Performance of Holstein dairy cows fed a diet supplemented with rosemary and ginger essential oils: milk production, milk fatty acid, and ruminal fermentation

Abstract

The study determined the impact of Rosmarinus officinalis and/or Zingiberene officinalis essential oil (EO) on milk yield, composition, milk fatty acids profile, blood biochemicals, and rumen fermentation in dairy cows. Twenty-eight Holstein lactating cows were distributed into four groups using a completely randomized block design in a 70-d experiment. The control diet consisted of 13 kg of concentrate and 40 kg of fresh berseem clover per head per day, without supplementation. In the other treatments, the control diet was supplemented with 10 mL of EO per head per day, using either ginger EO (GEO treatment), rosemary (REO treatment) EO or a blend of both at a 1:1 v/v ratio (BEO treatment). Supplementation did not affect intake, milk production, or composition. Omega-n3 and omega-n5 were increased with REO (p < 0.05) compared to the control. Both REO and BEO decreased (p = 0.003) serum globulin and increased (p < 0.005) albumin to globulin ratio, high-density lipoprotein cholesterol, and total lipid. Serum total antioxidant capacity was increased (p ˂ 0.001) with the supplementation, without affecting glucose, total protein, albumin, serum cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, and urea concentrations. In conclusion, supplementing Holstein dairy cows with GEO and/ or REO increased the level of omega-3 and omega-5 fatty acids while reduced saturated fatty acids in milk, without affecting feed intake, milk production or milk composition.