Assay of blood mineral profiles of dairy cows at various physiological status, seasons and production systems in two districts of east shoa zone, Oromia region, Ethiopia

This study was conducted in East Shoa Zone, Oromia Region, Ethiopia, to determine serum minerals of dairy cows at different season. The mineral assessed were Calcium (Ca), Magnesium (Mg), Phosphors (P), Iron (Fe), Copper (Cu), Cobalt (Co) and Zinc (Zn). The district and the production systems were selected purposively. A total of two hundred forty blood samples were collected. Blood serum was collected, digested and analyzed for minerals, using Atomic Absorption Spectrophotometer and Photoelectric colorimeter. The mean serum calcium level was 0.080 vs 0.082g/L for lactating and 0.090, vs 0.081gm/L for dry cows in both seasons, in Ada'a and Adama district, which was mean serum calcium level was very close to critical level (CL) or said to borderline. The mean serum phosphorus was 0.037vs 0.039 g/L) for lactating and 0.038 vs 0.037 gm/L for dry cows in both season in study districts. In general, in addition to Ca limited number of dairy cows were deficient for P, Cu and co. The difference in mean serum magnesium was significant (P<0.05) by production system, physiological state of the animals with seasons. Similarly, the difference in serum copper level was statistically significant (P<0.05) based on physiology of cows, production system and season. Iron serum concentration showed a significant difference (P< 0.05) by season, physiology and production system. In case of Zinc and cobalt serum concentration showed a significant difference (P<0.05) between production system, physiological stat and season. It could be concluded that in the study area most serum minerals of dairy cows were either below the critical level or very near to the critical level. The variation in serum level of measured mineral was also significant in many cases. Therefore, it is necessary to supplement these deficient minerals to the ration of dairy cows to improve production, productivity, health and reproduction efficiency.