**3.2 Lactate Dehydrogenase (LDH)**

Enzyme LDH catalyse reversible oxidation of pyruvate to lactate. The enzyme is present in numerous organs and tissues.

The activity of LDH in calves increased slowly in the first 24 hours of life, from 421 U/L immediately after birth to 759 U/L at the age of 24 hours and it is more likely this is a physiological event than it is due to absorption from colostrum (Kurz & Willet, 1991). The LDH activity increased slowly to the age of 56 days, later it remains on the same level to the age of 84 days (Egli & Blum, 1998).

#### **3.3 Creatin Kinase (CK)**

The highest activity of CK is in the skeleton and heart musculature. Measuring of the activity of CK in serum is first of all used for diagnostics of skeleton musculature damage. The activity of CK could be increased also after effort, long-lasting lying of the animal or convulsions. Miopathias as the consequence of vitamin E and Selenium deficiency which usually appear in veal animals (calves, lambs), sometimes also in adult animals, cause increased activity of CK (Smith et al., 1994).

The activity of CK in calves is high after birth later it decreased rapidly and almost did not change to the age of 60 days, at the age of 80 days it increased slightly (Knowles et al., 2000).

of various studies differ (Hanschke & Schulz, 1982; Bouda & Jagoš, 1984; Steinhardt et al., 1993; Knowles et al., 2000 Mohri et al., 2007). The majority of data available is for the calves in the first days after birth, and for the calves of few weeks or months of age there is very few data available. The changing of values of biochemical variables in the first days of life is the consequence of adaptation on the extra uterine life and is importantly influenced by

The enzyme AST is present in different tissues and is a sensitive indicator of soft tissue damage. In heart and skeleton musculature as in liver there is high activity of AST. The AST is present in cytoplasm and in mitochondria so its activity is increased chiefly by cell necrosis in smaller amount also by damage of the cell membrane (Kraft & Dürr, 1999a). Measuring of AST activity in combination with CK is used for diagnostics of muscle damage (Kaneko, 1997). High activity of AST is also in liver and in the case of liver damage AST

After first colostrum intake the AST activity in serum increased from 23 U/L before intake, to 38 U/L at the age of 3 hours, what is most likely due to absorption from colostrum or because of activation of enzymes in calf intestine as consequence of colostrum intake (Kurz & Willet, 1991). However Hammon and Blum (1998) established that in calves which received only milk replacer instead of colostrum, activity of AST increased on the second day after birth so they are of the opinion that also other factors influence on the increased activity of some enzymes. The activity of AST decreased after the first week, and from 42nd to 84th day of life it increased slowly (Egli & Blum, 1998). Mohri et al. (2007) observed the

Enzyme LDH catalyse reversible oxidation of pyruvate to lactate. The enzyme is present in

The activity of LDH in calves increased slowly in the first 24 hours of life, from 421 U/L immediately after birth to 759 U/L at the age of 24 hours and it is more likely this is a physiological event than it is due to absorption from colostrum (Kurz & Willet, 1991). The LDH activity increased slowly to the age of 56 days, later it remains on the same level to the

The highest activity of CK is in the skeleton and heart musculature. Measuring of the activity of CK in serum is first of all used for diagnostics of skeleton musculature damage. The activity of CK could be increased also after effort, long-lasting lying of the animal or convulsions. Miopathias as the consequence of vitamin E and Selenium deficiency which usually appear in veal animals (calves, lambs), sometimes also in adult animals, cause

The activity of CK in calves is high after birth later it decreased rapidly and almost did not change to the age of 60 days, at the age of 80 days it increased slightly (Knowles et al., 2000).

maturation of organs and intake of nutrients.

increase of AST activity from the 14th to the 84th day of age.

**3.1 Aspartat Aminotransferase (AST)** 

activity in serum increase.

**3.2 Lactate Dehydrogenase (LDH)** 

age of 84 days (Egli & Blum, 1998).

increased activity of CK (Smith et al., 1994).

**3.3 Creatin Kinase (CK)** 

numerous organs and tissues.

The mean activity of CK in calves of Simmental breed was 11.2 ± 2 μkat/L (671.8 ± 119.9 U/L) at birth then it decreased to the age of 7 days and remained on this level to the age of 42 days, later it increased to the 84th day when it was 21.3 ± 10.7 μkat/L (1277.7 ± 641.8 U/L) (Egli & Blum, 1998). Increased activity of CK after birth could be associated with the parturition and adaptation to the extra uterine life which represent for the newborn calf an effort on which it was not used in intrauterine life. The increasing of CK activity with age could be attributed to the growth of calves and gaining of muscle mass, partly also to the increased activity of calves, at this age they are in group pens where they have enough space for movement.

### **3.4 Alkaline Phosphatase (ALP)**

For a long time the enzyme ALP is used in diagnostics as indicator of liver damage. The ALP is important also by diseases of skeleton. The enzyme was found in the intestine, liver, kidney and bones. In serum of young fast growing animals predominates isoenzyme from bones, in older animals which grow slower its activity decrease (Kaneko, 1997). Serum activity of ALP is higher in young animals than in adult ones and it decrease with age. After first colostrum intake serum activity of ALP increased from 235 U/L before intake to 364 U/L at the age of 3 hours, what is most likely due to absorption from colostrum and activation of enzymes in the calf's intestine because of colostrum intake (Kurz & Willet, 1991). The activity of ALP was high in calves after birth then it decreased and remained stable to the age of 60 days, later it decreased slightly more (Knowles et al., 2000). In calves to the age of 6 months the activity of ALP can reach 1800 U/L, in young cattle to the age of 3 years it decrease to 500 U/L (Kraft & Dürr, 1999a). In adult animals activity of ALP can increase at increased activity of osteoblasts. Activity of ALP is increased at acute and chronic liver diseases (especially cholestatic hepatopathias) and in diseases of bones (rachitis, periostitis)
