Effect of Myrtus communis L. Plant Extract as a Milk Supplement on the Performance, Selected Blood Parameters and Immune Response of Holstein Calves

Simple Summary: The growing female calves are the future of the dairy farms and their balanced growth yields benefits in their adult lives. Natural herbal products and their extracts are considered as digestive stimulants, immune enhancers and anti-oxidants. The additions of these phytogenic extracts have proven to be beneficial in animals. This study involved the addition of myrtus leaves and root extract in the milk of the suckling calves and observed its benefits on their health, performance and immune status in the following days. It is concluded that the addition of the myrtus extract results in the improvement in the overall performance, reproduction and health status of the animals. This research aimed to understand the effects of adding myrtle plant extract obtained from its leaves (MPEL) and roots (MPER) to the milk fed to suckling female Holstein calves, focusing on performance, reproduction, selected blood parameters and immune response. The 50 Holstein female calves, one week of age, were divided into five groups: one group received no plant extract (Control), while the others were supplemented with myrtle plant extracts at doses of 25 mL/day leaf extract (MPEL-25), 25 mL/day root extract (MPER-25), 50 mL/day leaf extract (MPEL-50) and 50 mL/day root extract (MPER-50) for each calf in each treatment group. The extracts were given along with the milk to the experimental groups for 60 days, and for an additional 12 days post-weaning. The results reveal that the feed consumption and live weights increased significantly. Significantly higher leukocyte counts were observed in the 50 mL/head x day myrtle groups, and a higher IgG concentration was also noted in the MPER-50 group compared to the other groups. The serum non-esterified fatty acid (NEFA) concentration significantly decreased in the MPEL-50 and MPER-50 groups, whereas the betahyrdoxy butyric acid (BHBA) concentration increased and the serum glucose concentration significantly decreased with myrtle supplementation. In conclusion, it was determined that the performance, immune system and negative energy balance compensation of female Holstein calves were positively affected by administering extracts obtained from the leaves and roots of the Myrtus communis L. plant at dose levels of 25 and 50 mL/head x day for 72 days, without causing any side effects.