Trend in ash and mineral element content of milk from Haflinger nursing mares throughout six lactation months

Ten Haflinger nursing mares were controlled throughout a whole lactation period. Mares (400–540 kg live weight; 4–12 parities) were reared in a stud in Brescia province (Northern Italy). Eighty milk samples were taken by hand milking of one gland at days 4, 20, 40, 60, 80, 120, 150 and 180 post-partum. From days 4 to 180 post-partum, the ash content dropped from 0.58 to 0.28 g/100 g of milk (P<0.001). In the same period, the content of the mineral elements also decreased significantly (P<0.001): Ca from 1240 to 519 ppm; P from 704 to 310 ppm; Mg from 104 to 44 ppm; K from 773 to 387 ppm; Na from 297 to 166 ppm; Cl- from 279 to 181 ppm. Changes were most relevant in the first period of lactation (at day 40: -32% ash; -28% Ca; -30% P; -27% Mg; -29% K; -33% Na; -41% Cl-). Ash and minerals showed a curvilinear trend relative to days of lactation that was well described by cubic equations.