تأثیر تغذیه شبدر برسیم سیلویی مخلوط با تفاله ی خشک مرکبات بر عملکرد بره پرواری زل

Abstract

Introduction Feed contributes about 75% of the total cost of animal production, therefore utilizing of by-products such as Berseem clover and citrus pulp, as nutritive and low cost components of rations would decrease the production cost. In north of Iran over autumn and winter, utilizing of these by-products in making of silage as feed for ruminants provides good feed ingredient especially in feedlot operations, also eliminates pathogens, and reduces the effect of drugs and pesticides that are used locally without a serious control or discipline. However, little information available on utilizing silage made from these local by-products. The objectives of this research were to investigate the effects of ensiled Berseem clover and orange peels mixture on intake, digestibility, chewing behavior and performance of Zel fattening lambs. Materials and methods Twenty male Zel lambs fed with five experimental rations containing basal concentrate and 35% Berseem clover silage as: 1) without additives, 2) supplemented with 40% dried orange peels, 3) supplemented with 40% dried tangerine peel, 4) supplemented with 35% dried tangerine peel and 5% ground barley and 5) supplemented with 35% dried orange peels and 5% ground barley. Lambs were housed in individual box and fed ad libitum, twice daily at 09:00 and 21:00 h with total mixed rations as experimental treatments, allowing for at least 10% residuals (as-fed basis). Water and mineralized salt stone were available throughout the experiment. Feed particle size distribution, geometric mean and the standard deviation of geometric mean were determined by dry sieving in four replicates, using two set of Penn State particle separator. Feed, feces and orts were analyzed for dry matter, Kjeldahl N, ether extract, organic matter and ash at 605°C, neutral and acid detergent fiber (NDF and ADF) when α-amylase being added for concentrates during NDF extraction; sodium sulfite was not added. Neutral detergent fiber was expressed without residual ash. Non-fibrous carbohydrate (NFC) was calculated by 100- (%CP+ %NDF+ %Ash+ %EE). Cr-mordanted NDF alfalfa was used as single marker for ruminal digestive kinetic (3). Using PROC MIXED procedure of SAS® (2002), the experimental data were analyzed in a completed randomized design by following model: Yij = µ + Ti + eij; where, Yij was depended variable, µ is overall mean, Ti is fixed effect of the treatments (i = 1, 2, …. 5 for experimental diets); eij is experimental error. Means were separated using Duncan's multiple range tests with an alpha level of 0.05. Results and Discussion The distribution, geometric means and their standard deviation were significantly different.Therefore the ability of experimental rations in stimulating rumination, chewing activity, and maintain consistency of ruminal mat was not similar. Several studies have shown that the by-products have a physical effective factor about 50 % forage sources. Dry matter intake was similar in 5 treatments because ration had equal NDF, energy and crude protein content. However, digestibility of the dry matter and nutrients of rations increased when citrus pulp and barley or when citrus pulp. The citrus pulp has higher digestible non fiber carbohydrate than forages that improves the digestibility of dietary dry matter and nutrients of rations because increased ruminal entrapment of particulate and mat consistency. In addition, citrus pulp is a high pectin source that easily decomposes, produces more acetic and lower propionate or lactic acid than concentrates; thus, decreasing rumen pH is limited when using them. Inclusion of dried citrus pulp in silages significantly increased rumination time and chewing activities. Although we expected that physical effectiveness of ration reduces when supplemented silage were used, retention time and passage rate of ruminal particulate were similar because of increased ruminal mat consistency. The average daily gain was similar between treatments, however, inclusion of dried citrus pulp in silages significantly increased feed conversion ratio. Conclusion The results of experiment showed that citrus by-products are suitable for inclusion in ruminant diets because of the ability of ruminants to ferment high fiber feeds in the rumen and can provide relatively low cost ration.