Milk fatty acid profile related to energy balance in dairy cows

Abstract

Milk fatty acid (FA) profile is a dynamic pattern influenced by lactational stage, energy balance and dietary composition. In the first part of this study, effects of the energy balance during the proceeding lactation [weeks 1-21 post partum (pp)] on milk FA profile of 30 dairy cows were evaluated under a constant feeding regimen. In the second part, effects of a negative energy balance (NEB) induced by feed restriction on milk FA profile were studied in 40 multiparous dairy cows (20 feed-restricted and 20 control). Feed restriction (energy balance of À 63 MJ NEL/d, restriction of 49 % of energy requirements) lasted 3 weeks starting at around 100 days in milk. Milk FA profile changed markedly from week 1 pp up to week 12 pp and remained unchanged thereafter. The proportion of saturated FA (predominantly 10:0, 12:0, 14:0 and 16:0) increased from week 1 pp up to week 12 pp, whereas monounsaturated FA, predominantly the proportion of 18:1,9c decreased as NEB in early lactation became less severe. During the induced NEB, milk FA profile showed a similarly directed pattern as during the NEB in early lactation, although changes were less marked for most FA. Milk FA composition changed rapidly within one week after initiation of feed restriction and tended to adjust to the initial composition despite maintenance of a high NEB. C18:1,9c was increased significantly during the induced NEB indicating mobilization of a considerable amount of adipose tissue. Besides 18:1,9c, changes in saturated FA, monounsaturated FA, de-novo synthesized and preformed FA (sum of FA > C16) reflected energy status in dairy cows and indicated the NEB in early lactation as well as the induced NEB by feed restriction.

Effect of cow energy status on the hypercholesterolaemic fatty acid proportion in raw milk

“…These affect metabolism as biologically active substances. The UFA and mainly PUFA decline is a physiologically natural state, although undesirable from the aspect of nutrient quality of milk (Gross et al 2011). The above-mentioned relationships could be in direct A,B different superscript letters confirm statistical significance of differences between rows at P < 0.01; LSM -Least Square Mean conflict with the EU legislation continuously emphasising and requiring an increase in the quality, health, and safety of agricultural and food products (Velčovská & Sadílek 2014).…”

“…Changes in the milk content of individual FA or their groups in relation to NEB depth and NEB length have been evaluated in many studies (Gross et al 2011). The findings usually agree in a higher proportion of UFA and/or lower content of SFA early postpartum under NEB with a subsequent UFA decline and/or SFA increase with regard to balancing the current energy status and continued lactation.…”

“…The significantly higher value of SFA (+2.13%; P < 0.01) and/or equally lower UFA (-2.13%; P < 0.01) was evaluated after the NEB period. This fact corresponds with the findings of Soyeurt et al (2007), Stoop et al (2009), Gross et al (2011), and Ducháček et al (2013).…”

Milk fatty acid composition as an indicator of energy status in Holstein dairy cows

“…The first measurable indicator of ketogenesis is an increase in BHB concentration in the blood (Payne and Payne, 1987;Schulz et al, 2014) The utilization of energy reserves is also reflected in the milk fat content (Bauman et al, 2006), namely in the fatty acid (FA) composition and mutual ratios between individual FA groups (Ducháček et al, 2014). Milk FA and protein contents are correlated with metabolic status (Mulligan et al, 2006); therefore, measurement of these two parameters is usually recommended for the determination of negative energy balance (Gross et al, 2011). Several researchers (Berry et al, 2006;Soyeurt et al, 2006;Bastin et al, 2011) have determined the FA composition of milk to predict energy status.…”

Influence of glucogenic dietary supplementation and reproductive state of dairy cows on the composition of lipids in milk

“…adipose lipolysis rate is decreasing) and therefore, the effect of propylene glycol administration on NEFA plasma concentration (Burhans et al, 1997;Stokes and Goff, 2001) is expected to be modest. In addition, at this stage of lactation, the mammary gland utilizes more lipogenic precursors, such as acetate, and less NEFA for lipogenesis (Gross et al, 2011). To examine the effect of estrouscycle day on milk lipid composition, cows were synchronized and plasma levels of insulin and progesterone were determined on day 1 and 8 post-estrus in both treated (with propylene glycol) and untreated cows.…”