“…a, b, c, d, g and h = parameters of the lactation curve models; PY = peak yield (L/day), Pday = peak day and 305MP = 305 days corrected milk production (L). The model by Wood (1967) has been widely used in several types of studies, such as for new models assessment (Cobby & Le Du, 1978;Rook et al, 1993), genetic breeding (Schneeberger, 1982;Grossman et al, 1984;Ferris et al, 1985;Faro & Albuquerque, 2002), milk production simulation systems (Rotz et al, 1999;Rotz et al, 2005;Rennó et al, 2008a; Figure 2 -Lactation curves and lactation curve models selected, that best fit the data of the M1, M2 and M3 subgroups. M1 = medium milk production (MP) and first lactation order (LN); M2 = medium MP and second LN; M3 = medium MP and third or greater LN; y = milk production (L/day), x = days in milking.…”