In fact, although variable fluctuations with increases during pregnancy and decreases in the lactation phase have been reported in these mares, in women, ICa2+ concentrations remain constant within very narrow margins during gestation, although TCa2+ concentrations are considerably reduced in response to the expansion of extracellular fluids, the decrease in albumin concentrations (dilutional hypoalbuminemia of pregnancy), and the increase in the glomerular filtration rate, leading to an increase in calciuria [30,31,32]. This evidence concerns the gene ALB and Hypoalbuminemia.