Differences in sheep and goats milk fatty acid profile between conventional and organic farming systems

Abstract

The objective of this study was to investigate whether there is a difference in chemical composition and particularly in fatty acid (FA) profile, with emphasis on cis-9, trans-11 CLA, of milk obtained from conventional and organic dairy sheep and goats farms under the farming conditions practiced in Greece. Four dairy sheep and four dairy goat farms, representing common conventional production systems and another four dairy sheep and four dairy goat farms, organically certified, representing organic production and feeding systems were selected from all over Greece. One hundred and sixty two individual milk samples were collected from those farms in January-February 2009, about three months after parturition. The milk samples were analyzed for their main chemical constituents and their FA profile. The results showed that the production system affected milk chemical composition: in particular fat content was lower in the organic sheep and goats milk compared with the corresponding conventional. Milk from organic sheep had higher content in MUFA, PUFA, alpha-LNA, cis-9, trans-11 CLA, and omega-3 FA, whereas in milk from organic goats alpha-LNA and omega-3 FA content was higher than that in conventional one. These differences are, mainly, attributed to different feeding practices used by the two production systems. The results of this study show that the organic milk produced under the farming conditions practiced in Greece has higher nutritional value, due to its FA profile, compared with the respective conventional milk.

Relationship between production conditions and milk gross composition in ewe’s and goat’s organic and conventional farms in central Greece

“…In any case, as these results are based on one-factor analysis, it will not be possible to draw conclusions without taking under consideration other associated factors. This is also apparent by the diversity in the literature on this issue; differences in relation to fat have been reported by Tsiplakou et al (2010) in organic sheep and goat milk and Stergiadis et al (2012) and Benbrook et al (2013) in organic cow's milk, while other researchers reported that they did not identify substantial differences regarding the chemical composition of organic and conventional milk (Toledo et al 2002). Nevertheless, a longer monitoring period, or even a higher number of samples, may facilitate to improve borderline statistic associations.…”

“…So far, several studies have assessed the differences in the chemical composition of organic and conventional milk, mainly with focus on dairy cows production (Butler et al 2008;Benbrook et al 2013;Gabbi et al 2013), with conflicting results (Palupi et al 2012). Thus, there are limited studies on the nutritionally relevant compounds in goats and ewe's milk (e.g., protein, fat) focusing mainly on the organic/conventional status (Tsiplakou et al 2010) without taking to consideration several other parameters affecting the chemical composition (e.g., seasonality, breeds, way of milking).…”

Part-time grazing improves sheep milk production and its nutritional characteristics

“…Probably for these reasons, although the double bond of vaccenic acid is in the trans configuration, some countries exclude vaccenic acid and other naturally occurring trans-FA in milk and dairy products from the total trans-FA that must be declared on food labels (Kühlsen et al, 2005). Surprisingly, in milk of organically raised sheep the increase in concentration of the CLA isomer c9t11 and of vaccenic acid with respect to those found in milk of conventionally raised sheep was only 1.2-and 1.1-fold higher, respectively (Tsiplakou, Kotrotsios, Hadjigeorgiou, & Zervas, 2010). In all cases 75% of all FA were saturated.…”

Monitoring of blood metabolic profile and milk quality of ewes during lactation in organic farming

“…of milk are usually used for assessment of milk quality. Milk from ruminants is a well known source of fatty acids important for human health (Tsiplakou et al, 2010). The content of those is however significantly dependant on the nutrition (De la Fuente al., 2009).…”