This study is part of a research project entitled “Sustentability of milk cattle production into the agriculture family systems in the Amazon eastern region” developed by Embrapa with objective to evaluate problems envolving small and medium farms in the micro-region of Castanhal (local 1) and in the county of Uruará (local 2), State of Para, Brazil. The objectives of this research were define the features and effected the mineral supplementation, analyze the mineral content of forage (Brachiaria brizantha cv. Marandu) planted in two different regions during the dry and rainy season of the year and identified the practical factors of restriction of mineral nutrition management used by farmers. There were developed two studies, in the first were study the localities using the questionnaire/interview methodology when defined the features that define the mineral supplementation used in the both locals. The dates gotten by questionnaire/interview permited obtain twenty-two important variables that were grouped in four main groups to characterize the practical management of mineral supplementation used in the two different locals. There was used descriptive statistic and the Qui-square test at 5% of probability for determination of the degree of significance when the different locals variables were compared. In the second study the pastures (Brachiaria brizantha cv. Marandu) in two locals samples of forage were harvested in two different periods of the year, end of dry season (November of 1998) and end of rainy season (June of 1999) with objective to analyses the calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), cupper (Cu), zinc (Zn), iron (Fe), manganese (Mg) and cobalt (Co). A casual randomized design was used to compare the regions (local 1 and local 2) and for seasons (dry and rainy) was used a sub-plots design. The variance analyses was carried by the method of minimum square and the test of Fisher (F) was used to obtain the significance considering 5% as probability of effect. The Tukey’s test was used to compared the medium values. That was observed for both properties a high cost of mineral mixture used by farmers and this means an important significance in the economic costs for cows during the lactation period. In the local 1, Brachiaria brizantha cv. Marandu did not attempt the P, Na, Cu and Zn requirements for dairy cows during the lactation period and this is an indicative to procedure the mineral supplementation in a mineral feeder. The milk production is important for the economy of this region and farmers have problems to understand how in important supply different mineral mixtures for animals in different stages of production. Particularly in this micro-region was observed low concentration of P in the forage during the rainy season and this observation disagree from the other experiments concluded in this region, and can be an important problem during this period when the forage is more available and the level of protein and energy in the animal diet is high than an more intensive P imbalance can be present and this evidence is one more important feature responsible for low productivity of livestock. In the local 2, Brachiaria brizantha cv. Marandu did not attempt the P, Na and Cu requirements proposed by NRC (1996) for beef cattle, cows during the lactation period what indicated the importance to procedure the mineral supplementation in a mineral feeder. In this region was observed a low intake of mineral supplement and the condition of mineral feeder was neglected. The location of mineral feeder inside the enclosure, the limitation of animal access permited only during the milking activities were problems that indicated the reason to low intake of mineral supplement by cows. It was indicated a change of this management for one system that provide the mineral supplementation as the cows requirement. The main anormality frequency observed was abnormal appetite that was characterized when another problems were related which ould be characterized in reproduction problems, loss of appetite, bone abnormalities, and low body weight of the animals. These problems were more intensive when clinical deficiency of P and Cu were suggested.
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