Milk Physicochemical Properties of Holstein Friesian × Jersey Crossbreed Cows Under Different Feeding Management Systems in Tropical Southern Mindanao, Philippines

Effective feeding management is vital to improving milk quality in tropical dairy systems in the Philippines, where the domestic supply is limited. We evaluated how corn silage (CS), conventional fresh grass (FG), and mixed corn silage and spent grain (mixed CS & SG) feeding systems related to milk physicochemical properties in Holstein Friesian × Jersey crossbred cows on commercial farms in Southern Mindanao. Milk samples from 10 cows per farm were collected twice in May 2024 and analyzed for fat, SNF, density, lactose, protein, pH, and TSS. A two-way mixed ANOVA revealed farm-level effects (η² = 0.568-0.799) across all parameters. Mixed CS & SG feeding yielded superior SNF (8.48-8.66%), protein (3.09-3.15%), and density (29.65-30.37), while CS feeding produced the highest fat content (4.14-3.96%). FG feeding showed greater compositional variability. The collection period significantly affected lactose, pH, TSS, and milk temperature. Correlation analysis separated immediate temperature effects on density (r = −0.610*) from chronic heat-stress responses, reducing milk solids (SNF: r = −0.667**; protein: r = −0.458*). Overall patterns reflected combined influences from feeding, management, and the environment rather than feeding alone. Nonetheless, silage-based systems supplemented with spent grain showed strong potential for improving milk quality in tropical smallholder dairy systems, with temperature-based insights guiding targeted management interventions.