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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2005-723v1 85/5/1340    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Stuedemann, J. A. Articles by Franzluebbers, A. J. Search for Related Content PubMed PubMed Citation Articles by Stuedemann, J. A. Articles by Franzluebbers, A. J.

Cattle performance and production when grazing Bermudagrass at two forage mass levels in the southern Piedmont^1,2

J. Phil Campbell Sr. Natural Resource Conservation Center, Agricultural Research Service, USDA, Watkinsville, GA 30677

⁴ Corresponding author: afranz{at}uga.edu

Performance and production of growing cattle (Bos taurus) on Coastal Bermudagrass [Cynodon dactylon (L.) Pers.] pasture are affected by forage allowance, but possible interactions with fertilizer nutrient source (i.e., inorganic vs. organic) and time have not been well described. We evaluated the effects of 3 nutrient sources with equivalent N rates: 1) inorganic, 2) crimson clover (Trifolium incarnatum L.) cover crop plus inorganic, and 3) chicken (Gallus gallus) broiler litter, factorially arranged with 2 residual forage mass levels [grazing to maintain high (4,528 ± 1,803 kg/ha) and low (2,538 ± 1,264 kg/ha) forage mass], on cattle stocking density, ADG, and BW gain during 5 consecutive summer grazing seasons. Across grazing seasons, residual forage mass and nutrient source both affected response variables, but interactions between these variables were rarely significant (P 0.10). Across grazing seasons and nutrient sources, increasing grazing pressure to maintain a lower forage mass reduced ADG (0.67 vs. 0.88 kg/d; P < 0.001) but increased BW gain/ha (726 vs. 578 kg/ha; P < 0.001) due to greater stocking density (8.7 vs. 5.8 steers/ha, P < 0.001; mean BW of growing Angus steers of 212 kg). Inorganic fertilization led to greater stocking density than other nutrient sources (8.2 vs. 6.8 steers/ha, P < 0.001) because of greater forage production. Stocking density to achieve the 2 targeted forage mass levels was widely different during the initial grazing seasons of the study but nearly similar at the end of 5 yr. Cattle performance tended to decline with time during each grazing season under both residual forage mass levels, perhaps as a result of declining forage quality, because performance was positively associated with grazing season precipitation under high forage mass. Steer BW gain/ha was greater (P < 0.05) with lower forage mass early in the grazing season of all years but not necessarily later in the grazing season. Steer BW gain/ha was also greater (P < 0.05) with a lower forage mass during the early years of the study but was similar during the later years of the study. Significant variations in cattle performance and production with time confirmed the short-term seasonal effects but suggested that the long-term effects may also be of importance in maintaining productivity and environmental quality of grazed pastures.

Key Words: broiler litter • cattle production • daily gain • grazing pressure • inorganic fertilizer • stocking density

² We appreciate the technical expertise of Dwight Seman, Steven Knapp, David Lovell, Devin Berry, Robert Sheats, Fred Hale, and Anthony Dillard. We acknowledge the contributions of Rus Bruce and Stan Wilkinson in helping to initiate the study.

³ Retired.