The effects of myrtle extract added to drinking milk on performance and some blood parameters of simmental calves

The concept of one health is relatively a new term indicating that the environment, the animals and the humans are inter-dependent to each other. One of the important aspects of one health concept is food obtained from the animal sources. The concept of "feed safety for food safety" illustrates that the organic and natural feed or feed additives should be given to the food producing animals to ensure the availability of safe and healthy food, without any antibiotic residues or growth hormones, for the human consumption. To lead a healthy life, the humans need good quality animal protein having good profile of amino acids which can only be obtained from the healthy food producing animals. In this study, the effects of myrtle plant extract on growth performance, diarrhea rate and immune function were evaluated in Simmental dairy calves pre-weaning. Individually housed 48 Simmental calves (40 ± 4) birth weight, 3 days old) were randomly assigned to four groups with 12 calves (6 males, 6 females) in each group; C (control group), MP (10 g probiotic/calf/day), MM (50 mL myrtle extract/calf/day) and MMP (10 g probiotic + 50 mL myrtle extract/calf/day) groups. The experimental period was 75 days. All calves were fed 2 × 2 L whole milk (4 L/day) until the end of the experiment. Starter feed was offered ad libitum after 2 weeks and roughage after 4 weeks in different buckets throughout the experiment. In the beginning of 3rd week (from the 15th day), weighed and fresh feed was offered to the calves every day. On next day the remaining feed was collected from the feed pots and stored in air sealed empty bags specific for every calf and this practice kept on going for next 7 days. On the 8th day the bags, having remaining feed of previous 7 days, were weighed. Feed intake and fecal score were recorded every day before feeding until the end of the experiment. The health status i.e. temperature, fecal consistency (to examine diarrhea), scours (feces with dry matter below 10 %), respiration (to check pneumonia), skin was examined for any ecto-parasitic infestation, anhydrosis, alopecia, any fungal infection and overall body condition of calves was daily examined to check any possible disease. In the supplemented calves no severity, less frequency with no diarrhea sequels was observed so fluid therapy was not required during whole of the duration of trial. Calves affected by diarrhea in the trial were treated according to the same antibiotic treatment procedure, regardless of the supplemented or non-supplemented group. Treatments were continued for 3 consecutive days. The treatment was continued for 3 consecutive days. Body weight of all calves was measured for 3 times; at birth, weight at 1 month and final weight at day 75 of the trial. Blood samples were taken on the 7th, 20th, 40th, 60th and 75th days of the trial. All calves were vaccinated with 5 ml Bovilis (Bovipast, MSD) subcutaneously from the neck region to protect them from respiratory system diseases when they reached the age of 21 days. The booster of the vaccine was inoculated 21 days after the first administration (when the calves were 42 days old). The vaccine contains inactive BRS virus (EV 908) with a TCID50 value of 105.5, inactive Parainfluenza 3 virus with a TCID50 value of 105.5 (SF-4 Reisinger strain) and 9X109 inactive Pasteurella (Mannheimia) haemolytica cells (serotype A1). The growth parameters BW, FI, FCR, biochemical and hematological were statistically evaluated as GLM. Significance level was set at (p≤0.05). In the study, the feed intake of calves in the MM group was higher (p=0.0001) than the other groups. Body weight was higher (p=0.0085) in MM supplemented groups (MM and MMP groups) than control and MP groups. However, feed conversion ratio was similar between the groups. The incidence of frequency, severity and duration of diarrhae and pneumonia were lower in myrtle plant extract and probiotic supplemented calves compared to the control group. Glucose, NEFA, BHBA, BUN, ALT, GGT and creatinine levels of blood biochemistry parameters were similar between the groups. However, significant differences were found between the groups in terms of total protein (p=0.0001), AST (p=0.0352) and IgG (p=0.0001) levels. IgG levels were higher in all experimental groups compared to the control group. There were no significant differences in blood physiology parameters except MCH (p=0.0022), MCHC (p=0.0097) and WBC (p=0.0001) values. Thus, feed intake, growth performance and immunity of calves were significantly affected by MM supplementation during the experiment. MM decreased the incidence of diarrhea in calves before weaning. There was a significant improvement in growth performance, reduction in calf diarrhea and an overall improvement in serum immunity compared to the control group. Therefore, we recommend supplementing the milk of dairy calves with myrtle extract alone or mixture of myrtle extract and probiotics during the pre-weaning period.