Relationship between milk fatty acid composition and dietary roughage source in dairy cows

Abstract

According to a 2×2 crossover design, 14 Holstein dairy cows were fed two isoenergetic diets based on either grass hay (GH) or maize silage (MS). Milk samples were collected during the third week of each period, and fatty acid (FA) profiles were analyzed using gas chromatography. The data obtained were subjected to ANOVA. Dietary treatment had no effect on either dry matter intake or milk yield. Milk from animals fed the GH-diet contained lower concentrations of saturated FAs (61.9 vs. 63.4% of total FAs; P<0.05) and higher levels of polyunsaturated FAs (PUFAs) (6.1 vs. 5.8; P<0.01). Feeding additional hay also increased conjugated linoleic acid and n-3 FA levels and decreased C16:0 levels. Increases in both PUFAs and n-3 FAs resulted in lower (P<0.01) atherogenic and thrombogenic indices in milk from animals fed the GH diet compared with those fed the MS diet. A complete substitution of GH for MS appeared to improve milk FA profiles, even using different types of concentrates to provide a balanced diet.

Fatty acid composition of buffalo and bovine milk as affected by roughage source - silage versus hay

“…Although oxidation during hay production process is more detrimental to the favourable FA's than that during ensiling (Shingfield et al, 2005;Kalač and Samková, 2010), feeding hay results in improved PUFA in milk according to the results of Shingfield et al (2005), Staszak (2007) and Bernardini et al (2010). This appears to apply to the buffaloes in the present study with similarity in the effect of the shift in roughage source after one and two months, regardless of the differences in parity and lactation stage within the groups.…”

“…There are series of studies comparing the effect of different sources of roughage -including cereal and leguminous silages -on the lipid profile of bubaline and bovine milk (Shingfield et al, 2005;Nielsen et al, 2006;Fernandes et al, 2007). But those considering in particular maize silage versus hay are few and somehow inconsistent in dairy cattle (Dhiman et al, 1999;Staszak, 2007;Bernardini et al, 2010) and scarce in the water buffalo. Comparisons between the two species on experimental basis are also absent on national scale.…”

Fatty acid profiles and antioxidants of organic and conventional milk from low‐ and high‐input systems during outdoor period

“…The intake of ALA is highest from fresh, fast‐growing grass and therefore a decrease in ALA in milk occurs if grass is replaced by conserved forages or by concentrates . Maize silage negatively affects the FA composition in terms of long‐chain PUFA, n‐3 PUFA and OBCFA and total trans fatty acids (TFA) . In contrast to a grass silage‐based ration, the n‐6/n‐3 ratio in the milk of maize silage‐fed cows will increase as well in our B as in our C system group (Table ).…”

Discrimination of haymilk and conventional milk via fatty acid profiles

“…On the other hand, C14:0 and C18:0 showed significant differences between HM and CM in the cold season (Q1 and Q4). An explanation for this behavior of SFA can be seen in the fact that C18:0 in contrast to all the other even chained SFA is not only synthesized de novo in the mammary gland, by the regular FAs metabolism or provided by the diet, but also the final product of bio hydrogenation [22,26,36]. Therefore, this result was expected, since any possible differences could only be attributed to crowding-out effects of other FAs, which are affected by feed or microbial activity, which obviously did not occur to a significant extent.…”

“…In the warm season, fresh green feed (fresh grass, foliage and leguminous plants) dominates, whereas in the cold season hay is the dominant feed [4]. This feeding results also in an increase of PUFA including CLA, as confirmed in different studies [9,[22][23][24][25][26]. All these characteristics were extensively studied in raw milk or in feed monitored works [13,14,27].…”