Dietary and serum biochemical analyses in a dairy herd with increased acidity of fresh milk

摘要: A Holstein dairy herd consisted of 24 adult lactating cows in their fourth and fifth lactation was investigated for increased acidity of bulk tank milk. The ration consisted of corn silage, coarse dry grass hay, and a grain mix of ground ear corn, soybean meal, rumen buffer, and yeast. Results of dietary analysis and analysis of various serum biochemistry parameters in 10 cows are presented in this report. Ration analysis of lactating cows showed a high fiber, low protein contents. Moreover, the ration contained lower levels of phosphorus, calcium, and magnesium and higher levels of potassium. The bulk tank fresh milk was on the acidic side of the pH meter. Serum biochemical analysis of a representative sample of cows showed that serum concentrations of phosphorus, total calcium, ionized calcium and magnesium were situated at the lower edge of the normal range. Ration analysis and serum biochemical parameters in cows with increased bulk tank acidity is being reported here for the first time as well as a possible association between increased milk acidity and hypocalcaemia (milk fever) in Holstein dairy cows.