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Incremental levels of the phytase, OptiPhos® Plus, were fed to 150 weaned piglets (five treatments of 30 pigs) to determine the effect on piglet performance, nutrient digestibility and bone mineralisation. Piglets were fed a basal diet from four to six weeks and a pre-starter diet from six to ten weeks of age. The basal diets contained reduced digestible phosphorus (P) and calcium (Ca) (1.5 g/kg digestible P, and Ca 5.5 g/kg and 5.6 g/kg for weaner and pre-starter, respectively) to provide a negative control. Phytase was added at 0, 125, 250, 500 and 1000 phytase units (FTU)/kg feed. Faecal samples were collected at nine weeks of age and analysed for P, Ca and crude protein (CP) content to calculated digestibility. Metacarpal bone IV mineralisation was assessed by ash content and the weight and length of the bone. Incremental increases of phytase improved final body weight (BW) (P

Performance (from 10 weeks until slaughter), carcass and meat quality, and effectiveness of immunocastration was compared in crossbred offspring of stress positive (BP+) and negative (BP-) Belgian Pietrain and Canadian Duroc (CD) given the second vaccination of Improvac® at different times (4, 6, 8 weeks before slaughter). CD offspring had a significantly higher daily gain (DG) and feed intake (DFI), and lower predicted lean meat percentage (LMP) and dressing yield compared to BP+ and BP-, while feed conversion ratio (FCR) did not differ. CD offspring had significantly lower drip loss and higher pHi, intramuscular fat content than BP+ and BP- (except for pHi). No significant effect of vaccination time on DG nor FCR was observed. Predicted LMP tended to increase as time-post injection decreased, while meat quality was minor affected. Earlier vaccination had no effect on the effectiveness of immunocastration based on testosterone and GnRH-binding.

Trained expert panels are used routinely in boar taint research, with varying protocols for training of panelists and scoring methods. We describe a standardized process for training and scoring, to contribute to standardize the olfactory detection of boar taint. Three experiments are described in which we (1) evaluate the importance of training and the effect of the previous sample, (2) determine detection thresholds on strips and in fat for our panel, and (3) test priming panelists before boar taint evaluation. For the final evaluation of boar taint, we propose a consistent three-person evaluation scoring on a 0&ndash, 4 scale using a final mean score of 0.5 as the cut-off for boar taint. This gave an optimal sensitivity of 0.81 and a specificity of 0.56 compared to chemical cut-offs. Even limited training proved useful, but priming assessors with strips did not improve the evaluation of fat samples. Detection thresholds were higher in fat compared to strips, except for indole. We recommend panelists to always smell a non-tainted control sample after a tainted one as a &lsquo, reset&rsquo, mechanism, before continuing. For longitudinal studies, we additionally advise to set up an expert panel with a fixed number of assessors performing each evaluation in duplicate.

Simple Summary Due to welfare issues, the physical castration of male pigs is decreasing, and the entire male pig production is increasing. Fattening entire male pigs requires control due to the possibility of accumulating off odour/flavour called boar taint, which is mainly due to two compounds - skatole and androstenone. If carcasses with boar taint reach the market, it can cause a negative consumer reaction which may have economic consequences for the whole meat chain. Thus, it is necessary to sort out carcasses at the slaughter line. Today, a sensory quality control (human nose method) is used in some slaughter plants for this purpose. Detection by physical or chemical methods is also envisaged. A colorimetric method to determine skatole has been used in Danish abattoirs for decades, but it is foreseen that it will soon be replaced by the laser diode thermal desorption ion source coupled with a mass spectrometry equipment that allows a fully automated classification based on skatole and androstenone levels at speed line, with a delay of less than 40 min. Other potential methods such as the electrochemical biosensors, rapid evaporative ionization mass spectroscopy and Raman spectroscopy, still need further development and validation for an application at abattoir level. Abstract Classification of carcasses at the slaughter line allows an optimisation of its processing and differentiated payment to producers. Boar taint is a quality characteristic that is evaluated in some slaughter plants. This odour and flavour is mostly present in entire males and perceived generally by sensitive consumers as unpleasant. In the present work, the methodologies currently used in slaughter plants for boar taint classification (colorimetric method and sensory quality control-human nose) and the methodologies that have the potential to be implemented on/at the slaughter line (mass spectrometry, Raman and biosensors) have been summarized. Their main characteristics are presented and an analysis of strengths, weaknesses, opportunities and threats (SWOT) has been carried out. From this, we can conclude that, apart from human nose, the technology that arises as very promising and available on the market, and that will probably become a substitute for the colorimetric method, is the tandem between the laser diode thermal desorption ion source and the mass spectrometry (LDTD-MS/MS) with automation of the sampling and sample pre-treatment, because it is able to work at the slaughter line, is fast and robust, and measures both androstenone and skatole.

This study was performed to investigate meat quality traits of loin and ham of commercial pigs as affected by genetic differences in carcass and growth traits of the parent lines. Three hybrid sow lines were crossbred with two types of Belgian Pietrain with different breeding goals (BPgrowth and BPcarcass emphasizing daily growth and carcass conformation, respectively). Pig live performance and carcass quality of 270 offspring were measured, and meat quality of the loin and (cooked) ham was evaluated on 216 animals. Despite the differences in pig live performance and carcass quality for sow line, little effect on meat quality was observed. Only a lower (p

This study was designed to compare performance, carcass and meat quality of crossbred of a hybrid sow x three sire lines, i.e. stress positive Belgian Piétrain (BP), stress negative French Piétrain (FP) and Canadian Duroc (CD). BP offspring had a significantly higher carcass yield (p .001) and lean meat content (p .001) in comparison with FP, which was higher than CD. BP offspring had significantly lower pH (p .05), water-holding capacity (WHC) (p .001) and intramuscular fat (IMF) (p .001) content in the loin compared to FP and CD, but these meat quality parameters, with the exception of pH, were superior for CD as compared to FP. In accordance with loin quality, pH

Boar taint is an unpleasant taste and odor that can occur in entire male pigs and is caused by androstenone, skatole, and to a lesser extent indole accumulating in fat tissue. In the present observational study, we evaluated an extensive list of such potential risk factors which influence boar taint: social hierarchy and puberty attainment, housing, health, preslaughter conditions, season, feed, carcass composition, slaughter weight or age, and breed. Details on these factors were collected by interviews with the participating farmers, observations on each farm by trained observers and farmers, as well as slaughterhouse data. Twenty-two farms (in West- and East-Flanders, ranging from 160 to 600 sows, selected on suitability) raising entire male pigs were included in the study to evaluate the link between boar taint and potential risk factors related to the farm and slaughter batch (114 slaughter batches and 16 791 entire male pigs in total). Average olfactory boar taint prevalence was 1.8 ± 0.8%. Boar taint prevalence varied also within farms up to a maximum range between slaughter batches of 9.1% which suggests an effect of factors varying between slaughter batches such as season or other variables varying between slaughter batches. Less aggressive behavior at the end of fattening as well as lower skin lesion scores at fattening as well as at slaughter could be associated with less boar taint. The same might be said for sexual behavior, though less convincingly from this study. Measures that reduce aggression and stress have therefore have the potential to lower boar taint prevalence. The same might be said for sexual behavior, though less convincingly from this study. Furthermore, boar taint prevalence was generally higher in winter than in summer, which is relevant from a planning perspective for the slaughterhouses to seek alternative markets. Finally, increased CP gave significantly lower boar taint prevalences. This may to some extent be explained by the negative association between boar taint and lean meat percentage, as increased dietary CP levels promote the carcass lean meat percentages which can then be associated with lower boar taint levels. ispartof: ANIMAL vol:15 issue:3 ispartof: location:England status: published

Simple Summary Introducing alternatives to surgical castration of pigs bring welfare and economical benefits, but also reveal several quality-related issues. Most important is the presence of boar taint, but also includes low quantity and quality of fat, meat texture and color deviations in addition to inferior water binding properties, most of them negatively influencing meat product characteristics. The present paper highlights the important differences between the conventionally used surgical castrates and the most likely introduced alternatives: entire males and immunocastrates. Based on the review of the available research, the possible reasons for quality alterations are elaborated according to the type of meat product and recommendations for improving product quality or preventing boar taint perception are given. Abstract Due to the strong public initiative in Europe and increased regulator focus to mitigate pain, surgical castration of pigs is being gradually abandoned, while the importance of other sex categories like entire males (EM) and immunocastrates (IC) increases. Although beneficial for animal welfare and economics, their use also brings forward several quality problems. Besides the occurrence of boar taint in EM, these include excessive carcass leanness, softer fat, meat color and pH deviations, inferior water holding capacity and increased meat toughness. In this paper, the raw material differences between the male sex categories and their influence on product quality are reviewed, and possible solutions are presented. Using EM for dried or thermally processed products may result in lower processing yields and inferior sensory quality, which may partially be prevented by applying specific processing adaptations. Immunocastration is a viable solution, especially when prolonging the vaccination to slaughter interval. Low to medium levels of boar taint can be effectively managed in most of the meat products, applying procedures like cooking, microbial inoculation or masking (by spices and especially smoking), while highly tainted material can be valorized only by combining various methods and/or with dilution of the tainted meat.

Surgical castration of piglets without pain relief is still common practice in many countries. Possible alternatives for surgical castration are application of pain relief or anaesthesia or production of boars (entire males) and immunocastrates. Each of these alternatives faces advantages and disadvantages which may result in different citizen attitudes and consumers acceptability. Understanding which practice is acceptable to whom and why may further stimulate implementation. Consumer (n = 3251) and stakeholder (n = 1027) attitudes towards surgical castration without pain relief, surgical castration with anaesthesia, immunocastration, and production of boars were surveyed from April to June 2020 via an online questionnaire in 16 countries (&gt, 175 respondents per country). Surgical castration without pain relief was separated from each of the alternatives due to animal welfare and showed the lowest acceptability (32%). Within the alternatives, a further partitioning between the alternatives was based on perceived quality and food safety, with an acceptance of 85% for applying anaesthesia, 71% for immunocastration, and 49% for boar production. Differences depending on professional involvement and familiarity with agriculture could be observed, mainly for the acceptance of surgical castration without anaesthesia, immunocastration, and boars. Castration with anaesthesia was highly accepted by all types of respondents.

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.

One of the challenges in the production of entire male pigs is the occurrence of boar taint. We separately tested the effect of 3 management strategies to reduce boar taint on respectively 2, 3, and 6 Flemish pig farms: 1) adapted feeding strategies, 2) presence of gilts in the compartment, and 3) varying lairage duration at the slaughterhouse. A commercialized feed concept resulted in a significant reduction of olfactory boar taint prevalence when fed for 2 weeks (T2W) compared to control (T-CON) (P = 0.030). For T2W and when fed for 3 weeks (T3W), androstenone (AND) (P = 0.002 for T2W, P = 0.029 for T3W) and skatole (SKA) (P 0.001 for T2W and T3W) were significantly reduced compared to T-CON. Olfactory boar taint prevalence was significantly reduced when feeding 5% dried chicory roots (FI5%) (P = 0.032), but not for 3% dried chicory roots (FI3%) (P = 0.958). SKA concentration was significantly lower when feeding FI5% (P 0.001) and when feeding FI3% (P = 0.034). Rearing entire male pigs separately from gilts and increasing lairage duration from1 h to3 h did not significantly affect boar taint.

Pig delivery weight optimisation (PDWO) has been studied extensively and has resulted in several optimisation models. A previous participatory analysis of the problem has revealed that existing models are too complex and might therefore be under-valorised. Farmers desire a simple but reliable model based on available farm data to learn about the problem. A spreadsheet simulation model was therefore developed based on empirical animal performance models. The present study aims at conceptualising a stakeholder-driven model concerning PDWO that should provide insights into four key questions: I) how do the driving forces behind the optimisation determine the optima, II) what is the dependency of the optimal delivery weight on market conditions, III) how do the opportunity costs due to suboptimal delivery evolve, in addition to the mere optimisation results and IV) what is the effect of differences in animal performance profile, in terms of growth, feed intake and average carcass quality on the optimal delivery results? The results generated by the simulation model generally align with those generated using more sophisticated modelling approaches in previous studies. Our results indicate that the animal's growth and feed intake profile can more importantly affect the location of the optima, the stability of the optima and economic importance of delivery weight optimisation compared to market conditions. Moreover, the effect of market conditions on the optimisation was dependent on the animal profile, which determines the flatness of the payoff curve per pig. The possible flat payoff curves imply that the benefits of accurate PDWO can be limited and that some error margin in decisions on PDWO can be exploited. Moreover, this finding illustrates and corroborates the increased benefit of a shift in technology, i.e. an improved animal performance, compared to striving for the optimum on the production function of an inferior technology. Using this simplified model, farmers can investigate the flatness of their farm-specific payoff curve and the stability of their farm-specific optima. That information may help them to determine the appropriateness of a robust decision-supportive rule about optimal delivery weight on their farm.

During growth, pigs convert plant protein into animal protein. The major part of the ingested protein is excreted via manure, with potential nitrogen (N) losses to the environment. To limit N losses and increase sustainability of pork production, the efficiency of protein conversion should be maximized. The aim of this paper is to critically evaluate diet and management strategies linked with N efficiency. Besides nutrition, we discuss three management strategies observed in science and in practice to be linked with improved N efficiency: genetic selection, castration and slaughter weight. Because diet has a marked effect on eventual N losses, it must also be taken into account when evaluating management strategies. A reductionist approach, such as feeding the same diet across all management treatments, may overestimate the effect of a management strategy and eventually lead to incorrect conclusions. The amount of excreted N depends on the amount of ingested N, the amount of absorbed N, the amino acid (AA) balance in the diet and the animal's N and AA requirements. Daily multiphase feeding adapted to the individual animal's AA needs is likely to be the most N efficient. For animals housed in groups, phase feeding is necessary. When combined with periods of temporary AA restriction, N efficiency can be further improved. Specific AA consumption must be balanced by applying the ideal protein concept. With better knowledge of the requirements of individual animals and the commercial availability of certain AAs, the total dietary CP level can be lowered within limits. Further research is needed on the minimal CP level that allows maximal performance. For this end a useful parameter may be the ratio of standardized ileal digestible (SID) lysine : apparent total tract digestible CP level. By combining optimal nutrition and management, a whole body N efficiency approaching 60% may be achievable in the near future.

Rearing entire male pigs, one of the alternatives for surgical castration, entails the possible occurrence of boar taint. This study aimed at the investigation of the acceptability of meat from entire male pigs in 8 different meat products (cutlets, bacon, blade loin, tenderloin, dry fermented sausage, cooked ham, dry-cured ham and minced meat) by trained assessors. Generally, the sensory evaluation of meat samples was affected the most in the androstenone (AEON) group, indicating that AEON is the most offensive boar taint compound for sensitive assessors. Differences between the meat products showed the highest potential for processing tainted meat in cold meat products, which was most likely due to the serving temperature on the one hand and production-related influences on the other. However, more insights regarding reducing and masking effects of production-related factors on boar taint are necessary.

Androstenone, skatole and indole are main compounds responsible for boar taint, an off-odour in meat of some entire male pigs. Several feed ingredients derived from chicory have been reported to reduce fat skatole levels, while results for indole are more contradictory. The skatole-reducing effect is probably based on the prebiotic effects described for fructan compounds. Inulin and oligofructose have a high and low degree of polymerization, respectively. The fermentation rate decreases with an increasing degree of polymerization, which may result in differing effects of the compounds on skatole and/or indole levels. In this study we evaluated the effect of the inclusion of 5% inulin or 5% oligofructose during the last 3weeks before slaughter on carcass quality, concentration of skatole and indole in back fat as well as on the olfactory evaluation of boar taint in fat. Carcass weight did not differ between treatment groups but lean meat percentage increased when feeding oligofructose (P=0.019) compared to the control group, which is relevant for further research. Inclusion of 5% inulin or 5% oligofructose in the finisher diet of entire male pigs significantly reduced the back fat skatole concentration, without influence on indole. Olfactory score for boar taint tended to decrease when oligofructose was added to the diet.

There is a commitment by the European pig sector to ban surgical castration of male piglets in the European Union in 2018. One alternative to castration is to raise entire male pigs, with an increased risk of boar taint. A field study was performed to 1) evaluate inter- and intra-farm variation in boar taint prevalence, 2) investigate factors measured at slaughter influencing boar taint and 3) evaluate the relationship between sensorial scoring by a trained panel and the concentration of boar taint components. From 34 farms, neck fat samples were collected from all entire male pigs in at least 2 slaughter batches per farm (78 batches; 9167 animals). In addition to olfactory boar taint analysis, data was also collected on fresh skin lesions (score 0-3) at the slaughter line, slaughter weight, lean meat percentage, duration of transport, time spent in lairage, total delivery duration, day length, shortening of days and outdoor mean temperature. Using the hot iron method, neck fat samples were scored (8-point scale) for boar taint. Average boar taint prevalence (score ≥3) was 5.6 ± 2.5% and the mean difference between the maximum and minimum prevalence per farm was 4.3 ± 3.2%. Androstenone (AND), skatole (SKA) and indole (IND) concentrations were measured for a subset (n= 254) of the samples. According to binomial univariate mixed models, entire male pigs with a higher skin lesion score had higher odds of having boar taint (P=0.031), as did fatter entire male pigs (P

Uit onderzoek aan het Instituut voor Landbouw-, Visserij- en Voedingsonderzoek (ILVO) blijkt dat het voederen van immunocastraten met een laag energetisch voeder in de derde afmestfase de smakelijkheid van het vlees vermindert.

Genetic evaluation of Piétrain sires in Flanders occurs under standardized conditions, on test stations with fixed dam breeds, standardized diets and uniform management practices. As environmental conditions vary on commercial farms and differ from the test stations, this study aimed at understanding to what extent the sire, the dam breed and the interaction between both affects the translation of breeding values to practice. Dams of two commercial breeds were inseminated with semen from one of five different sires selected for contrasting breeding values (daily gain, feed conversion ratio and carcass quality). For each sire by dam breed combination, six pen replicates (with three gilts and three barrows per pen) were evaluated for growth performance from 9 weeks of age (20 kg) to slaughter (110 kg), and for carcass and meat quality. In our experimental setup, both sire and dam breed affected growth, carcass and meat quality traits. No significant sire×dam breed interactions on performance could be detected. Though a tendency for interaction on average daily feed intake between 20 and 110 kg (P=0.087), and on pork colour (lightness) (P=0.093) was present. In general, offspring of all tested sires behaved similarly in both dam breeds, indicating that estimated breeding values for Piétrain sires determined in one dam breed are representative in other dam breeds as well. ispartof: ANIMAL vol:13 issue:10 pages:2125-2132 ispartof: location:England status: published

Immunocastration (vaccination against boar taint) is an alternative method to prevent boar taint without the need for surgical castration. This study investigates the evolution of boar taint compounds in serum and fat, serum steroid compounds as well as behavior in immunocastrated pigs from 3 sire lines: 15 stress positive Belgian Piétrain (BP), 20 stress negative French Piétrain (FP), and 20 stress negative Canadian Duroc (CD). Hormone and boar taint compounds in serum were determined at 4 time points; boar taint compounds in fat were determined at 3 time points. Behavior, skin lesions, animal and pen fouling were also recorded before the first vaccination (V2). Aggressiveness, eating and drinking and general activity behavior declined from V2 for all sire lines. Pigs from BP were cleaner than FP and CD pigs. Even though immunocastration was effective in general (reduced testosterone, estradiol as well as androstenone in serum) for all sire lines, some individual pigs showed either androstenone or skatole levels in fat above cutoff values. While the immunocastration mechanism works as intended for androstenone, and also for skatole for the three sire lines, the risk of carcasses with boar taint compounds above cutoff levels (respectively 1.9 and 3.7%) still remains to some extent. ispartof: RESEARCH IN VETERINARY SCIENCE vol:124 pages:293-302 ispartof: location:England status: published

Lowering the crude protein (CP) level in the piglet diet reduces the risk of post-weaning diarrhea and nitrogen (N) excretion to the environment. The question remains at what point CP becomes limiting. Therefore 12 diets were formulated with 2 standardized ileal digestible (SID) lysine (LYS) levels (10 and 11 g SID LYS) and 6 CP levels (140, 150, 160, 170, 180, 190 g/kg) which were fed to piglets between 4 and 9 weeks of age in a 2 x 6 design with 6 pens of 6 animals per treatment. Serum urea levels were measured to assess N metabolism, with lower levels indicating a higher N efficiency. Linear plateau models could be fitted in function of the SID LYS:CP ratio. With 10 g SID LYS, serum urea decreased with decreasing CP levels down to a minimal level of 3.1 mg/dl at 63.9 g SID LYS/kg CP (156 g CP/kg). With 11 g SID LYS, serum urea decreased with decreasing CP levels to a minimum of 3.9 mg/dl at 63.3 g LYS/kg CP (174 g CP/kg). Over the 12 treatment groups, a breakpoint was calculated at 63.5 g SID LYS/kg CP, above which the protein breakdown was minimal and therefore N efficiency maximal. Both LYS and CP level affected daily gain and gain to feed (G:F). The breakpoint in G:F was at 60.6 and 62.5 g SID LYS/kg CP (165 and 175 g CP/kg) for pigs receiving 10 or 11 g SID LYS/kg, respectively. The results suggest that, apart from essential amino acids, the dietary profile of non-essential amino acids may be limiting performance. The ratio of 63.5 g SID LYS/kg CP may be a guideline/threshold value for maximizing the conversion of vegetal to animal protein in piglets.

In order to fine-tune standardised ileal digestible (SID) lysine (Lys) requirement of modern piglets (RA-SE genetics hybrid sow x Pietrain boar), two dose-response studies to Lys were conducted in 4 to 9 weeks piglets (8–24 kg). In trial 1, only commercially available feed-grade amino acids (AA) were used, without maintaining dietary crude protein (CP; 201–210 g/kg). Net energy was fixed at 9.8 MJ/kg. In trial 2, all the range of feed-grade AA needed were used while dietary crude protein was kept constant at 180 g/kg by adding L-Glutamic acid with decreasing Lys levels. Net energy level decreased slightly from the lowest to the highest Lys level (from 10.1 to 9.8 MJ/kg), because of the high energy content assigned to glutamic acid. All feeds were pelleted. On both trials, SID Lys ranged from 8.5 to 13.5 g/kg, divided over 5 levels. Six (trial 1) or nine (trial 2) pens of 6 piglets were tested per level. ADG, ADFI and G:F showed clear dose-responses to supplementation of Lys in both trials. In trial 1, it was not possible to reach an optimum for any of the growth parameters using a non-linear regression model, suggesting an optimum above 13.5 g/kg SID Lys. In contrast, in trial 2, best performance was observed at 11.4 and 13.2 g/kg SID Lys for ADG and G:F, respectively using a curvilinear-plateau model. While maximal performance was similar in the two trials (G:F=0.744-0.737, ADG=450-446 g/d), the effect of Lys shortage was higher in trial 1, probably due to an imbalanced AA:Lys ratio. To the contrary in trial 2, the SID Lys:CP ratio was 0.075 at the highest Lys level, suggesting that nitrogen or non-essential AA may have become limiting.

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.

Immunocastration or vaccination against boar taint can be used as alternative for surgical castration of male piglets. The vaccine is administrated twice. After the second vaccination (V2), the pigs behave like barrows instead of boars and their feed intake increases which may result in a lower lean meat percentage. The timing of V2 is therefore crucial to find the right balance between the advantages of entire males and barrows. In this study, we evaluated the effect of time post second injection within the advised time frame (4 v. 6 weeks before slaughter) on behaviour, performance, carcass and meat quality of immunocastrated male pigs. In total, 180 animals (hybrid sow×Pietrain): 60 gilts, 60 male pigs vaccinated 6 weeks before slaughter (IM-6) and 60 male pigs vaccinated 4 weeks before slaughter (IM-4), all slaughtered at comparable slaughter weights. After 20 weeks of age, IM-6 showed more inactive behaviour at the expense of playing and aggressive behaviour. Daily feed intake (DFI), daily gain (DG) and feed conversion ratio (FCR) did not differ significantly between IM-6 and IM-4. Gilts had a lower DFI and DG in the late finishing phase and a higher FCR overall compared with both IM groups. Gilts showed a higher lean meat content compared with both IM groups. Earlier vaccination increased dressing percentage, which could partly be explained by the lower weight of the gastrointestinal tract, but not by testes weight. Meat quality traits and palatability did not differ significantly between IM-6 and IM-4. Vaccination of immunocastrates at 6 compared with 4 weeks before slaughter improved the calmness in the stable and the dressing percentage, while maintaining performance and carcass characteristics.

Reduction of crude protein (CP) content in swine diets must be associated with an adequate quantitative and qualitative provision of amino acids (AA). In piglet diets, the fifth limiting AA is Val, where deficiency has been proven to reduce feed intake. In addition, depending on the overall level of CP and AA, diets high or low in standardized ileal digestible (SID) Lys will have different branched chain amino acid (BCAA) balances, which may in turn affect the feed intake response. Therefore, two Lys dose response trials (Exp. 1 and 2) were performed to study the influence of different AA concentrations on feed intake and overall performance. CP levels differed between the two experiments (201–210 g/kg in Exp. 1 and 180 g/kg in Exp. 2). Next, one Val dose response (Exp. 3) was carried out to establish the optimal SID Val:Lys ratio for 4 to 9-week-old Pietrain piglets. In Exp. 1, raising dietary SID Lys from 8.50 to 13.50 g/kg resulted in a significant linear and quadratic increase of average daily gain (ADG) and gain to feed (G:F) (P

Lowering the CP level in piglet diets reduces the risk of postweaning diarrhea and N excretion to the environment. The question remains at what point CP becomes limiting. An experiment was designed with 2 standardized ileal digestible (SID) Lys levels (10 and 11 g) and 6 CP levels (140, 150, 160, 170, 180, 190 g/kg) in a 2 × 6 factorial design (with 6 pens of 6 animals each per treatment). Linear and quadratic (QP) mixed models of performance in function of CP were fitted to study the effect of SID Lys and CP and their interaction. To determine optima, QP models and broken line models with linear (BLL) or quadratic (BLQ) ascending portions were fitted through the data. It was hypothesized 1) that the response to a decreasing digestible CP level could be described with broken line models and 2) that the break point of these models is dependent on the dietary SID Lys level. Decreasing the CP level decreased ADG (P < 0.001). For G:F, the effect of decreasing CP level depended on the SID Lys level (P of the interaction = 0.028 in the linear model and P = 0.002 in the QP model). According to the BLL model, with 11 g SID Lys in the diet, G:F started to decline with CP levels < 176 g CP [SID Lys:CP = 0.062, SID Lys:apparent total tract digestible (ATTD) CP = 0.077], and with 10 g SID Lys, CP levels < 165 g/kg (SID Lys:CP = 0.061, SID Lys:ATTD CP = 0.075) depressed performance. Serum creatinine levels showed a linear decrease with increasing SID Lys:CP levels (P < 0.001). Across both SID Lys levels, when fitting a BLL model, minimal serum urea levels were reached at an SID Lys:CP ratio of 0.064. This seems to be the point where CP and not Lys limits muscle deposition. The small difference in break point between serum urea level and performance suggests that the composition of nonessential AA may also be at stake. The effect of decreasing CP level depends on SID Lys, and using a maximal SID Lys:CP ratio may be useful for optimizing the AA profile of dietary CP. When the SID Lys:CP ratio exceeds 0.064 (SID Lys:ATTD CP > 0.079), protein and not individual AA limits growth in most piglets between 4 and 9 wk of age.

A consumer study was performed in four EU countries to further clarify the acceptability of meat with boar taint. In Denmark, France, Italy and Poland, a total of 476 female consumers evaluated 8 meat patties from boars with varying levels of skatole (0.10-0.40μg/g fat tissue) and androstenone (0.47-2.00 μg/g fat tissue), in a pair-wise comparison with patties from castrates. Boar meat patties were always less preferred than the castrate meat patties, regardless of the level of androstenone and skatole. Acceptability of the boar meat patties decreased with increasing skatole level. In samples with low skatole levels, higher levels of androstenone also reduced acceptability among androstenone sensitive consumers. No clear threshold levels for androstenone and skatole could be identified. Maps presenting the reduction in preference due to increasing levels of skatole and androstenone, and corrected for the general acceptance of the meat product were developed, taking into account androstenone sensitivity. Further work is needed, covering the whole range of androstenone and skatole levels found in entire male pigs and for a wider set of meat products. info:eu-repo/semantics/acceptedVersion

Uit onderzoek van ILVO en LANUPRO (UGent) blijkt het belang van de eindbeerkeuze op de technologische en sensorische vleeskwaliteit.

Since surgical castration of male piglets without anaesthesia is under heavy societal pressure, finding a sustainable solution to reduce boar taint has become urgent. One way to circumvent this animal welfare violation is raising entire male pigs whilst selecting against the tainted phenotype through marker-assisted selection. Since slaughtering at a lower weight is often suggested to reduce boar taint, selection using a marker for that trait could be a promising strategy. Therefore, in this study a melanocortin 4 receptor (MC4R) mutation, frequently described in different pig breeds as marker for fat content, weight gain and feed intake, was examined in relation to boar taint in pig breeds used in Belgian pig farms. Although results suggest an association between this mutation and a boar taint odour score assigned by experts, no association was found between the mutation and the concentration of the individual chemical boar taint components androstenone, skatole and indole.

Male piglets are castrated to reduce boar taint and also to reduce aggressive and sexual behaviour. However, the procedure as traditionally performed is painful and negatively affects performance. Large-scale results about the consequences of implementing alternatives on farms are lacking. We, therefore, investigated the practical applicability of the following five alternatives that can be implemented in the short term: surgical castration (1) without pain relief (CONT, control group), (2) with analgesia (MET, Metacam, 0.2 ml, 10 to 15 min before castration), (3) with general anaesthesia (CO2, inhalation, 100% CO2, 25 s, 3 l/min), (4) vaccination against boar taint (IM, two injections with Improvac) and (5) production of entire males (EM). The study consisted of the following two trials: (1) an experimental farm trial with 18 animals/treatment and (2) a large field trial on 20 farms with ~120 male pigs/farm per treatment and all treatments performed on each farm. Performance results as well as data on carcass traits, boar taint (hot-iron method) and testes development and weight were collected in both trials. Neither castration nor administration of analgesia or anaesthesia had an effect on daily gain of the piglets in the farrowing crates (P>0.05). Farmer records indicated that mortality in the farrowing crates (1.1%), nursery pens (1.8%) and fattening stable (2.2%) was not influenced by MET or CO2 compared with EM, IM or CONT (P>0.05). No significant differences were found for daily gain (P>0.05) nor slaughter age (P>0.05). Immunocastrates and EM had a better gain-to-feed ratio (P

The perspective of a possible ban on surgical castration of male pigs in the EU is a real challenge for pork production systems aiming at (very) high-quality products. Information was collected from a total of 272 situations in 16 European countries, including 170 situations related to EU protected designations (Database of Origin & Registration (DOOR) database) and 102 other situations related to high-quality products or differentiated production systems, in order to evaluate their potential sensitivity to the use of entire male pigs along four dimensions: BT_Inc, likelihood of increased levels of boar taint compounds compared with conventional production of entire males; BT_Per, extent to which (some of) the associated pork product(s) are susceptible to perception of boar taint by consumers; FatQQ, likelihood that the quality of (some of) the related products is decreased due to the lower fat quantity and quality in entire males; Manag, increased likelihood of animal management and welfare problems compared with conventional production of entire males. Situations corresponding to EU protected designations (DOOR situations) were on average more sensitive to entire male production but 11% of the non-DOOR situations were highly potentially sensitive, whereas one-third of the DOOR situations had low potential sensitivity. In total, 37% of the situations where castration is not formally specified as mandatory exhibited high potential sensitivity to entire male production. Three main patterns of situations were identified via ascending hierarchical clustering. A first pattern including 31% of the DOOR situations and 74% of the other ones, had potentially no increased risk compared with conventional production of entire males. A second pattern including 28% of the DOOR situations and 16% of the other ones had a high, moderate and low potential sensitivity for FatQQ, BT_Inc and Manag, respectively. The third pattern including 41% of the DOOR situations and 11% of the other situations had high potential sensitivity for BT_Inc and FatQQ, associated with moderate to high sensitivity for Manag. The approach used to evaluate the sensitivity to entire male pig production from the limited information collected for this study has many limitations. More precise approaches using more specific information are needed to evaluate the actual sensitivity of individual situations to the use of entire male pigs. Still, the present study provides a first global insight on the capacity of European production systems aiming at high-quality products to use entire male pigs as an alternative to surgical castration. info:eu-repo/semantics/publishedVersion

One of the main issues related to entire male pigs is the occurrence of boar taint, an off-odour, which compromises meat consumability. In this study, odour thresholds (indole: 24–65 µg kg−1, skatole: 44–89 µg kg−1, androstenone: 121–342 µg kg−1) for the boar taint compounds were estimated in minced meat, dry fermented sausage and dry-cured ham. Afterwards, sensory evaluation of these products containing 10% tainted meat (minced meat and dry fermented sausage) or moderate boar taint compound levels (dry-cured ham) occurred. The beneficial effect of diluting tainted meat was demonstrated, as no significant difference in consumability was observed between gilts and 10% tainted meat by experts as well as consumers. Also dry-curing proved a promising technique for masking boar taint and preventing consumer dissatisfaction. The obtained results demonstrate the applicability of the estimated thresholds in meat as a tool for identifying masking and reducing strategies on the perception of boar taint.

Dietary branched-chain amino acid and tryptophan concentrations have been associated with effects on daily feed intake; this study is an extension of that research. We evaluated eight dietary treatments in a Latin square cross-over design with 32 female piglets during 8 weeks (9.9 ± 0.6 kg to 44.9 ± 2.9 kg, mean ± SD). Treatments differed in dietary standardized ileal digestible leucine (10.8 and 21.3 g/kg), valine (7.0 and 7.8 g/kg), isoleucine (6.0 or 7.3 g/kg) and tryptophan (2.0 and 2.5 g/kg) content. A longitudinal model was fitted with the level of valine, leucine, isoleucine, tryptophan and the interactions leucine × tryptophan, valine × leucine, isoleucine × tryptophan as fixed effects. Increasing the dietary leucine content decreased feed intake (-169 g/day) and daily gain (-168 g/day) of the pigs and impaired the feed conversion ratio (+0.49 g/g) (p

Because research indicates that responses on dietary restrictions may depend on the gender of pigs, we examined the interaction between the lysine level in different feeding periods and the performance and carcass quality of barrows in a 2 × 2 factorial trial. In total 192 barrows were divided over 32 pens of six animals, and each pen was assigned to one of four dietary treatments: (1) high lysine levels in the growing (25-42 kg body weight [BW]), early finishing (42-73 kg BW) and in the late finishing period (73-110 kg BW) (Group HH); (2) high lysine levels in the growing and early finishing period, and low lysine level in the late finishing period (Group HL); (3) low lysine levels in the growing and early finishing period, and high lysine level in the late finishing period (Group LH); and (4) low lysine levels in all periods (Group LL). To obtain the high lysine diets, L-lysine, as well as L-threonine, DL-methionine and L-tryptophan, were added to the low-lysine diets. The low-lysine diets contained 20% (in growing) or 30% (in finishing) lysine less than the high-lysine diets. Feeding Diet LH increased the daily gain and decreased the feed-to-gain ratio in the subsequent late finishing phase (p

A dose-response study was performed to estimate the valine (Val) requirement in piglets between 4 and 9 weeks of age. For this end, 432 piglets (weaned at 4 weeks of age, 8.0 ± 0.9 kg) were distributed among eight diets differing in their Val to lysine (Lys) ratio expressed on a standardized ileal digestible (SID) basis. Two low crude protein diets (168 g/kg) only differing in SID Val:Lys level, one deficient in SID Val:Lys (0.58 SID Val:Lys) and the second one with a SID Val:Lys ratio expected to be above requirements (0.825 SID Val:Lys), were mixed in different proportions to obtain eight SID Val:Lys levels. The diets were formulated to be isocaloric (9.8 MJ net energy/kg) and with a sub-limiting SID Lys level (10.5 g/kg), allowing to estimate the Val requirement relative to Lys. The average daily gain (ADG) and feed intake (ADFI) were improved with increasing SID Val:Lys level; the best performance being obtained with 0.72 SID Val:Lys. Feed intake increased from 402 ± 45 g/day at 0.58 to 556 ± 42 at 0.72 Sid Val:Lys. Daily gain improved from 276 ± 37 g/day at 0.58 Sid Val:Lys to 391 ± 38 at 0.72 Sid Val:Lys. Using ADG and ADFI as response criteria, the requirement was estimated to be 0.675 and 0.742 SID Val:Lys with curvilinear-plateau and quadratic models, respectively. These results are in line with the literature and confirm that piglets react to a Val deficiency by lowering their ADFI which reduces their ADG without affecting feed efficiency. The results of the present experiment highlights that the Val level has to be controlled in piglet diets to avoid losing growth rate.

Sow lameness is a multifactorial condition which is mostly related to disturbances in the processes of bone remodelling, cartilage metabolism, and horn production. This review discusses how bone, articular cartilage and horn are affected by diet composition, particularly vitamins and minerals. For bone remodelling, the role of carbohydrates, proteins, and amino acids is uncertain. The macrominerals Ca and P are extremely important, as is vitamin D. Magnesium may be as important as Ca and P. Dietary deficiencies or toxicities of microminerals Zn, Cu, Mn and F also play a detrimental role. Articular cartilage (AC) depends on a diffuse nutrient supply. An impaired proteoglycan (PG) and collagen synthesis are precursors for AC related disorders. The addition of amino acids, especially combined with microminerals such as Cu and Si, reduces the occurrence and severity of osteochondrosis, whereas convincing evidence for a specific role for macrominerals in AC metabolism is not found. The microminerals Zn, Mn, and Fe are involved to a lesser extent in these disorders. A diffuse nutrient supply is also essential for horn production. Especially sulphur-containing amino acids such as cysteine are important for keratinisation. The dietary availability and diffuse supply of macro- and microminerals directly and indirectly activate enzymes responsible for the development of keratin fibres and synthesis of an intercellular cementing substance. Biotin supplemented in combination with minerals also benefits horn production. In conclusion, nutrition is an important predisposing factor of sow lameness and influences bone, articular cartilage and horn quality. The regulatory mechanisms are complicated and not yet fully understood. Nutritional components often interact with each other, and must be balanced since both deficiency and excessive dietary intake may disturb these processes.

This study evaluates 1) carcass quality, meat quality and palatability for barrows, immunocastrates and boars and 2) the effect of chicory supplemented feed during 10 days before slaughter on boar meat quality. At comparable carcass weights, estimated carcass lean meat percentage was higher in immunocastrates and boars than in barrows. Muscle thickness was higher for immunocastrates and barrows compared to boars, while fat thickness was lowest for immunocastrates and boars. Barrows, immunocastrates and boars differed in water holding capacity and boar taint. Home consumer panels were conducted to evaluate palatability. The consumers did detect differences in tenderness and juiciness, but not for boar taint. The chicory feed supplemented in boar feed decreased skatole concentration in backfat, without largely influencing meat quality or palatability. Not only boar taint, but also carcass and meat quality should be considered when evaluating alternatives for surgical castration.

No automated detection system for boar taint detection is currently available, thus boar taint at the slaughterline can currently only be assessed using the singeing method (olfactory scoring). This study compares several heating methods (microwave, soldering iron and pyropen) and evaluates the effect of habituation, cleaning the soldering iron, singeing the fat twice in the same place, and variations in the technical procedures. All methods seem to be suitable for detecting boar taint but the choice of heating method for sensory scoring of boar taint depends on habituation of the trained assessor and specific conditions applied. The pyropen seems to be most suitable because it does not contact the fat and is easy to handle (wireless). Finally, the intensity score may also be influenced by: contamination from not cleaning the soldering iron, singeing the fat twice in the same place, and the effect of habituation.