The objective of the study was to determine perceptions of the consumers on how they judged behaviour and beef quality of cattle slaughtered for traditional ceremonies in the Eastern Cape Province of South Africa. A survey was conducted where a sample of 200 consumers were randomly selected and interviewed. Fifty non-descript cattle were slaughtered during traditional ceremonies and two hundred and twenty four (224) cattle were slaughtered at 3 through-put abattoirs (high, medium and low). Meat quality attributes were determined from the cattle slaughtered for traditional ceremonies and from cattle slaughtered at the abattoirs. Data for questionnaires was summarized as frequencies for each ceremony and statistical differences were analysed using chi square test (X2). The effect of Age, breed and sex on beef pH, colour, meat tenderness, temperature and cooking loss of cattle slaughtered during traditional ceremonies, at low, medium and high throughput abattoirs were analyzed using General Linear Model (PROG GLM) of SAS (2003). There was a significant age effect (P < 0.05) on beef tenderness and cooking loss of cattle slaughtered for traditional ceremonies. Age of cattle that have milk teeth to 1 year and age of 6 years to 8 years had an effect on the beef tenderness (25.55 ± 8.05) and cooking loss (48.00 ± 4.26) of cattle slaughtered for traditional ceremonies in Table 4.1. There was no significant sex effect on beef tenderness and cooking loss of cattle slaughtered for traditional ceremonies. Non-descript and Angus cattle slaughtered at low throughput abattoir had an effect on the colour of the beef in Table 4.2. The lightness (27.49 ± 2.53) and yellowness (21.16 ± 0.79) of the beef shows that there was a significant breed effect on cattle that are slaughtered at Low throughput abattoir, however redness of the meat was not affected by breed after slaughter. Cattle that are slaughtered at high throughput abattoir between ages of 6 to 8 years and also cattle that are more than 8 years in Table 4.4 had an effect on cooking loss (p < 0.05). Age between 6 to 8 years had an effect on the beef tenderness from cattle that are slaughtered at medium throughput abattoir. It was concluded that the meat tenderness of the young cattle with milk teeth slaughtered for traditional ceremonies was affected. On the other hand the meat tenderness and cooking loss of beef from the cattle slaughtered from low, medium and high throughput abattoir were affected by sex and breed mostly.

The objective of the study was to determine growth performance, physico-chemical attributes, oxidative stability and sensory quality of pork from pigs fed one of three dietary treatments, eac containing 0%, 2.5% or 5% (T1, T2 and T3, respectively) Moringa oleifera leaf meal (MOLM). Dietary treatments were formulated to be isonitrogenous and isoenergetic for weaner (6 – 8 weeks) and grower (9 – 13 weeks) phases. Twelve Large White (LW) and 12 Kolbroek (KB) male pigs at 6 weeks of age, initially weighing an average 10 kg, were randomly allocated to one of the dietary treatments, each with four replicates, in individual pens. Feed and water were offered ad libitum. The Longissimus thoracis et lumborum (LTL) muscle of each carcass (n = 24) was sampled for meat quality and fatty acid analyses. Breed differences in measured parameters were observed. In pigs receiving 5% MOLM, the LW had significantly the highest ADFI (P<0.05) than KB pigs. In pigs receiving 2.5% and 5% MOLM, backfat thickness was significantly highest (P<0.05) compared to those receiving 0% MOML. Dietary inclusion of MOLM had no significant effects (P>0.05) on the physico-chemical quality of pork from LW pigs; although it significantly (P<0.05) increased a* and reduced WBSF values in pork from KB pigs. Pork from LW pigs receiving 5% MOLM had significantly increased (P<0.05) n-3 content of the subcutaneous tissue of LW pigs compared to KB, and also when compread to other treatment groups. In both breeds, the composition of PUFA: SFA and n-6: n-3 in the subcutaneous adipose tissue was significantly (P<0.05) lower in T2 and T3 than in T1. The n-3 levels for pork muscle from LW pigs receiving 2.5% and 5% MOLM, and from KB pigs receiving 5% MOLM, were significantly (P<0.05) lower. Inclusions of MOLM significantly (P<0.05) reduced the n-6: n-3 fatty acids in pork from both LW pigs and KB pigs. Consumer scores on sensory attributes (aroma intensity, initial impression of juiciness, first bite, sustained impression of juiciness, muscle fibre and overall tenderness and overall flavor intensity) significantly (P<0.05) increased as the level of MOLM inclusion in the diet increased; and higher scores were observed in fried meat than in boiled for most sensory attributes. It may be concluded that inclusion of MOLM in pig diets up to 5% improved the ADFI, a*, tenderness of pork without adversely affecting the FCR and other physico-chemical quality attributes; and resulted in desired increase in levels of n-3 and reduced the n-6: n-3 fatty acid ratio.

The purpose of this research was to study the effect of electrical stimulation of carcasses on the meat quality of impala (Aepyceros melampus). The impala is one of the most important species in game meat production. A total of 40 impala (Aepyceros melampus) were harvested on Mara Research Station (23° 05' S and 29° 25' E; 961 m.a.s.l.) in the Limpopo province, South Africa. Animals were obtained during daytime by shooting from vehicles and by the walk and stalk method. Animals were shot high in the neck with .308 calibre scoped rifles and were immediately exsanguinated by cutting the jugular veins and carotid arteries with a sharp knife. The harvested animals were then taken to the processing facility at Mara Research Station, electrically stimulated, eviscerated and the carcasses cleaned according to standard South African and Zimbabwean practices. The animals were then hung by their Achilles tendon in a cold room at ca 4 ºC and left in the cold room for 24 hours with the skins on after which the skins were removed. The 40 animals were randomly grouped in the following groups and marked accordingly: Group 1: Electrical stimulation (ES) group consisting of 20 impala of which 10 were male and 10 were female (Experimental group). Group 2: Non-electrical stimulation (NES) group consisting of 20 impala of which 10 were male and 10 were female (Control group). Impala were electrically stimulated within 40 minutes after being shot. ES was applied using a Jarvis BV-80 unit (Jarvis Products Corporation, Middletown, CT) that delivered an electrical charge (230V; 50 Hz for 60 seconds) via a clamp attached to the nose and a steel hook (probe) inserted into the anus. The live mass (kg) of each animal was recorded and after dressing the carcass, the dressed out percentage (%) was calculated per individual animal. The average live mass of impala males was 55.5 kg which was significantly (p<0.001) higher compared to the females with an average live mass of 46.4 kg. The dressing percentage however did not differ significantly between the sexes where males had a 60 % dressing percentage and females a 59.4 % dressing percentage. ES, sex and muscle group had a significant (p<0.001) effect on muscle pH as measured at 45 min. 3, 6, and 12 hours post mortem. ES had a significant (p<0.001) effect on the pH of m. semimembranosus (SM), m. semitendinosus (ST), m. biceps femoris (BF) and m. longissimus dorsi (L1-L6) (LM) at 45 min., 3,6 and 12 hours post mortem. The pH of m. triceps brachii (TB) samples from impala in the ES group did not differ significantly (p=0.096) from samples from the NES group, samples from TB had a significantly (p<0.01) lower initial rate of pH decline compared to BF, LM, SM and ST. The interaction between ES x sex was significant (p<0.01). Muscle pH of samples from male impala in the NES group had lower initial pH values (at 45 min., 3,6 and 12 hours post mortem; p<0.001) than samples from the female impala in the NES group while there was no differences between samples from male and female impala in the ES group. Electrical stimulation influenced the pHu-value (p<0.05) of m. semitendinosus, with muscles from the ES group having a lower pHu (pH 5.52 ± 0.02) than muscles from the NES group (pH 5.59 ± 0.02). No significant differences were observed between ES and NES for the pHu-values of m. semimembranosus, m. biceps femoris, m. longissimus dorsi et lumborum and m. triceps brachii. Sex had a significant (p<0.05) effect on the pHu-value of the m. triceps brachii, with muscles from the male group having a higher pHu (pH 5.64 ± 0.02) than muscles from the female group (pH 5.58 ± 0.02). Electrical stimulation had a significant (p<0.05) effect on the L*24-value of the m. biceps femoris muscle, with muscles from the ES group (35.8 ± 0.08) being lighter than muscles from the NES group (33.1 ± 0.08). No significant differences were observed between ES and NES for the a*24- and b*24-values for all muscle groups. The L*-, a*- and b*-values of m. longissimus dorsi et lumborum muscle from ES and NES carcasses declined significantly (p<0.001) from 24 hours post-mortem to post freeze-thaw. ES also had no significant effect on the L*F- and a*F-values of the m. longissimus dorsi et lumborum muscle. ES however, had a significant (p<0.05) effect on the b*F-values. The b*F-value for ES meat (7.1 ± 0.1) was higher than NES meat (6.5 ± 0.2).The muscle x ES interaction was not significant. A significant difference (p<0.01) was found before and after freezing between the L*-values, a*-values and b*-values for both the ES and NES groups whereas the NES b*-value (p = 0.0638), showed a tendency to differ. No significant differences were observed between ES and NES for the thaw loss, drip loss, cooking loss, pH u, sarcomere length and shear force for the m. longissimus dorsi et lumborum muscle. Sex of the animal influenced (p<0.05) the thaw loss and cooking loss of the m. longissimus dorsi et lumborum muscle. No significant differences were observed between male and female for the drip loss, pHu, sarcomere length and shear force of the m. longissimus dorsi et lumborum muscle. In conclusion, it was found that ES did not have a significant effect on the meat quality of impala Aepyceros melampus ES however decreased muscle pH early post-mortem for impala by accelerating post-mortem glycolysis and hastening the onset of rigor mortis. This decrease in muscle pH probably reduced the possibility of cold shortening especially as impala have leaner carcasses. Thus ES may provide a commercial advantage with a decrease in processing and cooling time and an increase in meat production and shelf life. Copyright / Dissertation (MSc(Agric))--University of Pretoria, 2009. / Animal and Wildlife Sciences / unrestricted

American lambs are often over-finished and lack consistent quality. It has been suggested that the use of intact ram lambs can decrease USDA YG and improve growth efficiency. However, ram lamb carcasses are underutilized because of potential issues, the most crucial being off-flavor development. Our hypothesis for this study is that U.S. producers can take advantage of intact ram lamb growth and performance with no detriment to product quality, as long as lambs are slaughtered before the attainment of puberty. Three breeds (Hampshire, Dorset, and Columbia), three slaughter weights (light, medium, and heavy) and two sexes (rams and wethers) were evaluated. Results indicate that ram lambs can provide a satisfactory eating experience, however, in one of our studies compounding of maturity and slaughtering intact rams increased incidence of off-flavors. It remains undetermined whether the small differences in sensory characteristics would be detectable by everyday consumers.

The objective was to determine how the interaction of implant strategies with the galanin receptor 2 genotype would influence feeding behavior, production efficiencies, carcass characteristics, and meat quality in finishing steers. Angus steers were selected based on GALR2-c.-199T>G genotype (n = 36 TT, 38 TG, and 19 GG). Calves were blocked by body weight and fed a standard feedlot ration, blood and BW were collected every 28 d. Steers were randomly assigned to an implant strategy of Revalor-S (1×) or Revalor-S (2×). Intake and feeding behavior data were individually recorded. There was an effect of genotype on DMI but not feed efficiency. Treatment interactions were observed for several meat quality attributes but not carcass characteristics. Altering implant strategy does not appear to interact with the GALR2-c.-199T>G genotype to alter production or carcass characteristics.

The objective of this study was to determine if there is a difference in pre-harvest stress and carcass characteristics between kosher and not-qualified-as kosher cattle. Cattle that had a shorter time from gate to exsanguination and a lower vocalization score were more likely to qualify for kosher. Kosher carcasses had a larger REA, a higher WBSF value, tended to have a heavier HCW. At each individual day, kosher steaks had lower L*, a*, and b* values. These data suggest that body composition and stress level may play a factor in the likelihood of a beef animal to qualify for kosher, and there is a defined quality difference between kosher and nonkosher steaks.

Research was conducted to evaluate the effect of dietary amino acid (AA) density (Deficient (D), Low (L), High (H), and Excessive (E)) on broiler breast and thigh meat quality. As expected, the feed conversion improved (P<0.05) as AA density increased. No differences (P>0.05) existed among treatments with regard to final pH, cooking loss, shear force, brine absorption proximate analysis, and average consumer acceptability of breast meat. The D AA diet yielded meat with less (P<0.05) moisture, less protein (P<0.05) and more fat (P<0.05) than all other treatments. Increasing AA density in the diet led to increased (P<0.05) concentrations of linoleic and linolenic acid in the thigh meat from the H and E treatments, thus making it more susceptible to oxidation (P<0.05) in comparison to the D and L treatments. Overall, data revealed that all four AA diets yielded high-quality breast and thigh meat with minimal product differences.

No description available.

High feed ingredient prices have increased the use of by-products containing a high proportion of polyunsaturated fatty acids (PUFA) in pig and chicken feeds. This can increase the oxidation of other feed nutrients as well as causing oxidative stress in animals. Two studies were conducted to evaluate the effects of a dietary antioxidant blend (AOX, ethoxyquin and propyl gallate) in pigs and broiler chickens fed a diet high in oxidants. The objective of the first study was to evaluate the antioxidant blend on growth performance, meat quality, liver function, oxidative status, carcass characteristics, meat quality, and fatty acid profile in pigs. Crossbred barrows (n = 100, 10.91 ± 0.65 kg, 36 ± 2 d of age, Landrace × Duroc) were allotted to 5 treatments based on body weight (BW, 5 replicate pens per treatment, 4 pigs per pen). Treatments included: 1) HO: high oxidant diet containing 5% oxidized soy oil and 10% PUFA source (containing docosahexaenoic acid, DHA, 3.7% of diet); 2) VE: the HO diet with 11 IU/kg of added vitamin E; 3) AOX: the HO diet with AOX (135 mg/kg); 4) VE+AOX: the HO diet with both vitamin E and AOX; and 5) SC: a standard corn-soy control diet. The trial lasted for 118 d; on d 83, the HO diet pigs were switched to the SC diet because the animals were displaying very poor health. Compared with SC pigs, HO pigs had decreased average daily gain (ADG) and average daily feed intake (ADFI) from d 26 to 82 (P < 0.05). However, after switching the HO pigs to the SC diet, the VE treatment became the most stressed treatment with the poorest performance from d 83 to 118 (P < 0.05). The AOX restored pig performance to a level similar to pigs fed the SC diet (P > 0.05) with greater gain to feed ratio (G:F) for the entire period (P < 0.05). The AOX added treatments also attenuated the enlarged liver symptoms and reduced markers of liver stress including total bilirubin and aspartate transaminase, thiobarbituric acid reactive substances (TBARS) and carbonyl concentrations. In addition, the AOX addition in the high oxidant diet restored the lighter carcass weight, less back fat, less lean body mass and smaller loin eye area, decreased dressing percentage and intensive lipofuscin deposition induced by the high oxidant diet. However, the traits of loin muscle redness and belly firmness were not fully corrected by AOX. The second study was to investigate the antioxidant blend and vitamin E on growth performance, oxidative status, meat quality, fatty acid profile, liver function and inflammatory response in broiler chickens. Cobb 500 male broilers (n = 1200, 44.7 ± 0.8 g, d 0) were randomly distributed into 60 floor pens across 6 treatments with 10 replicate pens of 20 chicks each. Treatments included: 1) HO: high oxidant diet with vitamin E at 10 IU/kg, 3% oxidized oil, 3% PUFA source; 2) VE: the HO diet with vitamin E at 200 IU/kg; 3) AOX: the HO diet with AOX at 135 mg/kg, 4) VE+AOX: the HO diet with both vitamin E at 200 IU/kg and AOX at 135 mg/kg, 5) SC: standard control, a corn soy diet with vitamin E at 10 IU/kg, 3% non-oxidized soybean oil, no PUFA source, and 6) PC: positive control, the SC diet with AOX at 135 mg/kg. Compared to the SC birds, the PUFA added treatments (HO, VE, AOX, VE+AOX) groups had greater body weight, ADG and ADFI from d 0 through d 21 (P < 0.05). However, the growth of birds fed the VE treatment fell behind that of other treatments (P < 0.05) during the last 21 d of the trial. Compared to the HO birds, the AOX birds had lower TBARS and greater uric acid concentrations in the plasma, greater gene expression of superoxide dismutase and less drip loss, suggesting enhanced systematic antioxidant capability. In addition, dietary addition of AOX or AOX plus VE moderately improved liver function and reduced inflammation in fat tissue to a level similar to control groups. In both studies, the AOX supplement was effective in preserving PUFA, especially DHA deposition in the back fat of pigs and abdominal fat of chickens. These results suggest that feeding the high oxidant diet caused a series of changes in growth performance, liver function, oxidative status, carcass characteristics and meat quality in pigs, and AOX addition attenuated many of these. The supplementation of AOX also showed some effects on reducing oxidative stress in chickens. However, the effects were not as profound as the pig study. / Ph. D.

Thesis (Msc Food Sc (Food Science))--University of Stellenbosch, 2006. / The aim of this study is to determine the effect of crossbreeding Zimbabwean Blue (ZB) and South African Black (SAB) ostriches on the morphological, physical, chemical and sensory quality of the meat. However, it is also necessary to determine the reproductive performance of these genotypes to scientifically support decisions made in the ostrich industry. In relation to reproductive traits and body measurements influencing these traits, results from the study suggested that ZB birds are between 9 and 15% heavier than their SAB contemporaries. Regarding SAB females, egg production was 47% higher, levels of shell deaths were lower, percentage of eggs not incubated was lower (P<0.01) and 84% more (P<0.01) chicks were produced in a season compared to their ZB contemporaries. Mates of SAB males produced a higher (P≤0.05) percentage of eggs not incubated and higher shell death percentages than the mates of ZB males. It has to be conceded that ZB females had a lower reproduction than SAB females, limiting the application of this genotype as a dam line in crossbreeding systems. With regard to morphological properties, the pure Blue genotype in comparison to the pure Black genotype differed significantly (P≤0.05), with 16 kg for live weight, 8.3 kg for carcass weight and 3.5 kg for leg weight. However, when comparing carcass yields (expressed as %) there were no significant differences (P>0.05) between genotypes. The M. gastrocnemius, M. femorotibialis accessorius, M. iliotibialis cranialis, M iliotibialis lateralis, M. iliofibularis and M. iliofemoralis showed significant genotype differences (P≤0.05) for individual muscle weight. When comparing the physical meat quality characteristics between the pure Blue genotype and the pure Black genotype, 70% of the muscles were higher (P≤0.05) in pH24, 50% of the muscles were redder (P≤0.05) and significantly less (P≤0.05) saturated in colour, 67% of the muscles had a lower (P≤0.05) percentage drip loss and 50% of the muscles had a lower (P≤0.05) percentage cooking loss. No significant (P>0.05) genotype differences were observed regarding the sensory quality of the meat. Regarding chemical meat quality characteristics, the percentage of moisture was higher and the percentage of lipid was lower for eight of the ten muscle groups from the pure Blue genotype. No significant differences (P>0.05) were found between genotypes or between muscles regarding the percentage of protein present in the meat. The highest (P>0.05) content of soluble collagen, myoglobin and cholesterol was found in the Blue x Black genotype, whereas the lowest percentage of the latter constituents was found in the pure Blue genotype. For the pure Black genotype the concentration of saturated fatty acids in the meat was lower (P≤0.05), the concentrations of total unsaturated fatty acids and desirable fatty acids in the M. illiofibularis were the highest (P≤0.05), while the concentration of monounsaturated fatty acids was also higher (P≤0.05) in both muscles of this genotype compared to the other two genotypes. Regarding both fat depots, the pure Black genotype had a lower (P≤0.05) concentration of saturated fatty acids, a higher (P≤0.05) concentration of monounsaturated fatty acids and total unsaturated fatty acids and a higher (P≤0.05) polyunsaturated:saturated fatty acid ratio. The percentage of desirable fatty acids in the abdominal fat depot was significantly higher (P≤0.05) for the pure Black and the Blue x Black genotype. In conclusion, crossbreeding between SAB and ZB ostriches seems to be a viable option to produce larger birds with more meat, without negatively affecting the overall quality of the meat.