“…LS i is the fixed effect of the ith lambing season class, where i = 1 when lambing occurred from August to November (conventional); i = 2, from December to March (winter); and i = 3, from April to July (late); TMY j is the fixed effect of the jth class of total milk yield adjusted (TMY adj ) for lactation length (Carta et al, 1998), where the classes were labelled, based on interquartile limits, as 1: TMY adj < 146.9 kg; 2: 146.9 kg ≤ TMY adj < 189.3 kg; 3: 189.3 kg ≤ TMY adj < 240.3 kg; 4 when TMY adj ≥ 240.3 kg; and 0 when TMY adj records were missing; fy k is the random effect of the kth flock by year of lambing subclass, with k = 1, …, 70 (from up to 17 flocks in 6 years of lambing, from 1998 to 2003); and a l is the random effect of the additive genetic component of the lth individual, with l = 1, …, 3114.…”