Assessment of zinc flow cycle in dairy buffalo: A case study on low input rural soil-plant-animal interaction in semi-arid zone of Telangana, India

Abstract

In dry areas, ruminants mainly graze on native grasses, crop residues and by-products of agro industry and suffer from mineral deficiencies. Present investigation was carried out to explain the zinc (Zn) flow in semi-arid resource driven areas, Kandlapally, Gangupalle and Yenkepally in Ranga Reddy district, Telangana, India in soil to soil through livestock cycle and suggest suitable measures to prevent its losses as well as alleviate Zn deficiency in dairy buffaloes. Ten farmers from each village rearing buffaloes were randomly selected for collection of samples (soil, plant, blood, faeces, urine and milk) and Zn of samples were analyzed with an atomic absorption spectrophotometer after suitable processing. It was observed that the 45% soil samples and most of the straws and stovers of the study area were classified as below critical level for Zn. Green fodder (Hybrid Napier Co-4 variety, Fodder sorghum, Grazing grass), tree leaves and concentrate ingredients were having sufficient Zn content. The buffalo serum Zn content in the samples were adequate, but 26.6% of the samples were having below critical level of Zn which suggests sizable amount of buffaloes suffering from Zn deficiency. Significant correlation values were obtained between feed and fodder and buffalo serum, however, such correlations were not observed between the mineral levels in buffalo and mineral levels in soil. Zn content in green fodder were more representative of soil, faeces and urine (R² = 0.267) than only soil (R² = 0.039) which suggests true recycling of nutrients through faeces and urine under rural semi-arid conditions. Based on soil, forage, feed, water and animal samples analyses, it was concluded that few sample was deficient in Zn, but animal was able to maintain the plasma Zn level to some extent (about 74%). Zinc homeostasis is largely regulated by its uptake and loss through the small intestine. Supplementation of Zn is required to overcome sub-clinical Zn deficiency mainly through feed fortification.