Cow and calf performance on Coastal or Tifton 85 bermudagrass pastures with aeschynomene creep grazing paddocks

¹ Department of Animal and Dairy Science, University of Georgia, Tifton 31793
² Dept. of Ent., Soils and Plant Sci., Clemson University, Clemson, SC 29634
³ Department of Animal and Dairy Science, University of Georgia, Athens 30602
⁴ Experimental Statistics, University of Georgia, Tifton 31793

^* To whom correspondence should be addressed. E-mail: gmhill{at}uga.edu.

	Abstract

Cow and calf performance was determined in a 2-yr 2 x 2 factorial grazing experiment using Coastal or Tifton 85 (T85) replicated bermudagrass pastures (4 pastures each; each pasture 4.86 ha), without or with aeschynomene creep grazing paddocks (n = 4; 0.202 ha; planted in May each year, 13.44 kg/ha). On June 10, 2004 and June 8, 2005, 96 tester winter-calving beef cows and their calves were grouped by cow breed (9 Angus, 3 Polled Hereford/group), initial cow BW (592.9 ± 70.1 kg, 2-yr mean), age of dam, calf breed (Angus, Polled Hereford or Angus x Polled Hereford), calf sex, initial calf age (117 ± 20.1 d, 2-yr mean), initial calf BW (161.3 ± 30.4 kg), and randomly assigned to pastures. Additional cow-calf pairs and open cows were added as forage increased during the season. Forage mass was similar for all treatment pastures (P > 0.70; 2-yr mean, 6,939 vs 6,628 kg/ha, Coastal vs T85; 6,664 vs 6,896 kg/ha, no creep grazing vs creep grazing). Main effect interactions did not occur for performance variables (P > 0.10; 2-yr means), and year only affected initial and final BW of calves and cows. The 91-d tester calf ADG were greater for calves grazing T85 than Coastal (0.94 vs. 0.79 kg, P < 0.01), and for calves creep grazing aeschynomene compared with calves without creep grazing (0.90 vs. 0.82 kg, P < 0.03). Calf 205-d adjusted weaning weights were increased for calves grazing T85 than Coastal (252.9 vs. 240.3 kg, P < 0.01), and for calves with access to creep grazing (249.9 vs. 243.3 kg, P < 0.05). Pasture esophageal masticate IVDMD had a forage x creep grazing interaction (P < 0.05; Coastal no creep grazing = 57.4%; Coastal creep grazing = 52.1%; T85 no creep grazing = 59.1%; T85 creep grazing = 60.0%), and IVDMD was greater (P < 0.05) for T85 than for Coastal pastures. Cows were milked in August, 2004 and June and August, 2005, with variable milk yields on treatments, but milk protein was increased (P < 0.05) for cows grazing T85 than Coastal pastures in August each year, contributing to increased calf gains on T85 pastures. These results complement previous research with T85, and indicated increased forage quality and performance of cattle grazing T85 pastures. Calf gains on T85 pastures and for calves on creep grazed aeschynomene paddocks, were high enough to influence efficiency of cow-calf operations.

Key Words: calf gain, creep grazing, bermudagrass, milk, aeschynomene