Effect of vegetable oil source supplementation on feed intake, nutrients digestibility and rumen biohydrogenation bacterial population in Thai Friesian dairy cows

The investigation aimed to study the effect of vegetable oil sources on feed intake, nutrient digestibility and biohydrogenation bacterial population in Thai Friesian dairy cows. Three fistula Thai Friesian cows with mean body weight (BW) of 600±100 kg were assigned to receive three vegetable oil sources i.e. palm oil (PO), soybean oil (SBO) and sunflower oil (SFO) included at 4 %DM in commercial concentrate. All cows were fed on different diets that contained concentrate of 1 %BW and rice straw of 1 %BW according to a 3×3 latin square design (LSD). The results revealed that dry matter digestibility (DMD) and organic matter digestibility (OMD) tended to be higher in cows fed on SBO and SFO (P=0.06). Moreover, the DNA copy numbers (copies/ml) of biohydrogenation bacteria (Ruminococcus albus) and cellulolytic bacteria (Ruminococcus flavefaciens and Prevotella ruminicola) were higher in cows fed on SBO (P less than 0.05). In summary, supplementation of SBO in diet resulted in a higher nutrient digestibility and rumen biohydrogenation bacteria population.