Invited review: Organic and conventionally produced milk—An evaluation of factors influencing milk composition

Abstract

Consumer perception of organic cow milk is associated with the assumption that organic milk differs from conventionally produced milk. The value associated with this difference justifies the premium retail price for organic milk. It includes the perceptions that organic dairy farming is kinder to the environment, animals, and people; that organic milk products are produced without the use of antibiotics, added hormones, synthetic chemicals, and genetic modification; and that they may have potential benefits for human health. Controlled studies investigating whether differences exist between organic and conventionally produced milk have so far been largely equivocal due principally to the complexity of the research question and the number of factors that can influence milk composition. A main complication is that farming practices and their effects differ depending on country, region, year, and season between and within organic and conventional systems. Factors influencing milk composition (e.g., diet, breed, and stage of lactation) have been studied individually, whereas interactions between multiple factors have been largely ignored. Studies that fail to consider that factors other than the farming system (organic vs. conventional) could have caused or contributed to the reported differences in milk composition make it impossible to determine whether a system-related difference exists between organic and conventional milk. Milk fatty acid composition has been a central research area when comparing organic and conventional milk largely because the milk fatty acid profile responds rapidly and is very sensitive to changes in diet. Consequently, the effect of farming practices (high input vs. low input) rather than farming system (organic vs. conventional) determines milk fatty acid profile, and similar results are seen between low-input organic and low-input conventional milks. This confounds our ability to develop an analytical method to distinguish organic from conventionally produced milk and provide product verification. Lack of research on interactions between several influential factors and differences in trial complexity and consistency between studies (e.g., sampling period, sample size, reporting of experimental conditions) complicate data interpretation and prevent us from making unequivocal conclusions. The first part of this review provides a detailed summary of individual factors known to influence milk composition. The second part presents an overview of studies that have compared organic and conventional milk and discusses their findings within the framework of the various factors presented in part one.

Enhancing the fatty acid profile of milk through forage‐based rations, with nutrition modeling of diet outcomes

“…The more natural FA profile of organic and grass‐fed meat and milk has received much attention in recent years (Średnicka‐Tober et al., ,b). The FA profile in modern meat and milk can be substantially changed by shifting animals from grain‐ or concentrate‐rich rations to diets largely based on grass and legume forages (Butler et al., ; Daley, Abbott, Doyle, Nader, & Larson, ; O' Callaghan et al., ; Schwendel et al., ; Stergiadis et al., ). This shift increases ω‐3 FAs and conjugated linoleic acid (CLA) and decreases ω‐6 FAs in meat and milk, changes that may help prevent CVD and other chronic conditions (Leikin‐Frenkel, ; Hibbeln et al., ; Simopoulos, ).…”

Contribution of organic farming to public goods in Denmark

“…The proportion of healthier fatty acids is more favourable to humans in organic eggs and milk compared to conventional (Anderson 2011;Larsen et al 2014;Shapira 2010;Schwendel et al 2015), although studies demonstrating the actual effect on human health are lacking.…”

Nutritionally Desirable Fatty Acids Including Cla of Cow's Milk Fat Explained by Animal and Feed Factors

“…The fatty acid composition of bovine milk fat is affected by animal factors (Samkova et al, 2012;Schwendel et al, 2015) and feed factors (Chilliard et al, 2001;Elgersma, 2015 (DLG-Futterwerttabellen, 1997), NE L = net energy for lactation (Sommer et al, 1994). heritability (Schennink et al, 2008;Stoop et al, 2008).…”