Concentrations of Certain Minerals in the Blood and Livers of Cattle as Related to Trace Mineral Supplementation and Bovine Brucellosis

Open Access
Publisher Website
Google Scholar
Abstract
In a study by Hart et al. (7) it was concluded that, "A high plane of nutri- tion, involving the feeding of alfalfa hay, minerals, cod liver oil and iodized salt, had no effect whatever in developing a resistance in cattle to Brucella abortus, as compared with a ration of lower protein content, supplemented with common salt, but no other minerals." More recently, however, some trace minerals which were not specifically considered by Hart et at. have been reported to have thera- peutic value in both bovine brucellosis and undulant fever in humans (20). The study reported herein was undertaken to determine whether cattle which were fed a practical dairy ration had lower concentrations of trace minerals in their tissues and organs than cattle which received a similar ration supplemented with trace minerals. A possible correlation between an active infection with Br. abortus and trace mineral concentrations in the livers of the cattle was also investigated. EXPERIMENTAL A large scale brucellosis study conducted at this station (3, 4) involved five experimental groups of approximately 20 Holstein cows per group. All groups were maintained throughout the experimental period on a practical dairy ration composed of either mixed legume hay or legume hay and corn silage, together with a grain mixture which was fed at the rate of 5 to 6 lb. daily, except in periods of lactation, during which time the cows received 10 to 12 lb. of grain per day. The percentage composition of the grain mixture was : whole oats, 19 ; corn or wheat, 48; bran, 17.5; soybean oil meal, 15; and iodized salt, 0.5. Only one of the groups of cows received a trace-mineral supplement which was mixed with 99 parts of the grain mixture to one part of a mineral mix composed of the following proportions of salts: Techmangam (product of Tennessee Eastman, containing 65 to 67 per cent MnSO4, 100 ; CuSo4, 1.0 ; CoSQ, 1.5 ; ZnSO4, 0.5 ; and lVIgSO~, 3.0. Of the cattle which received no trace-mineral supplement, all except one group were vaccinated against brucella infection with strain 19 at various ~imes. Cattle in the trace-mineral-su pplemented group were not vaccinated. For details concerning the exposure of all animals to brucellosis by the instilla- tion of 12 × l0 s Br. abortus organisms in January, 1950, see Berman et al. (3).

This publication has 11 references indexed in Scilit: