The sheep on the left received supp'emental cobalt. The one on the right received none. 

 Notice the difference in size of the sheep and the condition of the fleece. 



Cobalt Added to Dairy and Livestock Rations 



Shortly after it became evident that cobalt deficiency was having a marked 

 effect on the health of cattle, sheep, and goats throughout New Hampshire, 

 most feed manufacturers operating in this part of the. country started to 

 add cobalt to their mixed feeds for ruminants. The amount used was approxi- 

 mately two grams of cobalt sulphate per ton of feed. The cost to the feeder 

 ranged from nothing to five or six cents per ton of feed. This practice 

 practically eliminated cobalt deficiency from New Hampshire within a period 

 of a few months. Since that time a few cases of the deficiencv have been 

 observed when concentrates were not being fed or when the concentrate 

 mixture did not contain added cobalt. A few cases also have been observed in 

 which animals have benefitted from receiving more cobalt than is included 

 in the grain ration, but such cases have been very rare. It appears that the 

 benefit of cobalt in such cases may come from a stimulating effect on ru- 

 men activity. 



Laboratory Studies with Livestock 



Cobalt Tolerance Studies with Young Dairy Cattle 



When it became apparent that cobalt might be used rather widely to 

 correct or prevent cobalt deficiency, the question of just how much cobalt 

 an animal could consume without harmful effects was raised. Because very 

 little information on this subject was available, studies on this problem were 

 started in September. 1944. 



The experimental animals used were Holstein calves. Some animals re- 

 ceived relativelv large amounts of cobalt every day for periods of over a 

 year in length. In general cobalt was fed in proportion to body weight in 

 order to allow for growth. The effects of feeding large, amounts of cobalt were 

 determined by means of the effect on growth, appetite, and the hemoglobin 

 and packed red-cell volume of the blood. Many of the animals were 

 slaughtered at the end of the experiment and the amount of cobalt stored in 

 certain body tissues was determined. 



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