Effect of concentrate level and slaughter body weight on growth performances,carcass traits and meat quality of Barbarine lambs fed oat hay based diet

This study was conducted to evaluate concentrate level (CL) and slaughter body weight (SW) effects on growth performances, carcass traits and meat quality of Barbarine lambs. Twenty-four weaned male lambs (23.1 kg), receiving an oat-hay based diet, were allotted into two groups. The LCL group received low concentrate level (300 g) and the HCL group received high concentrate level (600 g). Lambs were slaughtered at two prefixed weights (35 and 42 kg). For each group and each weight, six lambs were slaughtered. Lambs from HCL group had higher ADG, carcass yields, carcass compactness and subcutaneous fat thickness, and lower carcass meat proportion. CL increase did not affect meat pH, meat and fat color, chemical and fatty acid composition. Late slaughtering improved carcass yields and increased carcass adiposity. However, it did not affect carcass meat proportion and shoulder tissue composition. SW had effect on meat color and fatty acid composition.     

Effect of sex grouping during growth on 5α-androstenone development in boars at three commercial slaughter weights

Groups of boars and gilts were grown in either single-sex or mixed groups to slaughter weights of 81, 93 or 110 kg liveweight to examine the effects of sex grouping on growth performance, animal behaviour and the development of androstenone-taint in the males. Results confirmed the well known growth advantages of entire males and showed that no husbandry problems of any significance were incurred with the boars and gilts raised together, particularly in those groups slaughtered before reaching 100 kg liveweight. In pigs taken to heavier weights, boars were successfully reared with gilts without incurring management problems, although growth performance was slightly poorer for the boar/gilt groups compared with mixed castrates and gilts, and some of the boars had high concentrations of androstenone in the fat. Thus, for pigs intended for slaughter at heavy commercial weight, the evidence suggests that split-sex rearing (and therefore feeding) should be practised. No useful correlations of androstenone concentration in fat were found with thickness of backfat, age, carcass weight or liveweight at slaughter.     

Effect of gender and castration of females and slaughter weight on performance and carcass and meat quality of Iberian pigs reared under intensive management systems

A total of 360 Iberian dam × Duroc sire pigs was used to study the influence of gender and castration of females (CM, castrated males; CF, castrated females; IF, intact females) and slaughter weight (SW; 145 and 156 kg body weight, BW) on performance and carcass and meat quality. Each treatment was replicated four times (15 pigs). Intact females ate less, tended to have better feed conversion and had less carcass fat and more primal cuts yield than CM and CF. Pigs slaughtered at 156 kg BW ate more feed and had worse feed conversion than pigs slaughtered at 145 BW. An increase in SW improved carcass yield, but tended to decrease trimmed ham yield. Intact females are an alternative to castrated females for intensive production of Iberian pigs. Also, the reduction in slaughter weight from 156 to 145 kg BW is recommended for this type of production.     

Effect of vaccination against gonadotrophin-releasing factor on growth performance, carcass, meat and fat quality of male Duroc pigs for dry-cured ham production

The aim of this study was to compare production, carcass and meat quality parameters, boar taint compounds and fat composition of green and dry-cured hams, between immunocastrated (IM), surgically castrated (CM) and female (FE) Duroc purebred pigs (n=75, 138.7±8.27kg). Liveweight and fat and muscle thicknesses were measured and average daily gain was calculated during growth. Carcass, meat and fat quality parameters were measured. Immunocastrated grew faster than CM or FE after the second dose of vaccine. IM had the lowest dressing percentage but similar % of ham and carcass lean to FE and CM. The effect of the immunocastration on carcass fatness depended on the location, did not affect fat and meat quality and reduced skatole and androstenone levels. Both in green and dry-cured ham, immunocastration slightly altered FA composition. Thus, Duroc pigs vaccinated with Improvac are suitable for the production of high quality dry-cured ham.     

Influence of sex and slaughter weight on carcass and meat quality in light and medium weight lambs produced in intensive systems

Effects of slaughter weight and sex on carcass characteristics and lamb meat quality of Manchega Spanish breed were analysed. Forty-five lambs were divided into two slaughter weight groups: light (LW=21.7±0.16 kg; n=24) and medium (MW=27.8±0.16 kg; n=21). Dressing proportion and conformation were significantly different between groups and sex. There were also differences between light and medium group in fatness but not between males and females. Water holding capacity decreased with increasing slaughter weight (p<0.05) and was lower in females than in males (p<0.001). The increase in weight was associated with a decrease in L* (p<0.01), while a* showed an increase which failed to reach statistical significance. Slaughter weight and sex affected neither pH and its decrease post-slaughter nor meat toughness. ?     

Reaction to boar odour by different South African consumer groups

A consumer sensory study of South African pork consumers (n=300) including equal numbers of males and females and consumers from three ethnic groupings (black, white and coloured consumers) was conducted to determine the effects of gender and ethnicity on consumer reactions towards boar odour compounds. Samples consisted of boar fat with varying concentrations of skatole and androstenone. Each consumer evaluated the odour of seven fat samples. Consumers’ liking of pork meat in general had a significant effect on the hedonic rating of the boar odour. The majority of consumers represented in this study would be dissatisfied with pork meat exhibiting detectable levels of skatole. In general, more females compared with males, will also respond more negatively towards samples with detectable levels of androstenone. An apparent liking for samples with medium levels of androstenone (0.5–1 μg/g) was found for some consumers, especially males, and can be partly attributed to the inability of some consumers to smell this compound at these levels or a genuine liking for the odour of androstenone. Significant differences in the sensitivity of consumers from different ethnic groups were found with white females responding more negatively than white males and blacks. Although it was not possible to compare responses directly with the white and black groups, it was found that a higher percentage of coloureds responded negatively to boar odour compounds. Coloured males responded particularly negatively towards samples with detectable skatole, while black males, in general, were found to be more critical than black females. Based on these results it is predicted that the majority of consumers would be less willing to consume pork meat exhibiting detectable levels of boar odour.     

Quantification of campylobacter in swine before, during, and after the slaughter process

Campylobacter has been implicated as a major cause of foodborne illness worldwide. Pigs can be subclinically infected, and fecal contamination of meat during slaughter is a food safety risk. The objective of this study was to determine the association between the concentration of Campylobacter pre- and periharvest with postharvest contamination in swine. Samples were collected from 100 individually identified swine during the pre-, peri-, and postharvest periods. For each animal, the following phases were sampled: on farm (fecal sample), in lairage (hide swab), post-stunning and exsanguination (rectal contents), prechilling (carcass swab), and final product (rib meat) sample. The proportions of samples that were Campylobacter positive were 90, 95, 76, 100, and 49% for fecal, rectal content, hide, carcass, and rib meat samples, respectively. The mean Campylobacter concentrations for each sample were fecal sample, 1.7 × 10(6) CFU/g; rectal content, 1.2 × 10(7) CFU/g; hide swab, 1.4 CFU/cm(2); carcass swab, 1.7 × 10(3) CFU per half carcass; and rib meat, 18 CFU/g. There was a positive correlation between Campylobacter concentrations in fecal samples (R = 0.20, P = 0.065) and concentration of Campylobacter on rib meat, and between rectal content sample concentration (R = 0.20, P = 0.068) and the concentration on rib meat. There was no association between the isolation of Campylobacter on rib meat and the isolation of Campylobacter at any pre- or periharvest stage. This could indicate that the risk of a meat product being contaminated is associated with pigs that shed higher concentrations of Campylobacter before slaughter.     

Effects of weight at slaughter and sex on the carcass characteristics of Florida suckling kids

The effect of slaughter weight and sex on some carcass traits of suckling kids of the Florida breed was evaluated. A total of 60 kids (30 male and 30 female), fed exclusively on milk replacers, were slaughtered at 7-8kg (group 1), 10-11kg (group 2) or 14-15kg (group 3) of liveweight (mean weights of 7.6kg, 10.8kg and 14.4kg, respectively). Higher slaughter weights decreased the percentage of subproducts (blood, skin, head, feet) and internal organs (lungs+traquea, heart, liver, spleen, thymus) but significantly increased the percentage of intestine and fat depots (omental fat and mesenteric fat). Higher slaughter weights also increased carcass measures (L 40.5 vs 49.1; F 22.5 vs 25.9; G 10.4 vs 14.2; Wr 10.1 vs 13.9; Wth 8.0 vs 10.5; Th 16.5 vs 199; B 32.3 vs 42.4; PT 41.5 vs 50.8), compactness carcass index (96.6 vs 152.3) and compactness leg index (27.5 vs 44.1). Sex only significantly affected the percentages of feet, internal organs, omental fat, measure L, carcass compactness index and hind limb compactness index. The meat colour and fat colour were mainly scored as pale and white respectively in the carcasses of the lightest animals, whereas heavier kids were scored as pink and cream. Slaughter weight also influenced significantly the carcass fatness (score 1 in lightest kids and 2 or 3 in heavier ones). There were no significant (p>0.05) differences between slaughter weight group and sex in dressing percentages. Percentages corresponding to the long leg, back and neck (30-33%, 18-19% and 8-10%, respectively) decreased when the slaughter weight increased, whereas the ribs (23-25%) and the flank (10-11%) increased slightly. The carcasses comprised 57-58% muscle, 22-25% bone, 5-6% subcutaneous fat and 9-12% intermuscular fat. The percentage muscle stayed the same with increasing slaughter weight, whereas the bone decreased and the fat increased. The carcasses of the heavier females contained less lean and more fat than the males. The bone percentage was significantly (p<0.05) lower in the females and the carcass fat percentage was significantly (p<0.05) higher than in the males.     

The effect of food deprivation prior to slaughter on performance, behaviour and meat quality

The effects of repeated food deprivation, prior to slaughter, on performance, feeding behaviour and meat quality of pigs was examined. Three experimental treatments were compared. In treatment 1 pigs had ad libitum access to feed up to the point of loading on the day of slaughter. Treatment 2 involved a 12-h fast prior to slaughter and treatment 3 involved a 20-h fast prior to slaughter. Pigs were slaughtered on a weight basis therefore each pen was emptied over a period of weeks. This meant some pigs experienced repeated food deprivation. The feeding pattern of pigs which were deprived of food for 12 h was very similar to that observed before feed restriction. Pigs which were deprived of food for 20 h spent significantly more time at the feeder post fasting. This was particularly marked during the first 2–3 h when access to feed was restored. Feed deprivation for 12 h prior to slaughter did not adversely affect performance, carcass weight, meat quality or welfare in the present study. Fasting for 20 h reduced carcass weight by 1 kg, which was not statistically significant but could result in financial losses related to carcass weight. The negative effects on meat quality, of repeated feed deprivation, resulted from slower growth rates rather than feed deprivation per se.     

Effects of live weight and processing on the sensory traits,androstenedione concentration and 5-alpha-androst-16-en-3-one (androstenone) concentration in boar meat

Twenty-nine crossbred boars were used to evaluate the effects of live weight and processing on the sensory attributes and concentrations of androstenedione and androstenone (boar taint) in boar meat. Boars were stratified by litter across six weight group endpoints (90.9, 95.5, 100.0, 104.5, 109.1, and 113.6 kg). Back fat and longissimus muscle from the lumbar region were used for androstenone determination, proximate analysis and sensory evaluation. Hams were cured for sensory analysis and were used to determine androstenone concentrations. Androstenone as an off-flavor did not differ (P > 0.05) among treatments for longissimus lean or cured hams and was found to be in the “threshold” to “none detected” range. Back fat androstenone concentration was positively correlated (P < 0.05) to hot carcass weight, however, lean androstenone concentration was not (P > 0.05). No relationship was found (P > 0.05) between androstenone concentration and days on feed, average daily gain or androstenedione concentration. Additionally, further processing decreased androstenone concentration by approximately 29%.     

Meat quality of "Galician Mountain" foals breed. Effect of sex, slaughter age and livestock production system

The effects of sex, slaughter age (9 vs. 12 months) and livestock production system (freedom extensive system (FES) vs. semi extensive system (SES)) of "Galician Mountain" foals breed on meat quality from the Longissimus dorsi (LD) muscle were investigated. Forty-two foals had been used for this study, 19 (11 females and 8 males) were reared in a semi extensive system and weaned three months prior to slaughtering (8 and 11 were slaughtered at 9 and 12 months, respectively) while the other 23 (11 females and 12 males) were reared together with its mothers in a system in freedom and were slaughtered at the age of 9 months. The obtained results showed that there were no significant differences between the sexes and the slaughter age whereas the livestock production system was a significant variation source on intramuscular fat content and meat tenderness because SES foals showed 51.6% more of IMF and the improved meat tenderness achieved a shear force of <3 kg. In general, the meat from foals of the study at hand showed very lean meat (<0.3% in IMF) with a high protein content (>20.5%) and heme-iron (1.62 mg/100g meat) comparable to veal meat. Furthermore, the meat samples showed a higher luminosity (L*>40), a very good water holding capacity, measured by cooking losses (<18.3%), and a tenderness less than 4 kg. Thus, it can be classified as "very tender" meat.     

The effects of method of castration,rearing condition and diet on sensory quality of pork assessed by a trained panel

Beside surgical castration possible alternatives helping to reduce the incidence of boar taint in cooked pork are rearing conditions, immunocastration and feeding strategies for entire males known to lower the skatole levels. The goal of this study was to assess the effects of these alternatives on the sensory acceptability of pork. In experiment 1, carcasses from barrows, entire males (EM) and entire males fed raw potato starch (EM+) 7 d before slaughter were selected based on the androstenone (≤ 2 µg/g) and skatole (≤ 0.32 µg/g) levels. In experiment 2, carcasses from barrows, immunocastrates (IC), entire males either group-penned (EMG) or individually penned (EMP) were selected based on the aforementioned criteria. Boar odour and boar flavour intensities of longissimus dorsi (LD) and neck chops were evaluated by trained panellists. Boar odour and flavour scores were higher (P < 0.01) in neck than LD chops. Although skatole tissue levels in barrows and EM+ were similar (P > 0.05), boar odour and flavour scores were greater (P < 0.05) in EM+ than barrows. In experiment 2, scores for boar odour and flavour were lower (P < 0.05) in pork from barrows and IC than EMP, with intermediate values for EMG. In conclusion, we observed a discrepancy between the known boar taint compounds androstenone and skatole and sensory acceptability, which indicates that other factors influenced the perception of boar taint. Thus, surgical castration with or without anesthesia or immunocastration are still the safest methods to avoid boar taint.     

Sensory characterization of meat from pigs vaccinated against gonadotropin releasing factor compared to meat from surgically castrated,entire male and female pigs

Boar taint is a sensory defect mainly due to androstenone and skatole. The most common method to control boar taint is surgical castration at an early age. Vaccination against gonadotropin releasing factor (also known as immunocastration) is an alternative to surgical castration to reduce androstenone content. In this experiment, loins from 24 female (FE), 24 entire male (EM), 24 vaccinated males (IM) and 23 surgically castrated males (CM) were evaluated by eight trained panellists in 24 sessions. Loins were cooked in an oven at 180 °C for 10 min. Furthermore loins were evaluated by consumers and its androstenone and skatole content were also chemically determined. Meat from EM had higher androstenone and skatole odour and flavour than meat from FE, IM and CM and lower sweetness odour scores. High correlations were found between androstenone and skatole levels assessed by trained panelists, chemical analysis and consumers’ acceptability. Moreover meat from EM is mainly related to androstenone and skatole attributes.     

Effect of surgical castration,immunocastration and chicory-diet on the meat quality and palatability of boars

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.     

Monitoring androstenone levels in boars by direct immunochemical analysis of serum samples

The possibility of using blood samples for screening high levels of boar taint steroid androstenone (5α-androst-16-en-3-one) was studied both in living animals at the farm and carcasses at the slaughterhouse. The steroid was measured from boar serum and fat samples with a simple time-resolved fluoroimmunoassay. Fat samples contained androstenone in the range of 90-7500 ng/g (n=214), and 74.8% of the samples exhibited fat androstenone levels above 500 ng/g. Androstenone concentrations in blood samples were measured by direct serum assay and ranged up to 215 ng/ml (n=214). The levels of androstenone were correlated (r=0.78-0.88, P<0.001) between the serum and fat samples obtained at slaughter and serum samples taken at the farm 7-11 days before slaughter. A direct serum analysis seems to give a reliable indication of the androstenone level in fat and it can also be used in the screening of living animals.     

Effects of slaughter weight on carcass composition and meat quality in pigs of two different growth rates

Three hundred and forty (340) Duroc×(Landrace×Yorkshire) crossbred piglets were allotted to a 2×2×3 factorial design experiment. The independent variables were the growth rate (fast: around -10 days at 100kg and slow: around +2 days at 100kg), based on two different EBV's (estimated breeding value) of the sire-line for age, the sex (barrows and gilts) and the live weight at slaughter (107, 115 and 125kg). A sub-population of 119 pigs (10 carcasses per treatment) was selected for the carcass and meat quality evaluation trials. As live weight increased there were significant increases in hot carcass weight and dressing percentage (P<0.05). Lean, fat and bone proportions were not affected by weight. Gilts had higher lean proportion (P<0.05) than barrows. Furthermore, carcasses of fast growing pigs were fatter (P<0.05) than those of slower growing ones. Loin muscle pH, drip loss and reflectance values did not vary significantly with any of the treatments. Intramuscular fat was higher in barrows (P<0.05) than in gilts and soluble collagen content decreased with increasing weight (P<0.05). Muscle protein (%) increased (P<0.05) from 107 to 115kg and gilts had a higher (P<0.05) content than castrates. No evidence was found that increasing slaughter weight detracts from carcass characteristics or meat quality.     

Influence of soiling on boar taint in boars

It has been suggested that skatole, one of the main compounds responsible for boar taint, can be lowered by keeping pigs clean, as skatole can be absorbed through skin and/or lungs (Hansen, Larsen, Jensen, HansenMoller & Bartongade, 1994). With this experiment, we further investigated this hypothesis by comparing extremely clean with extremely dirty animals with regard to the occurrence of boar taint. One group of boars was washed daily and pens were mucked on and littered down daily (CLEAN), a second group of boars was rubbed with faeces daily (DIRTY) and a third group of boars was kept in control conditions (CONTROL). The treatment was performed during the last four weeks before slaughter. According to the standardised consumer panel evaluations, boars subjected to extra soiling had a higher concentration of boar taint than boars that were kept extra clean. In contrast, expert panels judged general meat flavour to be inferior in CLEAN than CONTROL pigs. The home consumer panel, the hot iron method, and laboratory analyses, i.e., the presence of indole, skatole and androstenone in fat and serum, all showed no significant differences. So no clear indications towards skatole reduction by improving cleanliness of pigs were found.     

Threshold Detection of Boar Taint Chemicals Using Parasitic Wasps

Abstract: Surgical castration has been long used to prevent consumers from experiencing taint in meat from male pigs, which is a large problem in the pig husbandry industry. Due to obvious animal welfare issues, the EU now wants an alternative for castration, suggesting an urgent need for novel methods of boar taint detection. As boar taint is only a problem when taint chemicals exceed a well‐defined threshold, detection methods should be concentration‐specific. The wasp, Microplitis croceipes’ ability to learn and respond to particular concentrations of the boar taint compounds, skatole, androstenone, and indole was tested. Also tested was the wasps’ ability to discriminate between known concentrations of indole, skatole, and androstenone in real boar fat samples at room temperature. Wasps were trained using associative learning by providing food‐deprived wasps with sucrose–water in the presence of specific odor concentrations. Trained wasps’ responses were tested to a range of concentrations of 3 compounds. Wasps showed unidirectional generalization of learned concentration responses, whereby the direction of concentration generalization was shown to be chemical‐dependent. Through both positive (sucrose) and negative feeding experiences (water only) with varying compound concentrations, the wasps can also be conditioned to respond to concentrations exceeding a defined threshold, and they were successful in reporting low, medium, and high concentrations of indole, skatole, and androstenone in boar fat at room temperature. The need for threshold detection rather than simple detection of absence/presence applies to many food quality issues, including the detection of spoilage or pest damage in crops or stored foods. Practical Application: An inexpensive and reliable means of detecting boar tainted pork at slaughter to avoid tainted meat on the market and dissatisfied consumers.     

Effect of logistic slaughter on Salmonella contamination on pig carcasses

Previous studies have shown that infected pigs are the source of carcass and slaughterhouse environment contamination by Salmonella. The present study tried to evaluate the effect of a logistic slaughter, organised according to Salmonella seroprevalence, on Salmonella contamination on carcasses. The study was performed at the beginning of slaughtering during three consecutive days. Low risk herds (8 batches) were slaughtered on day I, high risk herds (6 batches) on day II, and finally, moderate risk herds (5 batches) were slaughtered on day III. Each slaughtering day, holding pens, five points of the slaughter line, and 80 carcasses were sampled. The number of positive carcasses on days I, II and III was 7 (8.8%), 5 (6.3%) and 19 (24.4%) respectively. The results evidenced no clear effect of the logistic slaughter on carcass contamination, with a three times higher risk of finding a positive carcass when moderate Salmonella risk batches were slaughtered. Carcass contamination in low risk herds was linked to the contamination of holding pens and the slaughter line activities. On the other hand, Salmonella was not detected in any of the sampled carcasses in three out of six high risk Salmonella batches, showing that proper slaughtering practices can prevent carcass contamination. The experience reported here, demonstrates that apart from an accurate batch separation according to their seroprevalence levels, strict measures for cleaning and disinfection in the lairage and the slaughterhouse facilities are needed when logistic slaughter is performed.