THE EFFECTS OF EITHER DIETARY ADDITIONS OR INTRARUMINAL INFUSION OF AMINES AND JUICE EXTRACTED FROM GRASS-SILAGE ON THE VOLUNTARY INTAKE OFSTEERS OFFERED GRASS-SILAGE

An experiment was carried out to assess the possible role of amines an d other end products of silage fermentation on food intake of steers. In total, 6 treatments were examined in a 9 period changeover design e xperiment with 4 steers, mean live weight 520 kg, fitted with rumen ca nnula. Each period was one week long. The 6 treatments comprised putre scine (P); cadaverine (C); gamma amino butyric acid (GABA); putrescine + cadaverine + gamma amino butyric acid (P + C + GABA); expressed jui ce from grass silage (S); water (W) control. These were either added t o the diet (D) or infused directly into the rumen (I). Amines were app lied at a rate of 2 g kg-l DM and were dissolved in water for infusion and addition to the diet. The basal diet consisted of a restricted fe rmentation grass silage, from which juice was expressed prior to feedi ng using a hydraulic press. Within each 7 day period, animals were off ered a standard siiage for the first 4 days following which treatments were applied for 3 days, with total dry matter intake recorded each d ay of the 3 day treatment period. On day 2, intakes were measured at 5 min intervals for the first 3 h following feeding and every 2 h for t he next 10 h. Dry matter intakes (g kg(-1) LW) for each of the treatme nts were as follows: 10.2 (W,I); 10.9 (W,D); 11.6 (S,I); 12.1 (S,D); 9 .0 (GABA,I); 10.5 (GABA,D); 10.8 (P,I); 10.4 (P,D); 12.2 (C,I); 10.4 ( C.D); 11.0 ([P + C + GABA],I); 10.3 ([P + C + GABA],D); SEM = 0.780. T hese results indicate that intraruminal infusion or dietary addition o f amines, GABA or silage juice at levels up to 2 g kg(-1) DM, had no s ignificant (P > 0.05) effect on the voluntary food intake of steers of fered grass silage.