The “Grass-Fed” Milk Story: Understanding the Impact of Pasture Feeding on the Composition and Quality of Bovine Milk

Abstract

Milk is a highly nutritious food that contains an array of macro and micro components, scientifically proven to be beneficial to human health. While the composition of milk is influenced by a variety of factors, such as genetics, health, lactation stage etc., the animal’s diet remains a key mechanism by which its nutrition and processing characteristics can be altered. Pasture feeding has been demonstrated to have a positive impact on the nutrient profile of milk, increasing the content of some beneficial nutrients such as Omega-3 polyunsaturated fatty acids, vaccenic acid, and conjugated linoleic acid (CLA), while reducing the levels of Omega-6 fatty acids and palmitic acid. These resultant alterations to the nutritional profile of “Grass-Fed” milk resonate with consumers that desire healthy, “natural”, and sustainable dairy products. This review provides a comprehensive comparison of the impact that pasture and non-pasture feeding systems have on bovine milk composition from a nutritional and functional (processability) perspective, highlighting factors that will be of interest to dairy farmers, processors, and consumers.

Seasonal Variation of Chemical Composition, Fatty Acid Profile, and Sensory Properties of a Mountain Pecorino Cheese

“…As to the neo-formed (C ≤ 15) and mixed (C16:0 and C16:1) FA [43], the OutS cheeses showed lower values of C12:0 (p < 0.05) and C16:0, C14:0 (p < 0.001), whereas the C4:0 content was tendentially higher (p < 0.1). A reduced synthesis of short and medium-chain FA in the mammary gland may be observed in lactating ruminants on pasture-based diets, due to either high levels of dietary PUFA from fresh forage that compete with de novo FA for the esterification in the mammary gland, or the negative energy balance that may often occur when milk yield is high [10]. Nevertheless, a lack of a marked reduction of de novo FA in animals fed fresh forage has been also reported [31].…”

“…In particular, it has been well established that pasture and fresh herbage can positively change the fatty acid (FA) composition of milk fat in terms of polyunsaturated fatty acids (PUFA). The latter are transferred into the corresponding dairy products affecting cheese flavor and texture [10].…”

Increasing Grazing in Dairy Cow Milk Production Systems in Europe

“…Apart from genetics, dairy cow feeding system is the greatest influence on the quality and nutritional value of milk and milk products [88,89]. Dairy cow diet influences the taste and nutritional and chemical composition of milk and the products made from milk [90][91][92]. Grazed grass has positive effects on milk composition, increasing unsaturated fatty acids, conjugated linoleic acids, vaccenic acid, and omega-3 fatty acids compared to milk other diets, including grass silage and concentrate-based diets [88,[93][94][95].…”

“…Consumers perceive milk production to involve cows grazing in green fields which they consider being natural and local, and indeed such images are often portrayed on milk cartons and in marketing campaigns. Increasingly, consumers are willing to pay a premium for grass-fed dairy products and there is an increasing body of work to support the claims that grass-fed milk is nutritionally superior (e.g., [90]). Methodologies are being developed in order to substantiate claims around the grass-fed milk and milk products and allow payment systems to be developed [98].…”

Effect of GH p.L127V Polymorphism and Feeding Systems on Milk Production Traits and Fatty Acid Composition in Modicana Cows

“…The role of pasture feeding on milk traits and fatty acid composition is well known. Milk fat from ruminants fed with pasture is generally characterized by higher levels of polyunsaturated fatty acids, isomers of conjugated linoleic acid (CLA) and omega-3 fatty acids, compared to milk from stall-fed ruminants [15].…”