The objective was to evaluate the animal production on oat (Avena strigosa Schreb) and ryegrass (Lolium multiflorum Lam.) mixed pasture, receiving or not receiving supplementation, with and without growth promoter. The experiment was conducted in Dairy Sector at Departamento de Zootecnia, Universidade Federal de Santa Maria, RS, Brazil, during the period of April to September, 2003. The utilised animals were weaned male dairy calves, Holstein breed, with initial average age of three months and initial average live weight (LW) of 88.7kg. The animals were submitted to continuous grazing with fixed stocking rate (average of 1,479kg of LW ha-1) in a pasture of oat and ryegrass receiving or not supplementation, with and without a growth promoter based on essential oils from plants. Treatments were: S-0%= cool season pasture without supplementation; S-1%=pasture + 1% LW as DM of supplement; S-1% PC250=pasture + 1% of LW as DM of supplement (with 250g growth promoter for ton of supplement); S-1% PC500=pasture + 1% LW as DM of supplement (with 500g growth promoter for ton of supplement). The experiment design utilised was a Latin Square 4x4, with two repetitions. Body measures and daily weight gain (DWG) of animals; forage height and mass, DM accumulation rate of the pasture, DM disappearance rate of the pasture and forage quality were evaluated. The average DWG was 622g animal-1 day-1 to the supplemented animals and 294.5g animal-1 day-1 to the non-supplemented animals (P<0.05). Average values for forage mass (943.9 kg ha-1 of DM ), daily accumulation rate (142.7kg ha-1 day-1 of DM) and DM disappearance rate (133.2kg ha-1 day-1 of DM) were not influenced by treatments (P>0.05). The growth promoter did not affect animal performance and development.
dairy calves; cool season pasture; concentrate; growth promoter
