2.1. Experimental design, animals and diets The effect of seeds and leaf of three famous traditional medicinal plants viz. E. officinalis Gaertn. or P. emblica Linn. (Euphorbeaceae), T. bellirica Gaertn. Roxb. (Combretaceae) and T. chebula Retz. (Com-bretaceae) as natural feed additives were evaluated on crossbred (Local ×Holstein Friesian) post-weaned bull claves at the Livestock and Poultry Farm, Faculty of Veterinary Medicine and Animal Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur-1706, Bangladesh. The feeding trial of traditional medicinal plants (TMP) was conducted for a period of 90 days. Twenty- four animals of almost similar age and body weight (about 6 months; body weight 51.0 ±1.0) were selected and randomly distributed to the control and treatment groups having six calves in each group. The control group received only roughage and concentrate feed without any TMP as feed additives. On the other hand, three treatment groups received different traditional medicinal plants as natural feed additives with the roughage and concentrate feed. The dietary treatment groups were TMP1 (basal diet =green grass +concentrate), TMP2 (basal diet +0.5% mixture of seed and leaf (75:25) of E. officinalis Gaertn.), TMP3 (basal diet +0.5% mixture of seed and leaf (75:25) of T. bellirica Gaertn. Roxb.), and TMP4 (basal diet +0.5% mixture of seed and leaf (75:25) of T. chebula Retz.). The experiment was ethically approved by BSMRAU, Bangladesh authority. All the animals were reared according to the animal care and management committee of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, and followed the guidelines and suggestions of Directorate of Livestock Services and Bangladesh Livestock Research Institute of the People’s Republic of Bangladesh. Where, ethical issues and animal welfare aspects were applied to confer the animal rights.
2.2. Preparation, processing and analysis of samples The whole seeds and leaves (75:25) of E. officinalis Gaertn. or P. emblica Linn. (Euphorbeaceae), T. bellirica Gaertn. Roxb. (Com-bretaceae) and T. chebula Retz. (Combretaceae) was dried at 60 0C, ground and stored in air tight containers. All the medicinal plants were collected from BSMRAU campus, Bangladesh that were authenticated by a plant taxonomist Professor Md. Abdul Baset Mia of the Department of Crop Botany of BSMRAU, Bangladesh. The medicinal plant materials were processed and prepared at Animal Science and Nutrition Labora-tory, BSMRAU, Bangladesh. Furthermore, processed medicinal plant materials were checked and authenticated by the ethical approval committee of BSMRAU, Bangladesh for using them as feed supplements for the ruminants. Additionally, primary experiments with poultry and ruminants, these medicinal plants did not show any detrimental impacts on health and productivity of the tested animals, rather these materials promoted health indicators (Bostami et al. unpublished; Bostami et al., 2015b, 2021). The whole seeds and leaves (75:25) of traditional me-dicinal plants as powder form were used as the natural feed additives in the current study.
Proximate analyses (dry matter, crude protein, ether extract and ash) of green grass and concentrates and traditional medicinal plants as natural feed additives were carried out for each sample in triplicate for dry matter (DM), crude protein (CP), Crude fat (EE), nitrogen free extract (NFE) and ash following the AOAC (1990). Official Methods of Analysis. Association of Official Analytical Chemistry (15 Ed), Wash-ington, D.C., U.S.A. While for determination of Ca, P, Na and K con-centrations the methods of Jackson (1969) was followed. In addition to that, the determination of Mg concentrations was estimated by following the methods as described by Kalra and Maynard (1991). Moreover, determination of Mn, Cu and Zn was done by following the method describe by McLaren, Swift and Quin (1984)). The proximate compo-sition of E. officinalis, T. belerica and T. chebula.
2.3. Management and monitoring of animals The trial was carried out at Livestock shed, Livestock and Poultry Farm, Faculty of Veterinary Medicine and Animal Science, Banga-bandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur-1706, Bangladesh. Where there was set up of separated pens, each of which was equipped with a feeding and watering trough as required for post-weaned bull calves. All pens were located in the same calf house and the calves were randomly allocated based on treatments. The total area per pen was provided 8.5 m2. The house was equipped with good ventilation and the bedding materials used in the pens was chopped straw. Fresh clean drinking water was available for the calves’ ad libitum. Intake of roughage and concentrate were measured separately and refusals were recorded daily. Manure was removed daily to ensure hygienic condition of the animal house. Temperature and humidity in the calf house was monitored regularly. There was sufficient sunlight as well as electricity facility for lighting based on necessity of animals. All calves were weighed monthly throughout the experimental period. Blood samples were collected from each group on the last week of the trial and the samples were further analyzed in the Laboratory of Faculty of Veterinary Medicine and Animal Science of BSMRAU, Bangladesh.
2.4. Estimation of digestibility of nutrients The digestibility coefficients were estimated from the fecal samples taken directly from the rectum of the animals from the seventh to the tenth day in each experimental period according to the following distribution: 7th day – 6 a.m. and 2 p.m.; 8th day – 8 a.m. and 4 p.m.; 9th day – 10 a.m. and 6 p.m.; and 10th day – 12 p.m. and 8 p.m. The feces samples were oven-dried (60 0C for 72 h) and processed in a Wiley mill (1 mm). Composite samples were elaborated per animal and experimental period. The digestibility coefficients were estimated by the method described earlier by Lazzarini et al. (2009). Feed ingredients in the experimental diet of post-weaned crossbred (Local ×Holstein Friesian) bull claves. Ingredients Percentage (%) as fed-basis Corn, ground 22.37 Wheat bran 15.00 Wheat, ground 15.00 Rice bran 10.00 Cotton seed meal 7.00 Corn gluten meal 4.50 Protein concentrate 9.90 Sunflower meal 2.50 Soybean meal 2.76 Rapeseed meal 1.00 Distillers dried grains 1.00 Molasses 5.00 Salt 0.60 Limestone (1 mm) 1.87 Di calcium phosphate (DCP) 0.50 Calcium sulfate 0.30 Mineral premix 0.35 Vitamin premix 0.35 Chemical composition Moisture 12.29 Crude ash 6.10 Crude fat 2.57 Crude fiber 5.71 Crude protein 14.74 NFE 58.71 NFE: Nitrogen free extract. Table 2 Proximate composition of experimental selective traditional medicinal plants provided with basal diet to post-weaned crossbred (Local ×Holstein Friesian) bull claves. Parameters Emblica Officinalis Terminalia bellirica Terminalia chebula % DM (air dry basis) 95.22 94.87 93.12 CP (% as DM basis) 4.89 6.78 4.32 CF (% as DM basis) 9.11 8.77 9.67 NFE (% as DM basis) 77.83 77.75 81.05 EE (% as DM basis) 1.42 1.27 1.25 Ash (% as DM basis) 6.81 5.42 5.12 Ca (ppm) 0.15 0.14 0.10 P (ppm) 9.21 6.42 8.42 Mg (ppm) 0.32 0.39 0.31 K (ppm) 6196.00 6668.00 6616.00 Na (ppm) 183.45 171.23 172.32 Mn (ppm) 209.76 53.33 36.53 Zn (ppm) 39.45 13.52 22.63 Cu (ppm) 6.02 6.23 7.82 DM: dry matter; CP: crude protein; CF: crude fiber; EE:ether extract; NFE: ni-trogen free extract. A.B.M.R. Bostami et al.