Lohan, O.P.Sunda, Surender Kumar2017-08-212017-08-212004http://krishikosh.egranth.ac.in/handle/1/5810029199The present study was undertaken with the objectives to study the effect of replacing wheat straw with different crop residues and leguminous hay in complete feed blocks on milk yield, growth rate and rumen metabolites. The in vivo study was completed in three experiments. Experiment-I Sixteen crossbred lactating cows randomly divided into 4 groups of 4 animals in each and fed on dry roughage based complete feed blocks. The wheat straw plus mixed berseem and cowpea hay (1:1) + concentrates complete feed blocks offered in T1. Wheat straw was further replaced with paddy straw in T2, sugarcane bagasse in T3 and mustard straw in T4 at 50 percent level and offered for 90 days. The roughage to concentrate ratio was maintained at 60:40. The roughage portion of feed was treated with 15 per cent molasses before mixing with concentrates mixture to increase the adhesive characteristics of roughages. There was no significant effect on milk yield, SNF and total solids content of milk due to different dietary treatments. However, milk protein content was significantly (P<0.05) higher in T1 as compared to other diets. Fat content diet was significantly (P<0.05) higher on T1 and T4 diets as compared to T2 and T3 diets. It was observed that DMI/Animal/d and DMI/100 kg BW/d was significantly (P<0.05) higher in treatment T1, T2 as compared to T3 and T4 treatments, while there was no significant difference between treatments T1 and T2 vis-a-vis T3 and T4. The digestibility of DM was significantly (P<0.05) higher in treatments T1, T2 and T3 as compared to T4 treatment, while there was non-significant difference in T1, T2 and T3. Similar trend was observed in respect of CP, CF, EE and NFE digestibilities. The NDF digestibilities were not differed significantly. However, ADF digestibility was significantly (P<0.05) higher in T1 and T2 as compared to T3 and T4 treatments, with non-significant difference between T3 and T4 treatments. Experiment-II In this experiment, 18 buffalo heifers were divided into three groups having six in each. The wheat straw in T1 was replaced with mustard straw at 20 (T2) and 30 percent level (T3), respectively. In each treatment roughage to concentrate ratio was kept 60:40. Molasses was added at 15 percent level. Water was added to keep the moisture level between 15-17 percent and the mixture was densified. The daily DM intake was 5.84, 5.71 and 5.22 kg in treatment T1, T2 and T3, and there was non-significant difference among them. The DM intake/100 kg BW was 1.92 kg in T1, 1.91 kg in T2 and 1.69 kg in T3; the differences were statistically non-significant. DM digestibility co-efficient was similar among treatments. Similar trend was observed for crude protein and fibre fractions digestibilities in these diets. The average daily weight gain (g) was significantly (P<0.05) higher in T1 (509.80) as compared to T2 (423.53) and T3 (355.00), however, the differences were non-significant between T1 and T2 and between T2 and T3 treatments. Feed consumed per kg gain was 11.90 kg in T1, 14.31 kg in T2 and 14.44 kg in T3. Experiment-III The complete feed blocks developed for experiment-I were also evaluated in rumen fistulated adult cattle in a 4x4 switch over design. The daily dry matter intake per animal, and per 100 kg body weight was significantly higher in T1 and T2 treatment as compared to T3 and T4 treatments, however, between treatment T1 and T2 vis-a-vis T3 and T4 there was no significance difference. The DM digestibility was significantly (P<0.05) higher in treatments T1, T2 and T3 as compared to T4 treatment. Protein digestibility was higher in T1 and T2 treatments as compared to treatments T3 and T4, whereas the differences between T1 and T2 vis-a-vis T3 and T4 were non-significant. Similar trend were observed in EE, NFE and fibre fraction digestibilities coefficients. There was no significant difference observed in rumen pH due to treatments, however, significantly (P<0.05) higher pH was observed at 0 h as compared to post feeding periods i.e. 3, 6 and 9 h. The mean total nitrogen was significantly (P<0.05) higher on T3 diet followed in descending order by T4, T1 and T2 diets. The time of sampling also affected significantly (P<0.056) total nitrogen. The NH3-N concentration was significantly (P<0.05) higher in T1, T3 and T4 than in T2 diets. The peak of NH3 production was attained at 3 h post feeding, irrespective of the diets. The protein nitrogen concentration was significantly (P<0.05) higher in T3 diet followed by T2, T4 and T1 diets. The T2 had significantly (P<0.05) lowest, the treatment T4 the highest production of TVFA, while T1 and T3 treatments had the intermediate value.enThesis