Monitoring of vitamin E status of dry, early and mid-late lactating organic dairy cows fed conserved roughages during the indoor period and factors influencing forage vitamin E levels

Abstract

Analysis of blood plasma of 60 cows selected on six Flemish organic dairy farms revealed that on average 12% of all samples and on one farm up to 28% of the organic cows showed plasma vitamin E concentrations less than 3.0 μg/ml, which is considered the minimum level to avoid health risks due to vitamin E shortages. Furthermore, this study showed early lactating and dry cows to be more at risk in relation to animals in mid-late lactation. In European organic farming, vitamin supplements are only allowed if granted by the local authority to satisfy daily requirements. Therefore, the vitamin E content of the feedstuffs used on the farms was determined. Grass clover silage (GCS) and mixed silage had significantly more vitamin E than hay, maize or grain (p < 0.05) [mean (SD): 52 (35), 29 (20), 4.5 (1.7), 4.9 (4.4) and 7.1 (3.8) mg/kg DM, respectively]. Apparently, variation in the vitamin E content in the silage samples was huge. Hence, the vitamin E content of ryegrass, white and red clover was determined in a second lab scale experiment and the effects of wilting, DM content and supplementation of ensiling additives were investigated. Fresh ryegrass had a higher vitamin E content than white and red clover (p < 0.05) [156 (11.3), 49.3 (0.67) and 74.3 (5.73) μg/g DM, respectively]. These differences remained after the wilting or ensiling. Supplementation of formic acid or lactic acid bacteria at ensiling had no significant effect on the vitamin E content. Overall, it can be concluded that GCS is the most important source of vitamin E in organic dairy farming. A legal possibility for case-related supplementation should be retained in organic dairy farming as approximately 18% of all dry and early lactating cows were at risk of vitamin E shortage.

Effect of legume–grass silages and α-tocopherol supplementation on fatty acid composition and α-tocopherol, β-carotene and retinol concentrations in organically produced bovine milk

“…For grasses, higher a-tocopherol and b-carotene concentrations have been reported in meadow fescue than in timothy (Danielsson et al, 2008). On the contrary, no difference in the concentration of a-tocopherol between red clover and white clover has been reported by several studies (Al-Mabruk et al, 2004;Beeckman et al, 2010;Danielsson et al, 2008). These differences between species indicate that the different grass species in the mixtures might explain the higher antioxidant intake on L3.…”

Carotenoids, ergosterol and tocopherols in fresh and preserved herbage and their transfer to bovine milk fat and adipose tissues: A review

“…Among the data in Table 5, the content reported by Lynch et al (2001) from Ireland is considerably lower than that from other European countries. Overall, α-tocopherol content of about 50-75 mg kg -1 DM seems to be believable for legumes, while the values reported for perennial ryegrass by Beeckman et al (2010) were at least double.…”

“…Beeckman et al (2010) reported a level of about 5 mg of α-tocopherol per kg DM in ensiled meal of maize cobs (CCM). This content was comparable with that in hay.…”

Effect of short-term versus long-term grassland management and seasonal variation in organic and conventional dairy farming on the composition of bulk tank milk

“…Concentrations of fat-soluble vitamins in silage decrease during storage (Beeckman et al, 2010), and therefore lower values in milk would be expected during the indoor feeding periods. This unexpected effect of season on vitamins warrants further study to clarify the mechanisms.…”