Does harvesting Urochloa and Megathyrsus forages at short intervals confer an advantage on cumulative dry matter yields and quality?

Background: Due to increasing demand for livestock products in sub-Saharan Africa, increasing livestock productivity is a priority. The core constraint is limited availability of feed of good quality. We assessed optimal harvesting time of three improved grasses, two Urochloa lines (Basilisk a selection from wild population, Cayman - a hybrid, a product of breeding) plus Mombasa, a Megathyrsus selection. All are released in Latin America and Kenya or in the registration in other regional countries. We assessed dry matter (DM) yields and quality at 4, 6, 8 and 12 weeks of age in two sites.

Results: DM yields (in t ha ) were of the order Cayman (9.6-14.3) > Mombasa (8.0-11.3) > Basilisk (5.5-10.2) in one site, and Cayman (6.4-9.7) > Basilisk (4.9-7.6) > Mombasa (3.3-5.9) at site two. The harvesting regimes produced DM largely similar for weeks 4 and 6, 6 and 8, 8 and 12. Across the sites quality was of the order Cayman > Mombasa > Basilisk for neutral detergent fiber (NDF), metabolizable energy (ME) and crude protein (CP). With increasing harvesting interval, MJ ME ha and kg CP ha were inconsistent across both sites, but significant differences returned for MJ ME ha unlike kg CP ha .

Conclusions: Harvesting at either 8 or 12 weeks is not recommendable as quality drops without an increase in DM yield that can compensate despite doubling and tripling time respectively, compared to 4 weeks. We recommend harvesting at 4 through 6 weeks for any of the three grasses based on yield against time, and demand at the intensified cut-and-carry smallholder systems. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.