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Images of the ostrich egg used to derive the percentage of the candled eggs occupied by the air cell from 3 days-42 days of incubation (A-G).
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... This pattern holds across both sites and through time, though the proportion of earlier stage eggs is slightly higher in the TP/EH at Kiowa. These data indicate that people at these two sites-and especially at Yuku-were preferentially harvesting eggs that contained cassowary embryos with fully formed limbs, beaks, claws, and feathers (3,(59)(60)(61). Furthermore, while there is overall agreement between our two models and visual inspection in the identification of later stage eggshells, the 4-predictor model appears to be picking up further microstructural variation that allows us to improve the resolution of our identifications. ...
Significance
Eggshell is an understudied archaeological material with potential to clarify past interactions between humans and birds. We apply an analytical method to legacy collections of Late Pleistocene to mid-Holocene cassowary eggshell and demonstrate that early foragers in the montane rainforests of New Guinea preferentially collected eggs in late stages of embryonic growth. This finding suggests that foragers regulated the exploitation of cassowaries and may have hatched eggs to rear chicks. The montane rainforests of New Guinea may thus present the earliest known evidence of human management of avian breeding.
... a by-product of ongoing research at Oudtshoorn aimed at reducing levels of reproductive failure (e.g. incidence of dead-in-shell (DIS) chicks) and improving the economic viability of the commercial ostrich production industry (Brand, 2012;Brand et al., 2014;Brand et al., 2017a;Brand et al., 2017b). As a result, eggshell fragments ranging in size from 5 to 10 cm 2 and representing every day (1-42) of embryonic development were obtained from three separate eggs (each from a different hen) for each day (3 eggs × 42 days = total of 126 eggs sampled from 126 hens). ...
... The tilt-series method generates equally high-resolution 3D surfaces of eggshell, but data capture (~1hr) and postprocessing time (~1hr) are greater than the laser and digital microscopy and Table 2 Summary of key stages of ostrich embryonic development and their relationship to changes in eggshell morphology. *Sources: 1 (Chien, et al., 2009); 2 (Bellairs and Osmond, 2014); 3 (Brand, 2012); 4 (Brand, et al., 2017a); 5 (Ar and Gefen, 1998); 6 (this paper). **Based on embryonic studies of chicken (Gallus gallus). ...
Archaeological eggshell is a commonly recorded, yet underutilized material for understanding human-environment interaction in the past. In addition to the use of archaeological eggshell as a paleoenvironmental proxy, archaeologists have innovated important new approaches to the study of archaeological avian eggshell, including the application of scanning electron microscopy (SEM) for the characterization of eggshell micro-structures. These studies have demonstrated the importance of eggshell for understanding how ancient communities exploited and interacted with avifauna. In this paper, we build on these methodological advances by testing new approaches to image avian eggshell and characterizing complex eggshell surface microstructures. We demonstrate the utility of capturing high-resolution 3-dimensional (3D) eggshell surfaces using advanced imaging modalities (optical profilometry, scanning electron microscopy, digital microscopy, computed tomogra-phy), to model changes in eggshell microstructures that are correlated with ontogeny. Using the Common Ostrich (Struthio camelus) as our model system, we introduce a statistical modeling approach to predict the ontogenetic age of ratite eggshell using roughness measurements of 3D features. Successful prediction of ontogenetic age has great potential to reveal archaeological patterns of human exploitation of avian eggs. These findings further illustrate the importance of archaeological eggshell for investigating human-environment interactions, emphasizing the need for archaeologists to use field methods (hand/trowel excavation and fine mesh screen) that facilitate eggshell recovery.
... Compared to those of the domestic fowl, Changkang et al. (1999) attributed the relatively low hatchability of the duck eggs to the large size of the eggs, their relatively thick shells and the excessive water loss due to large numbers of pores in the shell. In the ostrich industry, the greatest economic losses emanate from poor hatchability of the eggs (Burger and Bertram 1981;Bowsher 1992;Deeming et al. 1993;Button et al. 1994;Deeming and Ar 1999;Cooper 2001;Richards et al. 2002;Ş ahan et al. 2003;Brand 2012). Incubation procedures and structural defects of the eggshells are the main factors that reduce hatchability (Burger and Bertram 1981;van Toledo et al. 1982;Bowsher 1992;Deeming et al. 1993;Deeming 1995;Button et al. 1994;Sales et al. 1996;Brown et al. 1996;Deeming and Ar 1999;Richards et al. 2000Richards et al. , 2002Şahan et al. 2003). ...
The evolution of a cleidoic (self-supporting) egg in the amniotes was pivotal to the transition of animal life from water to land: embryonic development could occur without the direct presence of water. For birds, remarkable adaptive radiation occurred after the achievement of volancy. It has culminated in ~10,000 species. Among the air-breathing vertebrates, the taxon Aves is the most speciose. In the developing avian egg, exchange of respiratory gases (O2 and CO2) and water vapour occurs entirely by passive diffusion across the shell and the chorioallantoic membrane (CAM) along existing concentration gradients. A multifunctional structure, the shell displays compromise design. On one hand it has to be thin enough to allow optimal flux of O2 and CO2 and loss of water which is generated by metabolism of the developing embryo. On the other hand, the shell must not be too thin to admit pathogens and injurious substances and susceptible to failure (breaking). Also, the shell must not be too strong for the chick to be unable to break out of at hatching. The thickness of the shell and the numbers, shapes and sizes of the pores determine the hatchability of the egg and probably the incubation period of the egg. The CAM of the developing chick embryo is analogous to the placenta of the viviparous animals. While the number of pores may be fixed at the formation of the eggshell, during incubation, the surface area and vascularization of the CAM increase considerably. Here, the structure and function of the avian eggshell and that of the CAM are succinctly outlined. Particular consideration is given to the recent observations made using X-ray microcomputer tomography, a highly instructive technique for studying biological structures. The impact of the evolution of the amniotic egg on the diversification of the animal life especially that of birds, is highlighted.
... The adult mass M of this sauropod was calculated by using the result of Deeming and Birchard [69] to relate the hatching mass m h to the mass of the egg, m egg , and then the result of Dolnik [166] was used to relate m egg to the adult mass M. Before discussing the significance of this measurement of embryonic metabolism in dinosaurs, let us examine the embryonic and juvenile metabolisms of extant birds and reptiles. [117][118][119][120][121][122][123][124][125][126][127][128][129][130] and five reptiles [131][132][133][134] were analyzed using Eq. (3) in order to determine their embryonic metabolic prefactor B o . ...
The embryonic metabolisms of the ornithischian dinosaurs Protoceratops andrewsi and Hypacrosaurus stebingeri have been determined and are in the range observed in extant reptiles. The average value of the measured embryonic metabolic rates for P. andrewsi and H. stebingeri are then used to calculate the incubation times for 21 dinosaurs from both Sauischia and Ornithischia using a mass growth model based on conservation of energy. The calculated incubation times vary from about 70 days for Archaeopteryx lithographica to about 180 days for Alamosaurus sanjuanensis. Such long incubation times seem unlikely, particularly for the sauropods and large theropods. Incubation times are also predicted with the assumption that the saurischian dinosaurs had embryonic metabolisms in the range observed in extant birds.
... Embryonic mortality arising from genetic problems can negatively influence hatchability, but this has not yet been demonstrated in ostriches (Badley, 1997). Brand (2012) reported on embryonic development and hatchability of ostrich eggs from a combination of South African Black (SAB) male ostriches crossed with Zimbabwean Blue (ZB) female ostriches, to have had embryonic losses of 45.7%. The embryonic mortality of eggs produced by pure bred SAB or ZB breeding birds subjected to pure breeding was similar at around 33-34% but embryonic mortality was improved in eggs produced by ZB males and SAB female crosses (27%). ...
... In both broiler breeders and quail, young females had a higher proportion of early embryonic mortalities than mature females (Scott and Mackenzie, 1993;Reis et al., 1997;Hocking and Bernard, 2000;Yildirim, 2005), while for ostriches the opposite seems to be true in the sense that embryonic survival decreases over subsequent laying seasons (Badley, 1997). Female age had a significant effect on the proportion of chicks pipped, as well as on early and late embryonic mortalities (Brand, 2012). Bunter (2002) and Cloete et al. (2006) reported that older ostrich females are still capable of good egg production, chick production declined overall due to higher levels of embryonic mortality, while Brand et al. (2007) reported that fertile eggs produced by older females are less likely to hatch than eggs produced by younger females. ...
... Ar and Gefen (1998) suggested that ostrich eggs may benefit from a storage period of only 3-4 days. Chicks from eggs stored for intermediate periods, i.e. 3,4 and 6 days prior to being set, were more likely to pipe than chicks from those eggs set directly after collection without storage (Brand, 2012).The author also reported that embryonic mortality was increased in eggs that were set directly (32.0%) or subjected to longer than 6 days of storage (43.5%). ...
Intensification of ostrich farming revealed that egg hatchability was remarkably lower than the wild. This review considers the factors leading to, as pertaining to the ostrich, egg and incubator. Ostrich genotype, age, season and congenital problems affect clutch and egg sizes and egg quality- fertility to lead a successful hatch. Egg treatment prior incubation can later reduce hatchability, affected by storage conditions and duration. Most detrimental factors lie in the incubator and hatcher management. Egg correct positioning and turning in the appropriate incubator humidity and temperature are likely to yield high hatch. Variability in egg size, shell quality, pore sizes and numbers govern the water loss and exchange of gases. The hatcher management is important when chicks need intervention. Dead-in-shell embryos, early or late were likely to be affected by all of the above factors plus egg microbial contamination or be merely nutritional.Int J Appl Sci Biotechnol, Vol 3(4): 566-578
... Despite substantial advances in incubator design and incubation techniques since the ostrich industry began in South Africa during the 1800s, problems with embryonic mortality during artificial incubation are still one of the main constraints to the development of the industry worldwide. Research conducted by Brand (2012) found that methods of incubation and chick rearing were among the most important limitations on the development of the ostrich industry, hence egg production has been a strong research front for the industry. However, even though there have been limitations, the growing demand for ostrich products has resulted in increased interest in ostrich reproduction beyond South Africa's borders. ...
Predictive modelling of publication activity is a new concept in agricultural analysis. This study illustrates the potential for identifying and quantifying patterns from the past 42 years of ostrich husbandry research. Studies on ostriches have been influenced considerably by production challenges, opportunities and threats, and owing to the large size of and variations in data and the monopolistic nature of the ostrich industry, there has been limited progress in classifying these research-front trends. Identifying these fronts will facilitate understanding of likely future developments and enable forecasting and the appropriate allocation of resources. This paper presents one of the first exploratory studies to capture and visualise temporal changes in ostrich research activity in the Google Scholar database. The results suggest that there are associations between the deregulation of the industry and increased emerging ostrich research, between the time of political isolation of South Africa and substantially increased global research on ostrich reproduction by 1996, and between epidemiological research and the outbreak of the avian influenza virus between 2004 and 2006. This indicative study contributes to the development of a novel prototype for the prediction of future developments and trends in agricultural research.
... The binomial distribution of embryonic survival, as well as the sex-limited nature of egg production, probably contributed to these computational difficulties. Analyses conducted over a longer period of 13 years yielded plausible (co)variance components for embryonic survival (Brand, 2011) and it is likely that this limitation may be overcome with higher numbers of eggs, assessed over an extended time period. ...
1. A study was conducted on ∼14000 ostrich eggs to estimate genetic parameters for eggshell traits that could benefit the hatchability of ostrich eggs. Traits measured included the number of pores on the eggshell, the average diameter of these pores, the total area of pores on the eggshell, permeability (pore area/shell thickness) and eggshell thickness. 2. Heritability estimates ranged from 0·16 for total pore area to 0·41 for the natural logarithm of pore count. The heritability estimates for water loss on 21 and 35 d (WL21 and WL35) of incubation were high at 0·23 and 0·24, respectively. 3. On a genetic level, pore count was negatively correlated with average pore diameter (-0·73) and shell thickness (-0·28), whereas it was positively correlated with total pore area (0·58), WL21 (0·24) and WL35 (0·34). The direct and maternal genetic correlations of pore count with total pore area (0·58) and permeability (0·59) were high and significant. Permeability was positively correlated to WL21 and WL35, both on the direct and maternal genetic levels. 4. The estimated genetic parameters indicate that it should be possible to select for the various eggshell traits in ostrich eggs, or for permeability and water loss. However, as a trait with an intermediate optimum, direct selection for permeability and other eggshell traits would not be straightforward, and the possible application of these results to improve hatchability of ostrich eggs in the future needs consideration.
... Embryonic mortalities assessed as a trait of the egg was moderately heritable at 0.16-0.22 (Brand, 2011), and responded to selection for chick production and live weight. Survival post-hatch constrains efficient ostrich production. ...
... 68, June 2012 THE HATCHABILITY OF ARTIFICIAL INCUBATED EGGS Artificial incubation is an integral part of the commercial ostrich production system, therefore an improvement of incubation has been the subject of many studies. Successful artificial incubation has been found to be affected by a number of factors including storage conditions and duration prior to setting, water loss from the egg during incubation and year-season effects of female age (Van Schalkwyk et al., 1999; Blood et al., 1998; Brand et al., 2007; Brand, 2011). ...
This paper summarises research on farmed ratites and their industries over the past 100 years. Commercial ratite products include meat, skins, feathers and oil. Research on ratites has attempted to enhance the quantity and quality of these products by focusing on the disciplines of breeding and genetics, reproduction and incubation, assisted reproduction, nutrition and animal welfare. Advances in these disciplines are discussed, and directions for future research are provided.
Animal developments and organogenesis is one of the most interesting branches
biological sciences. Anatomical changes are essential in developmental biology.
The aim of this study was to describe the histological development of ovaries and
germ cells in the ostrich embryo and newly hatched chicken. The research was
carried out on the ovaries of 20, 26, 30 and 36 days old embryos and newly
hatched ostrich chicken. At first anatomical observations of different stages was
performed. After tissue processing, sections were stained by Hematoxylin and
Eosin, Periodic Acid Schiff, Masson’s trichrome and immune histochemistry
staining methods. Some ovaries were embedded in Epon and 1µm thickness
sections were stained with toluidine blue, and examined using regular optical
microscopy. Ultra-thin sections were stained with uranyl acetate and lead citrate.
The latter sections were observed with transmission electron microscopy. The
results showed that like many other birds, ovaries had an asymmetrical growth
resulting into a larger left ovary with obvious cortex and medulla. Cortex
consisted of germinal cells and germinal epithelium along with somatic cells.
Cortex and medulla were dissociated by connective tissue. During development,
growing of the cortex in the left ovary was obvious and abundant vessels with
connective tissue were increased. In the right ovary cortex was not visible and the
germinal epithelium had a thin layer. Lacunar channels, blood vessels and
interstitial cells along with germ cells were present in the medulla of both ovaries.
The medullary germ cells were observed as solitary cells or groups of several
cells. Morphometrical analysis showed an increase in the volume of lacunar
channels after birth relative to the embryonic period. Electron microscopy
revealed that around hatching time the germ cell nuclei undergo the early stages of
meiotic prophase. In 36 days ostrich embryo some germ cell nuclei were seen in
meiotic phase. In the newly hatch germ cell nuclei were more electron lucent and
the nucleoli were reappeared, indicating meiosis was under arrest. This work is
the first study that pinpoints to the existence of specific organelles including
Balbiany body in ostrich germ cells. In conclusion, this report has documented the
histological changes and ultrastructural characteristics of ovarian germ cells in the
left and right ovaries from 20 to 36 days old embryos and newly hatched ostrich
chicks. Further studies will be required to characterize developmental procedures
in a more cellular and molecular levels. The result of this investigation is a basis
for further studies.
Participation in the ostrich supply chain for emerging farmers in the Eastern Cape is unsustainable as a result of avian influenza, control and registration protocols for ostriches (VPN04), structural barriers in marketing, technical constraints and a lack of market participation.
