Grazing behavior of rangeland beef cattle differing in biological type.

Grazing behavior exhibited by different biological types (breed groups) of lactating beef cows was evaluated during the summers of 1985 (Trial 1) and 1986 (Trial 2). Animals grazed native Montana foothill grassland. In Trial 1, breed groups consisted of Hereford (HH), 50% Angus-50% Hereford (AH), 50% Simmental-50% Hereford (SH), and 75% Simmental-25% Hereford (3S1H) with six cows per breed group. Daily grazing hours were 11.8 +/- .2, 12.3 +/- .2, 11.6 +/- .2, and 11.6 +/- .5 h/d for HH, AH, SH, and 3S1H, respectively. There was a tendency for AH cows to graze longer than HH and SH cows (P = .10). Bite rates were 52.7 +/- 1.5, 56.2 +/- 1.5, 53.2 +/- 1.4, and 59.0 +/- 1.6 bites/min for HH, AH, SH, and 3S1H, respectively. The AH and 3S1H cows had higher bite rates (P less than .05) than the HH and SH cows. Means for distance traveled were 3.1 +/- .2, 3.4 +/- .2, 4.0 +/- .2, and 2.8 +/- .2 km/d for HH, AH, SH and 3S1H, respectively. The SH cows tended to travel farther (P less than .10) than cows of other breed groups. The AH traveled farther than the 3S1H but did not differ from the HH. In Trial 2, breed groups were Hereford (HH), Tarentaise-Hereford (TH), Tarentaise-Simmental-Hereford (T(SH], and Charolais-Simmental-Hereford (C(SH]; each group included six lactating cows. Means for bite rate were 56.9 +/- 1.1, 58.7 +/- 1.1, 60.9 +/- 1.0, and 59.0 +/- 1.1 bites/min for HH, TH, T(SH), and C(SH), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)