Ram J J, Atreja P P, Chopra R C, Chhabra A
Division of Dairy Cattle Nutrition, National Dairy Research Institute, Karnal, India.
Trop Anim Health Prod. 1994 Nov;26(4):199-206. doi: 10.1007/BF02240380.
Five Karan Swiss crossbred (Sahiwal x Brown Swiss) calves were abruptly switched over from a diet of concentrate and maize fodder to ad libitum air dried Leucaena leucocephala leaves plus twigs. After 17 days on the L. leucocephala diet, 3 of the calves were supplemented with copper sulphate (10 mg/kg DM L. leucocephala) for 12 days. Thereafter all the calves were taken off the L. leucocephala diet and returned to the pre-experimental concentrate and maize fodder diet. While on the L. leucocephala diet, the average DM intake/d of L. leucocephala declined to 497 g within 3 weeks and all calves lost weight. This weight loss was reversed in the 3 calves that received copper sulphate, and all calves gained weight when they resumed the concentrate and maize fodder diet. The toxic effects of L. leucocephala feeding for 24 days were characterised by poor growth, emaciation, alopecia, loss of hair from the tail switch, ear and eye lesions, ulceration of the mouth region, drooling viscid saliva and vomiting of thick green saliva in one of the calves. Mean levels of 3,4 dihydroxypyridone (DHP) (mg/100 ml) were 30.35 +/- 13.52 and 55.57 +/- 13.77 on days 2 and 4 respectively in rumen liquor and up to 136.01 +/- 80.18 in urine. The mean ratios of mimosine: DHP of 3.14, 0.12 and 0.04 in feed, faeces and urine respectively revealed extensive degradation of mimosine to DHP in the calves fed the L. leucocephala diet and it was concluded the calves were unable to tolerate a diet consisting solely of L. leucocephala.
五头卡兰瑞士杂交（萨希瓦尔×瑞士褐牛）犊牛突然从精饲料和玉米青贮饲料日粮转换为随意采食风干的银合欢叶加嫩枝。在采食银合欢日粮17天后，给其中3头犊牛补充硫酸铜（10毫克/千克干物质银合欢），持续12天。此后，所有犊牛停止采食银合欢日粮，恢复实验前的精饲料和玉米青贮饲料日粮。在采食银合欢日粮期间，3周内银合欢的平均干物质摄入量/天降至497克，所有犊牛体重减轻。在接受硫酸铜补充的3头犊牛中，体重减轻的情况得到逆转，并且所有犊牛在恢复精饲料和玉米青贮饲料日粮时体重增加。采食银合欢24天的毒性作用表现为生长缓慢、消瘦、脱毛、尾梢、耳部和眼部毛发脱落、口腔区域溃疡、流粘性唾液以及其中一头犊牛呕吐浓稠的绿色唾液。瘤胃液中3,4-二羟基吡啶酮（DHP）（毫克/100毫升）的平均水平在第2天和第4天分别为30.35±13.52和55.57±13.77，尿液中高达136.01±80.18。在采食银合欢日粮的犊牛中，饲料、粪便和尿液中含羞草素与DHP的平均比率分别为3.14、0.12和0.04，这表明含羞草素在犊牛体内大量降解为DHP，由此得出结论，犊牛无法耐受仅由银合欢组成的日粮。
