Effect of Standing Litter on Rough Fescue Utilization by Cattle

Abstract

Fescue grasslands are well suited to dormant-season grazing, whereas spring defoliation is detrimental to rough fescue (Festuca campestris Rydb.). Dormant-season grazing may also condition fescue plants for subsequent selection in spring by removing standing litter (i.e., senesced biomass). This relationship must be understood in order to manage grazing and conserve rough fescue. This study determined the effects of standing litter on plant selection and utilization by cattle in spring. Forty dormant rough fescue plants were conditioned in fall by removing standing litter in a 4 (treatments) 3 10 (blocks) randomized complete block design. This design was repeated with the use of 2 separately grazed paddocks. Treatments were a control (no litter removal) and standing litter removed at 14-, 7-, and 2.5-cm stubble height. Nonparametric plant selection data were analyzed with the use of v 2 methods. Spring biomass utilization was estimated nondestructively through height-weight modeling techniques, and data were analyzed with the use of analysis-of-variance procedures. The stubble height of standing litter affected (P , 0.05) plant selection by cattle in the first 2 days of the trial when grazing pressure was light. By the end of the 6-d grazing period 96% of fescue plants were selected at least once. Additionally, 18% of plants were regrazed at least once after 3 days, and 48% after 6 days. Thus, the protective barrier effect of standing litter had limited effect on plant selection by cattle except when grazing pressure was light. However, the degree of spring biomass utilization increased with shorter stubble heights. After 6 days of grazing, the current growth of plants with standing litter removed at 2.5 cm was utilized at 64%, and control plants were utilized 9%. Therefore, at high grazing pressure the mass of standing litter influenced the degree of utilization, suggesting litter retention is important in limiting grazing impacts on rough fescue. ResumenLos pastizales de ''Fescue'' están bien adaptados al apacentamiento en la época de dormancia, mientras que la defoliació n en primavera es perjudicial para el ''Rough fescue'' (Festuca campestris Rydb.). El apacentamiento en durante la dormancia también puede acondicionar las plantas para la selecció n subsecuente en primavera al remover el mantillo en pie (i.e., la biomasa senescente); esta relació n debe ser entendida para manejar el apacentamiento y conservar el ''Rough fescue.'' Este estudio determinó los efectos del matillo en pie en la selecció n y utilizació n de las plantas por el ganado en la primavera. Cuarenta plantas de ''Rough fescue'' fueron acondicionadas en otoñ o removiendo el mantillo en pie de ellas y se asignaron a 4 tratamientos en 10 bloques bajo un diseñ o de bloques completos al azar. Los tratamientos fueron: control (sin remoció n del mantillo) y remoció n del mantillo en pie a 14, 7 y 2.5 cm de altura del rastrojo remanente, este diseñ o se repitió usando separadamente dos potreros apacentados. Los datos noparamétricos de la se...