Abstract:

The change in feeding regime of dairy herds using summer grazing in mountainous areas has several implications on cows’ productivity and milk composition. The present study quantified the effect of summer grazing on the milk fatty acids (FA) profile of Simmental and crossbred cows in an alpine holding. A total of 616 milk samples of 71 cows were collected 3 days before the onset of the grazing season until 91 days of grazing. Individual and groups of FA were quantified through mid-infrared spectroscopy. Data were analysed using a linear mixed model including the fixed effects of breed, stage of lactation, parity, sampling period, and the random effects of cows nested within breed and the residual. The stage of lactation and the sampling period were the most significant factors associated with milk FA. The variance explained by the random cow effect ranged from 15.10% (C18:1) to 25.31% (medium-chain FA). The concentration of C14:0, C16:0, and short- and medium-chain FA decreased across the summer season. Long-chain FA and polyunsaturated FA concentrations were greater in milk obtained at pasture compared with milk obtained indoors. Given these outcomes, the present study demonstrated the positive effect of grazing on milk FA composition from a nutraceutical point of view.

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