Effect of mixed thyme and eucalyptus leaves aqueous extract on the performance and health of Holstein suckling calves

To determine the effect of mixed thyme and eucalyptus leaves aqueous’ extract on the performance and health of Holstein suckling calves, an experiment using 32 calves (16 females and 16 males) with 7±3 days old and an average weight of 40.4±3 kg was carried out in a completely randomized design with four treatments and 8 replicate for 70 days. The treatments were: diets with no extract (control); and diets containing10, 15, and 20 ml of extract (50 % thyme + 50% eucalyptus) in consumed milk. In order to evaluate changes in body weight, chest circumference and height, the data were measured and recorded on days 7, 28, 49, and 70 at 10 a.m. To determine the blood parameters, blood samples were taken from the jugular vein on the 70th days. It turned out that the extract can result in a higher mean body weight gain and larger body size (P <0.05). Moreover, thyme and eucalyptus extracts appeared not to have any effect on digestibility and feed intake, but feed efficiency improved with 20 ml (P <0.05). Fecal and eye secretion index in calves receiving diets containing 15 and 20 ml of extract improved compared to the control group (P <0.05). Also, adding 20 ml of the extract reduced the amount of glucose and increased the number of red blood cells and hematocrit in the blood of the receiving calves compared to other experimental groups. The findings indicated that adding 20 ml eucalyptus and thyme extracts in daily milk, can improve the performance and health of Holstein suckling calves