Abstract 281

Panditharatne,-S; Allen,-VG; Fontenot,-JP; Jayasuriya,MCN

Peradeniya Univ., Peradeniya, Sri Lanka.

Journal-of-Animal-Science. 1986, 63: 1, 197-207; 22 ref.

Three trials were conducted in Sri Lanka to study the effects of growth stage, chopping length and additives on ensiling characteristics of Panicum maximum cv. Guinea-A and Pennisetum purpureum X P. americanum cv. NB-21. In the 1st trial the grasses were harvested 1, 2 and 3 weeks after cutting to 12.5 cm height, chopped and ensiled in small laboratory silos (3-litre cardboard cylinders double-lined with polyethylene bags) alone or with addition of cassava tuber meal (5%, wet basis), coconut oil meal (5%, wet basis) or formic acid (3%, dry basis). Guinea-A contained an av. of 2.3% N and 70.6% NDF; NB-21 contained 3.8% N and 65.9% NDF. Acetic acid concn of silage was lowest when grasses were harvested after 1 week of growth. Addition of cassava tuber meal or coconut oil meal decreased pH and increased lactic acid concn of the silages. The effects were greater for cassava tuber meal. Formic acid did not affect ensiling characteristics compared with the control. In a 2nd trial, Guinea-A was harvested 3 weeks after cutting, chopped into 3 lengths (1.5, 7.5 and 15 cm) and ensiled in small silos. Lactic and acetic acid concn of silages increased whereas DM loss and pH decreased with fineness of chop. In a 3rd trial, 2- and 3-week growths of Guinea-A were harvested and ensiled in 210-litre metal drums, double-lined with polyethylene, chopped (1.5 cm) or unchopped. Cutting grass at 2 weeks decreased pH and increased lactic acid concn compared with cutting at 3 weeks. DM loss was lower for chopped silage. Chopping decreased pH and increased lactic acid concn of silage.