Silage Research Papers - Academia.edu (original) (raw)

MSc. Thesis by Haitham M. H. Al-Sultany, supervised by Prof. Dr. Ali A. Saeed
Abstract
This study was conducted to investigate the possibility of improving palatability and nutritive value of reed by ensiling due to desired taste that good quality silage characterized with and improving digestion and chemical composition by addition of urea. Silages were prepared in Animal field of Animal Resources Department-College of Agriculture/Al-Qasim Green University. Where reed was treated with solution containing debis at rate of 10% as source of soluble carbohydrates and urea as a source of nitrogen at 3 rates, 0, 1 and 2%. 24 Awassi male lambs were used with 4-6 months of age and mean initial weight of 20.59 kg. Lambs were randomly distributed into 6 groups in individual pens with 4 lambs per each.
Roughages (silage and reed) were offered ad libitum, whereas, concentrate was offered at rate of 2% of body weight. This study was lasted for 10 weeks following preliminary period for 19 days.
Results revealed that dry matter (DM) and crude fiber contents were reduced and crude protein (CP), ether extract and metabolizable energy (ME) contents were increased due to ensiling. Whereas, urea treatment increased CP and ME contents. Reed was characterized with higher increase in CP as compared with silage; this increase was 3.1 and 2.74 for reed vs. 1.76 and 2.74% for silage at urea levels of 1 and 2% respectively.
Regarding silage fermentation, it was observed that pH, ammonia nitrogen (NH3-N) and total volatile fatty acids (TVFA) assumed similar trend to increase with increasing level of urea treatment, urea untreated reed silage and that treated with urea at rate of 1% recorded low pH (3.7 and 4.3, respectively) as compared with high pH value for reed silage treated with high level of urea (6.7). These values were reflected on quality parameters, where, higher Fleig points were estimated for the former two silages (132.98 and 115.46, respectively). Lower DM loss was estimated in reed silage treated with lower level of urea as compared with untreated and that treated with high level of urea, these loss ratios were 14.05, 17.73 and 22.80 respectively. Concerning aerobic stability, better values were related with level of urea. Values were 39.5, 38.5 and 31.5 hours for reed silages treated with 2, 1 and 0% respectively. Regarding buffering capacity, results showed lower values with increasing urea treatment, where, released ammonia from degradation of urea during ensiling neutralized organic acids accumulated in stored mass.
Results also revealed that lambs fed reed were significantly superior in intake of all nutrients with exception of digestible DM intake and organic matter (OM) intake, where, values did not differed significantly due to improvement in digestion caused by ensiling. Intake of OM of roughages, total nitrogen (N), total digestible N, total rumen degradable N (RDN) and RDN:ME were affected (P˂0.01) by urea treatment. Moreover, intake of all nutrients except that of total digestible OM was significantly affected by interaction between ensiling and urea treatment.
Ensiling improved digestibility coefficients of all nutrients except that of nitrogen free extract and hemicellulose, whereas, it decreased (P<0.05) CP digestibility (67.03 and 69.59% for silage and reed, respectively. Digestibility was also affected by urea treatment, where, better values were generally achieved with 1% of urea except those of fiber components, in which, 2% level of urea was superior in acid detergent digestibility (P<0.05) and hemicellulose (P<0.01), and mathematically in NDF and cellulose digestibilities.
Final weight and average total and daily gain were not affected by ensiling and level of urea, corresponding values were, 25.93, 5.52 and 78.86 for lambs fed reed silage vs. 27.18 kg, 6.07 kg and 86.83 g/day for reed respectively. Final gain was not affected by interaction between ensiling and level of urea, whereas, lambs fed reed treated with low level of urea gained higher average final and daily gain. Ensiling was significantly superior in feed conversion ratio (FCR) estimated on basis of DM intake (7.74 vs, 8.86) and digestible protein (0.09 vs. 0.11). Whereas, 0% level of urea showed significant superiority in FCR regardless to basis of estimation. Lambs fed untreated reed silage recorded better FCR in comparison with other lambs.
Regarding ruminal fermentation, results pointed out that pH was increased (P<0.01) due to ensiling, values were 6.91 vs. 6.71 for silage and reed respectively, yet it was no affected by level of urea. Higher (P<0.01) value of ruminal NH3-N was detected in samples withdrawn from lambs fed read treated with high level of urea as compared with untreated silage (10.21 vs. 11.05 mg/100 ml for silage and reed respectively). Ruminal TVFA was not affected by ensiling (5.67 vs. 5.65 mmol/100 ml) and level of urea treatment. Untreated silage and reed treated with 2% of urea recorded higher pH and NH3-N respectively. Higher pH and TVFA were recorded in samples withdrawn before feeding to be decreased at 3 hours post feeding, than it increased after 6 hrs. Higher level of NH3-N in samples withdrawn 3 hours post feeding, then it decreased at 6 hours post feeding, however, it was still higher than those recorded at before feeding.
Results of study showed that there was a significant effect (P<0.01) for treatment with high level of urea on concentration of blood urea nitrogen (BUN), values were, 41.67, 40.88 and 48.39 ml/100 ml for 0, 1 and 2% levels of urea respectively. No significant effect was observed for ensiling and urea treatment on other blood parameters. However, a significant effect (P<0.05) was noticed for interaction between ensiling and urea treatment on concentration of total protein (TP) and NH3-N. Higher (P<0.01) blood glucose concentration was detected in samples withdrawn before feeding (79.86) as compared with those in samples withdrawn at 3 and 6 post feeding (71.92 and 69.61 mg/100 ml respectively), whereas, Higher concentrations of TP and NH3-N were detected in samples withdrawn 3 hours post feeding, values were 10.54 g/100 ml and 51.98 mg/100 ml respectively. Higher total triglycerides concentration was detected in samples withdrawn at 6 hours post feeding.