Magnesiumintagets betydelse för blodtryck och magnesiumkoncentrationen i stickprov av urin, träck och blodplasma hos häst
HästMagnesiumMagnesiumbristHypomagnesemiUrinTräckBlodtryckBlodprovHorseHypomagnesemiaIntakeUrineFecesBlood pressureSample
The purpose of this trial was to evaluate the possibility to use sampling of faeces, urine and plasma, and measurements of blood pressure as methods of discovering hypomagnesemia in horses, as well as the application handiness of these methods. The most commonly used method of checking the magnesium status of a horse is to analyze samples of serum or plasma. The trial was of a switch-back design, in which the horses were used as their own controls. The animal material was five Swedish warm blooded trotters between six to ten years old, and weighing between 485-620 kg. The trial consisted of three periods that were two months each. In period 1 and period 3, the horses were given a diet that completely covered their daily need for magnesium, and in period 2 they were put in a mild deficit of magnesium through a diet that only covered 50-60% of their daily need of magnesium. The horses were fed a haylage with low magnesium content, and a concentrate that had been made especially for the trial. Samples were taken of the haylage fed to the horses, as well as of the water they drank, to be able to estimate the magnesium intake. The horses were exercised once a week on a track during 30 minutes. The distance was approximately eight kilometers. During the three periods of the trial, samples were taken on a regular basis of the horse?s faeces and urine, and their blood pressure was measured during rest and before training sessions. Blood samples were taken once every period for each horse, three hours after the training sessions.
The results of this trial show that a low intake of magnesium lowers the concentration of magnesium in plasma, but no effect could be observed on the magnesium concentration in spot samples of faeces and urine. The interval for the concentration of magnesium in samples of plasma shows that even though there was a significant difference, the numeric difference was small, and the intervals overlap each other. A low intake of magnesium also seems to affect the circulation (blood pressure and HDO-amplitudes) during the period of deficit, and possibly during some time afterwards as well, even when the intake of magnesium is according to the daily recommendations. The reasons for this are unclear, and the results need to be investigated further.
The trial shows that for individual horses during field like conditions, spot sampling of plasma, faeces and urine does not work as methods of discovering hypomagnesemia in individuals on low magnesium intake (50-60% of recommended intake).