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Nodule size is an important indicator of leather quality in the ostrich leather trade. The present study investigated genetic variation in nodule size at five sites on the skin, namely the neck, back, upper leg, flank and butt. Nodule size increased with an increased chronological age at all sites. Estimates of h² for nodule size ranged from 0.09 ± 0.07 on the flank region to 0.24 ± 0.10 on the upper leg region. Genetic correlations between nodule sizes measured at different sites were generally lower than expected, linked to high standard errors and mostly not significant. These preliminary results seem to suggest that nodule size on different locations of the skin is not necessarily the same genetic trait. Apart from the limitations evident from these results, the objective measurement of nodules on ostrich skins is tedious when done manually, with little prospect for automation. The number of nodules per dm² (nodule density) was considered within skin sites as an indirect criterion for the improvement of nodule size. However, genetic correlations between nodule density and nodule size were negative, variable in size and generally not significantly different from zero or unity. Based on these preliminary results, alternative strategies for the genetic improvement of ostrich skin nodule size should be considered. [ABSTRACT FROM AUTHOR]

The effects were investigated of energy and protein concentrations (with associated amino acid concentrations) in ostrich diets on leather quality of the skins of 50 ostriches. Energy concentrations were 9.0, 10.5 and 12.0 MJ ME/kg diet and protein concentrations were 130, 150 and 170 g/kg diet. The physical leather parameters that were assessed included tensile strength, elongation, slit tear strength and skin thickness. All traits were assessed in samples taken parallel or perpendicular to the spine in the butt region of the slaughter bird. The raw skin weights of ostriches consuming the diets with energy concentrations of 10.5 and 12.0 MJ ME/kg diet were respectively 19.4 and 21.8% heavier at slaughter than those of their contemporaries on the 9.0 MJ ME/kg DM diet. A corresponding trend was found for trimmed skin weight, and the increase in skin weight with diets higher in energy exceeded 10%. Differences between skin area means only approached significance, with a tendency to increase with an increased energy concentration. Leather thickness taken parallel to the spine was increased by 13% in the diet containing 12 MJ ME/kg diet, compared to the diet containing 9.0 MJ ME/kg. Dietary protein concentrations failed to influence skin weight, skin area or any of the physical leather properties. The skins of male ostriches were thicker than those of females. The study suggested that the lowest levels of energy and protein supplied, were sufficient to prevent a decline in physical leather quality. [ABSTRACT FROM AUTHOR]

Ostrich skins (n = 214) were assessed by 28 participants involved in the ostrich leather production and marketing chain. The participants were from various sectors in the ostrich industry, including producers, skin graders, leather marketers, agents and process managers. Skins were evaluated during two occasions, firstly without any knowledge of slaughter age and thereafter with prior knowledge of slaughter age. Nodule acceptability and distribution for each skin were scored on a linear scale of 1 to 10. Slaughter age, as estimated by the participants during the first evaluation, was regressed on the actual age of the birds at slaughter. The derived regression indicated that actual slaughter age accounted for approximately 46% of the variation found in estimated slaughter age. Nodule acceptability scores generally increased with slaughter age. Average scores of at least moderately acceptability were found only in skins from birds slaughtered at 11 months of age and older. A corresponding trend with increase in slaughter age was found for nodule distribution scores. Between skin variance ratios were comparatively low for nodule acceptability (0.09-0.10, depending on prior knowledge of slaughter age or not) and nodule distribution (0.05-0.06). The between scorer variance ratio was generally higher, exceeding 0.35. Scores for nodule acceptability with or without prior knowledge of the age of individual skins at slaughter were essentially the same, as judged from a near unity covariance ratio between individual skins. A similar trend was observed for nodule distribution score. The need for practical methods for the objective assessment of the acceptability of nodules and ostrich leather quality was expressed. [ABSTRACT FROM AUTHOR]

Little is known about the factors affecting leather and skin traits in ostriches. The effect of age on physical skin traits of slaughter ostriches was consequently investigated. Forty skins representing slaughter ages ranging from five to 14 months were selected to represent means of the respective age groups with regard to skin size and slaughter weight. It was evident that leather thickness increased with age. A similar tendency was observed for tensile strength. The number of nodules/dm² declined by 2.8 nodules per month increase in slaughter age. Average nodule diameter increased at a rate of 0.08 mm per month of age. The number of nodules/dm² decreased towards body positions situated nearer to the ventral aspect of the ostrich (upper leg and lower flank). Positions nearer to the centre back had more nodules/dm². The nodules on the neck and mid-crown area were smaller in diameter than those situated on the other body positions, with little difference between the upper leg, lower flank and butt positions. Repeatability estimates for the physical skin traits were in the medium to high range. Age thus affects physical leather traits to a lesser extent, apart from leather thickness. It does, however, exert an important influence on the nodule traits that were considered, and needs to be considered in the marketing of ostrich leather. [ABSTRACT FROM AUTHOR]

The effect on ostrich muscle quality of an additional thoracic stick (TS) to the normal ventral throat slit to bleed ostriches after electrical stunning was evaluated. The additional TS had no negative or positive effect on the drip loss, cooking loss, colour or pH and temperature readings of the fillet (Muscularis iliofibularis), big drum (M. gastrocnemius, pars interna) and inside loin (M. iliotibialis cranialis). None the less, personal observations would recommend the use of TS due to ethical considerations. An early post mortem low voltage electrical stimulation (ES) of the carcasses also had no influence on the cooking loss, drip loss and colour of these muscles. Electrical stimulation did result in a lower pH45 in both the fillet and big drum muscles. However, after 24 h the pH of the muscles did not differ. Electrical stimulation also caused elevated initial muscle temperatures, although this effect was only temporary due to the efficient cooling mechanism used in the abattoir. Electrical stimulation also had no effect on the Warner Bratzler shear force values in the fillet. It can be concluded that low voltage ES has no advantage pertaining to physical quality characteristics of importance in an ostrich abattoir. [ABSTRACT FROM AUTHOR]

The study provides information on the reproductive performance of ostriches maintained at different stocking rates and male:female (M:F) ratios under intensive commercial conditions in the Little Karoo, South Africa. Breeding ostriches are concentrated on relatively small areas and through trampling have a most significant impact on the vegetation in the Little Karoo. Reproductive performance, as influenced by stocking rate and M:F ratio, was investigated. Stocking rates for the large flocks ranged from 114 to 210 birds/ha, and stocking rates for smaller flocks ranged between 9 to 13 birds in 0.13 ha and 0.30 ha camps, respectively. The different M:F ratios investigated, were 1M:1F (pairs), 1M:2F (trios) and 1M:3F (quads), for breeding systems maintained in 0.06 ha camps. In almost all breeding systems total and average egg production, fertility and hatchability were compromised when stocking rate was increased. High stocking rates were detrimental to the reproductive performance and reproductive behaviour of the flocks. Increasing the number of females per male had no negative influence on the reproduction traits, with a significantly higher production observed for breeding quads. Our findings indicated that ostrich breeding flocks can be maintained at stocking rates higher than those presently used on commercial ostrich farms. Breeding pairs, trios and quads can also be maintained on smaller areas, with acceptable production levels. Increasing stocking densities will have a possible inhibitory effect on the establishment of territories and use of space, thereby impacting on the reproductive behaviour of ostrich females and males in large flocks, respectively. This has important implications in terms of the intensification of ostrich farming especially in areas that are characterised by vegetation that is exposed to the trampling effect of ostriches. [ABSTRACT FROM AUTHOR]

Presents a study which investigated declawing of ostich chicks as potential management practice to minimize skin lesions that result from claw injuries. Materials and methods; Results and discussion; Conclusion.

Preliminary genetic parameters for nodule traits of ostrich skins were estimated to examine whether genetic improvement of skin quality is feasible. Average nodule size and density per dm⊃2 were determined on five localities on each of 439 ostrich skins. An animal model with random animal and skin permanent environmental effects was fitted for the traits considered. Fixed effects were locality on skin, age, year of hatch and gender. Locality significantly influenced nodule size and nodule density. Nodule size increased with an increase in slaughter age, while nodule density decreased. Estimates for heritability were low at 0.10 for both traits, but still differed significantly from zero. The genetic correlation between nodule density and average nodule size was very high at -0.72. The skin permanent environmental correlation was -0.33, the environmental correlation -0.17 and the phenotypic correlation was -0.28. More research into genetic variation within localities and correlations with other easily measurable traits is indicated for genetic improvement of ostrich leather quality. [ABSTRACT FROM AUTHOR]

Commercially reared ostriches (n=84) were randomly allocated to one of two groups. The first group (stressed: n=38) was deprived of food for a period of 2.5 days prior to slaughter, to simulate the stress experienced by slaughter ostriches held in holding pens (lairage) at a commercial ostrich abattoir over a weekend. The second group (control: n=46) was fed normally until 24 h prior to slaughter. Initial live weight as well as hot and cold drumstick weight were independent (P>0.05) of treatment. Stressed birds lost on average (±SE) approximately three times more weight than control birds over the experimental period (-3.2±0.6 vs. -1.0±0.5 kg, respectively). Full stomach and alimentary tract weights did not differ between treatments although there was a tendency for that derived from stressed birds to have lower stomach contents. The intra-muscular (Muscularis iliofibularis) pH(f) of stressed birds was 0.22 units higher (P<0.01) than that of contemporaries in the control group 1 h post-slaughter (6.03±0.06 vs. 5.81±0.05, respectively). After 26.5 h in a refrigerated room, this difference still remained at 0.25 units (6.46±0.07 vs. 6.21±0.07, respectively; P<0.05). Post-slaughter changes in intra-muscular pH followed approximately the same trend in stressed and control birds. Intra-muscular temperature was largely independent of treatment, although there was a suggestion of a slightly higher (P=0.18) temperature in stressed birds immediately post-slaughter. Cooking loss, drip loss and shearing values were not affected (P>0.05) by the withholding of food for 2.5 days. It can thus be concluded that withholding feed from ostriches on lairage over a period of 2.5 days does not have any negative influence on the meat yield or physical quality traits thereof.

1. The true metabolisable energy (TME) of canola oilcake and full-fat canola seed was determined for ostriches to broaden our knowledge of canola as a potential protein and energy source for ostriches. 2. Both test materials were diluted with a basal diet, fed to ostriches and TME-values estimated by multiple regression analysis. 3. The TME values for canola oilcake meal and full-fat canola seed for ostriches were respectively 13.76 MJ kg(-1) and 22.5 MJ kg(-1). 4. The TME values obtained for these 2 important protein sources will assist in the more accurate formulation of diets for ostriches.

1. Three trials were designed to study the effects of axis of setting, turning frequency and axis and angle of rotation on the hatching success of ostrich eggs. The joint effects of axis of setting and angle of rotation were investigated in a fourth trial. 2. The hatchability of fertile ostrich eggs artificially incubated in electronic incubators (turned through 60 degrees hourly) was improved substantially in eggs set in horizontal positions for 2 or 3 weeks and vertically for the rest of the time. 3. The hatchability of fertile eggs set in the horizontal position without any turning was very low (27%). It was improved to approximately 60% by manual turning through 180 degrees around the short axis and through 60 degrees around the long axis at 08.00 and 16.00 h. A further improvement to approximately 80% was obtained in eggs automatically turned through 60 degrees around the long axis in the incubator. Additional turning through 180 degrees around the short axis twice daily at 08.00 and 16.00 h resulted in no further improvement. 4. The hatchability of fertile eggs set vertically in electronic incubators and rotated hourly through angles ranging from 60 degrees to 90 degrees around the short axis increased linearly over the range studied. The response amounted to 1.83% for an increase of 10 (R2=0.96). 5. The detrimental effect of rotation through the smaller angle of 60 degrees around the short axis could be compensated for by setting ostrich eggs in the horizontal position for 2 weeks before putting them in the vertical position.