Introduction

At or near the time of parturition, the onset of lactation result in the

sudden loss of calcium through milk. Serum calcium level decline from a

normal of 9 12ـ mg/dl to 2 7ـ mg/dl. Serum magnesium is increased,

serum phosphorus is decreased. occur after parturition according to the

State of Food, more than 20.0% of cows develop post-pt paresis every

year. At the time of pt some changes in hormone balance take place,

resorption of nutritional materials from the digestive tract becomes

slower and intensive synthesis of colostrum starts. These changes cause

sudden decrease of calcium (Ca) and inorganic phosphorus (P) in serum.

On the other hand, the cow is not capable of complet exploiting its

endogenic reserves of calcium (Goff et al., 2005; Kurosaki et al., 2007).

The shortage of Ca and P causes changes in cell membrane permeability

impairing muscle contraction,

which results in muscle paresis. Paresis is observed in 10% of pt and

post-pt cows. Clinical hypocalcaemia often causes decrease of inorganic

P, therefore more than 20% of post-pt cows with paresis develop

recumbent cow syndrome (Menard and Thompson, 2007).

Materials & methods

1 -Animals study: 20 head of cows during the last months of pregnancy, and after giving birth for 14days .

several materials of blood collection : which include: 2- A . medical syringes . B . Tubes EDTA (Ethylene Diamine Tetracyclic Acid) containing

anti- clotting material to collect and save non- coagulant blood samples for the purpose of transferring the samples to the

laboratory for testing . C . Sterile solution ( iodine) and cotton .

D . Tubes (Eppendrof tubes) for the purpose of collecting and preserving serum resulting from the separation of blood samples by centrifuge.

E . Centrifuge (Centrifuge) for the purpose of separating serum (3000 r / min ) .

F . Test tubes (Test tubes) clean and sterile . 3 -Devices :

A . Burette and a pipette (Pipette) to adjust the measurement of additives

B. water bath (water bath) . C . device (Semiautomatic Chemistry Analyzer) to read the results

4 -several ready-made for the examination to measure all metal : A . Examine several calcium (CPC method) was used packaging from

this company (BIOLABO REAGENT) consisting of : * The first bomb detector (Vail R1) containing buffer solution

(Buffer). * The second bomb detector (Vail R2) on the container

(Chromogen) . * The third bomb detector (Vail R3) containing anti- clotting

substance (EDTA). * Explosive detector fourth (Vail R4) containing standard solution

(Standard)-Ca Kit .

B . Examined several magnesium (Colorimetric test.Calmagite- EGTA.) Been using this package from the company CYPRESS

DIAGNOSTICS) consisting of : * First Reagent (Reagent 1) on the container (Chromogen) . * The second reagent (Reagent 2) containing buffer solution (Buffer). * Standard solution (Standard)-Mg Kit .

C . Several screening phosphorus (UV-test. Phosphmolybdate.) Been using this package from a company (CYPRESS DIAGNOSTICS)

consisting of : * First Reagent (Reagent 1) . * Standard solution (Standard) - P Kit .

5 -Ways of working : 1 . Collection of 20 sample of blood from cows during last month of

pregnancy and after giving birth for 14day ,from the mishkab , by using syringes (Disposable syringe) withdraw (10ml) of the jugular vein and collected in test tubes container on anti- clotting substance (EDTA) and then transferred to the laboratory. And then using a centrifuge (Centrifuge) 3000 r / min for 10 minutes each were separated serum sample collected in tubes (Eppendrof tubes) and preserved frozen in (Deep freeze) until conducting the

necessary tests . 2 . Examination of calcium (CPC method): by (Calcium Kit) with

the addition (1ml) of Reagent to all tubes (Blank, Standard, & Assay) and added (25ML)of Demineralized water to the tube (Blank) only. and (25uL)of the standard solution to the tube (standard) only. and then add( 25uL) of Specimen to the tubes (Assay) only.

Mix all well and incubated for 5 minutes at room temperature and then read by semiautomatic chemistry Analyzer for all the tubes (Blank, Standard, & Assay tubes).

3 . Examination of magnesium (Colorimetric test. Calmagite EGTA) by (Magnesium Kit) with the addition(1ml) of (Working Reagent) to all pipes used in the test (Blank, Standard, & Assay). and added ( 10uL)of standard solution to the tube (Standard) only , then add(10uL)of serum sample to test tubes samples only .

Mix all well and incubated for 5 minutes at room temperature and then read by Semiautomatic Chemistry Analyzer for all pipes (Blank, Standard, & Sample tubes).

4 . Examination phosphorus (UV-test. Phosphmolybdate.) By (Phosphorus Kit) with the addition (1 ml) of (Reagent 1) to all the pipes used in the test (Blank, Standard, & Sample tubes). and added(10uL) of standard solution to the tube (Standard) only , and then add (10uL)of serum sample to the test tubes samples only. Mix all well and incubated for 5 min at 37 ° C, and then read by Semiautomatic Chemistry Analyzer for all pipes (Blank, Standerd, &

Sample tubes) .

Semiautomatic Chemistry Analyzer (cyanstar)

Results

Table (1) : Comparison between mineral change in cow at prepartum and postpartum period.

PostpartumPrepartumMinerals

3.13.93.84.03.9

5.76.16.37.06.2

Phosphorus

1.31.31.24.13.9

1.21.31.21.21.2

Magnesium

6.15.33.74.13.1

10.49.79.09.59.4

Calcium

Discussion

The P demands for maintenance and lactation were met instead by

mobilized P from bone and soft tissue. Bone was mobilized in response

to a need for Ca in the animal due to the insufficient amount of absorbed

dietary Ca to meet the Ca demand for milk production. Ca was mobilized

from bone to meet the Ca demand and that bone P was released

regardless of P supply under effect of parathyroid hormone. In both

Kronqvist, C., Emanuelson, U.,and Holtenius, K. (2011).a , a transient

increase in plasma magnesium level was found shortly after calving.

This has also been reported in other studies (Goff and Horst, 1997; Green

et al., 1981), and results from Thilsing-Hansen et al. (2002a) and Goff et

al. (2002) indicate that the increase in magnesium is related to the

decrease in plasma calcium level occurring at calving. The reason for this

has been suggested to be the elevated renal threshold for calcium when

parathyroid hormone is excreted as a response to the decrease in plasma

calcium level, resulting in a similar increase in the renal threshold for

magnesium (Goff, 2008). Results from Taylor et al. (2008) suggest that

there may be an effect of parathyroid hormone levels at calving on the

concentration of plasma magnesium. However, in Paper IV, urinary

excretion of magnesium was not decreased, even though urinary calcium

excretion decreased immediately after calving. As the concentration of

magnesium in plasma is very low compared with the concentration of

intracellular magnesium, the results from Paper IV may suggest that the

peak in magnesium occurring at calving may depend on movements of

magnesium between the intracellular and extracellular compartment,

rather than on decreased excretion. At 7 days after calving, plasma

magnesium had returned to prepartum levels in Kronqvist, C.,

Emanuelson, U., Spörndly, R. and Holtenius, K. (2011).

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