No description available.

No description available.

Orientador: Irenilza de Alencar Nääs, Marta dos Santos Baracho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola / Made available in DSpace on 2018-08-20T11:48:14Z (GMT). No. of bitstreams: 1 Poderoso_FabianaMariaGoncalvesdeLima_M.pdf: 1087757 bytes, checksum: 1db07cd336e1192d99ffb8537b7a5e02 (MD5) Previous issue date: 2011 / Resumo: No Brasil, a avicultura é uma atividade relativamente nova, apesar de ter seu início na década de 30, como atividade fornecedora de subproduto, o esterco para os cafezais, se tornando uma atividade econômica produtora de proteína de alto valor biológico, somente a partir da década de 60. Hoje ocupa um lugar privilegiado na economia mundial devido ao trabalho de muitos profissionais ligados à atividade, sendo os principais pontos que ocorreram grandes melhorias: avanço tecnológico nas áreas de produção, nutrição e sanidade, permitindo uma melhora significativa nos índices zootécnicos. O incubatório é o local onde se obtêm o produto final, ou seja, do pintainho de um dia, tem a responsabilidade de disponibilizar aos produtores, pintos de qualidade para maximizar o desempenho das aves a campo. O presente trabalho teve como objetivo geral avaliar a influência da temperatura e da umidade relativa do ar no ambiente do incubatório, sobre as respostas da taxa de eclosão durante o processo de incubação e nascimento. Os dados de temperatura e umidade relativa do ar foram registrados em uma das salas das incubadoras e em uma das salas de nascedouro do Incubatório São José no município de Amparo - SP e analisados com relação ao índice de eclosão dos ovos incubados que foi analisado no dia do nascimento dos pintos. Foram rastreadas 48 bandejas, tendo capacidade de 96 ovos cada bandeja, até o nascimento desses pintos, sendo estas divididas seis quadrantes na incubadora sendo oito bandejas em cada quadrante classificadas como lotes e após foram monitoradas na sala de nascedouro que foi dividida em quatro quadrantes. Os dados foram submetidos à análise estatística descritiva por lote e análise de comparação de médias, através do teste F na ANOVA e do teste não-paramétrico de Kruskal-Wallis. Os resultados obtidos foram: a temperatura do ambiente influenciou o descarte total de ovos no 14º dia de incubação (de 35.9ºC à 37.0°C) e no 21º de incubação (de 37,0 °C à 37,3 °C) e, comparados com a idade das matrizes (42 semanas e 56 semanas), identificou-se que a matriz mais velha obteve maior número de descartes nas variáveis analisadas como: ovos inférteis, mortalidade de 0 a 7 dias e ovos quebrados, a serem o volume maior do total de ovos descartados. E, somente houve influência da umidade relativa do ar aos 21 dias de incubação ( de 52,2% à 62%). Conclui-se que houve influência do ambiente térmico e da idade da matriz no descarte total de ovos no processo de incubação / Abstract: Poultry science is responsible for studying the birds. In Brazil poultry production is a relatively new activity, although had its beginning in the 30's decade as an activity that supplied waste which was used in coffee production. It became an economical activity that produces protein of high biological value just after the decade of 60. Today Brazil occupies a privileged place in the world's economy due to the work of several professionals connected to this activity. The areas were the greatest technological improvements occurred are: production, nutrition and health, allowing significant enhancement in animal production indexes. The hatchery is the place where the final product is obtained, the one day old pullet, and that has the responsibility of given the producers high quality chicks in order to maximize their performance in the field. The objective of this research is to evaluate the influence of ambient temperature and relative humidity of the air in the hatchery on the response during the process in both incubator and hatcher. Air temperature and relative humidity data will be registered in a incubator and hatcher at the Incubatório São José, county of Amparo - SP and they will be analyzed with relation to the hatcher index at the first day. Forty eight trays with 96 eggs each were screened trays until the birth of these chicks. The hatchery was divided in six quarters and eight incubator trays in each quadrant were classified as lots and they were monitored after the hatcher room, which was divided into four quadrants. The data were analyzed by descriptive statistics and analysis of batch mean comparison, using the F test in ANOVA and nonparametric Kruskal-Wallis. The obtained results were: the temperature of the environment influenced the discarding total egg on day 14 of incubation and 21 of incubation and compared with age of the array, we identified that it took the variables as: infertile eggs, mortality 0-7 days and broken eggs, to be the bulk of total eggs discarded. There was only influence of relative humidity at 21 days of incubation. It is concluded that there was influence of thermal environment and age of female breeder in total egg discarding in the process of incubation / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

Ostriches are an important commercial species in South Africa and are becoming increasingly so in other parts of the world. Fertility and hatchability of artificially incubated ostrich eggs, however, is generally regarded as low compared to other poultry species and to ostriches in the wild. Investigation into specific farming practices at present indicated scope for an overall improvement in productivity through a sound breeding strategy. This thesis investigated factors that affect egg production, fertility, and hatchability of artificially incubated eggs in the Little Karoo region of South Africa. Specific breeding pair combinations accounted for the major variations in egg weight, hatchability, chick production and offspring weight at slaughter age. An appreciable proportion of variation in reproductive traits was attributable to the repeatable nature of breeding pair performance from year to year, even from first breeding attempts, suggesting that selection of good breeding stock can be made from an early age. Artificially incubated eggs showed improved hatchability when eggs were collected two to three hours after lay rather than the following morning. Storing position of eggs did not significantly effect hatchability when eggs were stored for a maximum of one week. The critical zero temperature for ostrich eggs, below which no embryonical development takes place, was found to be ± 25°C and cooling eggs to temperatures below 20°C for complete cessation of embryonic development during storage resulted in better hatchabilities compared to eggs stored at 25°C room temperature. Hatchability decreased when incubator temperatures were raised from 36 to 37.3°C. Large temperature fluctuations and gradients, which encompass detrimental temperatures, persist within forced draught wooden incubators of the type most commonly in use in the Little Karoo region. The highest temperatures occurred at the top of these incubators and will consequently have a negative impact on hatchability. The ontogeny of ostrich egg metabolism showed an exponential increase during the first 70% of incubation followed by a decline to 75% of the peak value between days 31 and 38 of incubation. From peak levels of embryonic development it was calculated that single stage incubators needs an airflow of 54.4 1/egg.hour to maintain oxygen levels just below 21% and carbon dioxide levels below 0.5%. Lower embryonic mortalities were observed when eggs were turned twenty-four times/day in an electronic incubator compared to hand turning twice a day. Eggs rotated through increasing angles between 60 and 90° resulted in a linear improvement in hatchability. In incubators where turning angles were fixed at 60°, lower hatchabilities were overcome by incubating eggs for 2 - 3 weeks in a horizontal position before placing them vertically. No specific farming practice could be singled out as the main cause of low fertility or hatchability but rather a combination of certain practices applied wrongly.

Thesis (M.Sc. (Animal production)) --University of Limpopo, 2011 / A study was conducted to examine the effect of protein level of the diet of Naked neck hens on egg production, hatchability and chick productivity. The first part of the experiment determined the effect of protein level on feed intake, number of eggs produced, egg weight, egg white nitrogen content, egg yolk nitrogen content, egg hatchability and chick hatch-weight. A total of 25 hens aged 30 weeks were confined in cages and fed diets differing in protein content. A complete randomized design, comprising of diets differing in protein levels (P12.94%, P13.94%, P14.38%, P15.75% and P18.13% CP), replicated five times with one hen in each replicate was used. Semen was collected from one cock to fertilize all hens. Protein level had an effect on (P<0.05) feed intake and egg white nitrogen content. However, protein level of the diet of hens had no effect(P>0.05) on the number of eggs produced, egg white nitrogen content, egg yolk,egg weight, egg hatchability and chick hatch-weight. Quadratic analyses indicated that feed intake, number of eggs produced, egg weight, egg white nitrogen content, egg yolk nitrogen content, hatchability and chick hatch-weight were optimized at different protein levels of 14.7 (r2 = 0. 623),14.9 (r2 = 0.568),13.9 (r2 = 0.094), 18.2 (r2 = 0.563), 15.1(r2 = 0.424), 15.9 (r2 = 0.451) and 15.9 %(r2 = 0.898) , respectively. The second part of the experiment determined the effect of protein level of hens on productivity of their progenies from a day old up to 13 weeks of age. A total of 95 chicks hatched from the first part of the study were assigned to 20 floor pens according to the number of chicks hatched. Chicks had an average initial live weight of 35 ± 2 g per bird. The chicks were fed the same commercial grower diet and fresh water ad libitum up to seven weeks of age. Protein level of the diet of Naked neck hens had an effect (P<0.05) on feed intake, live weight and feed conversion ratio of chicks from a day old up to seven weeks of age. However, protein level of the diet of Naked neck hens had no effect (P>0.05) on growth rate and mortality of chickens from a day old to seven weeks of age. Feed intake, feed conversion ratio, growth rate and mortality of chickens were optimized atdifferent protein levels of 15.8 (r2 = 0.298), 16.1 (r2 = 0.236), 16.1 (r2 = 0.077) and 14.3 % (r2 = 0.617), respectively. Protein level of the diet of Naked neck hens had no effect (P>0.05) on feed intake, growth rate and feed conversion ratio of both their male and female progenies between eight and 13 weeks of age. Protein levels of the diet of hens had an effect (P<0.05) live weight of their male progenies and carcass weights of both their male and female progenies at 13 weeks of age. However, the level of protein of the diet of hens had no effect (P>0.05) on live weight of their male progenies, and breast meat yield, breast meat nitrogen content and fat pad weight of both their male and female progenies at 13 weeks of age. Live weight,breast meat yield, breast meat nitrogen content and fat pad weight of their male progenies at 13 weeks of age were optimized at different protein levels of the diets of hens of 18.9 (r2 = 0.666), 15.6 (r2 = 0.081), 15.4 (r2 = 0.786) and 17.7 %(r2 = 0.775), respectively. Similarly, live weight, carcass weight, breast meat yield, breast meat nitrogen content and fat pad weight of their female progenies at 13 weeks of age were optimized at different protein levels of 15.7 (r2 = 0.294),15.4 (r2 = 0.180), 15.8 (r2 = 0.059), 15.1 (r2 = 0.882) and 16.1 % (r2 = 0.405), respectively. It is concluded that protein level of the diet of the hen may affect its productivity and that of its progeny. However, the calculated protein levels for optimum productivity will depend on the production parameter in question. / National Research Foundation

Orientadores: Irenilza de Alencar Naas, Marta dos Santos Baracho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-10T18:24:30Z (GMT). No. of bitstreams: 1 Gigli_AnaCarolinadeSouza_M.pdf: 14015756 bytes, checksum: 3ff5e92049fc702484a226f1115b5db2 (MD5) Previous issue date: 2007 / Resumo: Sendo o incubatório um ambiente comum à cadeia avícola e que fatores relacionados à incubação podem influenciar o desempenho e crescimento de frangos de corte, é importante que o ambiente do incubatório tenha manejo adequado e seja homogêneo. Considerando a carência de informações sobre ambiência em incubação de ovos de matrizes pesadas, este trabalho levanta a hipótese de que o conhecimento das variáveis ambientais em incubatório permite o controle mais adequado da produção. Foram monitorados lotes de ovos férteis de duas linhagens de matrizes pesadas em incubatório comercial, verificando variáveis ambientais tais como: temperatura, velocidade do ar, umidade relativa, concentração de dióxido de carbono e concentração de fungos no interior e exterior dos equipamentos do incubatório para estabelecimento de correlação com dados de eclodibilidade e qualidade de pintinhos de um dia. Não foram apontados pontos de heterogeneidade no interior das máquina de incubação para as variávies coletadas. Os resultados apontam que o baixo desempenho produtivo está relacionado com baixa temperatura nas máquinas de incubação. 98 % e 90 % dos dados de temperatura registrados estavam abaixo do que é recomendado na incubadora e no nascedouro, respectivamente. Queda no desempenho também foi atribuída à umidade relativa e à concentração de dióxido de carbono. Quanto à qualidade sanitária, o nascedouro foi apontado como ponto crítico e apresentou alta concentração de unidades formadoras de colônias de Aspergillus fumigatus. Todas as salas do incubatório apresentaram baixo nível de contaminação que, no entanto, foi apontado como principal indicador de redução de produtividade e qualidade, o que indica iminente replanejamento dos programas de biosegurança para incubatórios de frango de corte / Abstract: Since the hatchery house is a common environment to the poultry chain, and factors related to incubation can have influence both broiler chicken development and growth, it is important to provide adequate handling and homogeneous environment. Considering the lack of information on the environment about broiler chicken incubation, this research investigated that environmental conditions knowledge, in hatchery houses allows a better control of the production. Subsequently, flocks of fertile eggs from different breeder strains have been monitored in a commercial hatchery house, in order to verify environmental variables such as: temperature, air velocity, relative humidity, carbon dioxide production, fungi concentration, inside and outside the hatchery equipments, and how they are correlated with hatchability and one-day-old chick quality. No heterogeneity was found inside hatchery machines regarding all the studied environmental variables. The results pointed that low productive performance is related with incubation equipments low temperature. 98.0 % and 90.0 % registered temperature data was under recomendated values inside both setter and hatcher. Performance decrease was also related to high relative humidity and high carbon dioxide concentration. Results concerning sanitary quality indicated hatcher room as a hatchery critical point due to high level of contamination by Aspergillus fumigatus colonies forming unities. Moreover, the monitored hatchetry rooms as a role presented contamination levels which may play the role of main indicator of negative impact over production and one-day-old chickling quality so that indicates eminet improvement of the biosecurity programs for broiler chicken hatchery house / Mestrado / Construções Rurais e Ambiencia / Mestre em Engenharia Agrícola

Thesis (MSc. Agriculture (Animal Production)) -- University of Limpopo, 2015 / Three experiments were conducted to determine the effect of in ovo glucose injection on egg hatchability, chick hatch-weight, productivity and carcass characteristics of indigenous Potchefstroom koekoek chickens. A complete randomized design was used in all the three parts of the study (from incubation, 1-49 days old unsexed chickens and 50-91 days old female chickens). On day 18 of incubation the developing eggs were subjected to the following treatments: 0- (no glucose or water injected), 0+ (only water injected), 5, 10, 15 or 20 mg of glucose per egg. Each treatment had three replications and there were 20 eggs per replicate. A quadratic model was used to determine in ovo glucose injection levels for optimal egg hatchability, chick hatch-weight and chick to egg weight ratio of Potchefstroom koekoek chickens. In ovo glucose injection improved (P<0.05) egg hatchability, chick hatch-weight and chick to egg weight ratio of the chickens. Egg hatchability, chick hatch-weight and chick to egg weight ratio Potchefstroom koekoek chickens were optimized at different injection levels of 4.50, 10.43 and 12.00 mg of glucose per egg, respectively. Unsexed day-old chicks from the first experiment (according to their initial treatments and replicates) were used in a complete randomized design having six treatments, replicated three times, and having ten birds per replicate. Glucose injection levels increased (P<0.05) feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention of female Potchefstroom koekoek chickens aged 1 to 49 days. However, growth rate, live weight, metabolisable energy intake and nitrogen retention of the chickens were optimized at glucose injection levels of 3.92, 4.36, 10.67 and 13.50 mg per egg, respectively. Female chickens from the second part of the study (according to their initial treatments and replicates) were used in a complete randomized design having six treatments, replicated three times, and having five birds per replicate. In ovo glucose injection levels improved (P<0.05) on feed intake, growth rate, feed conversion ratio, live weight, metabolisable energy and nitrogen retention of female Potchefstroom koekoek chickens aged 50 to 91 days. However, only feed conversion ratio and metabolisable energy intake of the chickens were optimized at glucose injection levels of 12.15 and 5.57 mg per egg, respectively. Injection level also improved (P<0.05) carcass, breast, v drumstick, thigh, wing, gizzard and liver weights of female Potchefstroom koekoek chickens aged 13 weeks. In ovo glucose injection increased (P<0.05) breast meat tenderness, juiciness and flavour of female Potchefstroom koekoek chickens aged 91 days. However, breast tenderness, juiciness and flavour of female Potchefstroom koekoek chickens were optimized injection levels of 13.50, 19.25 and 10.83 mg of glucose per egg, respectively. No chicken deaths were observe

Thesis (M. Tech. (Agriculture)) - Central University of Technology, Free state, 2013 / The objectives of the study were to find the relationship between live performance and testis traits of South African indigenous cockerels on Naked Neck, Ovambo and Potchefstroom Koekoek (Trial 1). Characterise Naked Neck, Ovambo and Potchefstroom Koekoek cockerels’ semen macroscopically and microscopically (Trial 2). To investigate the relationship between phenotypic and sperm traits of the South African indigenous cockerels Naked Neck, Ovambo and Potchefstroom Koekoek. (Trial 3). Quantification of indigenous cockerels sperm traits measured by Computer Assisted Sperm Analysis (CASA) technology and the relationship to fertility (Trial 4). The cockerels shank, comb and wattle length were recorded with a vernier calliper. A total of 198 ejaculates were collected from 33 cockerels; Ovambo (n=11), Potchefstroom Koekoek (n=11) and Naked Neck (n=11) by means of an abdominal massage technique. Following analysis, 0.25 ml undiluted semen dose from Naked Neck (NN, 11), Ovambo (OV, 11) and Potchefstroom Koekoek (PK, 11) cockerels were inseminated NN (30), OV (30) and PK (30) hens once per week for 6 weeks. Semen was analysed macroscopically and microscopically. The sperm motility rate was evaluated with the aid of the Computer Assisted Sperm Analysis (CASA) called Sperm Class Analyser (SCA) system. Breed significantly (P< 0.05) affected the body weight of Ovambo (2.5±0.4kg), Naked Neck (2.0±0.3kg) and Potchefstroom Koekoek (2.3±0.3kg) cockerels, OV was statistically heavier than NN and PK. The semen volume of Naked Neck (0.5±0.2ml) breed was significantly higher, when compared to Ovambo (0.4±0.2ml), but similar to Potchefstroom Koekoek (0.3±0.2ml) breed. The overall sperm motility rate of Ovambo (95.0±7.2%), Potchefstroom Koekoek (86.0±13.7%) Naked Neck (76.4±22.2%) group was significantly different. The normal sperm morphology in the Naked Neck (76.4±22.2%) was significantly lower when compared to Potchefstroom Koekoek (86.0±13.7%) and Ovambo (95.0±7.2%) cockerels. A positive correlation existed between body weight and semen volume for Potchefstroom Koekoek (r=0.1477) cockerels only. Moreover, there was a positive correlation between the body weight and total sperm motility for Naked Neck (r=0.3848), Ovambo (r=0.4871) and Potchefstroom Koekoek (r=0.2230) cockerels. However, a negative correlation existed between body weight and semen volume for Naked Neck (r=-0.4502) and Ovambo (r=-0.1244). There was no significant differences (P>0.05) on the shank length (SL), comb length (CL) and wattle length WL) of Naked Neck (8.4, 5.4 and 5.6 cm), Ovambo (8.3, 5.8 and 6.0 cm) and Potchefstroom Koekoek (7.7, 5.9 and 5.6). There was a positive correlation between shank length and wattle length, comb length, semen volume, sperm concentration, semen pH and live normal sperm, inversely, a negative correlation of body weight and total sperm motility was observed. Introspective a negative correlation existed between body weight and total motility. Ovambo (11.45±0.9 g) had the highest live weight of testis, it was significantly different from Naked Neck (9.2±0.8g) and Potchefstroom Koekoek (8.9±0.8 g). For average length of the testis there was a significant difference amongst all breeds, Ovambo (4.0±0.5 cm), Naked Neck (3.4±0.3 cm) and Potchefstroom Koekoek (3.7±0.4 cm). Following Al, significant differences were recorded in Potchefstroom Koekoek and produced eggs that had highest average egg weight (55.5 g), fertility (68.2 %), hatchability (78.6 %), percentage of normal chicks (80.1%) and chick weight (37.9 g) compared to Ovambo (40.4 g, 5 2.1 % , 70.2 %, 71.5 %, 32.8 g and Naked Neck (37.1 g, 50.6 %, 71.1 %, 75.8 % and 23.5 g). In order to achieve the highest level of fertility and hatched of fertile eggs, an adequate number of active males that are producing high quality semen should be maintained in the breeder house at all times. In conclusion, body weight positively affected semen volume and sperm motility rate but this was breed dependent. The Sperm of Potchefstroom Koekoek and Ovambo resulted in a better motility and morphology rate. The Sperm Class Analyser or CASA provided more precise, repeatable and objective information. Evaluation of the sperm motility rate of South African indigenous cockerels holds potential for future use in semen evaluation. Body weight of all three indigenous breeds was positively correlated with sperm concentration, semen pH, and total sperm motility. Shank and wattle length of all three indigenous breeds were positively correlated with semen volume, sperm concentration, and semen pH but not with total sperm motility. However, comb length was positively correlated with semen volume and pH, sperm concentration, and total motility. In conclusion, there is no correlation between live performance and testis traits. Though the study suggests that body weight and testicular length are good indicators of sperm production. Simple and indirect method of estimation is still needed to predict the fertility of the breeding cockerels. In order to achieve the highest level of fertility and hatch of fertile eggs, an adequate number of active males that are producing high quality semen should be maintained in the breeder house at all times. The Potchefstroom Koekoek, Ovambo and Naked Neck donated quality semen as well as in improving the fertility and hatchability traits of the indigenous chicken breeds. Chicken hatched from larger eggs had higher body weight, hatchability and fertility therefore breeders should select bigger egg sizes probably of 50-55g for breeding programmes. Consequently, the local cockerels have higher potential for use in natural mating and Al programmes since seminal traits could be a viable index for selection of breeding cockerels.

Thesis (PhD(Agric))--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The ostrich industry experiences high rates of embryonic mortalities during artificial incubation of eggs. Studies have been carried out to investigate factors influencing hatchability, as well as determining genotypic effects for commercial production. Eggs from the combination of South African Black (SAB) male ostriches crossed with Zimbabwean Blue (ZB) female ostriches 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%). Female age had a significant effect on the proportion of chicks pipped, as well as on early and late the embryonic mortalities. Chicks from eggs stored for intermediate periods, i.e. 3, 4 and 6 days prior to being set, were more likely to pip than chicks from those eggs set directly after collection without storage. Embryonic mortality was increased in eggs that were set directly (32.0%) or subjected to longer than 6 days of storage (43.5%). Chicks that pipped in the correct position had a higher probability of successfully hatching than those pipping in the incorrect position. Transfer of eggs between setters (i.e. disturbance of eggs) during incubation reduced the number of ostrich chicks pipping in the correct position. Incubated ostrich eggs with intermediate levels of water loss, i.e. between 9.0 and 19% of fresh egg weight, were more likely to pip in the correct position than those with higher or lower levels of water loss. Such eggs were also less likely to sustain early, late or overall embryonic mortalities. To optimise hatching success it is important to understand embryonic development. After 2 days of incubation the blastoderm area in eggs from the SAB x ZB crosses (104.5 mm) was lower (P < 0.05) compared to the pure SAB (141.0 mm), pure ZB (161.7 mm) and ZB x SAB crosses (166.1 mm). For embryos incubated for 7 to 42 days, both embryonic and leg growth during the 42 days of incubation was similar and approximately linear, more or less doubling in size up to 35 days of incubation. The embryo eye size increased more rapidly than beak length and reached full size of approximately 16.2 mm by 28 days of incubation, whereas the beak length continued to increase until the chick hatched at 42 days. Incubation position, vertical or horizontal, did not affect any of the measurements of the developing embryo throughout the 42-day incubation period. Air cell volume at 29 day of incubation for infertile eggs (19.3%) was significantly (P < 0.05) higher when compared to dead-in-shell eggs (14.3%) and eggs that hatched successfully (13.8%). Air cell volume was largely independent of strain (SAB or ZB) and whether chicks were assisted to hatch or not. After 41 days of incubation there was a significantly greater (P < 0.05) air cell volume in eggs that hatched normally compared to dead-in-shell eggs (28.3% vs. 21.7%, respectively, suggesting that insufficient water loss contributed to reduced survival. This study provides an insight into the complexity of embryo development and all the factors playing a role in successful hatching of ostrich eggs. Data from a pair-mated ostrich flock 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). Single-trait estimates of heritability (h2) were high and significant (P < 0.05) at 0.46 for EWT, 0.34 for CWT, 0.34 for WL21, 0.27 for WL35 and 0.16 for pipping time. Genetic correlations with EWT amounted to -0.21 for WL21 and to -0.12 for WL35. Corresponding correlations of CWT with WL were highly significant (P < 0.05) at -0.43 and -0.54. Physical characteristics of the eggshell were found to affect water loss and hatchability. Estimates of genetic parameters of 14 146 ostrich eggs for eggshell traits showed that heritability was 0.42 for pore count (PC), 0.33 for shell thickness (ST) and 0.22 for permeability (PERM). PC was negatively correlated with average pore diameter (-0.58) and ST (-0.23), while PC was positively correlated with total pore area (0.58), WL21 (0.24) and WL35 (0.34). The correlations of PC with total pore area and PERM were high and significant. ST was negatively correlated to WL21 and WL35. Additive genetic parameters strongly indicate that it should be possible to alter evaporative water loss and eggshell quality of ostrich eggs through genetic selection. When assessed as a trait of the individual egg or chick, embryonic mortalities exhibited moderate levels of genetic variation both on the normal scale (h2 = 0.16 - 0.22) and the underlying liability scale (h2 = 0.21 - 0.31). Early embryonic survival and late embryonic survival was governed mostly by the same genes (rg = 0.78). Late embryonic survival was genetically correlated to WL35, at -0.22. It was concluded that embryonic survival could be improved by using husbandry measures, a knowledge of the stage when incubation mortalities occur, and by genetic selection, using an integrated approach. Findings from this study will help to understand the mechanisms involved in hatching from artificial incubation better to improve hatchability and also implement selective breeding programs. / AFRIKAANSE OPSOMMING: Die volstruisbedryf ondervind tans ‘n baie hoë voorkoms van embrionale mortaliteite tydens die kunsmatige uitbroei van eiers. Studies is uitgevoer om die faktore wat uitbroeibaarheid beinvloed te ondersoek en om genotipiese effekte te bepaal vir kommersiële produsente. Eiers van die kombinasie van Suid-Afrikaanse swart (SAB) mannetjie volstruise, met Zimbabwean blou (ZB) wyfies, het embrionale mortaliteite van 45.7% gehad. Embrionale mortaliteite van eiers gelê deur suiwer SAB of ZB volstruise was dieselfde op omtrent 33 - 34%, maar embrionale mortaliteite was laer vir eiers geproduseer deur SAB wyfies wat gekruis was met ZB mannetjies (27%). Wyfie ouderdom het ‘n betekenisvolle effek gehad op die proporsie van kuikens wat gepik het, asook die aantal vroeë- en laat embrionale mortaliteite. Kuikens vanuit eiers wat vir die periode 3, 4 dae en 6 dae voor pak in die broeikaste gestoor is, was meer geneig om te pik as kuikens vanaf eiers wat direk na kolleksie gepak is. Embrionale mortalitiete het verhoog vir eiers wat direk na kolleksie gepak was (32.0%) of vir eiers wat langer as 6 dae gestoor was (43.5%). Kuikens wat in die korrekte posisie pik het ‘n hoër kans op uitbroei gehad as kuikens wat in die verkeerde posisie gepik het. Die skuif van eiers tussen verskillende broeikaste (of enige steurnisse) gedurende die broeiproses het ‘n verlaging in die aantal kuikens wat in die korrekte posisie pik, gehad. Volstruiseiers met ‘n gemiddelde vogverlies van tussen 9.0 en 19% van die vars eier massa, was meer geneig om in die korrekte posisie te pik as eiers met laer of hoër vlakke van vogverlies. Sulke eiers was ook minder geneig tot vroeë, laat en totale embrionale mortaliteite. Vir optimale uitbroeisukses is dit belangrik om die ontwikkeling van die embrio te verstaan. Na 2 dae van broei was die blastoderm area in eiers van SAB x ZB kruisings (104.5 mm) kleiner (P < 0.05) as die blastoderm area van suiwer SAB (141.0 mm), suiwer ZB (161.7 mm) en ZB x SAB kruise (166.1 mm). Beide embrionale- en beengroei tydens die 42 dae broeiproses was dieselfde en nagenoeg lineêr, met ‘n verdubbeling in grootte tot en met 35 dae broei. Die embrio se oog vergroot vinniger as wat die snawel verleng en bereik reeds volle grootte van ongeveer 16.2 mm op 28 dae van broei, terwyl die snawel aanhou groei tot uitbroei van die kuiken op 42 dae. Nie die vertikale of horisontale broeiposisie het enige invloed op die metings van die ontwikkelende embrio tot op 42 dae gehad nie. Lugsakvolume vir geil eiers (19.3%) op 29 dae van broei was groter (P < 0.05) as beide die lugsakke van eiers wat dood-in-dop (14.3%) en eiers wat suksesvol uitgebroei het (13.8%). Die lugsakvolume was onafhanklik van beide genotype en of die kuiken met of sonder hulp uitgebroei het. Na 41 dae broei was lugsakvolume groter (P < 0.05) vir eiers wat uitgebroei het teenoor eiers wat dood-in-dop was (28.3% vs. 21.7%, onderskeidelik), wat impliseer dat onvoldoende vogverlies moontlik kan bydrae tot ‘n verlaging in embrionale oorlewing. Hierdie studie gee ‘n insig in die kompleksiteit van embrionale ontwikkeling en al die faktore wat ‘n rol speel in die suksesvolle uitbroei van volstruiseiers. Tydens die bepaling van genetiese parameters vir spesifieke uitbroei-eienskappe in volstruise, is data gebruik afkomend van ‘n teelkudde in ‘n enkelparing stelsel om genetiese waardes vir eiermassa (EWT), dagoud kuikenmassa (CWT), vogverlies tot 21 dae broei (WL21), vogverlies tot 35 dae broei (WL35) en piktyd (PT) gebruik. Enkeleienskap-beraming vir oorerflikheid (h2) was hoog en betekenisvol teen 0.46 vir EWT, 0.34 vir CWT, 0.34 vir WL21, 0.27 vir WL35 en 0.16 vir piktyd. Genetiese korrelasies met EWT was -0.21 vir WL21 en -0.12 vir WL35. Ooreenkomstig was korrelasies van CWT met WL21 en WL35 hoog (P < 0.05) met -0.43 en -0.54 onderskeidelik. Fisiese eienskappe van die eiers het beide vogverlies en uitbroeibaarheid beinvloed. Beramings van genetiese parameters vir 14 146 volstruiseiers se dopeienskappe het gewys dat oorerflikehid 0.42 was vir die aantal porieë (PC), 0.33 vir dopdikte (ST) en 0.22 vir deurlaatbaarheid (PERM). PC was negatief gekorreleerd met gemiddelde porieë deursnee (-0.58) en ST (-0.23), terwyl PC positief gekorreleerd was met totale porieë area (0.58), WL21 (0.24) en WL35 (0.34). Die korrelasie van PC met totale porieë area en deurlaatbaarheid was hoog en betekenisvol. ST was negatief gekorreleerd met WL21 en WL35. Additiewe genetiese parameters het sterk daarop gedui dat dit moontlik sou wees om vogverlies en eierkwaliteit (bv. dopkwaliteit en poreusiteit) van volstruiseiers te verander deur genetiese seleksie. Indien embrionale mortaliteit geevalueer word as ‘n kenmerk van die eier of kuiken, toon dit matige vlakke van genetiese variasie op beide die normale (h2 = 0.16 - 0.22) en die onderliggende skale (h2 = 0.21 - 0.31). Beide vroeë- en laat embrionale oorlewing word deur dieselfde stel gene beheer (rg = 0.78). Laat embrionale oorlewing was geneties gekorreleerd met WL35 teen -0.22. Die gevolgtrekking was dat embrionale oorlewing verbeter kan word deur verbeterde broeikamerpraktyke, kennis van op watter stadium van ontwikkelings embrionale mortaliteite plaasvind en deur genetiese seleksie. Bevindinge vanuit hierdie studies sal help om die meganismes betrokke by die kunsmatige uitbroei van volstruiskuikens beter te verstaan om sodoende uitbroeibaarheid te verbeter en ook suksesvolle seleksie programme te implementeer.

Northern bobwhite populations have declined concurrent with global warming. The focal period of this study was the 12-d pre-incubation period, when bobwhite eggs remain in the nest without the thermal protection of the incubating parent. This study first established the storage and thermal limits of bobwhite eggs, then investigated how global warming may impact oviparous embryos and how bobwhite embryos react to acute and chronic doses of simulated drought temperatures during pre-incubation. First, the maximum storage limit of bobwhite eggs was determined by storing eggs &#8804;21 d and measuring hatching success and pH of egg albumen and yolk. Hatching success of stored eggs declined after 14 d, when yolk and albumen pH reached levels detrimental to embryonic development. Secondly, thermal limits were determined by exposing bobwhite eggs to hyperthermic temperatures (38-52 °C). Bobwhite embryos survived 50 °C for 1 h, 49 °C for 3 h and 46 °C for 6 h. Results indicate an adaptation to the naturally occurring temperature extremes that can occur in the bobwhite's southern range during pre-incubation. Subsequently, bobwhite eggs were exposed to either low constant (LC), low fluctuating (LF), high constant (HC), or high fluctuating (HF) temperatures during pre-incubation to determine if the nature of temperatures differentially affected development. Although eggs exposed to high heat loads (HC and HF), and low heat loads (LF and LC) had equal heating degree-hours within groups, they exhibited differential growth during pre-incubation. Oxygen consumption, hatch timing, and hatching success were also affected by the thermal regimes. Eggs in simulated drought (HF) had a 47% lower hatch rate than eggs in simulated non-drought (LF) indicating that thermal stress during pre-incubation may contribute to population declines during drought. Finally, northern bobwhite eggs were exposed to acute or chronic doses of simulated drought temperatures, which tested for critical periods of development during pre-incubation. Collectively, data indicated that the earliest stages of bobwhite development were more affected by hyperthermic temperatures. Indeed, a critical period of development exists during the first 2/3 of pre-incubation during which exposure to hyperthermic temperatures results in aberrant development, hatching plasticity, and reduced hatch rates.