Abstract: Ten, one-year old heifers with initial body weight at 150±10 kg were randomly divided into 2 groups according to receive concentrate at 14% CP (1 kg/head/day) + Ivermectin (T1), cassava hay (T2) (1 kg/head/ day) and means were compared using t-test. All animals were grazing on ruzi grass pasture. The results have revealed that supplementation of cassava hay as anthelmintics replace ivermectin was non significant affected to fecal parasitic egg counts and average daily gain in buffaloes grazing on ruzi grass pasture (p>0.05). In addition, fecal parasitic egg counts dramatically declined for both treatment groups with 60.5 and 50.6%, respectively. However, Average Daily Gain (ADG) tended to be higher in swamp buffaloes fed on groups cassava hay (T2) treatments than in those fed concentrate + ivermectin. However, digestion of coefficients of nutrients particularly organic matter was significantly higher in T2 than those in T1. It was, hence concluded that cassava hay could not only provide as a protein source but also high efficiency serve as an anthelmintics in heifer.