Venkata Seshaiah, Ch(MAJOR)ASHA LATHA, PSUDHAKAR, KSATYA VENKATA ANIL, TELIDEVARA2018-08-022018-08-022017-12http://krishikosh.egranth.ac.in/handle/1/5810063048THESESABSTRACT : An experiment was conducted to evaluate the effect of dietary supplementation of nano zinc oxide (nZnO) on growth performance, haematology, serum biochemical parameters and cost per kg weight gain in crossbred calves. A total of twenty four crossbred calves of about 6 months age were randomly selected and grouped into four groups wherein each group consisting of six calves on the basis of body weight. The calves were allotted to one of the following treatments randomly. Group I is set as control where only basal diet was fed. Along with the basal diet, Group II (Treatment 1) was supplemented with 25ppm conventional ZnSo4, Group III (Treatment 2) was supplemented with 5ppm nano zinc oxide and Group IV (Treatment 3) was supplemented with 10ppm nano zinc oxide. Zinc content in basal was estimated to be 26.24ppm. The feed intake in CB calves was not affected by the dietary supplementation of nZnO. However, the body weight gain and average daily gain were significantly (P<0.01) higher in the nZnO supplemented groups over the control and T1 groups and the feed conversion ratio was significantly (P<0.01) lower in the groups supplemented with nZnO over C and T1 groups. Significant difference was not observed in the body condition score of crossbred calves upon supplementation of nZnO. Similarly, nZnO supplementation has not shown any significant changes in the mean haemoglobin concentration, RBC count, WBC count, platelet count and mean corpuscular volume of crossbred calves and all the haematological parameters varied within the normal range. The biochemical parameters viz., serum zinc, total protein and serum globulin were significantly (P<0.01) higher in the groups supplemented with nZnO compared to the C and T1 groups. The serum albumin levels were significantly higher (P<0.01) in nZnO supplemented group when compared to T1. However, the albumin to globulin ratio was significantly (P<0.05) higher in the control group compared to the T1, T2 and T3. There was a statistically significant (P<0.05) difference in the blood glucose levels between C and T2 on 45th day. On the other hand, no significant difference was observed in serum calcium, SGOT, blood urea nitrogen and creatinine level between the groups throughout the experimental period. However, serum phosphorus level was significantly (P<0.05) higher in T2 compared to T1 and T3. The cost per kg weight gain was low in the T3 group calves over the other groups which might be due to higher growth rates in calves. Further, there is a scope for reduction in price of nano particles which may further cut down the cost of feeding in calves. Therefore, nZnO may be recommended in the diets of CB calves at the rate of 10ppm/day for better growth rates and reduced feeding costs in calf rearing.ennullThesis