Check it out: In this specific case, it is assumed that the jersolanda dam (a variation of girolando) is half-blood (50% jersey and 50% Holstein). When using a gir leiteiro bull (a pure zebu breed, i.e., 100% gir) in these dams, the result is a calf with a genetic composition that optimizes heterosis (hybrid vigor). The zootechnician explains that the resulting calf will have a composition of 50% gir leiteiro blood, coming from the pure zebu bull. The rest (50%) will be taurine blood, coming from the jersolanda dam, ...