NR 05. Mineral content in soil, herbage and blood serum of holstein cows in grazing Acatlan, Hidalgo, Mexico

Samples of soil, herbage and blood serum of grazing dairy cattle were taken with the objective of assessing mineral status of two ranches Santa Fe and Canutillo located at Acatlán, Hidalgo, Mexico. Dependent variables were concentrations of Ca, P, K, Mg, Na, Cu, Fe and Zn in soil, herbage and blood serum and in situ digestibility of herbage. Information was gathered on herbage disappearance rate, herbage utilization, daily herbage allowance and herbage intake. Mineral content in soils was above requirements for growth plant excepting K at Santa Fe and Na at Canutillo. No differences were found (P > .05) at Santa Fe between mineral content in soils of paddocks with alfalfa (Medicago sativa L.) and paddocks with ryegrass (Lolium perenne L.) clover (Trifolium repens L.) cocksfoot (Dactylis glomerata L.) pastures. At Canutillo, P, Mg, K, Fe, Cu, and Zn contents in soil were higher and Ca content lower (P < .05) in the lowlands than in the hills. At Santa Fe, Ca, Mg, Fe, Zn and Cu contents in herbage were below requirements, while P, Na and K were above normal. At Canutillo, Fe and Zn contents in herbage were normal, while Ca, P, Mg, Na, K, and Cu contents were high. Blood serum was deficient in P and K at Santa Fe and Ca and P at Canutillo. No differences were found (P>.05) between mineral concentration in blood serum of pregnant and non pregnant cows, with the exception of K which was higher (P<.05) in pregnant cows. Comparing cows at different physiological stages at Canutillo, Cu content in blood serum of primiparous cows at the end of lactation was highest (P<.05) and that for multiparous cows 15 days before calving was lowest (P<.05)