Hypophosphatemia during the transition period
Fernando Diaz
Phosphorus is an essential macromineral involved in several biological processes such as bone mineralization, energy transition, and acid-base buffer systems. During lactation, the NRC 2001 guidelines recommends to feed diets with 0.3 – 0.4% of phosphorus in a dry matter (DM) basis.
In general, in intensive dairy production systems, feeding feed ingredients with medium (cereal and cereal co-products) and high concentration of phosphorus (soybean meal) is normally enough to meet cow’s phosphorus requirement, thus, it is not necessary to supplement mineral phosphorous (phosphates).
Nonetheless, cow phosphorous requirement during the last trimester of gestation increases drastically. It has been reported that phosphorus accretion in fetus (fetal fluids and membranes) and uterine tissues increases from 1.9g/day at 190 to 5.4g/d at 280 days of gestation, respectively. For this reason, phosphorus deficiency and hypophosphatemia incidence in dairy cows are more common during the transition period.