An investigation into the mineral status, especially phosphorus, of cattle not offered licks, feeding exclusively in the communal grazing areas of Mogosane village, Molopo district, North West Province

Abstract

Twenty-five animals that were randomly selected on the basis of sex and age from among the animals feeding exclusively on communal grazing in Mogosane village and were used to investigate the mineral (P, Ca and Mg) status, especially P, based on blood and faecal P and to estimate the quantity of P they consumed from the pasture they were grazing. The project was conducted in the same area each month for one year, and no supplement was given. Months were blocks and seasonal changes were factors and the animals were experimental units within a block. Faecal, blood and grass samples were used as indicators of P, Ca and Mg minerals within experimental units, and Analysis of Variance was done to determine whether the P status of native pastures had a significant effect on the total P, Ca and Mg utilization and movement in and out of the blood and throughout the faeces during different periods the year. Body mass, condition scores and rainfall were also recorded during this trial. When the mineral status was investigated in this trial, it was found that mineral content in blood and faeces was directly related to the minerals in the pasture since these indicators were curvilinear increasing from winter months to spring months peaking in summer months with highly (P< 0.05) significant values when grazing was best and declining as the grazing became worse during autumn and winter months. The values of the body condition of the animals increased and declined with the values of body mass. Blood P concentration was very inconsistent and varied greatly and did not follow the same increasing and decreasing pattern followed by faeces and the grass. This emphasizes the fact that the P content of blood is not always good indicator of the P status in the animal. The mean faecal P concentration during winter was lower with the value of 1.23 ± 0.13 mg/g, during spring was low with the value of 1.8 ± 0.06 mg/g, during summer was higher with the value of 3.22 ± 0.12 mg/g and during autumn was high with the value of 1.98 ± 1.04 mg/g. The mean concentration of P in the grass during winter was lower with the value of 0.92 ± 0.04 mg/g, during spring was low with the value of 1.16 ± 0.08 mg/g, during summer was higher with the value of 1.68 ± 0.06 mg/g and during autumn was high with the value of 1.22 ± 0.09 mg/g. The seasonal rainfall correlated with the faecal and grass P values vary much with the value of 0 mm in the winter season, with the value of 26.33 mm in the spring, the value of 90.4 mm during summer and the value of 44.83 mm during autumn. Condition scores and body masses had the values of 2.08 units/201.4 Kg during winter season, had the values of 3.07 units/272.29 Kg in spring season, had the values of 3.88 units/371 Kg during summer season and the values of2.75 units/286.65 during autumn season, respectively.