Fat source and dietary forage-to-concentrate ratio influences milk fatty-acid composition in lactating cows

Abstract

On the basis of the potential benefits to human health there is an increased interest in producing milk containing lower-saturated fatty acid (SFA) and higher unsaturated fatty acid (FA) concentrations, including cis-9 18:1 and cis-9, trans-11-conjugated linoleic acid (CLA). Twenty-four multiparous Holstein cows were used in two experiments according to a completely randomized block design, with 21-day periods to examine the effects of incremental replacement of prilled palm fat (PALM) with sunflower oil (SFO) in highconcentrate diets containing 30 g/kg dry matter (DM) of supplemental fat (Experiment 1) or increases in the forage-to-concentrate (F : C) ratio from 39 : 61 to 48 : 52 of diets containing 30 g/kg DM of SFO (Experiment 2) on milk production, digestibility and milk FA composition. Replacing PALM with SFO had no effect on DM intake, but tended to increase organic matter digestibility, yields of milk, protein and lactose, and decreased linearly milk fat content. Substituting SFO for PALM decreased linearly milk fat 8:0 to 16:0 and cis-9 16:1, and increased linearly 18:0, cis-9 18:1, trans-18:1 (Δ4 to 16), 18:2 and CLA concentrations. Increases in the F : C ratio of diets containing SFO had no effect on intake, yields of milk, milk protein or milk lactose, lowered milk protein content in a quadratic manner, and increased linearly NDF digestion and milk fat secretion. Replacing concentrates with forages in diets containing SFO increased milk fat 4:0 to 10:0 concentrations in a linear or quadratic manner, decreased linearly cis-9 16:1, trans-6 to -10 18:1, 18:2n-6, trans-7, cis-9 CLA, trans-9, cis-11 CLA and trans-10, cis-12 CLA, without altering milk fat 14:0 to 16:0, trans-11 18:1, cis-9, trans-11 CLA or 18:3n-3 concentrations. In conclusion, replacing prilled palm fat on with SFO in highconcentrate diets had no adverse effects on intake or milk production, other than decreasing milk fat content, but lowered milk fat medium-chain SFA and increased trans FA and polyunsaturated FA concentrations. Increases in the proportion of forage in diets containing SFO increased milk fat synthesis, elevated short-chain SFA and lowered trans FA concentrations, without altering milk polyunsaturated FA content. Changes in fat yield on high-concentrate diets containing SFO varied between experiments and individual animals, with decreases in milk fat secretion being associated with increases in milk fat trans-10 18:1, trans-10, cis-12 CLA and trans-9, cis-11 CLA concentrations.

Manipulation of milk fatty acid composition in lactating cows: Opportunities and challenges

“…Enrichment of 18:3 n‐3 in milk was highest when high amounts of processed linseeds were fed to cows fed a high concentrate diet . Similarly milk 18:2 n‐6 concentrations were found to be higher (3.84 vs. 3.36 g/ 100 g total fatty acids) when sunflower oil (30 g/kg dry matter) was included in total mixed rations containing a higher proportion of concentrates (39:61 vs. 48:52; ).…”

Short communication: Effects of diets containing supplemental fats on ruminal fermentation and milk odd- and branched-chain fatty acids in dairy cows

“…We examined the effects of replacement of a saturated fat-enriched 16:0 (prilled palm fat; PPF) with an unsaturated fat rich in 18:2n-6 (sunflower oil; SO) in low-forage diets (experiment 1) or increasing the forage-to-concentrate ratio (F:C) in diets containing SO (experiment 2) on ruminal fermentation characteristics and milk OBCFA composition. The dietary effects on feed intake, digestibility, milk production and composition, and milk FA composition, except OBC-FA, were reported previously (Vazirigohar et al, 2014). Moreover, data from both experiments were used to explore the associations among ruminal VFA and milk OBCFA in cows fed diets containing supplemental fats using principal component analysis (PCA).…”

Supplementation with plant-derived oils rich in omega-3 polyunsaturated fatty acids for lamb production

“…A number of studies have demonstrated that n−3 PUFA content in red meat and cow milk are higher in animals fed pasture-based compared to concentrate-based diets ( Howes et al., 2015 , Jaturasitha et al., 2016 , Shingfield et al., 2013 , Vazirigohar et al., 2014 ). Eriksson and Pickova (2007) suggested that fresh grass exerts a greater protection for n-3 PUFA against rumen microorganisms than concentrates, because of the presence of other secondary metabolites that could inhibit ruminal BH ( Alves et al., 2017 , Girard et al., 2016 , Willems et al., 2014 ).…”

“…However, forage generally contains a low level of total FA, ranging about 1–3% dry matter (DM) ( Chilliard et al., 2007 , Jaturasitha et al., 2016 ). Thus, other lipid sources are commonly supplemented to increase dietary energy density to gain improved animal performance ( Parvar et al., 2017 , Vazirigohar et al., 2014 ).…”