Phosphorus deficiency is a common problem on dairy farms. It most often occurs in a subclinical form or follows an atypical course for this disease. The diagnosis of P (phosphorus) deficiency is only possible based on laboratory tests. The research objective was to explore the changes in red blood cell parameters over the course of subclinical phosphorus deficiency in dairy cows, and the possibility of using such information in early diagnosis. The study was performed on 35 cows (group I) with atypical clinical symptoms (pale mucous membranes and periodic problems with appetite) and subclinical phosphorus deficiency, and a group of 15 animals without clinical symptoms and with the correct concentration of inorganicnic phosphorus (Pi) in the blood. The results of the haematological and biochemical tests were statistically analysed using the Mann-Whitney rank test, Statistica 13 (StatSoft Poland). Before the treatment, a decrease in blood Pi concentration (1.34 ± 0.21 mmol l-1) and the significantly lower values of red blood cell parameters were observed in the study group as compared to the animals from the control group. The cows were diagnosed with hypochromic normocytic anaemia. Animals from group I were supplemented with phosphorus preparation (7.8 g P/100 ml, dipotassium phosphate, magnesium phosphate) for 3 weeks. After this period, the phosphorus concentration in the blood was recuperated and the red blood cell parameters (RBC 6.69±1.02 x1012 L-1, Hgb 94.33±11.93 g L-1, Htc 0.29±0.04 l L-1) increased significantly as compared to the first blood sampling (RBC 5.54±0.59 x1012 L-1, Hgb 78.33±10.61 g L-1, Htc 0.24±0.03 l L-1). Haematology examination is of prognostic significance regarding the occurrence of subclinical phosphorus deficiency in dairy cows and should be included in the panel of herd screening tests.

27.1.2022