Effects of cutting dates on nutritive value of Napi er (Pennisetum purpureum) grass planted sole and in association with Desmodium (Desmodium intortum) or Lablab (Lablab purpureus)

Abstract

The experiment was conducted at Pawe Agricultural Research Center located Northwestern Ethiopia to ass ess the effects of days at cutting on nutrient yield and quality of Napier grass ( Pennisetum purpureum ) planted sole and in association with desmodium ( Desmodium intortum ) or lablab ( Lablab purpureus ). The experimental design was a split plot design with three cutting dates (60, 90 and 120 days from planting) as main plots and five plant associations , namely, Napier grass sole, desmodium sole, lablab sole, Napier gra ss / desmodium and Napier grass / lablab associatio ns as subplots. The 15 treatments were replicated thrice. Significant (P<0.01) effects of days at cutting, pl ant associations and their interactions was observe d on crude protein yield (CPY), in vitro organic matter digestibility (IVOMD), content of C P, neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ash and h emicellulose. The CPY, NDF, ADF, ADL and hemicellulose increased significantly (P<0.01), whereas CP, ash a nd IVOMD decreased significantly (P<0.01) with advance in plant maturity. The CP content of all the treatments (inc luding the factors and their interaction) was above the minimum level of 7% required for optimum rumen function. Cutting Napier grass and the legume associations at 60 and 90 days could also satisfy the minimum CP contents of 15% required for lactation and growth. Relatively high IVOMD values of 71.9, 68.0 and 63.5% were respectively obtained at 60, 90 and 120 days of cutting for the Napier grass/ labl ab association. Digestible organic matter yield (DOMY) was maximum at 120 days of cutting. It was concluded that the association of Napier gra ss with both legume species generally improved the nutritive value of Napier grass, however, better results were obtained for the parameters of nutritive value considered i n the study when Napier grass was planted in association with lablab for all cutting days.