Sustainable Intensification? Increased Production Diminishes Omega-3 Content of Sheep Milk

Abstract

Intensifying agricultural production alters food composition, but this is often ignored when assessing system sustainability. However, this could compromise consumer health and influence the concept of "sustainable diets". Here, we consider the milk composition of Mediterranean dairy sheep, finding inferior fatty acid (FA) profiles with respect to consumer health as a result of a more intensive system of production. Semi-intensive management produced 57% more milk per ewe, with a 20% lower fat content (but inferior fat composition). The milk had a nutritionally poorer fatty acid (FA) profile, with an 18% lower omega-3 FA concentration (n-3) (19% fewer long-chain n-3s) and a 7% lower monounsaturated FA concentration but a 3% higher saturated FA (9% higher in C14:0) concentration compared to ewes under traditional, extensive management. A redundancy analysis identified close associations between fat composition and animal diets-particularly concentrate supplementation and cultivated pasture grazing-and n-3 was associated with grazing in diverse, native mountain pastures. This paper questions if identifying such key elements in traditional systems could be deployed for "sustainable intensification" to maintain food quality while increasing output.

Effect of Intensification Practices, Lambing Period and Environmental Parameters on Animal Health, and Milk Yield and Quality in Dairy Sheep Production Systems on Crete

“…The finding of 30% to 50% higher milk yield, but lower milk fat, lactose and non-fat solid concentrations in SI compared to EX-managed ewes in this study is consistent with the results of previous studies that compared milk yield/ewe and protein, fat and lactose content in bulk milk samples in the same region of Crete [16] and other regions [3,60]. This was reported to be mainly due to the higher concentrate and lower grazing time on natural pastures [16], and this view is supported by the results of the redundancy analysis of data from this study (see Section 3.3.3 below).…”

“…There is limited information on the effects of intensification practices on the nutritional quality of milk from small ruminants [16] and the study reported here, for the first time comparing the relative effects of dietary, management and animal health parameters on sheep milk composition. However, the results obtained for omega-3 fatty acid in this study are broadly consistent with recent studies comparing different bovine dairy production systems that showed that low-input/organic production methods result in higher ALA and VLC omega-3 concentrations in milk compared to conventional intensive production systems [69].…”

“…During the lactation, the SI farms relied more on grazing on improved/cultivated pastures (grassland sown after cultivation) and on home-produced whole crop oat, supplemented with bought-in alfalfa hay. In contrast, the EX farms utilized natural pastures all year round, but were fed more hay (mainly bought-in alfalfa) than the SI-farms [16,24]. From late spring/early summer until lambing, both systems relied almost exclusively on grazing of natural pastures.…”

“…At the same time, as lessons learned by bovine milk production systems [13][14][15] the introduction of semi-intensive production systems may have a negative effect on milk quality and animal health and welfare status. Specifically, there is concern that changes in production protocols may affect (a) sensory or processing quality (e.g., protein and fat content, and cheese yield) [16], (b) microbial safety (e.g., total microbial and enteric pathogen loads), and (c) nutritional quality parameters (e.g., concentrations of nutritionally desirable omega-3 fatty acids) of dairy production [16][17][18]. Furthermore, any change in milk processing or microbial quality will also affect the dairy industry, where the many small scale artisan cheese factories do not have the necessary knowledge or equipment to properly stabilize raw material composition and accordingly adjust their hygiene protocols [19][20][21].…”

Integrated Soil and Crop Management in Organic Agriculture: A Logical Framework to Ensure Food Quality and Human Health?

“…It is important to consider that there is also increasing evidence that the intensification of conventional livestock production had negative effects on the nutritional composition of both milk and meat [222,[241][242][243][244][245][246][247][248][249][250][251]. For example, studies which compared low-input and/or organic with intensive conventional livestock production systems have shown that the increased use of (i) cereal and grain/legume-based concentrate feeds, (ii) indoor production, (iii) high-yield potential dairy breeds, (iv) selection for high milk yield within breeds, and/or (iv) robotic milking systems in conventional systems may:…”