Milking performance of Blanco Orejinegro and Jersey crossbred cattle

SUMMARY Samples of a Colombian criollo breed of cattle, the Blanco Orejinegro, and contemporary onequarter Jersey crossbreds were kept on a farm in the Andes. Records were included of all calvings which occurred over an 8-year period, giving totals of 1357 lactations from 514 purebreds and 424 lactations from 137 crossbreds. Age at first calving was about 41 months for both breed groups. Cattle were milked twice daily by hand without calf at foot. Mean lactation yields were 220 kg (purebreds) and 612 kg (crossbreds). The repeatability and heritability of milk yield are estimated. Statistics are also given for lactation length, daily yield, calving interval and butterfat percentage. The effects on yield of age at first calving and calving year were negligible, but month of calving was important. It is concluded that the low level of performance was partly due to failure to eject milk without calf at foot, at least in the case of the purebreds, and that this was itself mainly due to genetic causes. The improvement in yield due to crossbreeding was not accompanied by a loss of other desirable traits. The development of the local cattle industry is discussed in the light of these results and the general characteristics of the region.