Enhancing in vitro degradation of alfalfa hay and corn silage using feed enzymes

A series of in vitro fermentation experiments was performed to assess the effects of 4 feed enzyme products (FE) that varied in enzymatic activities on the degradation of alfalfa hay and corn silage. The FE contained a range of endoglucanase, exoglucanase, xylanase, and protease activities, and a range of dose rates (DR) was used. The objective of the study was to identify effective formulations and optimum DR, and to establish if combining FE would further improve fiber degradation. For alfalfa hay, quadratic increases in gas production and degradation of dry matter (DM) and fiber were observed for all FE, with maximum responses at low to medium DR. For corn silage, none of the FE increased gas production or DM degradation, but all FE increased NDF degradation, with optimum DR in the low to medium range. The proteolytic enzyme papain improved fiber degradation of alfalfa hay and corn silage in a manner similar to that observed for polysaccharidase FE. Among the polysaccharidase FE, added activities of endoglucanase and exoglucanase were positively correlated with improvement in neutral detergent fiber (NDF) degradability of corn silage, whereas only added endoglucanase activity tended to be correlated with improvement in NDF degradability of alfalfa hay. Combining effective polysaccharidase FE further improved fiber degradation of both forages, with greater improvements for corn silage. Combining polysaccharidase and proteolytic FE further improved NDF degradation of corn silage, but not alfalfa hay. Combination treatments generally resulted in additive effects with increases in fiber degradation equal to the sum of the improvements for the individual enzyme components. Improved fiber degradation of corn silage was associated with decreased acetate to propionate ratios. Enzyme products that improve in vitro degradation of forages may have the potential to improve lactational performance of dairy cows.     

饲草压捆机动力设计理论研究

为降低饲草压捆机的能耗,寻找最佳性价比,结合自行研制的饲草压捆机的现场试验,提出一种新的有关稻草压缩的理论模型,提出了单方向压缩、多方向变化的理念,对其主要借鉴流变学理论中黏弹性体的基本性质进行理论推导．将稻草在压缩过程中的变化划分为5个阶段,解释了稻草在压缩过程中的一些实际现象．指出开式压缩中压缩仓长度接近2 m比较合适,在压实程度大约为8倍时,峰值压强约为0.8 MPa,减少捆绳消耗约1/3,为今后农牧业纤维物料压缩设备的动力设计提供了一定的理论依据．     

Chemical composition,fatty acid content and antioxidant potential of meat from goats supplemented with Moringa (Moringa oleifera) leaves,sunflower cake and grass hay

The present study determined the chemical composition, fatty acid (FA) content and antioxidant capacity of meat from goats supplemented with Moringa oleifera leaves (MOL) or sunflower cake (SC) or grass hay (GH). The meat from goat supplemented with MOL had higher concentrations of total phenolic content (10.62 ± 0.27 mg tannic acid equivalent E/g). The MOL significantly scavenged 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS) radical to 93.51 ± 0.19% (93.51 ± 0.19%) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical to 58.95 ± 0.3% than other supplements. The antioxidative effect of MOL supplemented meat on catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD) and lipid oxidation (LO) was significantly (P < 0.05) higher than other meat from goat feed on grass hay or those supplemented with sunflower seed cake. The present study indicated that the anti-oxidative potential of MOL may play a role in improving meat quality (chemical composition, colour and lipid stability).     

图像边界检测的区域对比度模糊增强算法

分析了Pal的区域对比度模糊增强边界检测算法的不足,给出了一种新的用于增强图像区域之间对比度的广义模糊算子,并利用升半梯形模糊分布将空间域的灰度图像变换为对应的广义隶属度.最后给出的两个实例表明该算法提取图像边界速度快、效果好.     

Feeding forages with reduced particle size in a total mixed ration improves feed intake,total-tract digestibility,and performance of organic dairy cows

The optimal utilization of forages is crucial in cattle production, especially in organic dairy systems that encourage forage-based feeding with limited concentrate amounts. Reduction of the particle size of forages is known to improve feed intake and thus might be a viable option to help cows cope with less nutrient-dense feeds. The main aim of this study was to evaluate the effects of reducing forage particle size with a geometric mean of 52 mm (conventional particle size; CON) to 7 mm (reduced particle size; RED) in a high-forage diet (80% of dry matter) on dairy cows' sorting behavior, feed intake, chewing activity, and performance as well as on total-tract nutrient digestibility. Both diets (CON and RED) consisted of 43% grass hay, 37% clover-grass silage, and 20% concentrate and contained roughly 44% NDF, 15% CP, and 0.5% starch (dry matter basis). For CON, particle size was set by mixing all components for 20 min in a vertical feed mixer. The RED diet was treated the same, but before the mixer was filled, forages were chopped (theoretical length of cut = 0.5 cm) and the hay was hammer-milled (sieve size = 2 cm). Four primiparous and 16 multiparous mid-lactating dairy cows were assigned according to milk yield, body weight (BW), days in milk, and parity into 2 groups and fed 1 of the 2 diets for 34 d. The first 13 d were used for diet adaption, followed by data collection of nutrient intake, chewing activity, sorting behavior, milk production, and nutrient digestibility for the last 21 d of the experiment. Seven days before the start of the experiment, data on BW, dry matter intake (DMI), chewing activity, sorting behavior, and milk production were collected for use as covariates. Results showed that the RED diet improved DMI (+1.8 kg/d) and NDF intake (+0.46 kg/d) but decreased intake of physically effective NDF >8 (?3.25 kg/d). The RED-fed cows increased their intake of smaller particles (<19 mm), whereas CON-fed cows sorted for long particles (>19 mm). The RED cows reduced eating and ruminating time per kilogram of DMI by 4.8 and 1.9 min, respectively, suggesting lower mastication efforts. In addition, the RED diet significantly increased apparent total-tract digestibility of nutrients. As a consequence, RED cows' energy-corrected milk yield was higher (27.0 vs. 29.3 kg/d) without affecting milk solids, cow BW, or feed efficiency. In conclusion, the data support a reduction of forage particle size in high-forage diets as a measure to improve energy intake, performance, and hence forage utilization under these feeding conditions.     

Replacing soybean hulls with grass hay on growth,intake, total tract digestibility,and rumen microbial nitrogen production of weaned Holstein dairy calves from 8 to 16 weeks of age

The objective of this experiment was to determine the effects of replacing soybean hull (SBH) pellets with grass hay (GH) on growth, intake, total-tract digestibility, and rumen microbial nitrogen production of weaned dairy calves from 8 to 16 wk of age. Holstein calves (n = 16) were randomly assigned to 1 of 4 rations containing, on a dry matter (DM) basis, 76% grower with the remaining 24% being made up of different amounts of SBH pellets and GH [0% GH, 24% SBH (0GH); 8% GH, 16% SBH (8GH); 16% GH, 8% SBH (16GH); and 24% GH, 0% SBH (24GH)]. Calves were weaned at 6 wk, housed individually, and studied from 8 to 16 wk of age. From 8 to 9 wk of age calves were offered a ration consisting of 50% of texturized starter (20% CP and 35% starch), which was offered from 3 d of age, and 50% of their assigned ration. From 9 wk until the end of the study, calves were offered 100% of their assigned ration. Intake and body weight were measured weekly, and frame measurements were taken at the beginning and end of the study. Animal behavior observations were recorded every 5 min over a 24-h period at 10 and 14 wk of age. Total fecal and urine collection was conducted for 4 d consecutively at 11 and 15 wk of age. Feed and feces were evaluated for DM, N, neutral detergent fiber, acid detergent fiber, and starch to determine total-tract digestibility. Feces were evaluated for geometric mean particle length (X_gm) and particle size distribution. Urine was evaluated for N, creatinine, urea, and total purine derivatives to estimate microbial N yield. Calves offered 0GH and 8GH had a 20% increase in intake, average daily gain (1.23, 1.27, 0.89, and 0.71 kg/d for 0GH, 8GH, 16GH, and 24GH, respectively), and feed efficiency compared with 16GH and 24GH. Calves offered 8GH had the greatest levels of neutral detergent fiber and acid detergent fiber digestibility, as well as the greatest estimated microbial N yields. Inclusion of forage increased rumination time (2.75, 6.89, 7.18, and 8.16 h/d for 0GH, 8GH, 16GH, and 24GH, respectively) and decreased fecal X_gm by ~35% compared with calves offered 0GH. In the current study, increasing the replacement of SBH with GH beyond 8% was detrimental to weaned calf performance. These results indicate that when diets containing 8% GH and 16% SBH were fed to recently weaned calves, rumen functionality and feed efficiency were optimized compared with the other GH-SBH combinations     

苜蓿草粉替代部分全价日粮对杜洛克生长育肥猪生长性能的影响

为探讨紫花苜蓿草粉在纯种杜洛克猪中的适宜添加量,考察了苜蓿草粉替代部分杜洛克猪全价日粮对其生长性能及经济效益的影响.结果发现:在生长阶段,5%、10%的替代水平使得生长猪的平均日增重显著增加,料肉比下降;对平均日采食量的影响不显著.在肥育阶段,苜蓿草粉替代组的平均日增重、平均日采食量均低于对照组,其中10%替代组略低于对照组.苜蓿草粉替代部分日粮均降低了饲料成本.在生长阶段,所有处理组每1 kg增重饲料成本均低于对照组,最低的是10%替代组;在肥育阶段,10%替代组每1 kg增重成本低于对照组(P＞0.05).苜蓿草粉对社洛克猪生长阶段全价日粮的适宜替代水平为5%、10%,肥育阶段为10%.     

Inter-laboratory comparison study for pyrrolizidine alkaloids in animal feed using spiked and incurred material

Pyrrolizidine alkaloids (PAs) are hepatotoxic metabolites produced by plants. PAs in animal feed can cause acute or chronic intoxications in animals and can be transferred to milk. An inter-laboratory comparison study among 12 laboratories, using their own methods of analysis, was conducted for the detection and quantification of PAs in animal feed. The participants were asked to quantify PAs in a blank test sample, a blank test sample to be spiked with a provided spiking mixture of seven PA standards, and a test sample contaminated with common groundsel (Senecio vulgaris). Ten of the participating laboratories used an LC-MS/MS method, one used an LC-ToF-MS method, and one used a GC-MS method. None of the laboratories reported false-negative samples, while two laboratories reported false-positive results in the blank sample. z-scores were calculated for each laboratory for seven PAs in test samples B and C. z-scores varied considerably between laboratories for the concentrations of the free bases and less for the N-oxides, probably due to the lower levels of the free bases as compared with the N-oxides in the contaminated feed. Questionable or unsatisfactory results for the z-scores were obtained for 8% of the cases for the spiked sample and for 12% of the incurred sample. Three laboratories scored consequently positive or negative results. No preferred method for quantification of PAs in feed could be identified within the methods used for this study due to the relatively small number of participants. It was concluded that this inter-laboratory study shows that the methods used for PA detection need further development for accurate estimation of PAs in contaminated feed.     

Effects of dietary carbohydrate sources on degradation kinetics of nitrogen from plant protein sources in the rumen

The effects of the nature of carbohydrate source on in sacco protein degradation of 15 samples of plant protein sources were studied in four mature fistulated rams fed a control diet (C) of meadow hay and soyabean meal (83:15 on dry matter basis) and three diets in which 36, 34 or 40% of diet dry matter was sugar beet pulp, maize or wheat (diets P, M and W respectively). Degradation parameters were estimated from the exponential equation p = a + b[1 ? exp(?ct)]. Diet composition significantly affected (P < 0.001) all the degradation parameters, the effect being more pronounced on the degradation rate (c). This parameter was stimulated (P < 0.05) by beet pulp but depressed (P < 0.05) by cereal inclusion in the diets, in particular when animals were fed the W diet (4.46, 5.65, 3.74 and 3.05% h^?1 for the C, P, M and W diets respectively). An interaction effect between carbohydrate source and incubated plant protein sources was observed (P < 0.001). The reason(s) for these differential effects were not elucidated. The practical consequences of these findings are discussed. Copyright © 2005 Society of Chemical Industry     

Emanating Objects: The Atmospheric Ecosystems Generated by Gelatinous Orb and Buru Buru

The Bittertang Farm is a New York‘based experimental design firm that strives to bring happiness into the built environment by exploring the pleasurable, frothy features of the world around us. Michael Loverich , who cofounded the practice together with Antonio Torres, here describes two of its interventions. Taking the form of fantastical narrative ecosystems, they inspire new experiential moods.