Kids and Management- Eighteen male Black Bengal kids of 3 weeks old were separated from their dams and divided into three groups (Groups A, B and C) that were equal for initial weight. Each group contained 6 kids. They were housed in 3 separate pens. The floor space per kid was 13.33 sq. ft. The house was well ventilated. Every day the floor, feeder and water trough were cleaned using phenyl as antiseptic. A separate feeder was used for roughage and concentrate feeding and no records were kept. After five weeks small amount of concentrate mixture and roughage were supplied to the kids. The three groups of kids were fed cow milk individually on different milk treatments: A -10%, B -15%, C - 20% of live weight per day in whole cow's milk. Kids fed three times daily from 4 to 6 weeks old, twice daily from 7 to 10 weeks old, and once daily from 11 to 13 weeks old. Thereafter, gradual weaning began at 9 weeks old and ended at 13 weeks old. The amount of milk fed to the kids was gradually reduced to zero by the end of week 13, using week 7 intakes as a base 2%, 3% and 4% level in 10 %, 15% and 20% milk feeding groups, respectively. This careful weaning method was employed to reduce the within treatment variation in weight gains. After five weeks small amount of concentrate mixture (24% crude protein) were supplied to the kids. Then after 6 weeks concentrate feeds were increased gradually up to the end of experiment. This study was approved as ethically sound by Bangladesh Agricultural University Research System (BAURES). Liveweight- Each kid was weighed weekly at 8.00 am using a digital balance. The kids were kept off feed overnight (17 hours) before weighing. Collection and processing of blood- Blood samples were collected at 8 weeks of experimental period at 9.00 am via jugular vein puncture into evacuated tubes containing EDTA (Ethylene diamino tetraacetate) for determination of blood parameters including red blood cell (RBC), white blood cell (WBC), haemoglobin (Hb), Erythrocyte sedimentation rate (ESR) and packed cell volume (PCV). Collection and examination of blood were performed following the procedure described by Sarker et al. (2015). In brief, the area from where blood is to be collected was shaved by blade. The needle was inserted into the raised vein and then removed from syringe for discharging the blood into vial containing anticoagulant gentle. For haematological test, blood was stored in EDTA tube. Carcass and non-carcass variates- Kids were sacrificed at 16 weeks of age. Liveweight, length of body, heart girth, circumference and length of neck, and height at withers of each kid were recorded prior to sacrifice. Kids were fasted overnight (17h) and sacrificed using the approved “Halal” method. By this method, goats were bled by cutting the throat and then slaughtered by severing the head at its articulation on the occipito-atlantal space. At the time of sacrifice, blood was collected in a pail and weights were recorded. The head was removed along with the pelt and feet and each weighed individually. The digestive tract was removed and weighed at full and empty conditions to obtain the weight of the “gut fill”. Liver, kidney, spleen, lung with trachea, heart, caul fat and renal fat were separated from attached tissue and weighed separately. Warm carcass weights were recorded immediately after completing dressing and evisceration. Testicles were removed and collected into phosphate buffered saline (PBS). Rumen development- After sacrifice, reticulo-rumens were emptied, and rinsed with cold water, then transported immediately to the laboratory. Rumen tissues were sampled from nine different positions: right side of cranial ventral sac (RD), left side of cranial ventral sac (LD), right side of cranial dorsal sac (RC), right side of caudal dorsal sac (RB), right side ventral portion of caudal ventral blind sac (RE), left side ventral portion of caudal ventral blind sac (LE), left side of cranial dorsal sac (LC), left side of caudal dorsal sac (LB), caudal portion of the caudal ventral blind sac (A) following the procedure described by Sarker et al.(2015). The thickness of the rumen was measured at each of these sites. To determine papilla density, the number of papillae per microscopic field was assessed at 5×10x, and visual observations were taken using a Stereo Zoom microscope (CZM6: Labo America Inc., California, USA) at the nine different sites. Histology- After collection adipose tissues surrounding the testes were removed carefully. Length and width of each testis were measured with Slide Callipers and their weights were also recorded. Tissue from testes and rumen were fixed in Bouin’s solution for subsequent measurement of testicular development and rumen papilla length and width respectively. After dehydration in graded alcohol and cleaning in xylene, tissues were infiltrated and embedded in melted paraffin. Five cm thick sections were prepared by using a rotatory microtome (Thermo Fisher Scientific) and placed upon glass slide and air dried in room temperature. The sections were then stained with haematoxylin and eosin. Finally, the stained sections were permanently mounted with a cover slip using DPX (Sigma-Aldrich) mounting reagent. Microscopy- For the rumen samples, the length and width of papillae were measured using an ocular micrometer attached with the Stereo Zoom microscope (Olympus, USA) at nine different position (5 × 10x) using thirty microscopic fields. Every fifth serial section was observed with a Differential Interference Contrast (DIC) microscope (Olympus, USA). Statistical analysis- Data were represented as the mean ± SE (standard error). All data were subjected to one-way ANOVA, and the significance of difference among means was determined using Tukey’s HSD test. All analyses were conducted in “SAS/STAT version 9.1.3” for Windows Service Pack 4, 2004 SAS Institute, Cary NC USA for Windows. Differences at p<0.05 were considered statistically significant.