Row Of Bars Research Articles

Consumer evaluation of meat quality from barrows, immunocastrates and boars in six countries

The practice of surgical castration of piglets and its alternatives is still under debate. Production of boars may impair meat quality due to boar taint and reduced tenderness compared to meat from surgically castrated male pigs, while immunocastration reduces boar taint and may improve meat quality but seems to be less accepted by the pig chain. In this study, we aimed to evaluate the consumer’s sensory appreciation of meat from barrows (BAs), immunocastrates (ICs) and boars (BOs) in six European countries, taking into account the selection of tainted carcass and consumers’ appreciation of boar taint. Loin chops of 30 BAs, 30 ICs and 30 BOs were evaluated by 752 consumers in six countries: Belgium, Czech Republic, Poland, Portugal, Romania and Spain. Consumers rated odour, flavour, tenderness, juiciness, overall liking and willingness to buy and sensitivity to and liking of androstenone (AND) and liking of skatole (SKA) was also tested. In each of the six countries, consumers liked the odour of the BO samples less than that of BA, and IC intermediate. For flavour, tenderness, juiciness, overall liking and willingness to buy, liking scores given by the Czech, Polish and Portuguese consumers significantly differed between the BA, BO and IC. Willingness to buy was highest for BA by Czech and Polish consumers and for BA and IC by Portuguese consumers. The frequency of the negative check all terms that apply terms also differed, with a higher frequency of disgusting for BO compared to BA and IC and of off-flavour, irritating, manure, sweat, disappointing compared to BA, and intermediate for IC. 31% of the consumers disliked the odour of AND (NEGAND), and 36% of them were not sensitive; in contrast, 77% of the consumers disliked SKA (NEGSKA). The decrease in flavour liking score for BO compared to BA and IC was more outspoken by the NEGAND consumer, while NEGSKA consumers gave an overall lower liking score independent of the type of male pig. The results of this study indicate that IC can be a valid alternative for surgical castration.

The effect of sex and slaughter weight on performance, carcass quality and gross margin, assessed on three commercial pig farms

Economic margins on pig farms are small, and changing slaughter weights may increase farm profitability. However, one can question if the optimal slaughter weight is the same for each sex. On three farms, crossbred pigs (n = 1128) were used to determine the effect of sex and slaughter weight on performance, carcass quality and gross margin per pig place per year. On each farm, an equal number of entire males (EMs), barrows (BAs), immunocastrates (IC) and gilts (GIs) were housed separately in group pens. Pens were randomly divided into three categories of different slaughter weights: 105, 117 and 130 kg BW. In BA, the high average daily feed intake (ADFI) and the lower capacity to gain muscle led to a higher feed conversion ratio (FCR) and lower lean meat percentage in comparison to EM and IC. In all sexes, ADFI and FCR increased with an increasing slaughter weight but the effect of slaughter weight on carcass quality varied between sexes. In BA and GI, slaughter weight had no effect on carcass quality, but in EM and IC, carcass quality improved at higher slaughter weights. Gross margin per pig place per year was calculated as gross margin per pig × barn turnover per year, taking into account fixed costs per round, feed costs and output price per pig. The slaughter weight that gained the highest gross margin per year differed between sexes. Slaughtering BA and GI at 130 kg BW, compared to 105 or 117 kg BW, decreased the gross margin per pig place per year due to the lower margin per pig and barn turnover at higher weights. In IC and EM, no difference in gross margin per pig place per year could be demonstrated between slaughtering at 105, 117 or 130 kg BW. In IC, the increasing gross margin per pig with increasing slaughter weights counteracted with the lower barn turnover. In EM, gross margin per pig did not differ between slaughter weights, but the effect of barn turnover was too small to demonstrate significant differences between slaughter weights on gross margin per pig place per year. In conclusion, slaughter weight has an impact on profitability in BA and GI: they should not be slaughtered at 130 kg BW but at lower weights, but no effect could be demonstrated in EM and IC.

The effect of GnRH vaccination on performance, carcass, and meat quality and hormonal regulation in boars, barrows, and gilts.

The aim of this study was to assess the effect of GnRH vaccination in boars (BO), barrows (BA), and gilts (GI) slaughtered at an average BW of 133 kg. Forty BO, 40 BA, and 40 GI were housed individually, fed ad libitum, and divided into 2 groups of 20 pigs per sex, a control group (CON) and a GnRH vaccinated group (IC). The IC group received 2 injections of GnRH vaccine (Improvac) at 70 and 105 kg. In BA, GnRH vaccination had minor effects on performance. Observed effects in BO and GI are therefore probably not caused by the GnRH vaccination itself but by the subsequent withdrawal of gonadal hormones. In BO, the increased feed intake after GnRH vaccination ( < 0.001), accompanied by a fall in estradiol and testosterone levels, led to faster growth ( = 0.014), increased back fat thickness ( = 0.021), and a tendency for a decreased meat percentage ( = 0.052). GnRH vaccination of BO decreased the boar taint-related sensory attribute scores similar to the levels of BA and GI ( < 0.001). In GI, the increased feed intake after GnRH vaccination ( < 0.001), accompanied by low progesterone levels, led to faster growth ( < 0.001), increased back fat thickness ( = 0.018), decreased meat percentage ( = 0.032), and a decreased shear force ( = 0.002) without significant differences in the sensory profile.

Numerical study of forced convection in a turbulent heat sink made of several rows of blocks of square form

Forced convection is a phenomenon associated with the heat transfer fluid flows. The presence of convection affects simultaneously the thermal and hydrodynamic fields, the problem is thus coupled. This form of heat transfer inside ducts occurs in many practical applications such as solar collectors, heat exchangers, cooling of electronic components as well as chemical and nuclear. In this work, we are interested primarily for a numerical study of thermo-hydraulic performances of an incompressible turbulent flow of air through a heat sink composed of several rows of bars of square section. Profiles and the axial velocity fields, as well as profiles and the distribution of the Nusselt number are plotted for all the geometry considered and chosen for different sections. The effects of geometrical parameters of the model and the operating parameters on the dynamic and thermal behavior of the air are analyzed.

The Application of Flow Control to an Aft-Loaded Low Pressure Turbine Cascade With Unsteady Wakes

The synchronous application of flow control in the presence of unsteady wakes was studied on a highly loaded low pressure turbine blade. At low Reynolds numbers, the blade exhibits a nonreattaching separation bubble under steady flow conditions without upstream wakes. Unsteady wakes from an upstream vane row are simulated with a moving row of bars. The separation zone is modified substantially by the presence of unsteady wakes, producing a smaller separation zone and reducing the area-averaged wake total pressure loss by more than 50%. The wake disturbance accelerates transition in the separated shear layer but stops short of reattaching the flow. Rather, a new time-averaged equilibrium location is established for the separated shear layer. The focus of this study was the application of pulsed flow control using two spanwise rows of discrete vortex generator jets. The jets were located at 59% Cx, approximately the peak cp location, and at 72% Cx. The most effective separation control was achieved at the upstream location. The wake total pressure loss decreased 60% from the wake-only level and the cp distribution fully recovered its high Reynolds number shape. The jet disturbance dominates the dynamics of the separated shear layer, with the wake disturbance assuming a secondary role only. When the pulsed jet actuation was initiated at the downstream location, synchronizing the jet to actuate between wake events was key to producing the most effective separation control. Evidence suggests that flow control using vortex generator jets (VGJs) will be effective in the highly unsteady low pressure turbine environment of an operating gas turbine, provided the VGJ location and amplitude are adapted for the specific blade profile.

Considerations on the performance of immunocastrated male pigs

With the ongoing social pressure on surgical castration of pigs, an increase in the population of pigs that are either not castrated or immunocastrated (IC) can be expected. In both cases, their nutrient requirements and performance will differ from surgically castrated pigs and will require changes in their management. Immunocastration is performed by giving two injections of a modified gonadotrophin-releasing hormone component along with an adjuvant, at least 4 weeks apart. This paper describes the reported differences in growth performance and carcass quality of IC male pigs in comparison with boars (BO) and barrows (BA). Theoretically, IC pigs remain physiologically boar until the second vaccination and therefore, growth may be comparable with BO until this second vaccination. From then on, IC male pigs consume more feed than BO and grow faster when fed ad libitum. IC showed a faster growth and better feed conversion ratio than BA. When fed restrictedly, BO grow faster and more efficiently than BA and IC. IC have a lower carcass yield than BA and BO, whereas meat percentage is intermediate.

Growth, Body Chemical Composition, and Tissue Deposition Rates of Nursery Pigs Fed Crystalline or Protein- Bound Lysine

<h2>ABSTRACT</h2> A4-wk experiment was conducted to compare the effect of feeding crystalline lysine relative to the lysine from soybean meal (SBM) on growth performance, body chemical composition, and tissue deposition rates in nursery pigs. Thirty-six pigs were used [18 barrows and 18 gilts, 15 d old; initial BW (mean±SEM)=6.11±0.11kg]. Six pigs (3 barrows and 3 gilts) were killed at the beginning of the experiment and the remaining pigs were killed at the end of the experiment to determine body chemical composition and deposition rates of protein, fat, water, ash, and amino acids. Pigs were blocked by sex and BW (3 blocks of barrows and 3 blocks of gilts) and randomly allotted to 1 of 5 dietary treatments. Pigs were individually penned in 2 nursery facilities, and each treatment was replicated 6 times. The dietary treatments consisted of a corn-SBM basal diet (1.05% lysine) and diets containing either 1.15 or 1.25% total lysine, which were achieved by adding lysine (0.10 or 0.20%) from either SBM or L-lysine hydrochloride (crystalline lysine) to the basal diet. Pigs were given ad libitum access to feed during a 28-d period. Blood samples were collected on the last day of the experiment, and plasma was analyzed for urea concentration. Average daily gain, ADFI, and G:F were similar among dietary treatments (P>0.50). Pigs fed diets supplemented with lysine from SBM had greater (P<0.001) plasma urea concentrations than pigs supplemented with crystalline lysine. Body protein concentration was greatest (P<0.01) in pigs consuming the diet with 0.10% added lysine from crystalline lysine. However, protein deposition was similar in pigs fed both supplemented diets (P>0.10). Body fat concentration and fat deposition were similar (P>0.25; P>0.10) in pigs fed diets supplemented with crystalline lysine or lysine from SBM, respectively. Ash concentration was greatest (P<0.05) in pigs fed 0.10% added crystalline lysine compared with pigs fed added lysine from SBM. Lysine concentration and deposition were similar in pigs fed crystalline lysine and pigs fed SBM-bound lysine. The results suggest there are no differences in growth, body chemical components, and tissue deposition rate between nursery pigs fed SBM-bound lysine and lysine from L-lysine hydrochloride.

Mechanical properties of lattice grid composites

An equivalent continuum method only considering the stretching deformation of struts was used to study the in-plane stiffness and strength of planar lattice grid composite materials. The initial yield equations of lattices were deduced. Initial yield surfaces were depicted separately in different 3D and 2D stress spaces. The failure envelope is a polyhedron in 3D spaces and a polygon in 2D spaces. Each plane or line of the failure envelope is corresponding to the yield or buckling of a typical bar row. For lattices with more than three bar rows, subsequent yield of the other bar row after initial yield made the lattice achieve greater limit strength. The importance of the buckling strength of the grids was strengthened while the grids were relative sparse. The integration model of the method was used to study the nonlinear mechanical properties of strain hardening grids. It was shown that the integration equation could accurately model the complete stress–strain curves of the grids within small deformations.

Anisotropic Mechanical Properties of Lattice Grid Composites

According to the equivalent continuum method and coordinates transformation, the anisotropic properties of the stiffness and the strength of planer lattice grid composites were researched. Anisotropic properties of various lattice grid composites with three to five stacks of struts were discussed and compared. The criteria of stiffness isotropy and orthotropy were concluded. Ordinarily, the grid stiffness is anisotropic. But with two or four symmetries the lattice is orthotropic and quasi-isotropic with at least six symmetries. The initial yield or brittle failure strength of typical lattice grid compoaites was studied and compared. The strength of the lattice grid composite is always anisotropic, even if their stiffness is quasi-isotropic. The degree of anisotropy of the strength is normally stronger than the stiffness anisotropy. With more symmetries, more bar rows and more uniform equivalent rigidities of struts, the variation of the strength gets smaller.

A simple procedure for assessing ataxia in rats: Effects of phencyclidine

The present study describes an objective, cost- and time-efficient procedure for characterizing the ataxic effects of psychoactive drugs. Male Sprague–Dawley rats were administered an intraperitoneal injection of either saline or one of three doses (1, 5 or 10 mg/kg) of phencyclidine (PCP) 15 min prior to being placed into an empty standard operant conditioning chamber (all manipulanda were removed). The floor of the test apparatus consisted of parallel rows of metal rods spaced approximately 1.5 cm apart. During a 5-min test, a single observer counted the frequency with which each animal's paws (front or back) slipped between the rows of bars that constituted the cage floor. The data demonstrated that while saline animals exhibited no instability in their ambulation, PCP-treated animals demonstrated a highly reliable dose-dependent increase in the number of “paw slips” in a single trial. Since animals are known to develop tolerance to the ataxic response to PCP, the validity of the test as a measure of drug-induced ataxia was examined in a separate group of animals treated with the middle (5 mg/kg) dose every other day over the course of a 9-day period (i.e., resulting in five injection trials). In this experiment, each subsequent test produced a reliable reduction in the magnitude of the ataxic response, and by the fifth drug challenge, the PCP animals were performing at near-control levels. These results suggest that the “paw slip test” can serve as a simple, reliable, objective and valid measure of drug-induced ataxia. The relevance of the ataxia data for interpreting the locomotor response of animals treated with PCP is also discussed.