Effects of environmental temperature and ammoniation on utilization of straw by sheep

Eighteen sheep were used to compare diets based on ammoniated wheat straw (AWS) or untreated wheat straw (WS) at three thermal environments: hot (HE, 36 degrees C, 70% relative humidity (RH], thermoneutral (TNE, 24 degrees C, 70% RH) and cold (CE, 4 degrees C, 70% RH). Six sheep were housed in each environment for at least 21 d prior to the trial. Two periods of 28 d were used in a crossover design. Within each period, digestibility was measured both under ad libitum intake (collections on d 16 to 20) and at restricted intake (collections on d 24 to 28). Diets consisted of 59% straw, 20% alfalfa hay and 21% concentrate. Urea was added to the untreated straw diet (.75%) to compensate partially for the N present in the AWS. Rectal temperature and respiration rates indicated that sheep in the HE were heat-stressed. Sheep housed in the CE had lower rectal temperatures and respiration rates than sheep in the TNE, but they did not shiver or show other visible signs of cold stress. Voluntary DM intake increased from 604 to 806 g/d, and ad libitum DM digestibility increased from 55.5 to 58.2% when AWS was fed. At restricted intake, ammoniation increased diet digestibility from 58.8 to 61.4%. Voluntary intake was lower in the HE (588 g/d) compared to 763 g/d in the TNE and 764 g/d in the CE. Digestibility of DM at ad libitum intake was lower in the HE (54.6%) than in the TNE (57.5%) or CE (58.6%); respective results at restricted intake were 58.5, 61.0 and 60.7%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 1. Feed intake, digestibility, metabolizability and net energy value

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP) at rates of 25 or 50% of the diet. Each of the 8 diets was fed to 8 sheep near ad libitum and near maintenance. Energy balances were determined by indirect calorimetry. Straw and feed intakes were doubled by the alkali treatment (P, BP25 and BP50 diets) or increased by 83% (M25 diet) and 63% (M50 diet). Near maintenance, energy digestibility (dE) and metabolizability (q) of the straw were improved by 36% and 40% respectively in the P diet and by 28% and 25% on average in the other diets. Ad libitum feeding reduced energy digestibility of treated straw by 11% and metabolizability by 5% on average in the BP25, BP50 and M25 diets; in the case of the M50 diet dE of the T straw was depressed by 30% and the beneficial effect of the alkali treatment was suppressed. The efficiency of metabolizable energy (ME) of the treated straw diets for maintenance was also raised by 9% (P diet) to 3% (M50 diet) and the corresponding net energy content of the treated straw was increased by 58 to 30%. ME efficiencies of the diets for fattening ranged from 44.0 to 52.8%. Energy retention of sheep was considerably increased by the alkali treatment of straw, whereas their maintenance requirement could not be met by the untreated straw diets supplemented with 25% concentrate.     

Feed intake,digestibility, nitrogen utilization,and body weight change of sheep consuming wheat straw supplemented with local agricultural and agro-industrial by-products

Effects of supplementing sheep consuming wheat straw with local agro-industrial by-products on feed intake, growth, digestibility and nitrogen utilization were determined. Thirty 1-year-old local wethers, with a mean (±SD) live weight of 19.8 (±1.06) kg, were assigned to five treatments: wheat straw + atella (T1), wheat straw + atella + poultry litter (T2), wheat straw + atella + coffee pulp (T3), wheat straw + atella + coffee pulp + poultry litter (T4), hay + concentrate (T5). A 7-day digestibility experiment and a 112-day growth trial were conducted. Total dry matter (DM) and organic matter (OM) intake as well as body weight gain was similar for all treatments. The highest (P < 0.05) nitrogen (N) intake was in sheep fed T1 and T4 diets, while the lowest was in those fed T2 and T5 diets. Sheep fed T1 and T2 diets had greater (P < 0.05) DM and OM digestibility than those fed T4 and T5 diets. The highest (P < 0.05) digestibility of N was for the T2, T4, and T5 diets, while the lowest was for the T1 diet. The highest N retention was in T4 diet, whereas the lowest was in T3 diet. In conclusion, in urban and peri-urban areas where atella, poultry litter, or coffee pulp are available, smallholder farmers could feed the mixtures as a supplement to straw with a good performance without using concentrate feeds.     

秸秆饲料加工利用技术简介

1我国秸秆资源开发现状及紧迫性 农作物秸秆是一种非常丰富的饲料资源,据估计．我国每年的农作物秸秆如麦秸、稻秸、玉米秸、豆秸等超过5．7亿t,而草原牧区每年贮草总和不过1000万t．只相当于秸秆数的2％左右。我国秸秆产量占世界秸秆产量的20％-30％。     

Energy utilization of sodium hydroxide treated or untreated straw supplemented with protein or concentrates by adult sheep. 2. Rumen digestion

NaOH treated (T) or untreated (UT) barley straws were supplemented either with protein (P) or with concentrates based on maize (M) or beet pulp (BP), the two last at rates of 25 and 50% of the diet. Each of the 10 diets was fed to two sheep ad libitum. Two diets were also fed at limited intakes. For these 12 diets in sacco cellulolytic activity in the rumen and ruminal fermentation were measured. Cellulolytic activity was measured with the studied straws, so that their digestion rate was also determined. NaOH treatment increased rate of digestion of straw, while high levels of concentrates decreased it. In contrast NaOH treatment and high levels of concentrate decreased cellulolytic activity but neither type of concentrate nor limitation of intake altered it. NaOH treatment only slightly modified pH because a higher level of VFA in rumen balanced NaOH presence. An important negative effect on pH of high levels of concentrate was observed, but there was no effect or type of concentrate or limitation of intake. Fermentation pattern was only slightly influenced by studied factors: +2.2 units of butyric acid and -2.1 units of acetic acid with treated straw; lower level of acetic acid occurred when concentrate was increased, especially for maize. Limitation of intake increased acetic acid molar proportion.     

Fermentation characteristics and nutritional value of ruminal contents and blood ensiled with untreated or sodium hydroxide-treated wheat straw.

Bovine ruminal contents and blood were ensiled with wheat straw, either untreated or treated with 4% NaOH (DM basis), with and without addition of 5% dry molasses. Proportions of ruminal contents, blood, and straw were 45:15:40, wet basis, respectively. Wheat straw also was ensiled alone, and water was added to attain 43% DM. After 60 d, all silages had a desirable aroma. The pH of the ensiled mixtures of ruminal contents, blood, and untreated straw was 4.43 and 4.56, with and without molasses, respectively. Values for silages containing treated straw, with and without molasses, were 5.95 and 7.37, respectively. All silages had substantial levels of lactic acid (2.4 to 4.9%, DM basis). Addition of molasses increased (P less than .01) lactic acid concentrations. In a metabolism trial, 36 wethers were fed a 50% orchardgrass hay basal diet alone or supplemented with ensiled materials (1:1 ratio, DM basis) such that final diets had about 7 and 4% of their DM from ruminal contents and blood, respectively. Among the diets containing the ensiled mixtures, digestibilities of DM, OM, energy, NDF, ADF, cellulose, and hemicellulose were 6 to 20 percentage units higher (P less than .01) for silages containing treated vs untreated straw. Addition of molasses increased apparent digestibility only of CP and only in sheep fed ensiled mixtures with treated straw (interaction of straw treatment x molasses addition, P less than .05). Nitrogen balance was increased (P less than .05) from 1.6 g/d to 2.9 g/d by NaOH treatment of straw. Metabolizable energy was higher (P less than .05) for diets containing silages with NaOH-treated straw.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nutrient utilization by sheep fed forage grown on soil treated with fluidized-bed combustion residue.

A mineral balance trial was conducted with 18 wether lambs fed sun-cured hay harvested from pastures located on a reclaimed strip-mined site. The following soil applications were made during each of 3 yr: 1) none, 2) dolomitic limestone and 3) fluidized-bed combustion residue (FBCR). Because FBCR had half the buffering capacity of limestone, it was applied at twice the rate of limestone. Apparent digestibility of hemicellulose was higher (P less than .05) for limestone-amended forage than for FBCR-amended forage (70.2 vs 67.0%), and apparent digestibility of cellulose was higher (P less than .05) for amended forages (66.7%) than for the control (63.9%). Apparent absorption and retention of N were similar among treatments, when expressed as a percentage of intake. Lambs fed control forage were in negative Ca balance, lower (P less than .01) than with amended forages. Apparent absorption and retention of Mg and Fe (g/d basis) were higher (P less than .05) for lambs on the limestone treatment than for lambs on the FBCR treatment. Apparent absorption of S was higher (P less than .01) for lambs on the FBCR treatment than for those on the limestone treatment. These differences were related to differences in mineral concentrations of the forages. Serum P was lower (P less than .05) for lambs fed FBCR-treated forage than for lambs fed limestone-treated forage (10.1 vs 12.9 mg/dl). Soil amendment with FBCR did not have deleterious effects on digestibility or mineral metabolism; in fact, it may have enhanced utilization of Ca and S and improved digestibility of some fiber components by lambs.     

Feeding value of urea molasses-treated wheat straw ensiled with fresh cattle manure for growing crossbred cattle calves

The study was carried out to evaluate the influence of urea plus molasses-treated wheat straw (WS) ensiled with cattle manure (CM) on nutrients intake, their digestibilities, and growth performance of crossbred (Sahiwal × Holstein Friesian) cattle calves. The CM was mixed with ground WS in a ratio of 30:70 on dry matter (DM) basis. The WS–CM mixture treated with urea (4% DM) and molasses (4% DM) was allowed to ferment for 40 days in a cemented pit. Four iso-nitrogenous and iso-energetic fermented wheat straw (FWS)-based experimental diets were formulated. The FWS0, FWS20, FWS30, and FWS40 diets contained 0%, 20%, 30%, and 40% FWS, respectively. Twenty calves (9–10 months of age) were randomly allocated to four dietary treatments in a randomized complete block design, five in each group. Increasing trends for DM, organic matter, crude protein, and neutral detergent fiber intakes by calves were observed with increasing dietary FWS level. Weight gain was significantly different among calves fed different levels of FWS. The highest weight gain (491.8 g/day) was observed in calves fed FWS40 diet, while calves fed FWS0 and FWS20 diets gained 350.0 and 449.6 g/day, respectively. The results from this study imply that the FWS can be added up to 30% in the diet of growing crossbred calves without any detrimental effect on their performance.     

Effects of alfalfa maturity on energy utilization by cattle and nutrient digestibility by cattle and sheep.

Two comparative slaughter experiments conducted with growing beef steers (300 kg to 480 kg BW) fed alfalfa cubes demonstrated that animal performance diminished as alfalfa matured. In each trial, ADG (empty BW basis) was 10 to 20% greater from pre-bloom than from early-bloom alfalfa. Net energy for maintenance (Mcal/kg) followed a pattern similar to that of ADG, but NEg (Mcal/kg) did not decrease (P greater than .05) as alfalfa maturity increased. Digestion trials with steers and wethers clearly indicated significant reductions in apparent digestibilities of DM, energy, and cell wall fractions as alfalfa matured. Steers fed at 110% of maintenance in digestion Trails 1, 2, and 3 consistently digested cubed alfalfa to a greater extent than wethers fed the same alfalfa ground and pelleted. Digestion coefficients (percentages) for ADF, cellulose, NDF, and crude fiber were 5 to 14% greater for steers fed cubes than for wethers fed pellets. Regression equations calculated from results of three digestion trials indicate that digestible DM % and DE (Mcal/kg) could be predicted from ADF %, but they were 4 to 5% lower for wethers fed pelleted alfalfa than for steers fed cubes.     

丝兰提取物对三角鲂摄食、生长、饲料利用及废物排放的影响

在室外养殖桶中进行8周饲养实验以评估丝兰提取物对三角鲂(Megalobrama terminalis)摄食、生长、饲料利用、鱼体组成及废物排放的影响。在三角鲂基础饲料中分别添加0%(Y0)、0.05%(Y1)、0.15%(Y2)、0.25%(Y3)、0.35%(Y4)和0.45%(Y5)的丝兰提取物,每天饱食投喂实验鱼(16.0±0.8)g两次。研究结果显示,随着丝兰提取物添加水平的增加,实验鱼的终末体重、增重率和特定生长率呈先上升后下降趋势。与对照组Y0相比,实验组Y3具有最高的终末体重、增重率、特定生长率、饲料氮储积效率,最低的饲料系数和磷废物排放量(P0.05)。实验组Y2的FI显著高于对照组Y0(P0.05),而各实验组与对照组Y0之间的饲料磷储积效率、肥满度、肝体指数、鱼体组成(水分、粗蛋白质、粗脂肪、灰分、磷和氨基酸)均无显著差异(P0.05)。研究表明,在三角鲂饲料中添加0.25%的丝兰提取物可显著提高三角鲂的生长和饲料利用效率,并降低养殖废物排放。     

家蚕吸收利用桑叶蛋白质的状况浅析

根据桑蚕生理生化规律，桑叶蛋白质经蚕体消化液中的水解酶分解生成肽后，进入中肠的管壁细胞，被肽酶进一步水解成氨基酸后，其中一小部份留存在管壁细胞内合成细胞蛋白质，大部分进入血液中，然后从血液进入各组织细胞，被各组织细胞所吸收的氨基酸，分别在不同的组织细胞内合成各组织所特有的蛋白质。     

茴香秸秆和茴香秕壳对绵羊营养价值的评定

选择6只体重28 kg左右,安装永久瘤胃瘘管甘肃高山细毛羯羊, 采用3×3无重复拉丁方试验设计,通过消化代谢试验,对茴香秸秆和茴香秕壳对绵羊的营养价值进行了评定。结果表明,绵羊对茴香秸秆和茴香秕壳的干物质消化率、氮消化率、氮存留率、有机物消化率、中性洗涤纤维消化率、酸性洗涤纤维消化率、钙消化率、磷消化率和消化能分别为62.11%和61.63%,63.83%和65.63%,50.58%和47.72%,62.63%和62.50%,54.95%和53.02%,52.18%和49.50%,23.19%和20.35%,31.98%和35.03%,以及9.86和9.51 MJ/kg。绵羊对茴香秸秆和茴香秕壳的消化率较高。饲粮中添加茴香秸秆对绵羊瘤胃液pH、乙酸摩尔比、丙酸摩尔比、丁酸摩尔比、乙酸/丙酸以及瘤胃液中尿素氮和蛋白氮浓度均产生了显著的影响(P<0.05),对其他酸摩尔比、瘤胃液总挥发性脂肪酸(TVFA)、总氮和氨氮浓度无显著影响(P>0.05);饲粮中添加茴香秕壳对绵羊瘤胃液乙酸、丁酸和其他酸摩尔比产生了显著的影响(P<0.05),对pH、丙酸摩尔比、乙酸/丙酸、瘤胃液TVFA和氮浓度无显著影响(P>0.05)。