The effects of either dietary additions or intraruminal infusion of amines and juice extracted from grass silage on the voluntary intake of steers offered grass silage

An experiment was carried out to assess the possible role of amines and other end products of silage fermentation on food intake of steers. In total, 6 treatments were examined in a 9 period changeover design experiment with 4 steers, mean live weight 520 kg, fitted with rumen cannula. Each period was one week long. The 6 treatments comprised putrescine (P); cadaverine (C); gamma amino butyric acid (GABA); putrescine + cadaverine + gamma amino butyric acid (P + C + GABA); expressed juice from grass silage (S); water (w) control. These were either added to the diet (D) or infused directly into the rumen (I). Amines were applied at a rate of 2 g kg−1 DM and were dissolved in water for infusion and addition to the diet. The basal diet consisted of a restricted fermentation grass silage, from which juice was expressed prior to feeding using a hydraulic press. Within each 7 day period, animals were offered a standard silage for the first 4 days following which treatments were applied for 3 days, with total dry matter intake recorded each day 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 the next 10 h. Dry matter intakes (g kg−1 LW) for each of the treatments 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. results indicate that intraruminal infusion or dietary addition of amines, GABA or silage juice at levels up to 2 g kg−1 DM, had no significant (P > 0.05) effect on the voluntary food intake of steers offered grass silage.