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Cycletourist GIS of Moravian wine trails

100%

Jezek J.

nr 3-4

Age related changes and reference intervals of haematological variables in dairy calves

51%

Jezek J. , Nemec M. , Staric J. , Klinkon M.

2011

tom 55

nr 3

The aim of the study was to investigate the physiological pattern of haematological variables and to acquire reference intervals for calves in different age periods. Sixty-five Holstein Friesian calves from two dairy farms were serially sampled from birth to the age of 24 weeks. Red blood cell count (RBC), haemoglobin concentration (Hb), mean corpuscular volume (MCV), haematocrit (PCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), number of platelets (PLT), and white blood cell count (WBC) were measured in blood samples. The health status of the calves was monitored. The age influenced significantly the values of all haematological variables (P<0.001). The effect of farm was significant for RBC (P=0.048) and MCHC (P<0.001), other variables did not differ significantly between farms. The temporal dynamics of RBC, Hb, and PCV values was harmonised. A progressive reduction in the values occurred over the first weeks of life; the lowest values were established at the age of 5 to 6 weeks. The reference intervals of haematological variables were calculated for three age groups of calves; 1-4 weeks, 5-8 weeks, and 12-24 weeks of age.

Beta-hydroxybutyrate in milk as screening test for subclinical ketosis in dairy cows

38%

Jezek J. , Cincovic M. R. , Nemec M. , Belic B. , Djokovic R. , Klinkon M. , Staric J.

nr 3

Ketosis is a very frequent metabolic disease in dairy cows, resulting in lower milk production, impaired fertility and increased frequency of other diseases. The course of the disease is often subclinical, so early detection is very important. The aim of the study was to investigate the relation between the concentration of beta-hydroxybutyrate in blood and milk and to determine the cut-off value in milk for detection of subclinical ketosis. The study included 94 cows, which were in the first third of lactation. Beta-hydroxybutyrate (BHB) concentrations were measured in blood and milk serum using a biochemical analyser. The average concentration of BHB in the blood serum samples was 1.14 mmol/L while in the milk it was about ten times lower at 0.117 mmol/L. A statistically significant positive correlation between the concentration of BHB in blood and milk (r=0.705, p<0.001) was found. In cows with BHB in blood below 2.0 mmol/L a stronger correlation between blood and milk BHB was established (r=0.658, p<0.001) than in cows with blood BHB above 2.0 mmol/L (r=-0.292, p=0.206). Therefore, BHB in milk is a very suitable indicator in the diagnosis of subclinical ketosis as there is a good correlation between BHB in the blood and milk of cows with subclinical ketosis. The cut-off concentration of BHB in milk set at ≥0.080 mmol/L (AUC=0.91±0.03; p<0.001) is a significant indicator for subclinical ketosis in dairy cows. The sensitivity of the test was 94% and specificity 74%. Beta-hydroxybutyrate in milk is a good indicator of subclinical ketosis in dairy cows and can be measured accurately with a biochemical analyser.