Evaluating the Inclusion of Cold-Pressed Rapeseed Cake in the Concentrate for Dairy Cows upon Ruminal Biohydrogenation Process, Ruminal Microbial Community and Milk Production and Acceptability

SIMPLE SUMMARY: Soybean meal and palm oil are important protein and energy sources in European livestock production, respectively. In the next decades, the demand for these feedstuffs is supposed to increase as the world population and its demand for meat and dairy products increases. Alternatives to replace those feedstuffs are necessary. It is necessary to promote low-input, local, and circular production systems: in this sense, adopting feeding systems that use cheaper and local alternative feedstuffs represents a good strategy. One of them is the product obtained after a simple pressing process for the production of biofuels. Cold pressing usually produces oil that can be used as biofuel and a cake rich in fat and with high oil quality but with lower protein content than the conventionally solvent-extracted cakes. Therefore, the availability of cold-pressed cakes can represent an example of integration between the industry and livestock production. The objective of this study was to assess the suitability of formulating cold-pressed rapeseed cake (CPRC) in a dairy cows’ concentrate as a substitute for conventional feedstuffs. Feeding CPRC has the advantage of slightly improving the milk fatty acid profile and consumer acceptance. In conclusion, CPRC can replace conventional feedstuffs without detrimental effects on milk production and composition. ABSTRACT: The aim of this trial was to assess the effect of feeding a concentrate including cold-pressed rapeseed cake (CPRC) on productive performance, milk quality and its sensory properties, ruminal biohydrogenation, and bacterial communities. Eighteen cows were paired, and two experimental diets (control vs. CPRC) were distributed within the pair. Concentrates were iso-energetic and iso-proteic and contained similar amounts of fat. The average days in milk, milk yield, and body weight of the animals were (mean ± SD) 172 ± 112 d, 585 ± 26 kg, and 25.4 ± 6.2 kg/d, respectively. The experiment lasted for 10 wk. Feeding CPRC resulted in lower ruminal saturated (p < 0.001) and higher monounsaturated (p = 0.002) fatty acids. Feeding CPRC increased Ruminococcus, Prevotella, and Entodinium but decreased Blautia; p-75-a5; undefined genera within orders Clostridiaceae and RF39 and within families Christensenellaceae, Lachnospiracease, and Ruminococcaceae; and fungi from the phylum neocallimastigomycota. The milk fatty acid profile was characterized by a lower n6:n3 ratio (p = 0.028). Feeding CPRC did not affect the milk yield, milk quality, or fat corrected milk (p > 0.05). Feeding CPRC improved the overall milk acceptability (p = 0.047). In conclusion, CPRC affected some microbial taxa, modified the biohydrogenation process, and improved the milk fatty acid profile and consumer acceptance without detrimental effects on milk production and composition.