Background. A cow feeding system had a significant effect on the basic parameters characterising milk technological usability. Milk from the Polish Black-and-White variety of the Holstein-Friesland cows kept in the Total Mixed Ration (TMR) feeding system or on the traditional feeding regime was compared in terms of its utility for yoghurt manufacture. Material and methods. Milk samples, collected six times a year at about 2-month intervals, were assayed for density, acidity, and contents of fat, protein, and lactose. Dry matter and solid-not-fat (SNF) contents were determined, as was the protein/fat ratio. Thermal stability of the milk was assessed with alcohol tests. The yoghurts manufactured (test yoghurts) were assayed for acidity, acetaldehyde content, and hardness. The yoghurts were also subjected to sensory evaluation.
Results. The cow feeding regime was found to have distinctly affected the composition and physico-chemical parameters of milk. Milk samples collected from cows fed in the traditional system contained more fat and dry matter than the milk yielded by the TMR-fed cattle. The latter produced milk that usually showed higher crude protein and casein contents, as well as higher SNF contents; in addition, the density of that milk was higher.
Conclusions. The feeding regime did not affect, in any clear-cut way, the sensory characteristics of the test yoghurts. However, those yoghurts manufactured from the TMR-fed cow milk contained more acetaldehyde and, in most cases, showed higher hardness, compared to the yoghurts made from milk produced by the cows kept on the traditional feeding regime.