Rumen fermentation in yearling rams fed different rations

V. Radev
Abstract. To establish the effect of different dietary lipid and protein content un rumen fermentation in yearling rams, three rations have been tested. The main component in them was ground barley and meadow hay (ration I), plus a different lipid and protein source – sunflower meal (ration II) or sunflower expeller (ration III). Rations were offered twice a day – at 8:00 AM and 1:00 PM. Nine Blackhead Pleven yearling rams, weighing 45.2 kg at the beginning of the experiment were divided into 3 groups of 3 animals each. Twenty days prior to the trial, the animals were fitted with cannulae of the dorsal rumen sac. Rumen content was sampled for 4 consecutive days, three times a day: before feeding, 2.5 h and 5 h after feeding. The following parameters were investigated: pH, ammonia concentrations and volatile fatty acid concentrations. The addition of 0.200 kg sunflower meal (ration II) and 0.200 kg sunflower expeller (ration III) to baseline ration consisting of 1.0 kg meadow hay and 0.8 kg barley mash did not alter significantly rumen pH of yearling rams. For all three rations, rumen pH decreased considerably (p<0.001) 2,5 hours after feeding.Feeding rations with sunflower meal or sunflower expeller resulted in increased rumen ammonia concentrations both before (p<0.001, p<0.01;), and after feeding (p<0.001, p<0.01). The highest levels of this parameter after feeding was observed for sunflower expeller ration. The total amount of volatile fatty acids in the rumen of experimental animals increased after feeding (p<0.05, p<0.01, p<0.001) for all rations tested. The relatively highest levels were established in the group fed sunflower meal-containing ration.