Effects of Ajwain (Trachyspermum ammi) and Thyme (Thymus vulgaris) Oils on Nutrients Digestibility, Blood Parameters and Growth Performance of Brown Swiss Neonatal Calves

The aim of this study was to compare the effects of dietary supplementation of ajwain (Trachyspermum ammi) and thyme (Thymus vulgaris) essential oils (EO) on nutrients digestibility, blood parameters and growth performance of neonatal dairy calves during eight weeks. Sixty suckling dairy calves with an initial body weight (43.2±3.8 kg) were randomly allocated to five treatments including CO, control without essen-tial oils (EO) supplementation; AJW-L, ajwain (AJW) oil mixed in milk at 1 mL/d per calf; AJW-H, AJW oil mixed in milk at 2 mL/d; THY-L, thyme (THY) oil mixed in milk at 1 mL/d and THY-H, THY oil mixed in milk at 2 mL/d. The experiment consisted of 7 d adaptation and 60 d sampling and data recording period. Experimental diets had no significant effects (P>0.05) on feed intake, average daily gain and feed conversion ratio. Dietary supplementation of both AJW and THY linearly improved (P<0.01) the apparent total tract digestibility of dry matter, organic matter, neutral detergent fiber, and acid detergent fiber while AJW improved (P<0.01) the digestibility of organic matter and neutral detergent fiber in a quadratic man-ner. AJW-L and THY-L decreased while their high level increased (P<0.05 for quadratic effect) white blood cell count. Also, increasing level of both EO increased (P<0.05) blood serum glucose linearly. In-creasing level of AJW increased (P<0.05) total triglyceride but decreased (P<0.05) blood urea nitrogen. Overall, the results of this study suggest that THY and AJW oils improved digestion, biochemical parame-ters, and some blood hematological parameters without influencing the performance of neonatal dairy calves.