Effects of dietary aluminum and phosphorus on magnesium metabolism in dairy calves2

Abstract

The metabolism of Mg was studied in young dairy calves fed two levels of added Al (0 and .20% Al) and two levels of added P (0 and .22% P) for 7 wk. The four treatments were 1) normal P-low Al, 2) low P-low Al, 3) normal P-high Al and 4) low P-high Al. The basal diet (low P-low Al) contained, by analysis, .132% P, .021% Al and .17% Mg. Added Al did not affect (P greater than .10) serum Mg. An Al x P interaction on bone Mg was detected (P less than .01). Magnesium was reduced in tibia shaft (.34 vs .44%) and in tibia joint (.43 vs .53%) in calves fed high Al in the presence of normal dietary P, but Mg was not reduced in the calves fed low-P diets. Apparent absorption of Mg was reduced by approximately five-fold (.18 g/d vs -.84 g/d, P less than .01); urinary Mg excretion was reduced 31% (1.12 g/d vs .77 g/d, P less than .01); and Mg retention declined 41% (-95 g/d vs -1.61 g/d, P less than .01) in calves fed added A1. Compared with calves fed low-P diets, calves fed normal levels of P had a higher Mg concentration in tibia shaft (P less than .01) and tibia joint (P less than .05). The data indicate that supplemental Al may adversely affect Mg metabolism in calves.

Effect of season and age on blood minerals, liver enzyme levels, and faecal egg counts in Nguni goats of South Africa

“…With excessive magnesium intake, the main route of excretion is through urine while with low intake or absorption, serum magnesium levels may be stabilized by magnesium mobilization from the bone (Neathery et al, 1990). This regulation might explain why there was no seasonal variation in the magnesium level.…”

Soil aluminium availability in Andisols of southern Chile and its effect on forage production and animal metabolism

“…High Al blood concentration, as a consequence of high Al ingestion, adversely affects weight gain, depresses food intake and interferes with cellular metabolism (Neathery et al. , 1990).…”

“…Research has demonstrated that Al depresses Mg absorption in the intestine (i.e. Neathery et al. , 1990).…”

“…, 1990). Neathery et al. (1990) found hepatotoxic effects of high Al dietary levels in growing calves, after the direct ingestion of 2000 mg kg −1 of Al.…”

“…High Al content in grass may interact negatively with essential elements such as phosphorus (P), calcium (Ca) and magnesium (Mg), affecting animal metabolism (Allen, 1984;Crowe et al, 1990). Neathery et al (1990) found hepatotoxic effects of high Al dietary levels in growing calves, after the direct ingestion of 2000 mg kg )1 of Al.…”