Rotational vs. continuous intensive stocking management of bahiagrass pasture for cows and calves

Rapid growth of warm-season grasses such as bahiagrass (Paspalum notatum Fl ugge) is associated with their rapid decline in nutritional value. Grazing management that better matches forage growth and animal intake may improve animal performance on warm-season grass pastures. A 3-yr study (1989-1991) was conducted at the USDA-ARS Subtropical Agricultural Research Station, Br ooksville, FL, to determine the effect of the same stocking rate with eithe r rotational or continuous intensive stocking (CIS; temporary increase in s tocking density during periods of rapid forage growth) management on herbag e mass, forage crude protein and in vitro organic matter digestibility (IVO MD), and the performance of cows and calves (Bos taurus). Cow performance w as judged on weight, body condition score (BCS), plasma urea nitrogen (PUN, mg dL(-1)), and pregnancy rate; calf performance was judged on average dai ly gain (ADG), adjusted 205-d weaning weight, and BCS. Herbage mass of both grazing treatments was similar until the start of the rainy season (June-J uly). Stocking density of CIS cattle increased by 75%, which resulted in an increase in herbage mass of 250 to 1150 kg ha(-1) on rotationally grazed p astures, but this tvas not significant. Even at the increased stocking dens ity, herbage mass of grazed CIS pastures continued to increase in 2 out of 3 yr, indicating that animal selectivity was not limited by grazing treatme nt. Crude protein and IVOMD concentrations were not affected by grazing. As a consequence, none of the animal performance variables measured was affec ted by grazing management. The main advantages of CIS are less labor and fe ncing, and reserving an area for production of winter feed. Herbage mass on ungrazed CIS pastures (3000-4200 kg ha(-1)) would have produced between 17 00 and 2400 kg hay ha(-1).