Twenty-five-centimeter pre-grazing canopy height in palisade grass and forage peanut

Abstract

Short-term grazing behavior variables are sensitive to the canopy structure and have an impact on daily forage intake. This study evaluated the effect of pre-and post-grazing canopy heights on the forage harvesting process at a patch scale in a mixture of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. syn. Urochloa brizantha R.D. Webster cv. Marandu (palisade grass) and Arachis pintoi Krapov. & W.C. Greg. cv. Belomonte (forage peanut).Treatments were allocated to a split-plot arrangement in a completely randomized design.The plots, in their entirety, consisted of two pre-grazing canopy heights: 25 cm (CH25) and 35 cm (CH35); subplots consisted of three levels of defoliation severity: no defoliation (DS0); 20% depletion of pre-grazing canopy height (DS20); and 40% depletion of pre-grazing canopy height (DS40), with eight replications. Heifers were allowed to graze the patches (0.7 × 0.7 m) and their grazing behavior was recorded. Canopy structure measurements were taken both before and after grazing. Patches from CH35 presented greater stem mass for grass (p = 0.001) and legume (p = 0.002) than did patches from CH25. Bite rate, bite mass and instantaneous intake rate were greater for CH25 than for CH35 (p < 0.001, p = 0.068, and p = 0.074), and bite mass and instantaneous intake rate were lower for DS20 compared to DS0 (p = 0.032 and p = 0.016). Greater stem mass in the grazing strata negatively influenced the instantaneous intake rate.

Forage intake and nitrogen metabolism of beef cattle grazing palisadegrass‐calopo mixed pasture managed using canopy light interception

“…To maintain the same canopy stubble height for all of the grazing management conditions, different defoliation severities were adopted (forage removal rate of 31%, 41% and 54% for the 90LI, 95LI and 100LI, respectively; Alviarez et al, 2020). Thus, the heifers that grazed the 100LI canopies had to ingest the lower canopy strata, which are characterized by higher proportions of stem and dead material (Ferreira et al, 2022) and, therefore, a lower nutritive value. Thus, heifers in the 100LI had the lowest CP intake and apparent OM digestibility, which negatively affected the N retained by heifers in this treatment.…”