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-1 ) 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-1 and kg CP ha-1 were inconsistent across both sites, but significant differences returned for MJ ME ha-1 unlike kg CP ha-1 . 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.

Effect of feeding oat and vetch forages on milk production and quality in smallholder dairy farms in Central Kenya.

Despite the significant livestock contribution to households' nutrition and incomes in many African smallholder farms, milk productivity remains low. Inadequate feeding is the main reason for the underperformance. To contribute towards addressing this, an on-farm feeding trial was undertaken in Ol-joro-Orok Central Kenya. A feed basket using oat (Avena sativa) cv Conway and vetch (Vicia villosa) was compared to farmers practice. Milk production (kg) and quality parameters, including butterfat, protein, lactose, and density, were monitored, and cost-benefit analysis (CBA) undertaken. Feeding both oat and vetch increased milk production by 21% (morning) and 18%, (evening), equivalent to 1.4 kg/day. Increases (%) in quality were butter fat (18.2), solid-non-fat (16.5), lactose (16.2), and protein (16.1). Concomitantly, the CBA returned positive results, supporting the hypothesis of economic advantage in using oat and vetch in milk production in the area, and possibly in other similar areas.

Assessment of Napier grass accessions in lowland and highland tropical environments of East Africa: water stress indices, water use and water use efficiency.

BACKGROUND: Low rainfall is a major limitation to expanding the dairy industry in semi-arid environments in East Africa. In such dry areas, plants need to keep their tissues hydrated and stomata open for carbon exchange and to grow. On this basis, we assessed the productivity of 10 lines of Napier grass (Pennisetum purpureum Schum.), which formed three yield clusters: low yielding (LYC), moderate yielding (MYC), and high yielding (HYC), in a wet highland (Muguga) and semi-arid lowland (Katumani) of Kenya. Stomatal conductance (gs ), leaf water potential (LWP) and relative water content (RWC) were monitored, and water use simulated, over four growth cycles in 2012. These were used with measurements of leaf area index (LAI) and plant dry weight to explore the possible use of these physiological parameters for assessing productivity potential of Napier grass accessions. RESULTS: The plants were less stressed at Muguga, where gs was 700-1000 mmol m-2 s-1 , LWP -0.4 to -0.9 MPa and RWC was 82-95%; these values at Katumani were 450-750 mmol m-2 s-1 , -0.7 to -1.4 MPa and 74-93%, respectively. Total water use at Katumani was of the order HYC ≈ MYC (390 mm) > LYC (370 mm), and water use efficiency (WUE, kg ha-1 mm-1 ) followed the same order HYC (34.3) > MYC (32.6) > LYC (24.9); whereas at Muguga water use averaged 710 mm for HYC and MYC, greater than 676 mm for LYC, and WUE (kg ha-1 mm-1 ) averaged 29.2 for HYC and MYC, and 19.4 for LYC. CONCLUSIONS: The three water stress indices were poor, whereas vigorous early canopy development (determined as LAI) was a more reliable predictor of productivity potential of Napier grasses. In these dry environments, therefore, early rapid canopy development can be an effective indicator of yield potential and a credible selection criterion. © 2016 Society of Chemical Industry.