Multispecies swards, a newly introduced and more sustainable cow diet, increase polyunsaturated fatty acid (PUFA) levels in milk within a seasonal, spring-calving system.

Monday, April 29, 2024

11:26 AM – 11:43 AM EDT

Room: 524b

Presenting Author(s)

Renata Kostovska, MSc

PhD Student
Teagasc Food Research Centre
Fermoy, Ireland

Co-Author(s)

GD

Gaetan Drouin

Research Officer
Teagasc Food Research Centre, Ireland
BH

Brendan Horan

Principal Research Officer
Teagasc, Animal & Grassland Research and Innovation Centre, Ireland
TO

Tom O'Callaghan

Senior Lecturer
University College Cork, Ireland
JT

John Tobin

Head of Department
Teagasc Food Research Centre, Ireland
AK

Alan Kelly

Head of School, Professor - Food Science
University College Cork, United States
LG

Laura G. Gómez-Mascaraque, Dr.

Senior Research Officer
Teagasc Food Research Centre, Ireland

Cow diet, breed and stage of lactation are factors causing variation in milk fat composition, resulting in nutritional and functional properties changes. This study evaluated, for the first time, the impact of two pasture-based feeding systems, namely the traditionally used perennial ryegrass (PRG) and a more sustainable, multispecies swards (MSS) diet, on the raw milk lipid profile. It focused on the two primary cow breeds in Ireland, Holstein-Friesian (HF) and Jersey Holstein-Friesian (JFX), throughout an entire lactation period. Bulk milk samples (n=144) for the four groups were collected on a weekly basis from March to November 2021. Changes in total fatty acid (FA) profiles were determined by GC-FID, and those in polar lipids (PL) content by HPLC-ELS-MS. Based on both multivariate and univariate analyses, both diet and breed influenced the milk FA profile, and these differences were more evident as lactation progressed. For both breeds, MSS diet increased levels of both ω-6 and ω-3 polyunsaturated fatty acids (PUFA), including ω-3 DPA, while the ω-6/ω-3 ratio was not impacted by neither diet nor breed. JFX cows showed increased de novo and short-chain FA, compared to HF. PL content significantly increased throughout the entire lactation (P < 0.001), with no significant impact on the individual PL species proportions.

Overall, these results indicate that introducing the more sustainable MSS diet to a seasonal, spring calving dairy system could add nutritional value to milk, by increasing the ω-3 and ω-6 levels, especially in mid and late lactation. Moreover, our study expanded to include the production of high value dairy derivatives from these groups, such as cream and butter, and their composition and functionality were analysed.