The present investigated differences in the apparent digestibility of phosphorus (ADP) in lactating
cows fed various feed materials containing organic forms of phosphorus (P) or a highly available
inorganic phosphorus source. Cows milking an average of 36 kg energy corrected milk (ECM)
were used in a 4 × 4 Latin square design with 4-week periods to measure the P excretion in
faeces. Four different concentrates with monosodium phosphate (MSP), rapeseed (RS), sunflower
seed/palm kernel (SSP) and wheat middlings/bran (WMB) as the main P source (0.56–0.67 of P
The environmental focus on the adverse effects of phosphorus (P) run-off from agricultural land has led to a renewed interest in P metabolism in dairy cows. Due to difficulties
in measuring P turnover in the cow, large safety margins in the dietary P recommendations
for cattle have been common. Excessive application of P on fields leads to accumulation
in the soil and a risk of leaching into waterways. Typical modern intensive dairy systems
may accentuate this strain on the environment. Due to detrimental effects on animal health
and production caused by a diet P deficiency, any possible environmental benefits must be
weighed against the cows’ requirements for P