45 Effects of Grazing Management Systems on Forage Quality, Forage Availability, and Cow Performance

Abstract

Abstract The objectives were to compare the effects of two rotational grazing systems on forage quality, forage availability, and cow performance. Multiparous, fall-calving beef cows (n = 360; BW = 597±62 kg) were stratified by body weight (BW), body condition score (BCS), age, and sire and allotted to 6 groups. Groups were randomly assigned to 1 of 2 treatments: 8-paddock system rotated every 5 d or 6-paddock system rotated every 7 d. All paddocks (6.1 ha) contained endophyte-infected tall fescue and were grazed in two rounds. Cow BW and BCS were obtained on d 0, 28, 56, and 84. Forage heights were measured using a rising plate meter upon the groups entering and exiting each paddock. Forage samples were clipped from each paddock for proximate analysis. Data were analyzed using the MIXED procedure of SAS. During the first and second grazing rounds, grazing management system had no effects (P ≥ 0.11) on dry matter, organic matter, neutral detergent fiber, acid detergent fiber, and crude protein of the forage. The 8-paddock system tended (P = 0.09) to have greater forage availability than the 6-paddock system at the end of each rotation in the first round with 3,665 and 3,263 kg DM/ha, respectively. However, grazing system did not affect (P = 0.13) forage availability at the end of the rotation in the second round. Cow BW was not affected (P ≥ 0.63) by grazing system on d 0, 28, or 56. On d 84, cows rotationally grazed through an 8-paddock system had greater (P = 0.04) BW than those who grazed the 6-paddock system. Treatment had no effect (P ≥ 0.37) on BCS at any time point. In conclusion, grazing management system did not affect forage quality; however, the 8-paddock system resulted in greater forage availability which led to greater cow BW.