Faktore wat die oorlewing van volstruiskuikens (Struthio Camelus) verhoog
- Authors: Janse Van Vuuren, Maryke
- Date: 2008
- Subjects: Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MTech
- Identifier: vital:10588 , http://hdl.handle.net/10948/848 , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Description: Hierdie verhandeling is ‘n samestelling van verskeie studies, elk opgeskryf in die formaat en styl soos vereis deur die Suid-Afrikaanse Vereeniging vir Diereproduksie (South African Society of Animal Science). Hoofstuk 1 is ‘n literatuurstudie bestaande uit ‘n algemene inleiding wat agtergrond oor die studie verskaf en sluit die probleemstelling in, naamlik die swak oorlewing van volstruiskuikens wat onder kunsmatige toestande grootgemaak word. Hoofstukke 2, 3, 4 en 5 bestaan uit die eerste vier studies, waartydens sekere bestuurs-aspekte, wat moontlik oorlewing van volstruiskuikens kan verbeter (nl: populasiedigtheid, tipe vloer-oppervlak, die aanwending van broeipare en die aanwending van peetouers), ondersoek is. Hoofstukke 6, 7, 8 & 9 handel oor studies wat gerig is om voeding meer aanloklik te maak vir volstruiskuikens teneinde voedselinname te stimuleer en sodoende produksie en oorlewing te verbeter (nl: verskaffing van groenvoer, geur van voer, kleur van voer en beligting van voer). Die laaste hoofstuk bestaan uit ‘n algemene gevolgtrekking en aanbevelings. Alhoewel daar gepoog is om herhaling in hoofstukke te beperk, was dit onmoontlik om herhaling van sekere gedeeltes van hoofstukke te voorkom.
- Full Text:
- Date Issued: 2008
- Authors: Janse Van Vuuren, Maryke
- Date: 2008
- Subjects: Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Language: Afrikaans
- Type: Thesis , Masters , MTech
- Identifier: vital:10588 , http://hdl.handle.net/10948/848 , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Description: Hierdie verhandeling is ‘n samestelling van verskeie studies, elk opgeskryf in die formaat en styl soos vereis deur die Suid-Afrikaanse Vereeniging vir Diereproduksie (South African Society of Animal Science). Hoofstuk 1 is ‘n literatuurstudie bestaande uit ‘n algemene inleiding wat agtergrond oor die studie verskaf en sluit die probleemstelling in, naamlik die swak oorlewing van volstruiskuikens wat onder kunsmatige toestande grootgemaak word. Hoofstukke 2, 3, 4 en 5 bestaan uit die eerste vier studies, waartydens sekere bestuurs-aspekte, wat moontlik oorlewing van volstruiskuikens kan verbeter (nl: populasiedigtheid, tipe vloer-oppervlak, die aanwending van broeipare en die aanwending van peetouers), ondersoek is. Hoofstukke 6, 7, 8 & 9 handel oor studies wat gerig is om voeding meer aanloklik te maak vir volstruiskuikens teneinde voedselinname te stimuleer en sodoende produksie en oorlewing te verbeter (nl: verskaffing van groenvoer, geur van voer, kleur van voer en beligting van voer). Die laaste hoofstuk bestaan uit ‘n algemene gevolgtrekking en aanbevelings. Alhoewel daar gepoog is om herhaling in hoofstukke te beperk, was dit onmoontlik om herhaling van sekere gedeeltes van hoofstukke te voorkom.
- Full Text:
- Date Issued: 2008
The effect of different slaughter age regimes on the primary and secondary production parameters of Ostriches (Struthio Camelus Domesticus) and the economic consequences of different slaughter ages
- Authors: Bhiya, Clovis Solomon
- Date: 2006
- Subjects: Slaughtering and slaughter-houses -- South Africa , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10735 , http://hdl.handle.net/10948/837 , Slaughtering and slaughter-houses -- South Africa , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Description: The South African ostrich industry is presently characterised by a drastic decline in the slaughter price of slaughter birds, due to the drop in the price of meat as well as leather. As a result, the economic viability of ostrich farming is severely hampered by these developments, and many generally accepted industry practices have to be reviewed. Among the practices under review is the possibility of slaughtering ostriches at an earlier age than the traditional slaughter age of 12 - 14 months, in order to minimise feed costs and the incidence of damage to the skin. However, little information is available on the effect of the slaughter age on the yield and quality of the economically important end-products. The effect of slaughter age on production and the economic viability of a commercially intensive ostrich production system was consequently evaluated in a completely randomised experimental design involving two batches (n= 81 and n= 94) of ostriches. The experiments took place at Kromme Rhee experimental farm of the Elsenburg Research Centre near Stellenbosch. The birds were subject to experimental treatment at the age of 4 months (n= 81, from May 2004 to March 2005) and 6 months (n= 94, from August 2004 to August 2005) respectively. The ostriches were randomly divided into 10 groups of between 16 and 20 birds per group. Standard production practices, as applied in an intensive ostrich production unit, were implemented. Clean drinking water and self-mixed grower diet (min 15 percent crude protein, 0.68 percent lysine and 11.4 MJ ME per kg feed) and finisher diet (min 14 percent crude protein, 0.55 percent lysine and 9.8 MJ ME per kg feed) were provided ad libitum to the birds. Birds were slaughtered at the ages of 8.5, 10.5, 12.5, 14.5, and 16.5 months respectively. Data on feed intake and yields of cold carcass, crust skin size, skin grade and total feathers was recorded for birds slaughtered at the respective ages. Data was analysed according to the analysis of variances. Values for meat yield, skin size yield and feed intake were predicted by regression analysis based on experimental values. Industry figures and norms were used as proxy for other production inputs and costs. A gross margin type analysis was performed to evaluate the effect of different slaughter ages on the profitability of each production system. There was a positive correlation between age and feed intake (r2= 0.40), slaughter weight (r2= 0.97), cold carcass yield (r2= 0.48), skin surface area (r2= 0.39), skin grade (r2= 0.19) and total yield of feathers (r2= 0.29). The dry skin grade showed deterioration as slaughter age was prolonged. Highly significant differences (P< 0.01) in slaughter weight, cold carcass yield, skin surface area, dry skin grade and total feathers were detected at the different slaughter ages. There were no significant differences (P> 0.05) with respect to gender for slaughter weight, skin surface area and dry skin grade within the different age groups. Males had significantly higher (P< 0.05) cold carcass yield and total feather yield than their female counterparts. From this study it can be concluded that an increase in slaughter age significantly increases feed intake, slaughter weight, cold carcass yield, and skin surface area. It is also clear that an increase in slaughter age can be detrimental to dry skin grade. The relative income contribution of the three main products (skin: meat: feathers) occurred in a ratio of 47:53:0, 52:47:1, 47:50:3, 44:51:5, 39:56:5 at the respective slaughter ages. Total income revealed an increase of 26 percent from 8.5 to 10.5 months slaughtering, an increase of 4 percent between 10.5 and 12.5 months, and an increase of 11 percent between 12.5 and 14.5 months. The income dropped by 0.3 percent between 14.5 and 16.5 months slaughtering. Total costs increased with slaughter age, particularly feed costs which showed an increase (at a decreasing rate) between the different slaughter ages. The margin above specified cost per bird was the highest for birds slaughtered at the age of 10.5 months. The margin above cost showed a steady decline as birds were slaughtered at higher ages. Slaughtering at 16.5 months revealed a negative margin. To compare the effect of differences in time span on different slaughter age regimes, margin above costs for each system over 5 years were discounted to a present value. In this study, with current feed costs and income from end products, slaughtering at 10.5 months revealed the highest present value for the margin above cost. Furthermore, slaughtering at 16.5 months revealed a negative present value on the margin above cost after 5 years. Financial viability calculations are relevant and valid for data obtained in this case study. Financial viability is however case-specific and may vary between producers, depending on their individual management practices, production systems and cost structures. Results from this study may be of significant value to managerial decision-making in the ostrich industry.
- Full Text:
- Date Issued: 2006
- Authors: Bhiya, Clovis Solomon
- Date: 2006
- Subjects: Slaughtering and slaughter-houses -- South Africa , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10735 , http://hdl.handle.net/10948/837 , Slaughtering and slaughter-houses -- South Africa , Ostrich farming -- South Africa , Ostriches -- Breeding -- South Africa
- Description: The South African ostrich industry is presently characterised by a drastic decline in the slaughter price of slaughter birds, due to the drop in the price of meat as well as leather. As a result, the economic viability of ostrich farming is severely hampered by these developments, and many generally accepted industry practices have to be reviewed. Among the practices under review is the possibility of slaughtering ostriches at an earlier age than the traditional slaughter age of 12 - 14 months, in order to minimise feed costs and the incidence of damage to the skin. However, little information is available on the effect of the slaughter age on the yield and quality of the economically important end-products. The effect of slaughter age on production and the economic viability of a commercially intensive ostrich production system was consequently evaluated in a completely randomised experimental design involving two batches (n= 81 and n= 94) of ostriches. The experiments took place at Kromme Rhee experimental farm of the Elsenburg Research Centre near Stellenbosch. The birds were subject to experimental treatment at the age of 4 months (n= 81, from May 2004 to March 2005) and 6 months (n= 94, from August 2004 to August 2005) respectively. The ostriches were randomly divided into 10 groups of between 16 and 20 birds per group. Standard production practices, as applied in an intensive ostrich production unit, were implemented. Clean drinking water and self-mixed grower diet (min 15 percent crude protein, 0.68 percent lysine and 11.4 MJ ME per kg feed) and finisher diet (min 14 percent crude protein, 0.55 percent lysine and 9.8 MJ ME per kg feed) were provided ad libitum to the birds. Birds were slaughtered at the ages of 8.5, 10.5, 12.5, 14.5, and 16.5 months respectively. Data on feed intake and yields of cold carcass, crust skin size, skin grade and total feathers was recorded for birds slaughtered at the respective ages. Data was analysed according to the analysis of variances. Values for meat yield, skin size yield and feed intake were predicted by regression analysis based on experimental values. Industry figures and norms were used as proxy for other production inputs and costs. A gross margin type analysis was performed to evaluate the effect of different slaughter ages on the profitability of each production system. There was a positive correlation between age and feed intake (r2= 0.40), slaughter weight (r2= 0.97), cold carcass yield (r2= 0.48), skin surface area (r2= 0.39), skin grade (r2= 0.19) and total yield of feathers (r2= 0.29). The dry skin grade showed deterioration as slaughter age was prolonged. Highly significant differences (P< 0.01) in slaughter weight, cold carcass yield, skin surface area, dry skin grade and total feathers were detected at the different slaughter ages. There were no significant differences (P> 0.05) with respect to gender for slaughter weight, skin surface area and dry skin grade within the different age groups. Males had significantly higher (P< 0.05) cold carcass yield and total feather yield than their female counterparts. From this study it can be concluded that an increase in slaughter age significantly increases feed intake, slaughter weight, cold carcass yield, and skin surface area. It is also clear that an increase in slaughter age can be detrimental to dry skin grade. The relative income contribution of the three main products (skin: meat: feathers) occurred in a ratio of 47:53:0, 52:47:1, 47:50:3, 44:51:5, 39:56:5 at the respective slaughter ages. Total income revealed an increase of 26 percent from 8.5 to 10.5 months slaughtering, an increase of 4 percent between 10.5 and 12.5 months, and an increase of 11 percent between 12.5 and 14.5 months. The income dropped by 0.3 percent between 14.5 and 16.5 months slaughtering. Total costs increased with slaughter age, particularly feed costs which showed an increase (at a decreasing rate) between the different slaughter ages. The margin above specified cost per bird was the highest for birds slaughtered at the age of 10.5 months. The margin above cost showed a steady decline as birds were slaughtered at higher ages. Slaughtering at 16.5 months revealed a negative margin. To compare the effect of differences in time span on different slaughter age regimes, margin above costs for each system over 5 years were discounted to a present value. In this study, with current feed costs and income from end products, slaughtering at 10.5 months revealed the highest present value for the margin above cost. Furthermore, slaughtering at 16.5 months revealed a negative present value on the margin above cost after 5 years. Financial viability calculations are relevant and valid for data obtained in this case study. Financial viability is however case-specific and may vary between producers, depending on their individual management practices, production systems and cost structures. Results from this study may be of significant value to managerial decision-making in the ostrich industry.
- Full Text:
- Date Issued: 2006
Improvement of fertility and hatchability of artificially incubated ostrich eggs in the little Karoo
- Van Schalkwyk, Salmon Jacobus
- Authors: Van Schalkwyk, Salmon Jacobus
- Date: 1998
- Subjects: Ostrich farming -- South Africa , Eggs -- Hatchability , Eggs -- Incubation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5713 , http://hdl.handle.net/10962/d1005399
- Description: 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.
- Full Text:
- Date Issued: 1998
Improvement of fertility and hatchability of artificially incubated ostrich eggs in the little Karoo
- Authors: Van Schalkwyk, Salmon Jacobus
- Date: 1998
- Subjects: Ostrich farming -- South Africa , Eggs -- Hatchability , Eggs -- Incubation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5713 , http://hdl.handle.net/10962/d1005399
- Description: 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.
- Full Text:
- Date Issued: 1998
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