Soil-plant-animal continuum in relation to macro and micro mineral status of Tswana sheep at Goodhope and Morale ranches in Botswana

Abstract

This study reports the concentration of macro and micro minerals in soil, forage, water and blood of Tswana sheep at Morale and Goodhope ranches. The main aim of the study was to evaluate mineral status of soil, forage, water and their absorption by sheep under the influence of season and site in relation to their critical requirement values. Soil, forage, water and blood plasma samples were collected from these two study sites once every' two months of wet (November to April) and dry (May to October) seasons. There was a significant (P<0.05) difference between the soil sampled from Goodhope and Morale ranches during the dry season on the concentration of Ca, Na, K, P, Zn, Cu and Fe, while during the wet season the difference between the two sites was on Ca, Mg, Na, K, P, Cu and Fc. Soils Ca, Mg, K, Mn, Zn, Cu, Fe concentration for both locations were found to be within the required range (250 mg/kg, 30mg/kg, I7mg/kg, 5mg/kg, 0.5mg/kg and 0.3mg/kg respectively) for growth of forage while Na and P concentrations were below' (62mg/kg and 17mg/kg) the forage growth requirement. There was a significant (P<0.05) difference between the forage sampled from Goodhope and Morale ranches during the dry season on the concentration of Mg, Na, K, P, Mn, Zn, Cu and Fe, while during the wet season the difference between the two sites was on Na, K, P, Mn, Zn and Fe. In water only Na was Influenced (P<0.05) by interaction of site and season. Forage K, Mn, Zn and Fe were within critical levels (0.60%, 20ppm, 30ppm, and 50ppm) respectively while Ca, Mg, Na, P, and Cu were below the sheep necessary requirement (0.35%, 0.20%, 0.08%, 0.25%, and 8ppm respectively. There was no noticeable difference (P>0.05) in plasma Ca, Mg, K, Na, Mn, Zn, Fe and Cu concentration between yearling sheep of Morale and of Goodhope ranches during wet and dry season. Plasma K and Fe for adult sheep in Goodhope ranch were influenced (P<0.05) by age during wet season, while plasma Ca, Mg, Na, Mn, Zn and Cu were not influenced (P>0.05). Age had a noteworthy effect (P<0.05) on plasma Na and Cu during the dry season of Goodhope ranch while plasma Ca, Mg, K, Mn, Zn and Fe were not influenced (P>0.05). There was a significant difference (P<0.05) on the concentration of Ca, Na, K, Mn, Zn and Cu for yearling sheep at Goodhope ranch between wet and dry season. At Morale ranch only K, Mn, Zn and Cu showed a noteworthy difference (P<0.05) on yearling sheep between wet and dry season. In Goodhope ranch Ca, Na, K, Mn, Zn and Cu minerals concentration for adult sheep were significantly different (P<0.05) between wet and dry’ season, while in Morale ranch the difference (P<0.05) was observed on Mn, Cu and Fc. Blood Ca and Mg were not within the adult and yearling sheep requirement (80mg/l and 20 mg/l respectively) hence supplementation was necessary.