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Differences Between Organic and Conventionally Produced Milk Reduce When Both Systems Use Pasture‐feeding
Author(s) -
Schwendel Brigitte H.,
Wester Timothy J.,
Morel Patrick C.H.,
Fong Bertram,
Tavendale Michael H.,
Deadman Craig,
Shadbolt Nicola M.,
Otter Don E.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.437.8
Subject(s) - conjugated linoleic acid , composition (language) , vaccenic acid , pasture , milking , forage , chemistry , food science , sheep milk , automatic milking , linoleic acid , zoology , biology , fatty acid , lactation , agronomy , biochemistry , pregnancy , linguistics , philosophy , genetics , ice calving
Milk fatty acid (FA) composition has been the main focus of comparisons between organic and conventionally produced milk. In addition, studies commonly report on differences in FA composition between grazed organic cows and housed, concentrate‐fed conventional cows. Our study investigated two farms sets, consisting of one organic and one conventional farm respectively, with each set managed similarly at the same location. We accounted for known influence factors on milk composition and selected farms that utilized Jersey×Holstein‐Friesian cows being fed > 95% forage. We investigated whether individual farm characteristics or farm system (organic or conventional) had greater influence on milk composition. Milk samples of all four farms where collected throughout the milking season (1–2 per week) and analysed for milk FA, major casein and whey proteins, free oligosaccharides, and milk fat volatiles. We demonstrated that FA composition, especially vaccenic acid, α‐linolenic acid, and conjugated linoleic acid was influenced by the farm system, independent of the farm set, as a consequence of differences in nitrogen fertilizer application. Similar to FA, system effects were observed for half of the observed oligosaccharides, however, these results cannot be explained at present and further research into the influence factors of individual bovine oligosaccharides is needed. Farm set was the dominant influence factor on protein composition, predominantly as a result of differences in pasture composition, while neither system nor farm altered milk fat volatile composition. Our observations show that individual milk compounds are affected differently by farm and system effects, and no comprehensive, universal conclusions can be drawn on differences in chemical composition between organic and conventional milk. Support or Funding Information This work was funded by grants from Fonterra Cooperative Group Limited (New Zealand), Ministry of Science and Innovation (New Zealand), and the Agricultural and Marketing Research and Development Trust (AGMARDT; New Zealand)