EFFECTS OF ROUGHAGE TYPE OR ADDED BENTONITE IN MAINTAINING FAT TEST

Four groups of five cows each were fed the following experimental rations having a grain to dry-roughage ratio of 3 to 1 for an eight-week period: Group I, hay + pelleted concentrate, Group II, same as Group I with addition of 5% sodium bentonite to the pelleted concentrate, Group III, corn silage + pelleted concentrate, Group IV, same as Group III, except for the addition of calcium lactate (equivalent to 5% of silage dry matter as lactic acid) to corn silage. The standard fat-depressing ration based on hay (Ration I) maintained fat test at 50% of normal. Addition of bentonite (Ration II) maintained test at 80% of normal (P < .05). This was accompanied by a higher rumen acetate/propionate ratio and greater mammary uptake of acetate. Rations III (corn silage) and IV (corn silage + lactate) maintained test at 70 and 50% of normal, respectively. © 1969, American Dairy Science Association. All rights reserved.