Abstract
Hypomagnesaemic tetany in lactating cattle is a partial dietary deficiency of Mg, but other nutritional or metabolic factors reduce the availability of Mg or increase its body loss. The aim of this study was to determine the biochemical changes and acute phase proteins response in serum of lactating cattle with hypomagnesaemic tetany. This investigation included 11 lactating cows suffered from nervous manifestations such as Nystagmus, muscular tremors, stiffness in gait and convulsion (hypomagnesaemic group) and 15 apparently healthy lactating cows (control group). One blood sample was collected from each cow in hypomagnesaemic and control groups. Total protein, albumin, glucose, liver and muscular enzymes, serum minerals including Ca, Mg, P, K, Na, Cl and acute phase proteins (APPs) including (Haptoglobin, serum amyloid A, C-reactive protein) were measured using commercially available test kits. The results revealed significant decreases in serum total protein, albumin and glucose in hypomagnesamic group. On the other hand, there were significant elevations in both hepatic and muscular enzymes activities including AST, ALT, GGT, CPK, LDH, and AP while serum electrolytes levels were variables. The diseased cattle showed significant hypomagnesaemia, hypocalcemia and hyperkalemia. There were highly significant increases in APPs in diseased cattle. It can be concluded that hypomagnesaemic tetany in cattle is a complex metabolic disorders associated with acute inflammatory response assessed by APPs, which could be used in the future as a prognostic indicators for such disease in cattle.

Key words: Acute phase proteins, biochemical parameters, hypomagnesaemic tetany, cattle