Blood Studies of Louisiana Dairy Cows. II. Calcium, Inorganic Phosphorus, Hemoglobin Value, Erythrocyte Count, Leucocyte Count and Differential Leucocyte Percentages

Abstract

Summary Variations in the blood picture of high-producing dairy animals in two separate herds which were fed and managed better than average are presented. Also included is the blood picture of low-producing animals of an experimental herd which were on a basal diet containing poor quality hay as the only source of roughage, supplemented with either calcium or phosphorus, both calcium and phosphorus, or neither of these minerals. Analyses were made on pooled citrated blood drawn on three consecutive days from 38 to 46 animals either monthly or bi-monthly over a period of approximately two years. A statistical analysis of 773 determinations for calcium and phosphorus and 613 observations for hemoglobin, erythrocyte count, leucocyte count, and differential leucocyte percentages was made. Using the analysis of variance it was found that significant differences existed between animals in a herd and between months (within animals) for calcium and phosphorus values. There were significant differences between months (within animals) in a herd for hemoglobin values, and between animals for the leucocyte count. No significant seasonal variations were found. Only low and nonsignificant correlations were found between either calcium or phosphorus and the hemoglobin value, erythrocyte, or leucocyte counts. Significant differences were found between herds for hemoglobin content, erythrocyte count, leucocyte count, percentages of lymphocytes, neutrophiles and monocytes. Poor quality hay in the ration of the experimental herd did not seem to influence the blood calcium content or amounts of the various cellular constituents, but the phosphorus and hemoglobin values were significantly different from those of the other herds. The range of means and their standard errors for the herds were as follows: