Crossbreeding Yak (Bos Grunniens) and Yellow Cattle (Bos Taurus): Simulation of a Rotational System and Estimation of Crossbreeding Means and Heterosis Effects

Wang, N., Vandepitte, W. and Wu, J.C. 1994. Crossbreeding Yak (Bos grunniens) and yellow cattle (Bos taurus): Simulation of a rotational system and estimation of crossbreeding means and heterosis effects. J. Appl. Anim. Res., 6: 1–12. Species differences and heterosis were estimated based on data from a crossbreeding experiment between the yak and yellow cattle (Lei, 1983) in Qinghai. Positive heterosis was found for 6 measured traits in the two sexes. The heterosis estimated on males for wither height, body length, heart girth and body weight was: 12.2%, 7.2%, 11.5% and 22.5% and on females: 9.5%, 6.3%, 8.8% and 17.1% respectively. The heterosis for milk production is 52.9% and for butterfat production 5.6%. For some traits, the species differences (Yak-Yellow cattle) are positive for males: wither height 1.8%, body weight 6.6%; for females: body weight 7.9% and milk production 41.5% and negative for males: body length −9.7% and heart girth −1.3%; for females: wither height −1.3%, body length −6.2%, heart girth −1.0% and butterfat production −39.6%. The performances of alternative combinations were predicted. It was found that the best combinations are the rotational cross and F1 crosses. The rotational cross is particularly interesting in the higher mountaneous areas. A simulation program to evaluate rotational crossbreeding with selection in a crossbred population was elaborated. The simulation results indicate that monetary gains from rotational crossbreeding with selection are superior to rotational crossbreeding without selection, the discount rate has also a considerable effect and tends to reduce the cumulative effect of selection in monetary terms.