Silvopastoral systems with wild sunflower (Tithonia diversifolia (Hemsl.) A. Gray) and lipid supplementation: a strategy to improve the fatty acid profile of milk in dairy livestock systems

Abstract

This study evaluated the effect of T. diversifolia on the fatty acid (FA) profile of milk, with and without lipid supplementation, through two trials. Trial 1 compared a monoculture system of Kikuyu grass—Cenchrus clandestinus (Hochst. ex Chiov.) Morrone (MONO)—with a silvopastoral system (ISS) incorporating Kikuyu grass and wild sunflower (5% of forage dry matter, FDM). The objective was to assess the effect of shrubs as grazing forage on the FA profile of dairy Holstein cows, using a Latin rectangle design with two periods and 12 cows (experimental units) in a crossover arrangement. Trial 2 evaluated the effect of increasing wild sunflower in the forage diet (17.5% of FDM) and supplementing concentrates with different lipid sources (LS1: Concentrate with commercial saturated rumen bypass fat; LS2: Concentrate with 1% soybean oil, 0.5% fish oil, and 1.5% rumen bypass omega-3 fat; LS3: Concentrate with 2.5% soybean oil and 0.5% fish oil). A completely randomized block design with a 2 × 3 factorial arrangement (two production systems × three lipid sources in the concentrate) was used. The milk FA profile was positively influenced by wild sunflower intake (5% FDM in trial 1, 17.5% in trial 2) and soybean/fish oil inclusion (trial 2). In trial 1, trans-vaccenic acid (TVA) increased by 10% compared to MONO. In trial 2, TVA increased by 41%. Overall, incorporating wild sunflower and lipid supplements into the ISS diet improved milk nutritional quality.