Variation in absorption and excretion of calcium in grazing sheep in a semi-arid grazing ranch, Punjab, Pakistan

The calcium status of lactating, non-lactating, and male sheep on farm in southwestern Punjab, Pakistan was studied. Pasture and animal were sampled at the end of the first month of summer and winter. All samplings were carried out fortnightly. A mineral supplement was available to all animals throughout the year. Plasma calcium in all animals was not affected by the physiologic state and gender as it was severely deficient in all classes of animals. The calcium concentrations of forage and plasma in all classes of sheep, and milk in lactating sheep were affected by the season (P<0.001). In the lactating sheep, the marginal deficient levels of calcium for requirement (1200-2600 mg/kg) in summer and moderate deficiency (1200-2600 mg/kg) for sheep requirement during winter were found. In non-lactating sheep, plasma calcium was moderately deficient during winter and marginally deficient in summer. In male sheep, plasma calcium level in summer was marginally deficient while plasma calcium during winter was moderately deficient. Soil and forage calcium concentrations were found within the same range during both seasons and showed a positive association between them (P<0.001). Based on these analyses, it was concluded that the calcium status of grazing sheep in this specific region needs supplementation with specifically tailored mixture to achieve the maximum potential of grazing sheep in this ranch.