MILK-YIELD AND COMPOSITION IN 1ST-CROSS AND BACKCROSS BEEF-COWS

Milk yield arid composition from three distinct milkings (spring, Augu st, and fall) were evaluated on first-cross and backcross cows maintai ned under two contrasting environments. The dam crosses at Brandon (se mi-intensive cultivated pasture management) were HA, SN, CN, ACA, CCA, ASA, SSA, HCH, CCH, HSH, SSH, NCN, CCN, NSN, and SSN with H = Herefor d, A = Angus, N = Shorthorn, C = Charolais, S = Simmental and a SSA cr oss was 3/4 Simmental-1/4 Angus. At Manyberries (semi-arid and short g rass rangeland) the dam crosses were HA, SN, ASA, SSA, HSH SSH, NSN, a nd SSN. All cows were bred to Limousin bulls and milkings took place f rom 1981 to 1985, inclusive. Definitive differences among the backcros ses and between the backcrosses and the F1 crosses were not present. P ossible genotupe x environment interactins were observed for milk yiel d and composition. Milk yield arid composition were affected by age of cow and influenced cow and calf weight changes.