Authors: NİHAT DENEK, SUPHİ DENİZ
Abstract: The objective of this study was to evaluate the effects of the addition of 0.5% urea or 0.5% urea plus 4% (w/w) molasses into corn varieties (Rx-947, 33-94, Frassino, and Arifiye) harvested at the early-milk stage on silage quality, in vitro digestibility and digestible dry matter (DM) yield. The addition of urea into silage increased the CP content (P < 0,05). The neutral detergent fiber and acid detergent fiber contents of the control silages were 69.40 and 38.68 for Rx-947, 69.34 and 38.69 for 33-94, 62.67 and 34.93 for Frassino, and 64.35 and 37.04 for Arifiye (P < 0,05). The addition of urea or urea plus molasses into silage increased the silage pH in all varieties, except for Rx-947 (P < 0,05). The lactic, acetic, propionic and butyric acid contents of the silage samples were between 23.2 and 153.3, 7.8 and 23.4, 0.6 and 1.6, and 0.0 and 0.54 g/kg DM, respectively. The addition of urea or urea and molasses into Rx-947 and Frassino varieties and the addition of urea only into the 33-94 variety increased silage lactic acid levels. The addition of urea and molasses into Rx-947, Frassino and Arifiye varieties also increased silage acetic acid levels (P < 0,05). There was a significant difference only between the Frassino and Arifiye varieties on this parameter (P < 0,05). The addition of urea only into silage decreased DM digestibility; the addition of molasses with urea, however, eliminated this negative effect of urea on digestibilit in all varieties, except for Frassino (P < 0,05). Digestible DM yields of untreated silage were 863.68, 1142.43, 1044.43, and 1075.07 kg/decare (10 decares = 1 hectare) for Rx-947, 33-94, Frassino and Arifiye, respectively (P < 0,05). The digestible DM yield of untreated Rx-947 silage was significantly lower than those of the others (P < 0,05). It can be concluded that corn varieties harvested at the early-milk stage (20% DM) can be ensiled, and that urea and molasses can be used as silage additive to increase CP and energy content of silages.
Keywords: Corn silage, urea and molasses addition, in vitro digestibility
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