Fig. 3

Pearson correlations between hepatic cystathionine β-synthase (CBS), betaine homocysteine methyltransferase (BHMT) and 5-methyltetrahydrofolaare-homocysteine methyltransferase (MTR) activity with dry matter intake (DMI) and milk yield (MY) from 3 studies [11, 64, 71]. In the studies by Zhou et al. [27, 71] cows were fed a total mixed ration with or without rumen-protected Met (RPM) at 0.08% DM for 21 d prepartum and 30 d postpartum. Batistel et al. [11] fed diets with or without RPM at 0.10% DM for 28 d prepartum and 60 d postpartum. Enzyme and metabolite data from this study was reported by Vailati-Riboni et al. [28]. In the last study, a 2 × 2 factorial design of body condition score (BCS) and energy level during the peripartal period was used: 2 prepartum BCS categories [4.0 (thin, BCS 4) and 5.0 (optimal, BCS 5); 10-point scale [72]] and 2 levels of energy intake during the 3 weeks preceding calving (75% or 125% of estimated requirements) obtained via allowance (m²/cow) of fresh pasture composed of mostly perennial ryegrass and white clover [64]. Data in the graphs are split between cows receiving Met and those that did not receive Met