The effects of sorbic acid in high moisture sorghum grain diets on performance of weanling swine

Three experiments were conducted with 288 weanling pigs to determine the effects of sorbic acid (SA) added to dry (DSG), high moisture (HMSG) or reconstituted (RSG) sorghum grain diets on gains and feed conversion. Dietary treatments for Exp. 1 were: DSG with and without .1% SA; HMSG with .1% SA and RSG with .1% SA. The DSG diets were fed ad libitum. The HMSG and RSG diets were mixed fresh from oxygen-limiting storage every 3 and 7 d and were also fed ad libitum. Pigs fed RSG diets consumed more feed than those fed HMSG diets (P less than .08). Performance was similar between pigs fed DSG diets without or with SA. Dietary treatments for Exp. 2 and 3 consisted of sorghum grains reconstituted to two moisture contents (MC), with additions of either 0, .05 or .1% SA. The diets were mixed fresh from oxygen-limiting storage every 7 d and fed ad libitum. In Exp. 2 and 3, pigs fed the higher MC diets were more efficient in feed conversion (P less than .03) than those fed the lower MC diets. In Exp. 3, a quadratic response (P less than .04) for average daily gain and average daily feed intake was observed for the main effect of SA. Feed efficiency improved (P less than .05) in a linear fashion as SA levels were increased in the diets. The results of these experiments indicate that weanling pigs may be fed HMSG or RSG without adverse effects on pig performance. Inconsistencies in pig response to SA were observed.(ABSTRACT TRUNCATED AT 250 WORDS)     

玉米秸秆青贮饲料和谷草组合效应的研究

本试验利用体外瘤胃发酵技术,研究玉米秸秆青贮饲料(CS)与谷草(MS)的组合效应(AE)。将玉米秸秆青贮饲料与谷草以100∶0,80∶20,60∶40,50∶50,40∶60,20∶80,0∶100的比例进行组合,结合二者之间24 h、48 h、72 h产气量和瘤胃发酵特性及其组合效应,筛选出玉米秸秆青贮饲料与谷草的最优组合(BCM)。结果表明,1)体外发酵同一时间点的不同比例组合中,CS∶MS比例为80∶20的产气量(GP)显著或极显著高于其他比例组合(P0.05或P0.01);发酵24、48和72 h的干物质消失率(DMD)在CS占80%时最高,显著或极显著高于其他组合(P0.05或P0.01);发酵24、48和72 h的氨态氮(NH_3-N)浓度和微生物蛋白(MCP)产量均以CS∶MS为80∶20时最大(P0.05或P0.01),然后随CS比例的减少而逐渐降低。2)发酵24 h、48 h和72 h,乙酸、丙酸和丁酸的浓度均以CS∶MS为80∶20时显著或极显著高于其他组合(P0.05或P0.01)。3)CS∶MS为80∶20时的多项组合效应指数(MFAEI)高于其他比例组合,分别为AE_(24 h)1.09、AE_(48 h)0.95和AE_(72 h)0.68。因此,在本试验条件下,玉米秸秆青贮饲料和谷草比例为80:20的组合最有利于瘤胃发酵。     

Effects of altering the grain content of sorghum silage on its nutritive value

The effects of increasing grain content of sorghum silage at the soft dough or the mature stages on nutrient digestibility, rate of passage and ruminal characteristics were investigated. A hetero-yellow grain sorghum (WAC 710DR) was harvested at the soft dough and the mature stage. Conventional sorghum silage was harvested by harvesting only the material more than 12 cm above the ground, high-energy silage by cutting it at a 40-cm height and headchop by harvesting at a 65-cm height. Regular silage was supplemented with either 17% or 34% grain to provide amounts of grain equal to that in the high-energy silage and headchop; high-energy silage was supplemented with 25% grain to equal the grain content of headchop. Diets were supplemented to 11.0% CP with soybean meal. Grain content was greater for headchop than for regular silage (72% vs 53%) but DM yield was lower (2,900 vs 4,600 kg/ha). Silages harvested at the more mature stage had lower digestibility of DM (62 vs 68%), CP (60 vs 64%), NDF (46 vs 50%), ADF (48 vs 52%) and starch (89 vs 97%). Increasing the height of cut did not increase DM digestibility of the silage. Compared with conventional silage, headchop had depressed NDF (43 vs 51%) and ADF (46 vs 55%) digestibility. Supplementation of silages with grain did not increase digestibility. The failure to increase DM digestibility was not due to depressed fiber or starch digestion, but rather to an increased fecal excretion of cell contents. The digestibility of grain sorghum silage was not improved by increasing the height of cut or adding supplemental grain.     

反刍动物秸秆基础日粮补饲苜蓿的组合效应

本文综述了反刍动物秸秆基础日粮补饲苜蓿的组合效应，并对该类饲料组合效应的产生机理进行了归纳，指出经作者改进的卢德勋（2003）提出的组合效应综合评定指数（MFAEI）可对饲料间组合效应进行整体量化．指导反刍动物秸秆基础日粮的补饲。     

Site of protein digestion in steers fed sorghum grain diets. II. Effect of grain processing methods

Seven crossbred, abomasally fistulated yearling steers (400 kg) were used in two digestion trials (crossover design) to study the effect of processing sorghum grain on the site and extent of feed and microbial protein digestion. Steers were fed an 81.5% sorghum grain diet in which the grain was either dry-rolled (DR; four steers) or steam-processed, flaked (SPF; three steers). At the end of the first trial steers were switched to the opposite treatment. Dysprosium (21 to 23 micrograms/g of feed) was used as a digesta marker. Feed, abomasal contents and fecal grab samples were collected at 12-h intervals during a 6-d total fecal collection period. Organic matter (OM) intake for SPF and DR grain diets averaged 6,426 and 6,787 g/d, respectively. Compared with DR, SPF increased (P less than .05) the apparent total digestibility and ruminal digestibility of OM. Trichloroacetic acid precipitable protein consumed by the steers was lower (P less than .05) for SPF than the DR treatment. Processing method had no effect on ruminal digestion of crude protein (CP), bacterial protein (BP) synthesis, quantity of CP entering the small intestine or on total digestion of feed protein. There was a trend for increased total and post-ruminal digestion of CP with the SPF diet. Post-ruminal digestion of BP was increased (P less than .05) by SPF grain as compared with DR. Percentage of non-BP digested ruminally, post-ruminally or in the total tract was not significantly affected by processing method.(ABSTRACT TRUNCATED AT 250 WORDS)     

利用体外法研究精料、玉米秸秆青贮与谷草的组合效应

试验采用体外瘤胃发酵法来研究肉牛日粮中不同比例精料与粗料间的组合效应(AE)。用注射器法将精料与玉米秸秆青贮、谷草以100∶0(CR100),80∶20(CR80),60∶40(CR60),50∶50(CR50),40∶60(CR40),20∶80(CR20),0∶100(CR0)的比例进行组合,分别测定产气量(GP)、干物质消失率(DMD)、氨态氮(NH_3-N)浓度、微生物蛋白(MCP)产量和挥发性脂肪酸(VFA)浓度及其组合效应值,确定最适宜的精粗比。结果表明,1)CR80组合的体外发酵GP最高,组合效应值最大;CR100组合的DMD最高;而CR50组合的单项组合效应值最大,NH_3-N浓度和MCP产量最高,产生了最大正组合效应。2)乙酸浓度随精料比例的降低呈先上升后下降的趋势,丙酸和丁酸浓度则随精料比例的下降而降低。3)综合分析各组合的多项组合效应指数(MFAEI),CR50组合最大(AE_(24h)0.56,AE_(48h)0.67,AE_(72h)1.00)。因此,在本试验条件下精粗比为50∶50的组合最有利于瘤胃发酵。     

Nutritive value of sorghum silage for sheep

This study compared ensiled sorghum (ES) from two varieties (first and second cuts) with corn silage (CS) for chemical analysis, total-tract nutrient digestibility, ruminal variables and blood biochemistry metabolites in sheep. Five experimental silages representing first cut ES var. Pegah (PS1), second cut ES var. Pegah (PS2), first cut ES var. Speedfeed (SS1), second cut ES var. Speedfeed (SS2) and CS were assessed for chemical analysis, silage fermentation and anti-quality compounds. Diets consisted of lucerne hay, silage and a premix (at the ratio of 53.5:46:0.5 on a dry matter [DM] basis). Feed consumption, total-tract nutrient digestibility, microbial nitrogen supply (MNS), ruminal variables and blood biochemistry metabolites were determined in a Latin square design of five periods with five male sheep. Compared to sorghum, CS had lower (p < 0.01) concentrations of ash, water-soluble carbohydrates and crude protein, but higher starch, lignin (sa), non-structural carbohydrates and apparent nutrient digestibility. The measurements of pH, lactic acid, NH₃-N and volatile fatty acids (VFA) confirmed that all silages were well-preserved. The anti-quality compound levels in the silages were below the safe limits for ruminants. No differences were observed in feed consumption (p > 0.05) and total-tract digestibility of DM and nutrients (p > 0.05). Rumen pH, NH₃-N, VFA concentrations and acetate to propionate ratio showed no difference among treatments (p > 0.05). Sheep fed on sorghum silage showed a decrease (p < 0.01) in total protozoa, and particularly in the Entodiniae population. There were no differences in cellulolytic bacteria counts (p > 0.05) among treatments. Urinary N, MNS and blood biochemistry metabolites showed no difference among treatments (p > 0.05). Silages from both cuts of sorghum had comparable total-tract nutrient digestibility to CS, therefore, these varieties could be used as a more drought resilient silage source in the feeding of sheep.     

Splanchnic nitrogen metabolism by growing beef steers fed diets containing sorghum grain flaked at different densities

The objective of this study was to determine effects of processing method, dry-rolled (DR) vs steam-flaked (SF), and degree of processing (flake density, FD) of SF sorghum grain on splanchnic (gut and liver) N metabolism by growing steers. Diets contained 77% sorghum grain either DR or SF at densities of 437, 360, and 283 g/L (SF34, SF28, and SF22, respectively). Eight crossbred steers (340 kg initial BW), implanted with indwelling catheters into portal, hepatic, and mesenteric veins and the mesenteric artery, were used in a randomized complete block design. Blood flows and net output or uptake of ammonia N, urea N (UN), and alpha-amino N (AAN) were measured across portal-drained viscera, hepatic, and splanchnic tissues. Plasma arterial, portal, and hepatic concentrations of individual amino acids were also measured. Decreasing FD linearly increased (P = .04) net absorption of AAN (51, 73, and 78 g/d for SF34, SF28, and SF22, respectively) and transfer (cycling) of blood UN to the gut (49, 48 and 64 g/d; P = .02). Net UN cycling averaged 38% of N intake across all diets. Hepatic uptake of AAN or UN synthesis, and splanchnic output of AAN and UN, were not altered by FD. Lowering FD linearly increased (P < or = .02) portal-arterial concentration differences for blood AAN and UN and plasma arterial concentrations for alanine. Steers fed SF compared to DR tended to have greater (P = .11) blood UN cycling (percentage of hepatic synthesis; 64 vs 50%) and decreased (P = .03) net splanchnic UN output (30 vs 50 g/d), but other net fluxes of N were not altered across splanchnic tissues. Steam-flaking compared to dry-rolling tended to decrease (P = .12) portal, but not hepatic, blood flow and increased (P < .01) hepatic-arterial concentration differences for blood UN. Except for a decrease (P = .01) in hepatic-arterial concentration differences of glutamine, plasma amino acid concentrations were not altered by feeding SF vs DR sorghum. Processing method (steam-flaking vs dry-rolling) or increasing the degree of processing (by decreasing FD) of SF sorghum grain resulted in greater transfer of blood UN to the gut. Reducing FD also linearly increased the absorption of AAN by growing steers, which explains (in part) published responses of superior performance by steers fed SF grains.     

Effect of grain processing and silage on microbial protein synthesis and nutrient digestibility in beef cattle fed barley-based diets

Effects of the extent of grain processing and the percentage of silage in barley-based feedlot diets on microbial protein synthesis and nutrient digestibility were evaluated using four steers (initial BW of 442 +/- 15 kg) with ruminal and duodenal cannulas. The experiment was a 4 x 4 Latin square with four periods of 21 d each. Dietary treatments were arranged as a 2 x 2 factorial with two levels of barley silage (20 and 5% DM basis) and two degrees of barley grain processing (coarsely and flatly steamrolled to a processing index [PI] of 86 and 61%, respectively). The PI was quantified as the volume weight of the barley grain after processing, expressed as a percentage of the volume weight prior to processing. Digest a flow (Yb) and microbial (15N) markers were continuously infused into the rumen for a period of 13 d. Ruminal, duodenal, and fecal samples were collected at various times over the last 6 d of marker infusion. Diurnal ruminal pH was measured for 48 h. Intake of DM averaged 1.8% of BW, and was not different among the dietary treatments (P > 0.10). Ruminal starch digestibility was higher (P < 0.05) for the more extensively processed grain and tended (P < 0.10) to be highest when the more extensively processed grain was combined with 5% barley silage. In contrast, ruminal fiber digestibility for the 5% silage diets was reduced (P < 0.05) when the grain was more extensively processed. There was, however, no effect of grain processing on ruminal OM digestibility (P > 0.10), and hence, no inhibitory effect on microbial N flow to the intestine (P > 0.10). There was also no effect of the level of silage on microbial N flow (P > 0.10), but there was a tendency for improved efficiency of microbial protein synthesis for the 20% silage diets (P = 0.072). Ruminal escape of nonmicrobial N (P = 0.003) was greater, and thus, protein flow to the intestine was greater for the 5% silage diets. Diurnal ruminal pH was lower (P < 0.05) for 11 of the 24 hourly time points in steers fed the 5% silage diets than those fed the 20% silage diets. In conclusion, barley grain rolled to a PI of 86 to 61% and combined with 20 and 5% barley silage had little effect on microbial protein supply. Microbial protein supply was not inhibited when the barley grain was extensively processed (PI of 61%) and the silage was limited to only 5% of the diet DM, but feed intake of steers in this study was lower than would be expected in the feedlot.     

饲用甜高粱和全株玉米青贮对肉羊前胃微生态的影响

本试验旨在探究饲用甜高粱青贮（sweet sorghum silage, SS）和全株玉米青贮（whole-plant corn silage, CS）对肉羊前胃微生态的影响。选择健康的3~4月龄杜泊母羊［（33.40±1.68） kg］14只,随机分为2组,每组7只羊,每只羊为1个重复,分别喂甜高粱青贮（SS组）和玉米青贮（CS组）,单栏饲喂并自由饮水。预饲期15 d,正试期90 d,在正试期测定并计算生长性能指标,正试期结束后,每组选取4只羊进行屠宰,采集前胃（瘤胃、网胃和瓣胃）食糜和组织样品,对前胃发酵参数、微生物表达量、上皮颜色和组织结构进行观察和测定。结果表明：1）CS组肉羊的干物质采食量显著高于SS组（P<0.05）。2）甜高粱青贮和玉米青贮育肥肉羊90 d后,对前胃的pH值未产生显著影响（P>0.05）;在网胃内容物中,SS组肉羊氨氮浓度显著高于CS组（P<0.05）,CS组肉羊丁酸含量显著高于SS组（P<0.05）;SS组肉羊瘤胃总挥发性脂肪酸含量显著高于CS组（P<0.05）。3）SS组肉羊瘤胃内短普雷沃氏菌、栖普雷沃氏菌、产琥珀酸丝状杆菌和黄色瘤胃球菌的表达量显著高于CS组（P<0.05）。4）饲粮处理显著影响前胃颜色,CS组肉羊的前胃上皮颜色比SS组深（P<0.05）。5）SS组肉羊瘤胃乳头宽度显著高于CS组（P<0.05）,饲喂甜高粱青贮和玉米青贮对肉羊网胃黏膜厚度、黏膜下层厚度和肌层厚度并未产生显著影响（P>0.05）,CS组肉羊的瓣胃黏膜上皮厚度显著高于SS组（P<0.05）。综上所述,在本试验条件下,和饲用玉米青贮相比,饲用甜高粱青贮肉羊的采食量较低,且这两种青贮料饲喂对肉羊的微生态有影响,甜高粱青贮组肉羊的瘤胃总挥发性脂肪酸含量、前胃内纤维分解菌的表达量以及瘤胃乳头宽度等指标显著高于玉米青贮组,且甜高粱青贮组肉羊的前胃上皮颜色较浅,角质化程度低,有利于肉羊的胃肠道健康。     

Improved enzymatic method to measure processing effects and starch availability in sorghum grain

A modified enzymatic method to measure processing effects and starch availability in steam-flaked sorghum grain (SFSG) was developed. To establish the method, experiments were conducted to determine the required enzyme concentration, color reagents, precipitants, sample particle size, shaking frequency and buffer pH. Glucose release at different incubation times (0 to 48 h) from uncooked (UNC) or fully cooked (CK, 100% gelatinized) ground sorghum grain, a 50:50 mixture of UNC and CK (C50) and SFSG was determined. Glucose release from UNC, CK and SFSG was expressed as one-component equations with rate constant k and r2 of .119 and .98, 1.781 and .98, and .368 and .99, respectively; C50 was characterized by having two starch components, one with a fast rate constant, 2.624/h, and one with a slow rate constant, .066/h (R2 = .99). Different degrees of gelatinization were obtained by mixing different proportions of CK and UNC. Glucose release from these samples was highly correlated with starch gelatinization (r2 = .99). By adjusting the tension between mill rollers, five SFSG samples with bulk densities ranging from 476 to 283 g/liter (37 to 22 lb/bu) were produced; respective roller mill electrical load ranged from 21 to 51.5 amps. Enzymatic determination of glucose release resulted in values of 422, 512, 588, 618 and 678 mg/g, which were more closely related to bulk density than birefringence measurements. The modified method for starch availability determination was found to be relatively simple, fast and sensitive, and is recommended.     

饲用高粱青贮的饲喂价值和经济效益分析

高粱生物产量高、抗逆和适应性强,将其制作成青贮饲料,干物质产量、蛋白质含量、有氧稳定性高.草食家畜养殖是节粮型畜牧业的代表.采用高粱青贮饲喂草食家畜,不仅可以提高生产性能、增强免疫力、改善胴体品质,而且可以缓解冬季青贮饲料资源缺乏的问题,提高经济效益.为促进草食家畜养殖业健康稳定发展,文章对饲用高粱青贮的饲喂价值和经济...     

Site of protein digestion in steers fed sorghum grain diets. I. Effect of level of feed intake

Two digestion trials were conducted with seven crossbred, abomasally cannulated yearling steers (400 kg) to study the effect of level of feed intake on the site and extent of feed and microbial protein digestion. Steers, in a crossover design experiment, were fed an 81.5% steam-processed flaked (SPF) sorghum grain diet at either 95% (four steers) or 75% (three steers) of their ad libitum intakes. At the end of the first trial, steers were switched to the opposite treatment. Dysprosium (31 to 32 micrograms/g) was used as an external marker. Feed, abomasal contents and fecal grab samples were taken at 12-h intervals advancing by 2 h each day over a 6-d total fecal collection period. Organic matter (OM) intakes were 6,102 and 4,570 g for the two treatments. Higher level of intake increased (P less than .05) quantities of OM, crude protein and trichloroacetic acid precipitable protein entering the small intestine, digested post-ruminally and digested in the total tract. The higher level of intake decreased (P less than .05) the percentage of bacterial protein (BP) present in the abomasum and percent post-ruminal BP digestion; however, the amounts of BP and non-BP entering the small intestine and digested post-ruminally were greater (P less than .05) in steers fed 95% ad libitum. Most of the feed protein was degraded in the rumen with both treatments. Predicted true feed protein digestibilities were 91.1 and 91.7% for 95 and 75% of ad libitum intakes.(ABSTRACT TRUNCATED AT 250 WORDS)     

乳酸菌和晾晒处理对籽粒苋青贮品质的影响

试验旨在研究不同乳酸菌和晾晒处理对籽粒苋(Amaranthus hypochondriacus L.)青贮饲料发酵品质和营养成分的影响。以成熟期籽粒苋为原料,设置两个含水量,分别为新鲜籽粒苋(F)和晾晒4 h的籽粒苋(W),并将这两个含水量的籽粒苋均设置四个不同的处理组:对照(CK)组,植物乳杆菌1(LAP1)组、植物乳杆菌2(LAP2)组和布氏乳杆菌(LAB)组。青贮45 d后,开袋取样分析,用榨汁液检测青贮样品的pH值、氨态氮、可溶性碳水化合物、有机酸,用固体样品检测酸性洗涤纤维、中性洗涤纤维、淀粉、粗蛋白含量。结果表明,布氏乳杆菌显著降低了可溶性碳水化合物含量(P<0.05);相比其他处理组,LAP2组显著降低了青贮饲料的淀粉含量;晾晒和乳酸菌添加对籽粒苋青贮淀粉、中性洗涤纤维、酸性洗涤纤维含量均没有显著影响(P>0.05);相比新鲜籽粒苋,LAP1晾晒处理组显著提高了饲料蛋白质含量(P<0.05)。从发酵指标来分析,添加乳酸菌降低了青贮饲料的p H值和氨态氮的含量;晾晒和添加乳酸菌对籽粒苋青贮乳酸、乙酸、丙酸、丁酸含量均没有显著影响(P>0.05)。未经晾晒处理的籽粒苋难以制作高质量的青贮饲料。     

Effects of total replacement of corn silage with sorghum silage on milk yield,composition, and quality

Background: In the last years, difficulties occurring in corn cultivation(i.e., groundwater shortages, mycotoxin contamination) have been forcing dairy farmers to consider alternative silages. Some experiments conducted on lactating cows have proven that the total replacement of corn silage with sorghum silage did not reduce milk yield.However, this kind of substitution involves supplementing sorghum-based diets with grains, to compensate for the lower starch content of sorghum silage compared to corn silage. Change of silage type and inclusion of starch sources in the diet would influence rumen fermentations, with possible effects on milk composition(i.e., fatty acid profile) and coagulation properties. A worsening of milk coagulation properties would have a negative economic impact in Italy, where most of the milk produced is processed into cheese.This study was designed to compare milk composition and quality, with emphasis on fatty acid profile and coagulation properties, in dairy cows fed two diets based on corn or sorghum silage.Results: The sorghum diet reduced milk yield(P = 0.043) but not 4% fat corrected milk(P = 0.85). Feeding sorghum silage did not influence milk contents of protein(P = 0.07) and lactose(P = 0.65), and increased fat content(P = 0.024).No differences emerged for milk concentrations of saturated(P = 0.61) and monounsaturated fatty acids(P = 0.50),whereas polyunsaturated fatty acids were lower(P 0.001) for the sorghum diet. Concentrations of n-6(P 0.001) and n-3 fatty acids(P = 0.017) were lower in milk of cows fed the sorghum diet. Milk coagulation properties did not differ between the two diets, except the "a30"(the curd firmness, expressed in mm, 30 min after rennet addition), that was lower(P = 0.042) for the sorghum diet.Conclusions: Feeding a forage sorghum silage, properly supplemented with corn meal, as total replacement of corn silage maintained milk composition and did not influence negatively milk coagulation properties, which have a great economic relevance for the Italian dairy industry. Thus, silages obtained from forage sorghums could have a potential as substitute of corn silages in dairy cow diets.     

不同品种玉米和甜高粱的产能比较

为推动"粮改饲",提高种养效益,本研究比较了4个玉米(Zea mays)品种和4个甜高粱(Sorghum bicolor)品种的产能,以期筛选出适合在我国关中地区推广种植的高产优良青贮品种.结果表明,种间或品种间的农艺性状和产能均存在显著差异(P<0.05),其中玉米生长期为99～116 d,甜高粱为124～175 d;玉米的叶片数约为14片,甜高粱为8～23片;玉米株高为225.8～281.5 cm,甜高粱为165.3～338.8 cm;玉米青贮产量为40.2～83.9 t·hm?2,甜高粱为35.6～125.3 t·hm?2;玉米干物质产量为12.0～25.1 t·hm?2,甜高粱为10.7～37.7 t·hm?2.产量最高的玉米品种为'D B 08',甜高粱为'极光',比对照籽粒型玉米品种'强盛58'分别增产了84.5％和211.6％.营养分析发现,玉米和甜高粱的粗蛋白、粗纤维、粗脂肪、灰分和无氮浸出物等营养物质种间或品种间均存在差异,且各单一最优营养指标并不聚集于同一品种中.综合考虑青贮产量和反刍动物营养需求,本研究建议选择玉米'DB08'和甜高粱'极光'作为青贮饲料在关中地区进行推广种植.     

Whole grain diets for pullets

1. Three experiments, each involving over 400 pullets, were conducted into the use of whole grain rearing diets. They were concerned with the cereal to be used, the age from which such diets may be used, and the value of a vitamin‐trace element supplement. Each experiment was performed on a brown‐egg and a white‐egg strain.

2. Whole maize was found to be unsuitable.

3. Whole wheat or whole barley diets should not be introduced before the age of 10 weeks to avoid unacceptably high mortality due to cannibalism. Thereafter the principal results are reduced body weight at caging and retarded sexual maturity.

4. The addition of a vitamin‐trace element supplement had some effect in reducing mortality when whole grain diets were introduced before 10 weeks of age.     

利用体外产气法评价玉米秸秆黄贮与甜菜块根组合效应

为探讨玉米(Zea mays)秸秆黄贮与甜菜(Beta vulgaris)块根的体外发酵组合效应,本研究将玉米秸秆黄贮与甜菜块根以100:0(T1)、80:20(T2)、60:40(T3)、50:50(T4)、40:60(T5)、20:80(T6)、0:100(T7)的比例进行组合,利用体外瘤胃发酵技术,分析其养分降解率、发酵参数及总产气量,以评价组合效应的功效.结果表明:1)随着甜菜块根比例的增加,干物质消化率(dry matter degradability,DMD)、中性洗涤纤维消化率(neutral detergent fiber degradability,NDFD)、酸性洗涤纤维消化率(acid detergent fiberdegradability,ADFD)先升高后降低,且组合后的养分降解率均高于单一原料养分降解率.2)随甜菜块根比例的增加,发酵液pH逐渐降低,T1组pH显著高于其他组(P<0.001),T3、T6组NH3-N浓度显著低于其他组(P=0.003).当甜菜块根比例为40％时,总挥发性脂肪酸(total volatile fatty acids,TVFAs)和各挥发性脂肪酸浓度最高,当甜菜块根比例大于40％时,其浓度又呈现降低趋势,T3、T4、T5组乙酸/丙酸值显著高于其他组(P<0.001).3)发酵时间对总产气量有显著影响(P<0.001),且时间和处理具有显著互作效应(P=0.006),总产气量随发酵时间的延长逐渐升高,随着甜菜块根比例的增加,呈现先升高后降低趋势.发酵4、8、12 h,T3组总产气量显著高于T1、T6、T7组(P<0.004),发酵24、48 h,T4组总产气量均显著高于T6、T7组(P<0.008).4)不同比例的单项组合效应值各有差异,但是从综合组合效应值来看,结果为T3>T5>T4>T2>T6.因此,玉米秸秆黄贮与甜菜块根的最优组合为60:40.     

有机肥施用量对饲用高梁青贮品质的影响

摘要：采用田间试验研究有机肥（基肥）施用量对饲用高粱（Sorghum bicolor）青贮饲料品质的影响。结果表明,在施氮量相等的条件下,随着有机肥施用量的增加,青贮饲料的发酵品质先增高后下降,施用量以75和150 t/hm2为最好;同时,青贮饲料的酸性洗涤纤维和中性洗涤纤维含量不断增加,粗蛋白含量和干物质体外消化率不断下降。综合青贮饲料的发酵品质和饲用品质,饲用高粱青贮利用栽培时,施用有机肥基肥75～150 t/hm2较适宜。     

体外产气法评价生薯条加工副产品-稻草混贮与全株玉米青贮组合效应的研究

旨在探究生薯条加工副产品-稻草混贮(以下简称"薯稻混贮")与全株玉米青贮间的组合效应."薯稻混贮"是按照1:2混合(混贮后的干物质含量为35％)、添加青贮添加剂、用搅拌机混匀、打捆裹包机裹包、发酵60 d制成.根据"薯稻混贮"与全株玉米青贮的不同比例分为7个组合,分别为T0组(0:100)、T20组(20:80)、T4...