Effect of partially replacing a barley-based concentrate with flaxseed-based products on the rumen bacterial population of lactating Holstein dairy cows.

AIMS: The effects of partial replacement of a barley-based concentrate with flaxseed-based products on the rumen bacterial population of lactating Holstein dairy cows were evaluated. METHODS AND RESULTS: Treatments fed were CONT, a normal diet that included barley silage, alfalfa hay and a barley-based concentrate that contained no flaxseed or faba beans; FLAX, inclusion of a nonextruded flaxseed-based product containing 55·0% flaxseed, 37·8% field peas and 6·9% alfalfa; EXT, similar to FLAX, but the product was extruded and EXTT, similar to FLAX, but product was extruded and field peas were replaced by high-tannin faba beans. The rumen bacterial population was evaluated by utilizing 16S rRNA gene sequencing. Most abundant phyla, families and genera were unaffected. However, some taxa were affected; for example, unsaturated fatty acid content was negatively correlated with Clostridiaceae, and tannin content was negatively correlated with BS11 and Paraprevotellaceae. CONCLUSIONS: Predominant rumen bacterial taxa were not affected, but the abundance of some taxa found in lower proportions shifted, possibly due to sensitivity to unsaturated fatty acids or tannins. SIGNIFICANCE AND IMPACT OF THE STUDY: Flaxseed-based products were effective for partially replacing barley-based concentrate in rations of lactating dairy cows. No negative effects of these products were observed on the abundance of predominant rumen bacterial taxa, with only minor shifts in less abundant bacteria.

Low-intensity ultrasound activates vestibular otolith organs through acoustic radiation force.

The present study examined the efficacy of 5 MHz low-intensity focused ultrasound (LiFU) as a stimulus to remotely activate inner ear vestibular otolith organs. The otolith organs are the primary sensory apparati responsible for detecting orientation of the head relative to gravity and linear acceleration in three-dimensional space. These organs also respond to loud sounds and vibration of the temporal bone. The oyster toadfish, Opsanus tau, was used to facilitate unobstructed acoustic access to the otolith organs in vivo. Single-unit responses to amplitude-modulated LiFU were recorded in afferent neurons identified as innervating the utricle or the saccule. Neural responses were equivalent to direct mechanical stimulation, and arose from the nonlinear acoustic radiation force acting on the otolithic mass. The magnitude of the acoustic radiation force acting on the otolith was measured ex vivo. Results demonstrate that LiFU stimuli can be tuned to mimic directional forces occurring naturally during physiological movements of the head, loud air conducted sound, or bone conducted vibration.

Effects of extruding wheat dried distillers grains with solubles with peas or canola meal on ruminal fermentation, microbial protein synthesis, nutrient digestion, and milk production in dairy cows.

Our objective was to examine the effects of feeding coextruded and nonextruded supplements consisting of wheat dried distillers grains with solubles with peas (WDDGS-peas) or canola meal (WDDGS-CM) on ruminal fermentation, omasal flow, and production performance in Holstein cows. Eight cows (4 ruminally cannulated) were used in a replicated 4×4 Latin square with 28-d periods and a 2×2 factorial arrangement of dietary treatments. Dietary treatments were coextruded or nonextruded mixtures of WDDGS-peas and WDDGS-CM that were included in total mixed rations at 15.1% [dry matter (DM) basis]. Diet had no effect on DM intake. Milk yield was greater in cows fed coextruded diets compared with those fed nonextruded diets. Milk fat content was greater in cows fed nonextruded diets compared with those fed coextruded diets, but milk fat yield was greater in cows fed coextruded diets compared with those fed nonextruded diets. Milk yield tended to be greater and milk protein yield was greater in cows fed WDDGS-peas compared with those fed WDDGS-CM. Cows fed nonextruded diets had a greater milk urea-N concentration compared with those fed coextruded diets. Cows fed coextruded diets had greater ruminal digestion of DM and tended to have greater ruminal digestion of organic matter compared with those fed nonextruded diets. Total-tract digestibilities of organic matter, crude protein, ether extract, and starch were greater, whereas that of acid detergent fiber and neutral detergent fiber tended to be greater in cows fed coextruded compared with those fed nonextruded diets. Total-tract digestibility of ether extract was lower whereas that of starch was greater and that of crude protein tended to be greater in cows fed WDDGS-peas compared with those fed WDDGS-CM. Total N excretion and milk N efficiency were unaffected by diet. Ruminal NH3-N concentration tended to be greater in cows fed WDDGS-CM compared with those fed WDDGS-peas. Ruminal propionate concentration was greater whereas plasma urea-N concentration tended to be lower in cows fed coextruded compared with those fed nonextruded diets. Plasma glucose concentration was greater in cows fed diets containing WDDGS-CM compared with those fed diets containing WDDGS-peas, but the difference in plasma glucose concentration between WDDGS-CM and WDDGS-peas was greater in cows fed coextruded diets compared with those fed nonextruded diets. In summary, feeding coextruded compared with nonextruded supplements or WDDGS-peas compared WDDGS-CM increased yields of milk, fat, and protein.

Effects of dietary crude protein and rumen-degradable protein concentrations on urea recycling, nitrogen balance, omasal nutrient flow, and milk production in dairy cows.

The objective of this study was to determine how interactions between dietary crude protein (CP) and rumen-degradable protein (RDP) concentrations alter urea-nitrogen recycling, nitrogen (N) balance, omasal nutrient flow, and milk production in lactating Holstein cows. Eight multiparous Holstein cows (711±21kg of body weight; 91±17d in milk at the start of the experiment) were used in a replicated 4×4 Latin square design with a 2×2 factorial arrangement of dietary treatments and 29-d experimental periods. Four cows in one Latin square were fitted with ruminal cannulas to allow ruminal and omasal sampling. The dietary treatment factors were CP (14.9 vs. 17.5%; dry matter basis) and RDP (63 vs. 69% of CP) contents. Dietary RDP concentration was manipulated by including unprocessed or micronized canola meal. Diet adaptation (d 1-20) was followed by 8d (d 21-29) of sample and data collection. Continuous intrajugular infusions of [(15)N(15)N]-urea (220mg/d) were conducted for 4d (d 25-29) with concurrent total collections of urine and feces to estimate N balance and whole-body urea kinetics. Proportions of [(15)N(15)N]- and [(14)N(15)N]-urea in urinary urea, and (15)N enrichment in feces were used to calculate urea kinetics. For the low-CP diets, cows fed the high-RDP diet had a greater DM intake compared with those fed the low-RDP diet, but the opposite trend was observed for cows fed the high-CP diets. Dietary treatment had no effect on milk yield. Milk composition and milk component yields were largely unaffected by dietary treatment; however, on the low-CP diets, milk fat yield was greater for cows fed the low-RDP diet compared with those fed the high-RDP diet, but it was unaffected by RDP concentration on the high-CP diets. On the high-CP diets, milk urea nitrogen concentration was greater in cows fed the high-RDP diet compared with those fed the low-RDP diet, but it was unaffected by RDP concentration on the low-CP diets. Ruminal NH3-N concentration tended to be greater in cows fed the high-CP diet compared with those fed the low-CP diet, and it was greater in cows fed the high-RDP diet as compared with those fed the low-RDP diet. Nitrogen intake and both total N and urea-N excretion in urine were greater for cows fed the high-CP diet compared with those fed the low-CP diet. However, N balance and urinary excretion of purine derivatives were unaffected by dietary treatment. Urea-N entry rate (UER) was greater in cows fed the high-CP diet compared with those fed the low-CP diet; however, UER was unaffected by dietary RDP concentration. The proportion of urea-N recycled to the gastrointestinal tract (as a percentage of UER) was greater in cows fed the low-CP diet compared with those fed the high-CP diet. In summary, reducing dietary CP concentration decreased urinary N excretion but had no effect on milk yield, thus resulting in an overall improvement in milk N efficiency.

Effects of MRTI sampling characteristics on estimation of HIFU SAR and tissue thermal diffusivity.

While the non-invasive and three-dimensional nature of magnetic-resonance temperature imaging (MRTI) makes it a valuable tool for high-intensity focused ultrasound (HIFU) treatments, random and systematic errors in MRTI measurements may propagate into temperature-based parameter estimates used for pretreatment planning. This study assesses the MRTI effects of zero-mean Gaussian noise (SD = 0.0-2.0 °C), temporal sampling (tacq = 1.0-8.0 s), and spatial averaging (Res = 0.5-2.0 mm isotropic) on HIFU temperature measurements and temperature-based estimates of the amplitude and full width half maximum (FWHM) of the HIFU specific absorption rate and of tissue thermal diffusivity. The ultrasound beam used in simulations and ex vivo pork loin experiments has lateral and axial FWHM dimensions of 1.4 mm and 7.9 mm respectively. For spatial averaging simulations, beams with lateral FWHM varying from 1.2-2.2 mm are also assessed. Under noisy conditions, parameter estimates are improved by fitting to data from larger voxel regions. Varying the temporal sampling results in minimal changes in measured temperatures (<2% change) and parameter estimates (<5% change). For the HIFU beams studied, a spatial resolution of 1 × 1 × 3 mm(3) or smaller is required to keep errors in temperature and all estimated parameters less than 10%. By quantifying the errors associated with these sampling characteristics, this work provides researchers with appropriate MRTI conditions for obtaining estimates of parameters essential to pretreatment modeling of HIFU thermal therapies.

Protein fractionation byproduct from canola meal for dairy cattle.

Fiber-protein is a byproduct arising from a process for fractionating high-quality protein from canola meal. The objective of this study was to evaluate the fiber-protein fraction by examining the chemical profiles, rumen degradation, and intestinal digestive characteristics and determining the nutritive value of the fiber-protein fraction as dietary components for dairy cattle in comparison with commercial canola meal and soybean meal. Available energy values were estimated based on National Research Council guidelines, whereas total true protein content potentially absorbable in the small intestine (DVE) were predicted using the predicted DVE/degraded protein balance (OEB) model. The results show that fiber-protein was a highly fibrous material [neutral detergent fiber (NDF): 556; acid detergent fiber (ADF): 463; acid detergent lignin: 241 g/kg of dry matter (DM)] compared with canola meal (NDF: 254; ADF: 212; acid detergent lignin: 90 g/kg of DM) due to the presence of a higher level of seed hulls in fiber-protein. Compared with canola meal, fiber-protein contained 90 g/kg of DM less crude protein (CP), 25% of which consisted of undegradable acid detergent-insoluble CP. Most of the ruminally undegradable nutrient components present in canola meal appeared to be concentrated into fiber-protein during the manufacturing process and, as a result, fiber-protein showed a consistently lower effective degradability of DM, organic matter, CP, NDF, and ADF compared with both canola meal and soybean meal. Available energy content in fiber-protein contained two-thirds of that of canola meal. The DVE was one-third that of soybean meal and one-fifth that of canola meal [DVE value: 58 vs. 180 (soybean) and 291 g/kg of DM (canola meal)]. The OEB value of fiber protein was positive and about half of that of soybean and canola meal [OEB value: 74 vs. 162 (soybean) and 137 g/kg of DM (canola meal)]. Fiber-protein can be considered as a secondary source of protein in ruminant feed.

An analytical solution for improved HIFU SAR estimation.

Accurate determination of the specific absorption rates (SARs) present during high intensity focused ultrasound (HIFU) experiments and treatments provides a solid physical basis for scientific comparison of results among HIFU studies and is necessary to validate and improve SAR predictive software, which will improve patient treatment planning, control and evaluation. This study develops and tests an analytical solution that significantly improves the accuracy of SAR values obtained from HIFU temperature data. SAR estimates are obtained by fitting the analytical temperature solution for a one-dimensional radial Gaussian heating pattern to the temperature versus time data following a step in applied power and evaluating the initial slope of the analytical solution. The analytical method is evaluated in multiple parametric simulations for which it consistently (except at high perfusions) yields maximum errors of less than 10% at the center of the focal zone compared with errors up to 90% and 55% for the commonly used linear method and an exponential method, respectively. For high perfusion, an extension of the analytical method estimates SAR with less than 10% error. The analytical method is validated experimentally by showing that the temperature elevations predicted using the analytical method's SAR values determined for the entire 3D focal region agree well with the experimental temperature elevations in a HIFU-heated tissue-mimicking phantom.

Effects of replacing canola meal as the major protein source with wheat dried distillers grains with solubles on ruminal function, microbial protein synthesis, omasal flow, and milk production in cows.

A study was conducted to determine the effects of replacing canola meal (CM) as the major protein source with wheat-based dried distillers grains with solubles (W-DDGS) on ruminal fermentation, microbial protein production, omasal nutrient flow and animal performance. Eight lactating dairy cows were fed in a replicated 4 × 4 Latin square design with 28-d periods (20 d of dietary adaptation and 8 d of measurements). Four cows in one Latin square were ruminally cannulated for measurements of ruminal fermentation characteristics and flow of nutrients at the omasal canal. Cows were fed either a standard barley silage-based total mixed ration containing CM as the major protein supplement (0% W-DDGS, control) or diets formulated to contain 10, 15, and 20% W-DDGS (dry matter basis), with W-DDGS replacing primarily CM. Diets were isonitrogenous (18.9% crude protein) and contained 3.0, 3.2, 3.5, and 3.7% ether extract for 0, 10, 15, and 20% W-DDGS, respectively. Diets contained 50% forage and 50% concentrate. Inclusion of W-DDGS linearly increased dry matter intake (29.5, 31.2, 30.2, and 31.9 kg/d for 0, 10, 15, and 20% W-DDGS, respectively). The addition of W-DDGS in place of CM resulted in a 1.2- to 1.8-kg increase in milk yield (42.9, 44.7, 44.1, and 44.5 kg/d for 0, 10, 15, and 20% W-DDGS); however, a quadratic change in feed efficiency (i.e., milk yield/DM intake) occurred as the dietary level of W-DDGS increased. Treatments did not differ for milk fat, protein, and lactose concentrations; however, quadratic changes were observed in milk yields of fat (1.48, 1.56, 1.62, and 1.55 kg/d for 0, 10, 15, and 20% W-DDGS, respectively), protein (1.44, 1.46, 1.49, and 1.42 kg/d) and lactose (1.96, 2.02, 2.09, and 1.93 kg/d). Ruminal fermentation characteristics did not change except that the inclusion of 20% W-DDGS resulted in a decrease and a tendency for a decrease in molar concentrations of isobutyrate and total volatile fatty acids, respectively. Omasal flow of total bacterial nonammonia N (NAN) and bacterial efficiency (g of total bacterial NAN flow/kg of organic matter truly digested in the rumen) were not different among diets; however, feeding W-DDGS resulted in a quadratic increase in nonammonia nonbacterial N flow at the omasal canal (271, 318, 336, and 311 g/d for 0, 10, 15, and 20% W-DDGS, respectively). These data indicate that W-DDGS can substitute for CM as the major protein source in dairy cow diets without negatively affecting ruminal fermentation, microbial protein production, and omasal nutrient flow, and can potentially increase dry matter intake and milk yield.

Modeling degradation ratios and nutrient availability of anthocyanidin-accumulating Lc-alfalfa populations in dairy cows.

Dairy cattle eating fresh or ensiled alfalfa as the main portion of their diet often have low protein efficiency because of the rapid initial rate of ruminal protein degradation of fresh and ensiled alfalfa. Ruminal protein degradation of alfalfa might be reduced by introducing a gene that stimulates the accumulation of mono- or polymeric anthocyanidins in alfalfa. The objectives of this study were to fractionate protein and carbohydrates by in situ and chemical approaches, to evaluate in situ ruminal degradation characteristics and synchronization ratios, to determine protein availability to dairy cattle using the 2007 digestible intestinal protein/rumen-degraded protein balance (DVE/OEB) protein system, and to determine net energy for lactation using the Dutch net energy for lactation (VEM) system for 3 newly developed transgenic winter hardy anthocyanidin-accumulating T(1)Lc-alfalfa populations. These T(1)Lc-alfalfa populations, called (T1)BeavLc1, (T1)RambLc3, and (T1)RangLc4, had an average anthocyanidin accumulation of 163.4 µg/g of DM, whereas AC Grazeland (selected for a low initial rate of degradation) did not accumulate anthocyanidin. The basic chemical composition of the original samples, soluble and potentially degradable fractions, and degradation characteristics of crude protein and carbohydrates were similar in T(1)Lc-alfalfa and AC Grazeland. The undegradable in situ crude protein and neutral detergent fiber fraction had 1.3% lower CP and 4.8% lower CHO, respectively, in T(1)Lc-alfalfa compared with the amounts in AC Grazeland. The T(1)Lc-alfalfa had a 0.34 MJ/kg of DM higher calculated net energy for lactation and 1.9% of CP higher buffer soluble protein compared with that in AC Grazeland. By the protein evaluation model, it was predicted that T(1)Lc-alfalfa tended to have 11.9, 6.9, and 8.4 g/kg of DM higher rumen degradable protein, OEB, and intestinal available protein, respectively, compared with the amounts in AC Grazeland. The hourly OEB included an initial and substantial peak (oversupply) of protein relative to energy, which was highest in (T1)RangLc4 and lowest in (T1)RambLc3. The hourly OEB between 4 and 24h was similar and more balanced for all 4 alfalfa populations. In conclusion, T(1)Lc-alfalfa accumulated anthocyanidin, tended to have higher predicted intestinal protein availability, and had higher predicted net energy of lactation availability for dairy cattle than did AC Grazeland.

Effects of dietary Cu, Mo and S on urinary Cu and Zn excretion in Simmental and Angus cattle.

This study determined the effects of dietary copper (Cu), molybdenum (Mo) and sulphur (S) on urinary Cu and zinc (Zn) excretion in cattle. Four Simmental and four Angus heifers were fed low (L) or high (H) levels (mg/kg DM) of Cu (5,40), Mo (1,10) and S (0.2,0.5%). Initially two of each breed was fed either LCu or HCu (2 mo). Then all eight animals were fed sequentially LCuHS (1.5 mo), HCuHS, HCuHMo and HCuHMoHS (2 mo each). Simmental had a higher urine flow, increased concentration and total excretion of urinary Cu and Zn compared to Angus, but only total Zn excretion was significantly higher. Urinary Cu excretion was greatest with the HCuHMoHS diet. Urinary Zn excretion significantly increased with HS but not HS in combination with HMo and/or HCu. This study, together with previously reported biliary excretion, allows a direct comparison of urinary and biliary Cu and Zn excretion responses to dietary Cu, Mo and S.

Effects of type of canola protein supplement on ruminal fermentation and nutrient flow to the duodenum in beef heifers.

Ruminal fermentation, nutrient digestion, and flows to the duodenum in growing cattle fed differently produced canola protein supplements were studied in a 4 x 4 Latin square design using Speckle Park heifers (initial BW = 451 +/- 26 kg). Canola protein supplement treatments consisted of the following: 1) 8.78% regular canola meal (RCM); 2) 9.25% RCM plus 1.80% canola oil (RCMO); 3) 11.1% canola presscake from biodiesel oil extraction (CPC); and 4) 8.14% high ruminally undegradable protein (RUP) canola meal (RUCM) plus 1.32% canola oil (RUCMO). Experimental diets also contained 39.9, 40.2, 39.9, and 39.9% barley grain; 31.7, 31.4, 31.2, and 31.4% barley silage; and 17.5, 15.2, 15.6, and 16.5% oat hulls for the RCM, RCMO, CPC, and RUCMO diets, respectively. Feeding the CPC, RCMO, and RUCMO diets decreased (P < or = 0.05) ruminal NH(3)-N concentration compared with feeding the RCM diet. Compared with the RCM diet, adding canola oil in the RCMO diet or residual oil in the CPC diet resulted in greater ruminal concentrations of propionate (P < or = 0.09). Additionally, feeding the RCMO diet also resulted in greater ruminal concentrations of acetate (P = 0.07), valerate (P = 0.06), and total VFA (P = 0.07) compared with the RCM diet. Also, compared with the RCM diet, heifers on the RUCMO diet had decreased acetate (P = 0.02) concentrations. The changes in ruminal concentrations of acetate and propionate resulted in reduced acetate:propionate ratios in the RCMO (P = 0.08), CPC (P = 0.02), and RUCMO (P < 0.01) diets. Ruminal digestion and flows of nutrients to the duodenum were not affected by dietary treatment. However, adding canola oil to the RCMO and RUCMO dietary treatments decreased the digestibility of ADF (P < or = 0.08) and NDF (P < or = 0.08) in the total tract compared with the RCM diet. Total tract digestibility of OM was also decreased (P = 0.02) in heifers fed the RUCMO compared with the RCM diet. Notwithstanding the different processing methods employed in making RCM, CPC, or RUCM, there were no differences among the diets for ruminally degraded protein, ruminal microbial protein synthesis, and the flow of N fractions to the duodenum.

Heat-induced protein structure and subfractions in relation to protein degradation kinetics and intestinal availability in dairy cattle.

The objectives of this study were to reveal protein structures of feed tissues affected by heat processing at a cellular level, using the synchrotron-based Fourier transform infrared microspectroscopy as a novel approach, and quantify protein structure in relation to protein digestive kinetics and nutritive value in the rumen and intestine in dairy cattle. The parameters assessed included 1) protein structure alpha-helix to beta-sheet ratio; 2) protein subfractions profiles; 3) protein degradation kinetics and effective degradability; 4) predicted nutrient supply using the intestinally absorbed protein supply (DVE)/degraded protein balance (OEB) system for dairy cattle. In this study, Vimy flaxseed protein was used as a model feed protein and was autoclave-heated at 120 degrees C for 20, 40, and 60 min in treatments T1, T2, and T3, respectively. The results showed that using the synchrotron-based Fourier transform infrared microspectroscopy revealed and identified the heat-induced protein structure changes. Heating at 120 degrees C for 40 and 60 min increased the protein structure alpha-helix to beta-sheet ratio. There were linear effects of heating time on the ratio. The heating also changed chemical profiles, which showed soluble CP decreased upon heating with concomitant increases in nonprotein nitrogen, neutral, and acid detergent insoluble nitrogen. The protein subfractions with the greatest changes were PB1, which showed a dramatic reduction, and PB2, which showed a dramatic increase, demonstrating a decrease in overall protein degradability. In situ results showed a reduction in rumen-degradable protein and in rumen-degradable dry matter without differences between the treatments. Intestinal digestibility, determined using a 3-step in vitro procedure, showed no changes to rumen undegradable protein. Modeling results showed that heating increased total intestinally absorbable protein (feed DVE value) and decreased degraded protein balance (feed OEB value), but there were no differences between the treatments. There was a linear effect of heating time on the DVE and a cubic effect on the OEB value. Our results showed that heating changed chemical profiles, protein structure alpha-helix to beta-sheet ratio, and protein subfractions; decreased rumen-degradable protein and rumen-degradable dry matter; and increased potential nutrient supply to dairy cattle. The protein structure alpha-helix to beta-sheet ratio had a significant positive correlation with total intestinally absorbed protein supply and negative correlation with degraded protein balance.

Anomalous high-frequency oscillations in a field emission tube and their significance in pulsed field emission.

Relaxation oscillations occur when a capacitor is inserted in series with a field emission tube, a DC high-voltage power supply, and a ballast resistor. The waveform of these oscillations is highly reproducible with a dominant frequency of 200 MHz and a decay time of 20 ns. The peak current as high as 320 mA has been observed although the tungsten emitter is only rated for 10 microA. We have shown that these oscillations are due to a displacement current, charging of the anode-tip capacitance, and are not of a field emission origin. We conclude that the effects of displacement current should be considered in measurements of field emission with microsecond pulses, where high-current densities can be observed.

Effects of corn silage particle length and forage:concentrate ratio on milk fatty acid composition in dairy cows fed supplemental flaxseed.

This study aimed to evaluate the effects of length of chop of corn silage and forage:concentrate ratio (F:C) on performance and milk fatty acid profiles in dairy cows supplemented with flaxseed. Our hypothesis was that decreasing forage particle length and F:C ratio would increase unsaturated fatty acid flow to the small intestine and subsequent transfer of these unsaturated fatty acids into milk. Eight Holstein cows (648.1 +/- 71.5 kg body weight; 109.6 +/-43.6 days in milk) were used in a replicated 4 x4 Latin square design with 21-d periods and a 2 x2 factorial arrangement of dietary treatments. Dietary factors were: 1) F:C ratios (dry matter basis) of 55:45 and 45:55; and 2) corn silage particle lengths of 9.52 and 19.05 mm. All experimental cows received 1 kg of flaxseed to substitute for 1 kg of a rolled barley grain-based concentrate daily. Diets were fed twice daily as a total mixed ration. Corn silage particle length and F:C ratio had no effect on dry matter intake, milk yield, and milk composition; however, feeding short cut corn silage depressed milk protein yield. Significant particle size xF:C ratio interactions were observed for milk fat proportions of C(16:0), C(18:1) cis-9, and C(18:2) cis-9, trans-11 (a conjugated linoleic acid isomer). At short corn silage particle size, decreasing F:C ratio depressed milk fat proportion of C(16:0). Conversely, feeding short corn silage at high F:C ratio increased the proportion of C(18:1) cis-9 and C(18:2) cis-9, trans-11 in milk fat. The milk fat proportion of C(18:2) trans-10, cis-12, a conjugated linoleic acid isomer that is associated with milk fat depression, was not affected by dietary treatment. Our results show that corn silage particle length and F:C ratio influence milk fatty acid profiles in dairy cows fed supplemental flaxseed as a source of polyunsaturated fatty acids.

Improving the nutritional value of oat hulls for ruminant animals with pretreatment of a multienzyme cocktail: in vitro studies.

Relatively high amounts of hydroxycinnamic acid in oat hulls, mainly ferulic acid, are believed to be inhibitory to digestion by ruminal microorganisms. Ferulic acid is produced via the phenylpropanoid biosynthetic pathway and covalently cross-linked to polysaccharides by ester bonds and to components of lignin, mainly by ether bonds. Ferulic acid also forms dimers or trimers. As a result, polysaccharides become extensively cross-linked by ferulate dimerization or trimerization and incorporation into lignin. Previous studies have shown that Aspergillus ferulic acid esterase and Trichoderma xylanase act synergistically to release ferulic acid from feruloyl-polysaccharides in complex plant cell walls of oat hulls. This activity opens the remainder of the polysaccharides to further hydrolytic attack and facilitates the accessibility of the main polysaccharide chain to cellulase, thereby increasing the release of reducing sugars. In Exp. 1, the best multienzyme cocktail (ferulic acid esterase, xylanase, cellulase, endo-glucanase [I, II], and beta-glucanase) was developed using an orthogonal experimental design, L25 (5(6)), where L = orthogonal table; 6 = factors; 5 = five levels of each; and 25 = experimental number, for further in situ and/or in vivo study. In Exp. 2, in vitro biodegradation studies with a 3 x 2 x 4 factorial arrangement of treatments were used to evaluate the responses of three feedstuffs, oat hulls or standard references (wheat straw and alfalfa hay), two particle sizes (1 mm and 250 microm), and four in vitro incubation treatments with the best multienzyme cocktail developed in Exp. 1. Addition of the multienzyme cocktail to the forages improved (P < 0.01) in vitro ruminal fluid degradability. With respect to feedstuff, the order of response (P < 0.05) to the treatments was oat hulls (+12% unit) > wheat straw (+5% unit) > alfalfa (+2% unit). This multi-enzyme cocktail seems best suited for oat hulls containing feruloyl ester bonds. In conclusion, data from this study suggest that the addition of the multienzyme cocktail to poorly digestible feeds before feeding enhanced degradation of DM.

Effects of alfalfa particle size and specific gravity on chewing activity, digestibility, and performance of Holstein dairy cows.

Two experiments were carried out to test the effects of alfalfa particle size and functional specific gravity (FSG) on chewing activity, digestibility, rumen kinetics, and production of lactating dairy cows fed corn silage based rations. In experiment 1, water-holding capacity (WHC), insoluble dry matter, hydration rate, and FSG changes were determined in alfalfa hay (varying in particle size) and corn silage. Reduction of particle size increased bulk density, FSG, and the rate of hydration, and decreased WHC of alfalfa. In experiment 2, 9 midlactation Holstein dairy cows fed total mixed rations containing 3 sizes of alfalfa hay (with geometric mean 7.83, 4.04, and 1.14 mm) were used in a replicated 3 x 3 Latin square design. The diets contained 20, 20, 35, 7, 7.5, 10, 0.3, 0.1, and 0.1% of DM alfalfa, corn silage, barley, soybean meal, beet pulp, wheat bran, dicalcium phosphate, vitamin premix, and salt, respectively. The geometric means (GM) of rations were 3.34, 2.47, and 1.66 mm in long, medium, and fine alfalfa treatments, respectively. Reduction of particle size increased daily NDF intake (kg), but decreased the proportion of physically effective factor (pef) and physically effective NDF (peNDF) in the ingested rations. Reduction of particle size increased the FSG of rations and intake of DM but reduced digestibility of NDF and ash. Reduction of particle size decreased ruminal mean retention time (RMRT), but increased the ruminal particulate passage rate. Milk and FCM yield were not affected by treatments. The rumen pH, total chewing activity, rumination, eating time, and milk fat were reduced as particle size decreased, but milk protein increased. This study showed that reduction of forage particle size increased bulk density, FSG, and hydration rate of alfalfa and was the most influential factor affecting DMI, milk composition, and chewing behavior. Reduction of forage particle size had minimal impact on digestibility and milk production.

Nutrient supply to dairy cows from processed white lupines.

The objective of this study was to compare the DVE/OEB system (DVE = truly absorbed protein in the small intestine; OEB = degraded protein balance (DPB) in Dutch) and the NRC-2001 model in the prediction of supply of protein to dairy cows from processed white lupines (Lupinus albus L.). Comparisons were made in terms of (1) ruminally synthesized microbial CP, (2) truly absorbed protein in the small intestine, and (3) degraded protein balance. In addition, the systematic investigation of roasting of the white lupines at various temperatures (110, 130, or 150 degrees C) and times (15, 30 or 45 min) on manipulation of digestive behaviour and the potential nutrient supply to dairy cows were also carried out, to obtain information on best processing conditions as intestinal protein sources (to achieve target values for potential high net absorbable protein in the small intestine while holding any N loss in the rumen to a low level). The results showed that the predicted values from the DVE/OEB system and the NRC-2001 model had significant correlations with high R ( > 0.83) values. However, using the DVE/OEB system, the overall average microbial protein supply based on available energy was 11% higher and the truly absorbed protein in the small intestine was 7% higher than that predicted by the NRC-2001 model. The difference was also found in the prediction of the degraded protein balances (DPB), which was 8% higher based on data from the NRC-2001 model. These differences are due to considerably different factors used in calculations in the two models, although both are based on similar principles. This indicates that a further refinement is needed for a modern protein evaluation and prediction system. In addition, this study showed that the roasting at higher temperature and time was effective in shifting protein degradation from rumen to intestines and it increased the DVE or MP values without reaching the negative degraded protein balance. The processing at 15 degrees C for 30 or 45 min might be the best treatments for white lupine due to its higher DVE and MP values and the very low DPB values.

Ultrasound-triggered drug targeting of tumors in vitro and in vivo.

The new modality of drug targeting of tumors that we are currently developing is based on drug encapsulation in polymeric micelles, followed by the localized release at the tumor site triggered by focused ultrasound. The rationale behind this approach is that drug encapsulation in micelles decreases systemic concentration of drug, diminishes intracellular drug uptake by normal cells, and provides passive drug targeting of tumors, thus reducing unwanted drug interactions with healthy tissues. Ultrasound irradiation is used to release drug from micelles at the tumor site and to enhance the intracellular drug uptake by tumor cells. An important advantage of ultrasound is that it is noninvasive, can penetrate deep into the interior of the body, can be focused and carefully controlled. Here we describe factors involved in the ultrasound interaction with viable cells in the absence and presence of drug carriers and anti-cancer drugs. We present in vivo effects of 1 MHz ultrasound on drug biodistribution, intratumoral distribution, and survival rates of immuno-compromised athymic nu/nu mice bearing ovarian carcinoma tumors.

Experience with the first three years of an accelerated dual-degree program in biomedical engineering.

Our Department of Bioengineering has instituted a pilot program aimed at helping a select group of highly qualified students obtain both bachelor's and master's degrees in an accelerated timeframe - approximately four years from the beginning of their university studies. A key element of this program is the introduction of the students to research in their second year of studies via a directed and closely supervised cohort mechanism. These students also come to the university with substantial AP credit and spend two summers fulfilling some general education requirements of the university. Our first three years with the program have shown positive results, with most students on track in both academics and research. There have been some challenges, however, with regard to tight scheduling, leaves for religious missions, and continued student stipend funding.

Hot topic: an association between a leptin single nucleotide polymorphism and milk and protein yield.

Allelic variation (C to T transition that results in an Arg25Cys) in the leptin gene has been associated with increased fat deposition in beef cattle. We report that this same genetic variant is also present in dairy breeds. Body fat reserves play an important role in sustaining high milk production in early lactation, when energy intake is limited. To test for an association between the leptin single nucleotide polymorphism and milk productivity, we genotyped 416 Holstein cows and compared lactation performance data using a mixed model. Animals homozygous for the T allele produced more milk (1.5 kg/d vs. CC animals) and had higher somatic cell count linear scores, without significantly affecting milk fat or protein percent over the entire lactation. The increase in milk yield is most prominent in the first 100 d of lactation (2.44 kg/d), declining to 1.74 kg/d between 101 and 200 d in lactation. The milk yield advantage, observed in cows homozygous for the T allele, could represent a major economic advantage to dairy producers.