# Effects of a Phosphorus-Binding Feed Supplement on the Blood P and Ca Levels in Dairy Cows

## TL;DR

Adding aluminum sulfate to dairy cows' diets before calving helps prevent low blood calcium levels, improving their health and milk production.

## Contribution

This study shows aluminum sulfate supplementation in close-up dairy cows effectively prevents postpartum hypocalcemia by reducing blood phosphorus and increasing calcium levels.

## Key findings

- Cows supplemented with aluminum sulfate had significantly higher blood calcium levels post-calving.
- Aluminum sulfate reduced serum phosphorus levels in treated cows compared to controls.
- Milk yields were slightly higher in supplemented cows, though other health indicators remained similar.

## Abstract

Dairy cows often experience low blood calcium levels after calving, leading to health problems, reduced milk production, and fertility issues. This study tested whether adding aluminum sulfate to the diet of pregnant cows in the final weeks before calving could help prevent this issue. Aluminum sulfate binds phosphorus, a mineral that can interfere with calcium levels. Researchers divided 34 cows into two groups: one received aluminum sulfate, and the other did not. Blood samples were taken before and after birth to measure calcium, phosphorus, and other important indices. Cows that received aluminum sulfate had higher calcium levels in their blood after calving and lower phosphorus levels than cows that did not receive the supplement. Although milk production was slightly higher in the supplemented group, other health indicators were similar between the groups. These findings suggest that aluminum sulfate could be a valuable dietary addition to prevent calcium deficiency in dairy cows.

Subclinical hypocalcemia negatively impacts dairy cows’ health, milk production, and reproduction, posing a global challenge. This study evaluated the effects of aluminum sulfate supplementation in the close-up diet to reduce blood phosphorus levels and prevent postpartum hypocalcemia. Thirty-four cows were assigned to the Control (CTRL, n = 17) and Treatment (TRT, n = 17) groups. The TRT group received 400 g/cow/day of aluminum sulfate at least 14 days before calving, with identical post-calving diets. Blood samples were analyzed for total and ionized calcium (tCa, iCa), phosphorus (P), magnesium (Mg), and beta-hydroxybutyrate (BHB). Milk yields were recorded. TRT cows had 0.22, 0.18, and 0.14 mmol/L higher tCa levels than CTRL cows at 12 h, 1 d, and 2 d postpartum, respectively, with elevated iCa levels from 10 days prepartum to 3 days postpartum. Lower serum P levels were observed in TRT cows until day 2 postpartum, while Mg levels remained similar. BHB levels differed only on day 14 postpartum. These findings suggest that aluminum sulfate supplementation effectively lowers serum P and increases tCa, offering a promising strategy for hypocalcemia prevention in dairy cows.