POST-WEANING GAIN OF CALVES FROM FIRST-CROSS AND RECIPROCAL BACKCROSSCOWS

Data on post-weaning gains and final test weights are reported for 201 0 Limousin-sired steer and heifer calves from cows of 15 different F-1 cross and backcross breed types incorporating Charolais, Simmental, H ereford, Angus and Shorthorn breeding. Calves representing all 15 dam breed types were born and weaned under semi-intensive management at Br andon, Manitoba, then finished there on a self-fed all-concentrate die t. A subset representing eight dam breed crosses was born and weaned u nder extensive range management at Manyberries, Alberta, then fed at L acombe, Alberta, on a lower energy diet of silage and concentrate mixe d and fed to appetite in bunks. A comparison of common breed types rev ealed that the Brandon calves were lighter at weaning but gained more rapidly in the post-weaning test than the Manyberries/Lacombe calves. Under the Lacombe feeding regime, there were no significant difference s in rate of gain on the feedlot test, but progeny of breed types cont aining some Simmental breeding generally reached a higher final weight than progeny of Hereford x Angus cows because of differences in weigh t at the beginning of the test. Under the higher energy feeding regime at Brandon, progeny of breed types containing Charolais or Simmental generally gained faster and attained higher final weights than progeny of Hereford x Angus cows. Progeny of Charolais x British and Simmenta l x British F-1 cross cows generally performed as well as, or better t han, the progeny of either backcross.