New Hampshire on which cobalt deficiency had been troublesome in cattle 

 the previous winter. 



Only one of the low-cobalt animals developed severe, cobalt deficiency 

 symptoms, but the others were borderline cases. In spite of a lack of severe 

 cases of the deficiency, those animals which received cobalt gained on the 

 average two and a half times as much in weight as those which did not re- 

 ceive supplemental cobalt. Feed and water consumption were found to be 

 depressed by the deficiency just as they were in the field studies. It was 

 concluded that cobalt deficiency can be produced by feeding low cobalt hay. 

 such as found in New Hampshire, and that the effects of even a borderline 

 deficiency are of considerable importance. 



A Study of the Function of Cobalt in Ruminant Nutrition 



Having established the. existence of cobalt deficiency in New Hampshire, 

 the next step was to determine just how cobalt functions in the nutrition of 

 the ruminant. It had been observed for several years that cobalt deficiency 

 did not appear to affect non-ruminants. It also had been reported that co- 

 balt fed to a deficient animal was much more effective in correcting the 

 deficiency than that injected into the blood stream. From those two observa- 

 tions it was deduced that cobalt is essential for the. synthesis of some sort 

 of nutritional factor by the flora of the rumen. 



In order to learn more about the role of cobalt in the nutrition of rumi- 

 nants, a second experiment was carried out with sheep. This experiment 

 started with 10 pairs of yearling lambs and 10 unpaired animals. One mem- 

 ber of each pair was given 3^ mg. of cobalt twice a week as a drench. The 

 remainder did not receive any supplemental cobalt until after cobalt deficiency 

 symptoms had developed. The sheep were fed a concentrate mixture composed 

 of nine parts of a low-cobalt corn obtained from North Carolina and one 

 part of skim milk powder and a low-cobalt grass hay which was purchased 

 several miles west of Durham. This experiment started in March. 1948. and 

 continued for 64 weeks. 



Every animal fed the deficient ration without supplemental cobalt de- 

 veloped marked cobalt deficiency symptoms before the experiment was termi- 

 nated. Every one of the 10 animals which were given cobalt remained 

 healthy in every respect. At the time the first treatment was given to the 

 deficient animals, the cobalt supplemented animals had gained nearly 7 times 

 as much in body weight, were eating 5 times as much concentrates, 6 times 

 as much hay, and were drinking twice as much water as the deficient ani- 

 mals. Wool production of the deficient sheep was approximately 62 percent 

 that of those which were given cobalt. 



Cobalt sulfate when fed to the deficient sheep corrected the deficiency 

 in every case. When injected intravenously cobalt sulfate brought about a 

 response, if large enough amounts were given over a long enough period. The 

 first indications of response, however, were slow in coming. Cobalt car- 

 bonate, a compound which is relatively insoluble in water, also was found 

 to be effective in relieving the deficiency. It was not possible to correct the 

 deficiency by the use of vitamins, other trace elements, certain amino acids. 

 liver extract, fresh rumen liquid from a cow, or fresh raw milk. This work 

 indicated that cobalt was essential for the production of some unidentified 

 nutritional factor in the rumen. 



10 



