Browsing by Author "Brand, Z."

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    Dead-in-shell positions of near-term ostrich embryos
    (South African Society for Animal Science, 2016-12-06) Brand, Z.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe); Malecki, I. A.; Brown, C. R.
    The patterns of embryonic development in ostriches, especially in the last stage of hatching, are still not well understood. This study examined between 3468 and 3484 dead-in-shell (DIS) eggs with chicks that died between day 35 and day 42 of artificial incubation. Most DIS chicks were positioned correctly with their heads towards the air cell (52.6%). DIS chicks that positioned their heads near the equator of the egg amounted to 46.5%, while a small percentage (0.9%) were positioned with their upper body towards the bottom of the egg. More DIS chicks tended to pip internally near the equator of the egg (37.6%) than DIS chicks that pipped internally through the membranes into the air cell (34.4%). Most DIS chicks had their heads turned in the correct position from left to right (54.4%), though their beaks were mostly positioned towards the air cell (52.9%). The highest percentage of DIS chicks had their feet in the upwards position (52.4%), while 46% had their feet across or below the head. The wings of all DIS chicks were positioned next to the body. Results from the study showed that most of the DIS chicks were roughly in the correct position, but were still unable to hatch. This warrants future research to investigate the reasons that prevent correctly positioned chicks from hatching.
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    The effect of different combinations of dietary energy and protein on the composition of ostrich eggs
    (South African Society for Animal Science, 2003) Brand, Z.; Brand, T. S.; Brown, C. R.
    Nutrition of breeding female birds can influence egg quality and is therefore extremely important for the development of the embryo and the successful hatching of a high quality chick. We investigated the effect of combining different levels of dietary energy and protein, with accompanied amino acid levels, in the diets of female ostriches on the composition of their eggs. Ninety pairs of breeding ostriches were divided randomly into nine groups of 10 pairs per group in a factorial design with three energy and three protein levels. The groups were fed diets with levels of 7.5, 8.5 and 9.5 MJ metabolisable energy/kg, each combined with each one of three protein levels 105, 120 and 135 g/kg respectively. Fresh eggs were collected from each group at the end of the breeding season and the albumen and yolk separated and analysed for protein and lipid content and for amino acid and mineral composition. No significant interaction between energy and protein levels occurred. Despite some differences in egg composition and amino acid concentrations, different dietary energy and protein levels for the most part had little or no effect on the composition of ostrich eggs.
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    The effect of different dietary vitamin and mineral levels on certain production parameters, including egg shell characteristics of breeding ostriches
    (South African Society for Animal Science, 2014-08-24) Brand, T. S.; Tesselaar, G. A.; Hoffman, L. C.; Brand, Z.
    Earlier studies on breeding birds indicated no effect of dietary energy-content on feed intake. This observation is contradictory to results for other animals and/or poultry where feed intake decreases with an increase in dietary energy level. Literature revealed that a lack of certain nutrients may cause animals to consume more feed than necessary to satisfy their nutrient requirements for these limiting nutrients. In this study eight diet groups were evaluated. A standard commercial diet plus one of the following supplements: (i) Standard diet without a vitamin and mineral premix pack (control diet), (ii) with a normal premix pack, (iii) with normal vitamin and 2 x trace elements (M x 2), (iv) with normal trace elements and 2 x vitamins, (v) with a normal premix pack and limestone added as calcium source; (vi) with a normal premix pack and monocalcium phosphate added as phosphorus source, (vii) with a normal premix pack and soybean oilcake added as crude protein source, (viii) with a normal premix pack and linseed added as a fatty acid source. Significant differences were recorded in the quantity of feed ingested by birds between the diet with surplus minerals (M x 2) (Group 3) (2.3 ± 0.3 kg/bird/day), the diet with no vitamins and minerals added (Group 1) (2.7 ± 0.3 kg/bird/day) and the diet with added fatty acids in the form of linseed (Group 5) (2.9 ± 0.5 kg/bird/day). This indicates the possibility that ostriches may adjust feed intake to satisfy their mineral requirements. No statistically significant relationship was found between the thickness and strength of the shell. Significant differences in shell strength (mean value of 154.7, 109.9, 140.4, 142.7, 153.0, 143.4, 138.4 and 151.1 N/cm2, respectively) were found between all treatments, but no specific pattern could be identified. Results further revealed no effect of dietary treatment on egg production, dead-in-shell eggs (DIS), infertile eggs or chick production. Further experiments that include certain dietary treatments during the five months rest period are currently being done to quantify the effect of the addition of minerals and vitamins during this period on the production of breeding ostriches.
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    An exploratory analysis to determine the impact of fixed effects and to establish genetic parameters across six types of ostrich feathers
    (South African Society for Animal Science, 2015-02-24) Brand, Z.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe)
    After a decline in value, ostrich feathers have again become an important part of the income of ostrich producers. Between 22586 and 22753 feather weights, as well as length and width measurements, were obtained from feathers harvested annually during the resting period from a pair-bred ostrich flock maintained at Oudtshoorn Research Farm from 2001 to 2012. The flock consisted mostly of the South African Black (SAB) genotype, but birds from the Zimbabwean Blue (ZB) and Kenyan Redneck (KR) strains were also introduced to study strain effects, as well as the effect of crossbreeding between these genotypes (ZB x SAB; SAB x ZB; KR x SAB; SAB x KR). The feathers were sorted into six feather-type categories, namely floss, short hard body feathers, long hard body feathers, tail feathers, white plumes and short body floss. White plumes had the highest average feather length (AFL), average feather width (AFWD) and square-root-transformed feather weight (SRFW) at 66.2 ± 0.38 cm, 21.2 ± 0.23 cm and 13.66 ± 0.17 g, respectively. A significant decline in AFL took place from 2001 and 2012 (40.0 ± 0.25 cm and 38.7 ± 0.56 cm, respectively), while AFWD stayed fairly constant. Feather weights were higher for males than females resulting in a 24% higher geometric mean for backtransformed feather weights (GMFW) for males relative to females. SAB birds outperformed ZB and KR birds for AFL, AFWD and SRFW. Crosses were intermediate and sometimes comparable with the SAB genotype. Except for long hard body plumes, the weights for all the feather types were higher for the purebred SAB breeders compared with purebred ZB and KR breeders. Heritability estimates of AFL, AFWD and SRFW across the six feather categories were low to moderate at 0.080 ± 0.012, 0.044 ± 0.009 and 0.116 ± 0.017, respectively. The animal permanent environmental effect for the feather traits was lower in magnitude and ranged between 0.025 ± 0.008 for AFL and 0.041 ± 0.012 cm for SRFW. Direct genetic correlations of feather dimensions with SRFW were moderate to high at 0.287 ± 0.117 with AFL and 0.614 ± 0.072 with AFWD. The present results indicate that feather quantity can be improved by genetic selection in ostriches, and further studies should be conducted.
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    Genetic parameters for ostrich incubation traits in South Africa
    (South African Society for Animal Science, 2009) Brand, Z.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe); Malecki, I. A.; Brown, C. R.
    Data obtained from a pair-mated ostrich flock located at Oudtshoorn, South Africa, were used to estimate genetic parameters for egg weight (EWT), weight of day-old chicks (CWT), water loss to 21 (WL21) and 35 (WL35) days of incubation, and pipping time (PT) for between 13 806 and 19 913 artificially incubated ostrich eggs during the 2003 - 2006 production years. Data were initially analysed as single traits using ASREML. Covariance components and ratios were subsequently derived from two-trait analyses. Single-trait estimates of heritability (h2) were 0.46 ± 0.08 for EWT, 0.34 ± 0.07 for CWT, 0.34 ± 0.07 for WL21, 0.27 ± 0.06 for WL35 and 0.16 ± 0.04 for pipping time. Estimates of maternal genetic effects (m2) were 0.23 ± 0.12 for EWT and 0.29 ± 0.10 for CWT. A maternal permanent environmental effect amounted to 0.25 ± 0.10 for EWT, 0.12 ± 0.09 for CWT, 0.25 ± 0.04 for WL21 and 0.30 ± 0.04 for WL35. Genetic correlations with EWT amounted to -0.21 ± 0.13 for WL21 and to -0.12 ± 0.14 for WL35. Corresponding correlations with CWT were -0.43 ± 0.07 and -0.54 ± 0.11. Parameters indicate that it should be possible to alter evaporative water loss of ostrich eggs by genetic selection. A feasible selection strategy, however, needs to be devised as it is challenging to effect genetic change in a trait with an intermediate optimum.
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    Influence of dietary energy level on the production of breeding ostriches
    (South African Society for Animal Science, 2009) Olivier, T. R.; Brand, T. S.; Brand, Z.
    A study was conducted to determine the influence of dietary energy level on the production of breeding ostriches. Six diets varying in ME content (7.5, 8.0, 8.5, 9.0, 9.5 and 10.0 MJ ME/kg feed) were provided to both males and females at an average rate of 3.4 kg/bird/day. Dietary protein and lysine levels were held constant respectively at 120 (g/kg feed) and 5.8 (g/kg feed). The trial ran over one breeding season and production records recorded included egg production, chick production, number of infertile eggs, number of dead-in-shell eggs and weight change of breeders. No significant differences were observed for total eggs produced per female per season (44.3 ± 7.6), number of chicks hatched (15.6 ± 4.1), number of infertile eggs (11.8 ± 3.9) and for number of dead-in-shell eggs (11.9 ± 3.1). Analysis of variance revealed no significant difference in the weight change of female birds on different treatments, although regression analysis revealed an increase of 2.4 kg per female bird per 0.5 MJ increase in dietary energy value of the feed. Significant differences in the weight change of male breeders were observed which ranged between 6.3 ± 2.7 kg and 18.4 ± 2.8 kg over the breeding season. Overall, the weight of male breeders increased by 1.9 kg per 0.5 MJ increase in dietary energy content (R2 = 0.09). It was concluded that the energy supplied for both male and female breeders was in excess of their requirements, since both sexes increased in weight over the season.
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    Influence of incubation management on pipping position, hatching ability and survival of ostrich chicks
    (South African Society for Animal Science, 2011) Brand, Z.; Cloete, S. W. P. (Schalk Willem Petrus van der Merwe); Malecki, I. A.; Brown, C. R.