Reducing Mortality Rates in Ostrich Chicks RIRDC Publication No. 08/187

RIRDC

Innovation for rural Australia

Reducing Mortality Rates in Ostrich Chicks

by Phil Glatz and Zhihong Miao

November 2008 RIRDC Publication No 08/187 RIRDC Project No PRJ00081

© 2008 Rural Industries Research and Development Corporation. All rights reserved.

ISBN 1 74151 776 1 ISSN 1440-6845 Reducing Mortality Rates in Ostrich Chicks Publication No. 08/187 Project No. PRJ-000081 The information contained in this publication is intended for general use to assist public knowledge and discussion and to help improve the development of sustainable regions. You must not rely on any information contained in this publication without taking specialist advice relevant to your particular circumstances. While reasonable care has been taken in preparing this publication to ensure that information is true and correct, the Commonwealth of Australia gives no assurance as to the accuracy of any information in this publication. The Commonwealth of Australia, the Rural Industries Research and Development Corporation (RIRDC), the authors or contributors expressly disclaim, to the maximum extent permitted by law, all responsibility and liability to any person, arising directly or indirectly from any act or omission, or for any consequences of any such act or omission, made in reliance on the contents of this publication, whether or not caused by any negligence on the part of the Commonwealth of Australia, RIRDC, the authors or contributors. The Commonwealth of Australia does not necessarily endorse the views in this publication. This publication is copyright. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. However, wide dissemination is encouraged. Requests and inquiries concerning reproduction and rights should be addressed to the RIRDC Publications Manager on phone 02 6271 4165 Researcher Contact Details Dr Phil Glatz Davies Building Roseworthy Campus, 5371 South Australia Phone: (08) 83037786 Fax: (08) 83037689 E-mail: [email protected] In submitting this report, the researcher has agreed to RIRDC publishing this material in its edited form. RIRDC Contact Details Rural Industries Research and Development Corporation Level 2, 15 National Circuit BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: Fax: Email: Web:

02 6271 4100 02 6271 4199 [email protected]. http://www.rirdc.gov.au

Published in November 2008 Printed by Union Offset Printing, Canberra

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Foreword Successful ostrich farming is largely dependent on the ability of farmers to rear sufficient numbers of viable and healthy chicks. However, high mortality of ostrich chicks particularly during the first few months of life is a problem. This project involved a review that examined factors both prior to hatch and after hatch that could lead to high mortality in chicks. Appropriate breeder management, fertile egg handling and storage and incubation can improve hatchability and survival rates of chicks. Ostrich chick mortality can also be reduced by correct housing, feeding and health management of chicks at hatch and during the brooding period. This report was funded from industry revenue, which is matched by funds provided by the Federal Government and is an addition to RIRDC’s diverse range of over 1800 research publications. It forms part of our New Animal Products Program, which aims to foster the development of New Animal Industries. Most of our publications are available for viewing, downloading or purchasing online through our website:

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downloads at www.rirdc.gov.au/fullreports/index.html

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purchases at www.rirdc.gov.au/eshop

Peter O’Brien Managing Director Rural Industries Research and Development Corporation

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Acknowledgments The authors are grateful for the support from the New Animal Products Program of the Rural Industry Research and Development Corporation who funded this project and information provided by ostrich farmers in Australia.

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Contents Foreword ............................................................................................................................................... iii Acknowledgments................................................................................................................................. iv Executive Summary............................................................................................................................. vii Introduction ........................................................................................................................................... 1 Literature Review: Management strategies to reduce ostrich chick mortality................................ 2 Introduction..................................................................................................................................... 2 Breeders ........................................................................................................................................... 2 Hatching........................................................................................................................................... 3 Incubation........................................................................................................................................ 5 Ostrich chick rearing ...................................................................................................................... 7 Brooding systems ....................................................................................................................... 7 Rearing systems.......................................................................................................................... 8 Housing ............................................................................................................................................ 8 Flooring/Bedding........................................................................................................................ 9 Heating ..................................................................................................................................... 10 Ventilation ................................................................................................................................ 11 Feeding chicks ............................................................................................................................... 11 Preventing infection ...................................................................................................................... 12 Toe trimming ................................................................................................................................. 13 Stocking rate.................................................................................................................................. 13 Transport/handling....................................................................................................................... 13 Stress ........................................................................................................................................ 14 Ventilation ................................................................................................................................ 15 Ostrich health ................................................................................................................................ 15 Leg problems............................................................................................................................ 15 Impaction.................................................................................................................................. 15 Heavy metal poisoning ............................................................................................................. 16 Infections and diseases ............................................................................................................. 16 Summary........................................................................................................................................ 18 References ...................................................................................................................................... 20

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Tables Table 1.

Incubation variables in ostrich related to different ages (mean ±SEM) ................................ 4

Table 2.

Mean (±SE) egg weight loss and hatchability of ostrich eggs subjected to short vs. long periods of pre-incubation storage .......................................................................................... 5

Table 3.

Parasitic species found in the faeces from 336 ostriches..................................................... 17

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Executive Summary What the report is about This project involved a review that examined factors both prior to hatch and after hatch that could lead to high mortality in chicks. Appropriate breeder management, fertile egg handling and storage and incubation can improve hatchability and survival rates of chicks. Likewise ostrich chick mortality can be reduced by correct housing, feeding and health management of chicks at hatch and during the brooding period. Low mortality (10-15%) can be achieved by good hygiene, proper feeding and housing and good management. Who is the report targeted at? This report is targeted at Australian and overseas ostrich farmers. Background High chick mortality in commercial ostrich farming is a problem around the world. In South Africa, chick mortality up to 3 months of age is reported to be 50% (Smith et al., 1995). In Queensland, More (1996) reported that average mortality for chicks at 4 months was 37%. In Israel, mortality rates range from 15-50%. Increasing chick survivability will increase profitability for ostrich farmers and will make the ostrich industry more competitive. Chicks are especially vulnerable during the first few weeks after hatching and frequently succumb to disease, various disorders and stress (Huchzermeyer, 1994; Samson, 1997). Stressors are not only a direct cause of mortality but can also make chicks susceptible to disease and infection (Jensen et al., 1992). Other factors affecting survivability include: 1) starvation; 2) leg problems; 3) navel infection and; and 4) yolk sac infections. Aims/objectives This review was undertaken to examine the effect of management issues on chick mortality. Issues examined included: Floor materials (eg. concrete floors with rub mats, native grass or lucerne pasture and earth floor), litter materials (eg. chopped straw, lucerne hay, dry hay and sheep manure covered with wire grids), housing/sheds (eg. traditional, mobile shed and eco-sheds), heating (eg. temperature and methods and sources of heating), stocking rate, probiotics and enzymes, preventative health measures (eg. clostridial, avian influenza and avian pox vaccination), feeding fibre (eg. sources of fibre and chopped length of fibre), egg collection time (eg. collection methods), egg cleaning (eg. cleaning methods), egg pre-storage (eg. storage period, temperature and relative humidity), incubation and hatching conditions (eg. temperature, carbon dioxide levels, relative humidity levels, oxygen level and ventilation). Methods used Extensive literature searching of materials on the internet and through literary data bases was used to track past and current research on the effect of management on chick mortality. Consultation was made with various ostrich farmers in Australia. Results/key findings Through this literature review, the following issues should be addressed by industry to reduce ostrich chick mortality. These include: 1) collecting eggs soon after lay and keeping them under proper storage conditions; 2) proper set up of incubator and hatch parameters and keeping both areas clean; 3) elimination of cold stress and hence susceptibility to infection and disease; 4) keeping the brooding area clean with proper bedding, not over stocked, optimum heating and exercise; 5) recommended nutrition and feeding systems; 6) condition chicks to human presence and handling; 7) gentle restraint, handling and transport of ostrich chicks; 8) good biosecurity and hygiene and recommended vaccination to minimise bird infection.

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Implications for relevant stakeholders for: Ostrich farmers should be beware of the factors associated the chick mortality on their own farm and improve the management and rearing conditions accordingly, which will improve the chick health and welfare and hence improve the profitability. Total chick costs in Australia have been reported to be $239/chick. Average mortality at 4 months was 37.1% for 394 chicks on 11 farms in Queensland (More, 1996). Using appropriate management strategies could reduce the mortality and make savings of $50/chick. This equates to a saving of $1.125m/year for the ostrich industry based on 22,500 ostriches predicted to be slaughtered in Australia in 2008. Recommendations The ostrich industry should adopt the following protocols to minimise ostrich chick mortality: •

Collect and store fertile eggs appropriately,

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Ensure incubator and hatching are operating as per instructions,

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Establish best practice methods for brooding, rearing, management and feeding,

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Maintain biosecurity, and

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Condition chicks to handling.

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Introduction Proper farm management and adequate feeding of younger ostrich chicks are key factors determining the profit of ostrich farming and the competitiveness of the industry in the international market. Successful ostrich farming is largely dependent on the ability of farmers to rear sufficient numbers of viable and healthy chicks. High mortality of ostrich chicks particularly during the first few months of life is well documented around the world (Adams and Revell, 1998; Lopes et al., 2005; Iji per.comm.; More, 1996; Peters et al., 2005). In South Africa, chick mortality is reported to be 50% up to 3 months of age (Smith et al., 1995). In Australia, More (1996) reported that average mortality for chicks at 4 months was 37%. In Israel, mortality rates range from 15-50%. In Europe, mortality up to 4 weeks of age is still over 50% (Adams and Revell, 1998). The reason for this may be because of inadequate knowledge of the feeding and management of younger ostrich chicks. Ayo and Minka (1994 cited by Peters et al., 2005) reported factors which caused the death of chicks in a Nigerian ostrich farm were lower limb deformities which affected 36.7% of the chicks hatched. Inappropriate feeding due to lack of knowledge of chick nutrition and digestive physiology resulted in death of chicks due to solid masses such as lucerne hay and maize found in the proventriculus and gizzard (Sato et al., 1994). Bodyweight of ostriches increases 11-fold from 3 days to 72 days of age. Compared with bodyweight, the relative weight of the proventriculus/gizzard, caeca and colon increases significantly with age. The relative weight of the small intestine is highest at 41 days of age (Iji et al., 2003). Shorter villi at the duodenum was found in ostrich digestive tract from day 3 to 72 days of age. This may indicate that the total activity of membrane-bound enzymes is low at these ages. Iji et al. (2001) reported that the total activity of those enzymes in broiler chickens increases with age as the villi grow longer. However, trypsin was not detected in the newly hatched ostrich but the enzyme was active from 27 days of age. The activity of amylase was also low and relatively unchanged from hatch to 72 days of age (Iji et al., 2003). In ostriches, enzyme and acid secretion is restricted to an area of only 25% of the total inner surface area of the proventriculus. This is in contrast to other birds in which the entire surface of the proventriculus secretes digestive enzymes (Cooper and Mahroze, 2004). This may indicate that the enzyme activities are low for ostriches, particularly at young ages and may be a factor contributing to chick mortality. Ostriches are born without gut bacteria, but after 10 days some of the microbes appear (Mead, 2000). Clearly fermentation ability at very early ages in ostriches is poor but gradually develops after gut bacteria are present. Gas production from the hind gut is rapid at 55 days and increases with age (P. A. Iji and T. S. Boomker, per. comm. University of New England, Australia), indicating that fermentation is very active at this age. There were also higher activities of microbial protease, β-Dglucosidase and β-D-galactosidase in the caeca and colon than in the ileum. Lopes et al. (2005) reported that bacteria from a healthy ostrich gut could prevent pathogenic bacteria infection, reduce chick mortality, improve absorption of yolk sac and increase the profit. Feeding live insects and adult dung could improve the protein and fibre utilization. Milton et al. (1993) fed termites (Microhodotermes viator) to ostrich chicks aged 3-9 weeks as protein source. The benefits of coprophagy have been described as adding useful gut microflora to help chick digestion (Cooper, 2000). This report reviews issues that occur during the breeding and incubation stage that may result in high mortality of chicks at hatch. In addition, hatching, rearing and feeding, handling, transport and health of ostrich chicks that impact on chick mortality are reviewed. In general, good hygiene, proper housing and feeding are factors that reduce chick mortality.

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Literature Review: Management strategies to reduce ostrich chick mortality Introduction Since the mid-1980s, there has been worldwide interest in the farming of ostriches for feathers, meat, skin and oil. Concerns about the high levels of ostrich chick mortality have largely been a result of the move toward intensive and semi intensive conditions which are not typical of their native habitat (Uhart et al. 2006). Two main factors affect the production of ratites; one is poor hatchability and the other is low chick survival rate (Navarro et al. 1998; Navarro and Martella 2002). The major causes of ostrich chick mortality up to 3 months of age are the paresis syndrome and limb deformities (Ashash et al. 1996). In assessing ostrich chick mortality it is important to examine the key factors that may impinge on mortality particularly those that relate to impact of breeder background, hatchery management, brooding, rearing and transport. Appropriate management of breeders, good egg hygiene, incubation, hatching, and best practice brooding, handling and transport of chicks will result in reduced mortality. For example, in Israel, one farm achieved 10-15% mortality of ostriches up to 3 months of age under a semi-extensive rearing system. Chicks were reared on lucerne and concentrate during the day and kept in heated shelters at night (Verwoerd et al. 1999).

Breeders It is important females select their own partner which apparently contributes to superior egg production, fertility and hatchability leading to healthier chicks. This can be done by careful observation of birds in a large communal pen to detect whether the hen shows a preference for a male and then pair them in a breeding pen (Adams and Revell 1998; Essa and Cloete 2004). Adams and Revell (1998) recommended that young breeders are best kept in pairs for good productivity, while in trios for 5-6 years of age. It is vital that owners keep a wide range of records, which should be kept, including percentage of fertile eggs, percentage hatchability, percentage of chicks surviving to 12 months and individual bird pedigrees for selecting good breeders (Glatz 2000a; 2000b). An aggressive bird should be culled according to temperament because they spend time fighting other males at the expense of mating frequency. Aggression can be inherited and progeny will generally be more flighty and due to interactions between birds have poorer skin grades and higher mortality during the chick stage. Hens without supplementary calcium are likely to be in negative calcium balance during periods of egg production, leading to poor egg quality and greater chance for death of chicks at hatch. Free access to a calcium supplement such as coarse shell grit in a separate feed container is suggested for all laying hens. Shell grit also aids in this process and provides calcium to the birds (Glatz 2000a). A high energy and protein diet for ostrich breeders could cause a high percentage of infertile eggs (Brand et al. 2000). Smith et al. (1995) reported that breeding birds fed ad libitum laid 24.5% infertile eggs, while 11.5% infertile eggs was found when feeding birds with 2 kg (dry matter basis) of a breeder diet. Deficiency of vitamins (vitamin A and E) and minerals (Se) had been linked to infertility (Hastings 1991; Hicks 1993). Vitamin A and D is important for egg production, hatchability and fertility and vitamin E and K for hatchability (http://www.blue-mountain.net/articles/p47.htm). Junqueira et al. (2007) reported that additional lipids (such as sunflower seeds) provided to breeders one month before beginning of laying period tended to increase the numbers of eggs, improve fertility and hatchability.

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Hatching Low hatchability of ostriches is well known and many chicks that do hatch subsequently die. The factors that affect hatchability including egg hygiene, egg storage conditions and period, incubation temperature, humidity, egg orientation, egg turning, ventilation and sanitation. Incubation temperature for ratites ranges from 35.9-36.5ºC (Wilson 2003). Estimated relative humidity requirements are 1520% during incubation and 40% during hatching. Optimal turning frequency has not been determined for ostrich fertile eggs. However, better results can be achieved by turning the eggs once per hour automatically. Eggs set with large end (air cell) up and turned around the small axis gives good results (Wilson 2003). Levels of oxygen and carbon dioxide that need to be maintained in the incubator for ostrich eggs are 21% and 0.05-0.10% respectively. Egg weight loss during incubation is important if high hatchability is to be achieved. An egg weight loss of 12-17% during the 38 days of incubation is recommended for ostrich eggs. The major factors contributed to egg weight loss are shell porosity and relative humidity. Other factors include egg size and incubation temperature (Wilson 2003). Hygiene of egg, incubator and hatchery plays an important role in achieving high hatchability. When the chicks are not hatched in optimum conditions or exposed to stress conditions during incubation, high chick mortality can result. It is well documented that the hatchability of ostrich eggs is low and varied, ranging from 3.3% to 80% (Deeming and Ar 1999). Low hatchability could be caused by poor control of incubation parameters (temperature, humidity, air circulation, egg position and turning), improper egg handling (egg collection, egg washing methods, improper egg storage) and egg quality (egg size, nutrients in eggs, shell thickness and porosity) (Philbery et al. 1991; Wilson et al. 1997; Cooper 2001). There are also reports that the nutritional status of female ostriches (Angel 1993), and microbial contamination of the eggs (Deeming 1996a) affect the hatchability and subsequent survival rate of chicks. However, oedemas and malposition are key factors causing embryo mortality (Deeming 1997), particularly when the head of the embryo is positioned at the end of the egg away from the air space (Deeming and Ar 1999). More evidence was reported by Ley et al. (1986), who found death in embryos was caused by severe oedema (45%) alone and in combination with malpositioning (55%). A similar result was reported by Brown et al. (1996). Malpositioning resulted in 55% of embryo death during the last 1014d of incubation. Other factors which impact on hatchability and liveabilty of hatched chicks include nutrition of breeders and breeding season (Ipek and Sahan 2004; Cooper 2001). Egg quality: Ostrich egg weight ranges from 350g to over 2,200g. Jost (1993) (Cited by Cooper 2001) recommended that eggs weighing 1,300 to 1,700g give the best hatchability. Ideally, incubating eggs of similar weight in the same batch will yield good results as the incubation conditions are easier to maintain (Deeming and Ar 1999). Extremely large and small eggs have lower hatchability due insufficient weight loss during incubation (Deeming 1995; Gonzales et al. 1999; Sahan et al. 2003). The oversized eggs have a smaller proportion surface area for gas exchange and water vapour while undersized eggs may lose excessive water during incubation. Egg weight loss during the incubation was 8.8-19.7% (Jarvis et al. 1985), 13.2% (Swart et al. 1987) and 15.6% in nature (Burger and Bertram 1981). Weight loss of 13-15% during artificial incubation is recommended by Ar et al. (1996). Eggshell thickness also affects hatchability (Sahan et al. 2003). More chicks hatch from eggs with thinner shell (Satteneni and Satterlee 1994; Brown et al. 1996; Gonzales et al. 1999). Egg pore density of ostrich eggs is positively related to egg weight loss and hatchability (Satteneni and Satterlee 1994; Gonzales et al. 1999; Sahan et al. 2003). Eggshell thickness is not related to egg size, but medium sized eggs had significantly higher eggshell porosity (number of large pores per cm2 of shell), higher egg weight loss and higher hatchability compared to small or large eggs (Gonzalez et al. 1999). Eggs laid toward the end of the season or from hens fed diets deficient in Ca or P, or from hens with a defective oviduct function will have a lower hatchability. These eggs are more susceptible to infection (Shane and Minteer 1996). A high energy grain-based diet may result in mid-embryonic mortality such as oedematous chicks with subcutaneous haemorrhages (Stewart 1996). However, Brand et al. (2003a) showed that different energy levels (7.5, 8.5 and 9.5MJ/kg) combined with different protein

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levels (105, 120 and 135g/kg) and relevant amino acids had little or no influence on ostrich egg composition. Breeding season also plays a role in hatchability. Ipek and Sahan (2004) compared egg hatchability between seasons and found that hatchability was 64.3% in the first season, increased in the subsequent years and reached 73.1% in the fifth year, but seasons did not influence weight loss of eggs and length of incubation (Table 1). Table 1. Incubation variables in ostrich related to different ages (mean ±SEM) (Ipek and Sahan 2004) Breeding season

1998

1999

2000

2001

2002

P

Weight loss of eggs

12.97±0.7

12.89±0.6

12.24±0.6

12.64±0.6

12.41±0.5

N S

Mean length of incubation

1025±23.6

1027±24.1

1028±22.0

1026±21.3

1028±22.8

N S

Chick weight at hatching

950.4c±22. 4

988.7b±26. 7

1031.2a±28. 8

1039.7a±27. 3

1035.5a±26. 4

**

Hatchability of fertile eggs

64.3c±2.8

69.6 b ±1.6

70.2ab±2.0

71.8a±2.3

73.1a±2.8

**

Hatchability of total eggs

37.5c±1.1

43.2 b ±1.3

48.1a±1.2

50.9a±1.3

51.7a±1.3

**

Fertility

58.3c±2.0

62.2 b ±1.9

68.5a±2.0

71.0a±2.9

70.7a±2.7

**

Malpositioned embryos

14.3a±1.8

8.7 b ±1.3

8.1 b ±1.1

7.7 b ±0.9

7.3 b ±0.7

**

Deformed chicks

11.1a±1.5

6.2 b ±0.9

4.0 c ±0.6

3.6 c ±0.4

3.3 c ±0.8

**

22.2a±2.3

18.7 b ±1.8

12.0 c ±1.7

10.7 c ±1.8

10.0 c ±1.9

**

Assisted hatching

chicks

during

Time of egg collection: Eggs should be collected several times a day with the last collection at sundown. Copper (2001) recommended that eggs should collected 10-15 minutes after laying. Eggs left in the nest are frequently rolled, damaged or even eaten by adults and increases susceptibility to bacterial infection, particular when left overnight (Stewart 1996). Eggs collected in the evening resulted in lower mortality of chicks than collected next morning (van Schalkwyk 1998). Immersion sanitization of the egg shell does not improve hatchability of internally contaminated eggs. Large numbers of eggs should be placed in padded crates to minimize shaking during transport (Stewart 1996). Eggs should be handled with disposable gloves or a plastic bag (Shane and Minteer 1996) or sterile towel (Cooper 2001) to prevent possible contamination. Egg cleaning: Keeping eggs clean is an effective way to prevent contamination. Nests should be located away from feeding areas to reduce faecal contamination (Cooper 2001). Sand should place in the nests and regularly replaced to keep the nests clean and dry. A common practice is to remove adherent dirt on the egg with a dry cloth or sand paper when collected (Glatz 2000a). A dry egg should be lightly buffed with a soft-bristle brush only on specific areas to remove adherent dirt without destroying the cuticle. Eggs may be carefully rinsed, sprayed, or immersed in warm solutions, including sodium hypochlorite, chlorhexidine, quaternary ammonium compounds or phenolics. However, these methods may damage the cuticle and lower resistance to subsequent bacterial contamination (Stewart 1996). If the egg is wet or contaminated, the surface is dried with a blow drier and then buffed. The eggs can be air dried and placed in storage (Stewart 1996). In the domestic poultry industry, the egg surface is coated with a fine layer of commercial disinfectant solution

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containing either a quaternary ammonium or phenolic compound formulated to prevent contamination. Disinfectants are applied either by a hand spray, aerosol, or by fogging. Disinfectants should not produce any residue on the shell surface which may interfere with air exchange through pores during incubation (Glatz 2000a). Severely contaminated eggs can be washed by immersed in a 37.8°C phenolic or quaternary ammonium solution for 30-45 seconds, but the procedure may reduce hatchability by encouraging movement of micro-organisms from the surface into the interior of the egg. Eggs are rinsed in clean water and dried using a sterile towel (Shane and Minteer 1996). Cooper (2001) recommended that eggs can be safely cleaned by a dry cloth first and then lightly mist-sprayed with 5g/L of a Virkon solution. Van Schalkwyk et al. (1997) studied different disinfection methods on hatchability and found that the hatchability percentage was higher and late embryonic death was lower for the eggs disinfected by UV compared to eggs washed using a peroxigen powder compound and quaternary ammonium. Storage: There is no standard method to store ostrich eggs in terms of temperature, humidity and turning. Embryos start to develop at 29.4°C. Ostrich eggs held at or above this temperature results in an increase in early embryonic mortality after the second day of incubation. Cooper (2001) recommended that eggs can be stored for 7 days under UV lighting but no storage temperature and relative humidity (RH) were mentioned. Eggs maintained between 12.8°C and 18.3°C may be safely stored for 7d (Berry http://www.osuextra.com), but hatchability will be significantly reduced after 10d (Shane and Minteer 1996). Eggs stored up to 6d in different positions such as with air space at the top or bottom, or held with long axis horizontal did not affect egg embryonic mortality (van Schalkwyk 1998). However, Gonzalez et al. (1999) recommended that ostrich eggs can be stored for a minimum of 10d without reduction of hatchability under storage conditions used in the poultry industry (Table 2). A similar result was reported by Bertram (1979), who found that eggs can be safely stored up to 10d at 18ºC and 69% RH. Table 2. Mean (±SE) egg weight loss and hatchability of ostrich eggs subjected to short vs. long periods of pre-incubation storage (Gonzalez et al. 1999)

Length of pre-incubation egg storage

Egg weight loss (%)

Hatchability (%)

Short (≤5 d)

13.0 ± 0.6

63.2 ± 7.9

Long (>5 d and ≤ 10d)

13.3 ± 0.7

74.3 ± 7.5

However, Nahm (2001) reported that eggs can be safely stored up to 19d at 15.5-15.6ºC without controlling the humidity level. Hassan et al. (2005) suggested that the most effective storage period was ≤15d (20°C and 65% RH) to maintain hatchability for ostrich eggs when eggs were incubated at 36.5-37.0°C and 25% RH for 38d. RH near 75% is recommended to prevent water loss from eggs during storage (Shane and Minteer 1996). In contrast, Foggin and Honywill (1992) recommended storage RH should be around 35% to prevent the development of over hydrated chicks. Eggs should be turned daily (Berry http://www.osuextra.com) or rotated 180º once daily (Deeming 1996b) during storage. Heating ostrich eggs at 36°C for 4h prior to setting them in the incubator significantly reduced embryonic deaths compared with eggs that were not preheated (Brand et al. 1997).

Incubation The incubator and incubation room should be properly managed. The incubator should be cleaned and properly disinfected and tested at least 12 hours prior to use to allow adjustments to be made (Glatz 2000a). Proper maintenance of the incubation conditions including temperature, humidity, air circulation and correct positioning of eggs and adequate turning could improve the hatchability and subsequent health and welfare of the hatched chicks and reduce mortality. Cooper (2001) recommended that optimal incubation temperature is 36-36.5°C with a RH of 20-30%.

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Incubation temperature: Eggs can be successfully incubated over the range 35.0-37.0°C (Deeming 1993). Ar et al. (1996) recommended the optimum incubation temperature is 36.4°C. Increasing incubation temperature from 36.0-37.2° will reduce hatchability from 73 to 44% (Stewart 1996). Similar results were found by Hassan et al. (2004), who reported that mortality was increased at 37.5°C compared to at 36.5°C. van Schalkwyk et al. (1999) also found lower hatchability (33.8%) at 37.3°C compared to 36°C (63.3%) and 36.5°C (60%). However, low incubation temperature also increases embryonic mortality and results in soft, weak chicks (Shane and Minteer 1996). The incubation period reduces by about 2d when the incubation temperature increased from 36.5 to 37.5°C (Hassan et al. 2004). However, Stewart (1996) noticed that increasing incubation temperature from 35.0 to 36.7°C decreases the incubation period by 3d. It is suggested that for every degree increase in incubation temperature there will be a reduction in the incubation period by 2.5 days (Jarvis et al. 1985; Deeming et al. 1993). Incubation humidity: Ideally, the actual humidity level used to incubate ostrich eggs should be based on the average weight loss for all eggs produced from the flock (Shane and Minteer 1996). A weight loss of 13.4% to 39d of incubation was suggested by Deeming et al. (1993), similar to egg weight losses (13.2%) under natural hatching conditions (Swart et al. 1987). To achieve this egg weight loss, RH should be less than 30-35% during incubation (Cooper 2001). Philbey et al. (1991) reported that a 20-40% of RH during incubation improves the hatchability. Insufficient egg weight loss (Gonzalez et al. 1999) or the lowest weight losses (17%) (Deeming and Ar 1999) will result in low hatchability. RH level used depends on selected temperature, egg quality and air circulation in the setter. For example, higher incubation temperatures require lower humidity. This is because higher temperatures increase the metabolic rate of the embryo and hence produces more metabolic water (Glatz 2000a). Ideally, eggs should be separated by size and shell quality and incubated under different conditions to compensate for variability. General, small or large eggs or with thick shells lose less weight than medium or thin-shelled eggs (Gonzalez et al. 1999) and hatchability was high for high eggshell porosity. However, Deeming and Ar (1999) reported that low or high eggshell conductance will result in insufficient or excessive egg weight loss respectively during incubation. Adjusting the humidity of the incubator according to the shell properties may be a useful technique to achieve sufficient egg weight loss for successful hatching (Rahn et al. 1981). Decreasing RH during incubation for eggs with low conductance shells could improve hatchability by 5% and increasing RH for eggs with high shell conductance could increase hatchability about 9% (Ar et al. 1996). Christensen et al. (1996) recommended that humidity of the incubator should be less than 25% to allow a 15% initial egg mass loss during the 45d incubation period. Clearly humidity levels in the incubator play a key role in hatchability and subsequent mortality of chicks. Air circulation and ventilation: Circulation is the movement of air within the incubator. Cooper (2001) recommended air flow rate in the incubator of about 45L/h/egg. Ventilation is required to supply oxygen and reduce carbon dioxide level in the incubator. However, there is lack of information on ostrich incubation ventilation. Recommendations for commercial poultry incubation are above 20.5% of oxygen and below 0.5% of carbon dioxide. Hatchability was reduced by about 5% for each 1% decrease in oxygen (Shane and Minteer 1996). Above 0.5% CO2 in the incubation air can increase embryonic deathsvf (Smith et al. 1995). Position and turning of eggs: During incubation eggs should be positioned with the large end up, and if possible, at a 45º angle. Positioning the eggs on the side is also acceptable (Glatz 2000a). Shane and Minteer (1996) recommended to incubate ostrich eggs for 10days in a horizontal position then reposition the egg with the air cell upward for the rest of the incubation period. Eggs positioned with their long axis horizontal for 2-3 weeks in an incubator and then re-positioned with their long axis vertical for the rest of incubation has improved hatchability compared to the eggs either vertically or horizontally positioned throughout incubation period (Smith et al. 1995; van Schalkwyk 1998). However, vertical setting of ostrich eggs is common in commercial hatching to save incubator space. van Schalkwyk et al. (2000) recommended that vertical setting eggs and rotated through 90º around the short axis will produce acceptable hatchability.

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Turning eggs during incubation improves hatchability by stimulating the growth of the embryo (Deeming 1993) and preventing the embryo attaching to the inner shell membrane and providing a uniform temperature (Hallam 1992). The eggs should be turned at least twice daily (8 to 10 times per day is better) until 39d when the eggs are transferred to the hatcher. Setting eggs in the horizontal position without turning will have lower hatchability (27%) (van Schalkwyk et al. 2000). Frequency of turning can be reduced if the turning angle is large. Manually turning of eggs through 180º twice a day is sufficient, but hatchability is lower compared to eggs turned hourly (van Schalkwyk et al. 2000). Hatchability was about 60% by manually turning eggs through 180º around the short axis and through 60º around the long axis twice a day and about 80% by automatically turning eggs through 60º around the long axis. Cooper (2001) reported that 85.7% of hatchability could be achieved by positioning eggs in a vertical position and turning eggs 8 times/day. Hatching: Turning eggs will reduce hatchability during the last few days of development as the embryos rotate by themselves into position for hatching. Ar et al. (1996) reported that only 19% of fertile eggs needed assistance if egg weight loss was 13%, but 75% of hatching chicks needed assistance when the weight loss was 6%. Deeming and Ayres (1994) found that mortality of assisted chicks was 75% and the birds that survive birds had extremely poor growth. It is not recommended that the chick is assisted out of the shell unless the incubation period is over 42 days. If the chick is rushed, the navel may not have properly closed. An infected navel results in a dead chick (Berry http://www.osuextra.com). Sahan et al. (2003) suggested that the ostrich farmers should determine the characteristics of their eggs and match incubator conditions to these eggs to improve the hatchability.

Ostrich chick rearing Ostrich chicks are susceptible to disease and infection, various disorders and stress during the first few weeks of their life (Jensen et al. 1992; Huchzermeyer 1994a; Deeming and Angel 1996; Samson 1997; Barri et al. 2005). These problems often result in high mortality, which is one of the major welfare problems in the ostrich industry. They require special attention during this period to ensure chick welfare is not compromised. Once the chicks reach three months of age, they are relatively hardy and only need protection from bad weather (Glatz 2000a). It is important to keeping young ostriches warm, raise them in stress free environments and give them sufficient space for exercise. Allowing them to go outside as soon as possible for exercise and sunshine are important for their growth and development.

Brooding systems Ostrich chicks normally remain in the hatchery for a few hours or for 2 days until their navels close and are dry. The newly hatched chick navel may be swabbed with an iodine/Betadine solution to prevent bacterial infection. The brooding area should be clean, sanitary and provide a comfortable and secure environment. Brooders can be a cardboard box with proper bedding (such as hay) and heating (such as a heat lamp) in one corner of a room. Small brooder boxes are recommended by Verwoerd et al. (1999) because chicks can be kept warm is a small isolated area. In South Africa and Australia, a common practice is to keep 20-30 newly hatched ostrich chicks enclosed in small area inside a building, which can be fenced by a circle of plastic crates or hardboard or a raised welded metal mesh (Verwoerd et al. 1999). The floor of the brooder area should be covered with slip proof material to avoid leg damage. Overhead heat is recommended in the brooder area due to floor heating causing more leg problems. In the USA, heat pads or similar materials are used in brooder area to keep chicks warm (Verwoerd et al. 1999). However, there should be enough space to allow ostrich chicks to move away from heat source in case chicks overheat. Temperature recommended for ostrich chicks in a brooder box varies because the rearing environmental conditions are differ. Deeming et al. (1996) recommended 32ºC, but 26.532ºC was recommended by Jensen et al. (1992) and 24ºC by Kocan and Crawford (1994).

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Chicks should be encouraged to exercise in outside pen runs as soon as possible (if weather permits) to strengthen their muscles. Ostrich chick activities should be monitored to prevent impactions since they will eat almost anything when they are grazing outside. The chicks should initially only be allowed outside for short periods and then gradually increase the time. Early exercise is required to prevent ostrich chicks suffering from leg problems.

Rearing systems Ostrich chick rearing systems include all-in all-out systems or mixed age groups kept in the same large enclosure. All-in all-out system keeps similar age chicks in the one facility up to 12 weeks of age (Deeming et al. 1996; Verwoerd et al. 1999). This system could control the rearing environment better, improve biosecurity and prevent disease (Verwoerd et al. 1999). There is considerable debate in both Australia and overseas on which rearing system produces the lowest mortality. Intensive rearing: In Australia, chicks are kept indoors during the first 3-7d with a rearing temperature of 26-32ºC (Jensen et al. 1992). The chicks are moved out onto pastures during the day. Under this system, chicks can be kept in the rearing house until 3-4 weeks of age (Glatz 2000a). In Israel, 30-50 chicks are kept in a 3 x 3m enclosure and 3 x 10m exercise area for 4 weeks. Then birds are moved to large areas (25 x 25m) with heated (22ºC) shelters (Verwoerd et al. 1999). Outdoor enclosures can be made of timber or steel posts sheets with 75% shade cloth about 1.0-1.2m high is sufficient to keep ostrich chicks up to 12 weeks of age (Tuckwell 1997). Semi-intensive: In this system, 25-50 day old ostrich chicks are raised on pasture (usually lucerne) with 45cm high fences until about 6 weeks. A concentrate diet is provided. Chicks are kept in a shelter with heating during the night. Movable shelters are common which enable birds to have access to fresh pasture. Birds (about 6 weeks of age) will be moved to large enclosure which can hold 150 birds and fed on chopped lucerne and concentrate (Verwoerd et al. 1999). Foster parent rearing: Foster parent rearing is a common practice in South Africa (de Kock 1996). Ostrich chicks can be reared extensively with foster parents up to 25 chicks younger than 14 days of age per adult female (Verwoerd et al. 1999; Earle 1994). Chicks also can be reared semi extensively with foster parents (about 100 chicks per adult pair) with housing at night only. Using foster parents encourages chicks to exercise (Glatz 2000a). Regions with sudden changes in weather are not suitable for this rearing system as adult birds can only shelter 10-15 chicks (Verwoerd et al. 1999). A pair of adults can be fostered around 30-35 chicks in colder months while 60 chicks can be fostered in warmer months (de Kock 1996). Foster rearing may be impossible if there is lack of breeding stock (Verwoerd et al. 1999). It is important for foster parents to have good fostering behaviour skills and accept the new chicks, otherwise the young birds could be killed or injured by being trampled, kicked or from being thrown (de Kock 1996).

Housing Brooders and shelters protect ostrich chicks from predators (dogs, foxes, etc.) and bad weather. The facilities should have good ventilation and be easy to clean. In South Africa and Australia, shelters are constructed from a variety of materials, including modified shipping containers, wooden shacks, modified corrugated iron agricultural sheds and modified pig and poultry houses as well as custombuilt buildings (Verwoerd et al. 1999). Traditional sheds: Traditional sheds have a solid floor with an exercise run. The runs should be bedded with sand or light soil sown with lucerne or short hard wearing grasses (Tuckwell 1997). The shed can be divided into a few "runs". The disadvantages of this method include high labour, risk of pathogen build-up and high capital cost (Glatz 2000a).

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Igloos: 30 chicks at 3-5 days of age can be kept in small portable igloos on a lucerne pasture paddock until 4-5 weeks of age. Chicks can forage on lucerne or grass inside the enclosure, which could be moved 2-3 times a day. Igloos are heated by gas lamps and covered by plastic blinds to control the temperature (Tuckwell 1997). Chicks are kept within a 30cm high cardboard ring under the heat lamp at night. Each night, clean straw bedding should be provided in the ring. A hessian cover can be used to cover the top of the cardboard ring to reduce heat loss in cold conditions. The cardboard ring is removed in the morning and the igloo is moved to a different location (Tuckwell 1997). High ammonia levels are a problem in the igloos and can contribute to chick death. In addition, provision of heating to outdoor igloos using gas needs to be carefully managed to avoid overheating, loss of gas supply and ammonia build up. Transportable shed: The sheds can be built from various materials such as insulated "fridge panel" or plastic. The shed can be moved by wheels or by a skid system attached to the shed or by using a fork lift. Common pasture used is lucerne. Normally, the chicks are restricted inside the sheds overnight or during bad weather and then the sheds are moved to different locations each morning until 8 weeks of age (Glatz 2000a). A sterile carpet mat is placed on the sand floor of the shed. A gas heater can be used as heating source. Around 50-60 ostrich chicks (2-3 days of age) can be introduced into the shed (Tuckwell 1997). Similar problems of maintain in inadequate heating to birds has resulted in high mortality of ostrich chicks.

Flooring/Bedding Proper flooring and bedding is important to reduce ostrich chick mortality. A cold or slippery floor could cause bird infections and leg injuries. The common types of floor in Australia are concrete, dirt, sand or deep litter floors (Glatz 2000a). In South Africa, floors are earth, sheep manure, rough concrete or concrete covered with rubber mats, or galvanized welded mesh raised 2-100cm above the floor. In Israel, the floor is concrete with dry hay bedding covered by mesh to stop hay ingestion and to separate the chicks from urine (Verwoerd et al. 1999). In UK, a rough concrete floor with an area electrically heated to 20°C is used (Deeming et al. 1996). In USA, heated floors were common, but it resulted in leg problems due to birds sitting down to keep warm. In Australia, a sterile carpet mat floor is used in removable sheds and hard surfaces are used in traditional sheds (Tuckwell 1997). Glatz (2000a) recommended that a rubber coated floor will prevent chicks eating foreign material (e.g. straw bedding) which can cause impaction. Concrete floors: Concrete floors should have a non-slip surface, and are easy to clean and disinfected particularly in brooding units. However, chicks do not do well on concrete floors in Australia, although Mushi et al. (1998) reported that concrete floors have been used in Botswana for growing ostrich chicks up to 14 weeks of age. Dirt floors: Dirt floors need to be replaced regularly by replacing the surface layer of soil with fresh earth. Dirt floors can be difficult to keep clean and can generate significant dust or mud (Glatz 2000a). Sand floors: Relatively fine sand floors can be successful. However, the sand cannot be too fine due to the high dust levels generated as ostriches prefer to sit on sand when resting. Producers have noticed birds having sand baths especially at night. Sand should be replaced regularly (Glatz 2000a). Deep litter: Litter materials that can be used are sawdust, chopped straw, pine shavings, washed builder’s sand, hay or rice hulls. The litter should be covered by wire mesh for the first 7-10d to prevent ostrich chicks eating the litter and develop impaction. Litter should be changed frequently to remove urine and faecal output from ostriches (Glatz 2000a). Newspaper, cardboard, plastic, or other slippery flooring should not be used. Litter management is essential to minimize chick mortality. If litter gets wet, ammonia concentrations increase and can contribute to hock burn and breast blisters. If the litter becomes dusty, it can reduce chick growth by depressing the immune system. Respiratory infections resulting from

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lung lesions increase when the air is contaminated. Litter moisture levels of 25-30% are recommended as it benefits the litter condition, manure handling, air quality and health and safety for farmers or workers. Sawdust can generate high dust levels and health problems. Spraying oil to reduce dust may be a solution. Less than 2.4mg/m3 dust level is recommended. Similarly rice hulls have poor absorbency and straw is slow to break down and thus both are best mixed with wood shavings. It is important to ensure there are no risks of chemical contamination, including insecticides, rodenticides, agricultural chemical residues and mycotoxins as a result of fungal contamination and no risks of contamination by wild birds and rodents. The recommended depth for litter is a minimum of 50mm (Glatz 2000a).

Heating Cold rearing conditions could result in poor yolk sac absorption or secondary infections of ostrich chicks since they are very sensitive to cold (Verwoerd et al. 1999). Chicks under 3 months of age will not perform well in a cold environment. The chicks normally require heat in the sheds overnight for the first 2-3 weeks (Glatz 2000a). Some authors recommend keeping chicks indoors for 3-4 weeks after hatching with suitable heat source (du Preez 1991; Jensen et al. 1992). Others suggest chicks be allowed outdoors when the weather is sunny and temperatures are not too cold (>15 to 20ºC) and kept indoors with heating at night or when there is bad weather during the day (Hicks-Allredge 1993). Ostrich chick behaviour can indicate whether they are too hot (wings extended and panting) or too cold (huddling near the heat source and not feeding) (Deeming et al. 1996). When ostrich chicks are heat stressed for long periods normal development of the immune system is affected (as observed in other avian species) (Hicks-Allredge 1993) and results in poor appetite (Deeming et al. 1996), increased risk of dehydration (Verwoerd et al. 1999) and bacterial infections (Glatz 2000a). Temperature: In a commercial farming environment, ostrich chicks are normally kept in the hatcher or brooder at a temperature about 32ºC for 1-2 days after hatching (Deeming et al. 1996). However, temperatures used for young ostrich chicks vary from 21-26.5ºC to 32-35ºC in the industry. Verwoerd et al. (1997) recommended that the youngest chicks should be raised under temperature starting around 30ºC with a drop of 0.5ºC each day until reach 26ºC (±1ºC). However, the maximum weight gain of ostrich chicks will be achieved in 10-22°C temperature range in the 4-5 week rearing period. In South Africa, the whole brooder room is heated by domestic oil heaters and temperature maintained above 30°C for 2-7 days (Verwoerd et al. 1999). Heating sources: Heating sources can be infrared light, ceramic oil, gas lamp or electrical heaters in South Africa (Verwoerd et al. 1999). Gas lamps in igloo shelters are used on both South African and Australian farms (Tuckwell 1997). Heated floors were reported to cause chick leg problems. Success with focal gas heating in the sheds is also possible but automatic thermostat control of temperatures is crucial to prevent overheating (Glatz 2000a). Heating methods: The South Africans prefer room heating rather than spot heating. Whole room heating has been tried in Australia with limited success probably because of density problems and lack of environmental control. Preference in Australia is given to placing chicks in a masonite circle and covering with hessian bags depending on the heating required. Sometimes chick areas have been preheated by using a heated blanket or to preheat the sand or the floor with no additional heating provided (Glatz 2000a). Chicks can be held in groups of 10-15 in solid rings and partially cover the rings with hessian bags. This utilises the heat generated by each chick to warm the others (Glatz 2000a). Best results are obtained when rearing houses are provided with overhead heating combined, with adequate air movement to eliminate drafts and ensure constant temperatures throughout the housing unit (Glatz 2000a).

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Ventilation Poor ventilation in enclosures results in high ammonia levels, which influences the health of chicks. Levels of 10-15ppm of ammonia in the air of the shed can be smelt while 25-36ppm of ammonia will cause eye and nasal irritation in humans (Glatz 2000a). The ventilation rates applying to poultry may be applicable for ostriches. Ventilation rates for poultry range from 1.0 to 9.7 m3/hr/kg at normal temperatures or about 12.1 m3/hr/kg in hot weather (>30°C) for adults. Equivalent rates for younger birds are 0.1 to 1.0m3/hr/kg or 1.3m3/hr/kg and for older birds 1.0 to 10.4 m3/hr/kg or 13.0 m3/hr/kg, respectively. Ventilation rates can be checked with hand held meters (Glatz 2000a). Vertical fans can be used to stop ammonia accumulation at chick level and extractor fans can be used to exchange air from this level (Verwoerd et al. 1999).

Feeding chicks Absorption of the yolk sac provides nutrients for ostrich chicks for the first few days, but differences of opinion still remain on when feed should be provided to them. Generally, ostrich chicks lose weight in the first few days. For example, weight loss of ostrich chicks occur in the first 7 days due to utilization of egg yolk and then weight increases by about 1.3 kg/week up to 12 weeks (Mushi et al. 1998). Kocan and Crawford (1994) recommended that chicks can be kept without food and water for 6-8 d after hatching. However, Verwoerd et al. (1999) recommended that chicks should have access to feed and water from day one to help the development of the digestive tract. This is supported by Noy et al. (1996), who reported that feed consumption soon after hatch increases the rate of yolk utilization. Ostrich chicks will eat any soft food such as finely cut lucerne, lettuce, cabbage or other vegetables. Supplying a certain amount of green feed at short intervals will encourage ostrich chicks to forage. For example, chopped fresh lucerne fed with starter diets will stimulate intake of food (Glatz 2000a). Christensen and Nielsen (2004) also reported that leaving cabbage inside the pen, encouraged chicks to peck at the cabbage and reduces pecking at fixtures in the pen, reducing boredom and improving the welfare of chicks. After one week chicks can be allowed to graze on lucerne pasture during the day, ensuring the area is free of wire or sticks which can be ingested and penetrate the proventriculus, resulting in death. There are a number of methods which can be used to stimulate chicks to commence eating: 1) place young chicks with older chicks; 2) foster parenting; 2) provide boiled infertile eggs; 3) stir the feed by hand at least eight times a day on day 2, 3 and 4; 4); use attractive colours (e.g. hammer milled corn); and 5) provide insects such as live crickets and mealworms. In general feed intake can be increased by making the feed more attractive, improving the palatability and stimulating feeding by frequent stirring of the feed or frequent operation of automatic feeders (Glatz 2000a). Ostrich chicks should be fed ad libitum with a good quality and balanced feed ration for at least the first 4 months of age. Feed and water containers can be hung from the roof to prevent ostrich chicks falling over containers on the floor (Verwoerd et al. 1999). A plastic trough is better than a metal trough because the sharp edges of metal trough can cause injury (Musa et al. 2005) or death. At night chicks should be kept indoors with an infrared heat lamp during the colder weather. Some farmers provide water only during night in the shelters (Glatz 2000a). Rearing chicks in groups of similar weight can improve chick growth (Mushi et al. 1998). Rapid growth over 2-4 months of age results in leg deformation which eventually leads to the death of some ostrich chicks with mortality rates as high as 41.20% (Musa et al. 2005). High fibre diets and more exercise may be help to reduce the mortality. Feeding fibre to ostrich chicks: Inappropriate feeding due to lack of knowledge of chick nutrition and digestive physiology resulted in death of chicks due to solid masses such as lucerne hay and maize found in the proventriculus and gizzard (Sato et al., 1994). Shorter villi at the duodenum was found in ostrich digestive tract from day 3 to 72 days of age. This may indicate that the total activity of membrane-bound enzymes is low at these ages. The activity of amylase was also low and relatively unchanged from hatch to 72 days of age (Iji et al., 2003). Low enzyme activities, particularly for younger ostriches, may be a factor contributing to their mortality. Lopes et al. (2005) reported that

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bacteria from a healthy ostrich gut could prevent pathogenic bacteria infection, reduce chick mortality, improve absorption of yolk sac and increase the profit. Feeding live insects and adult dung could improve the protein and fibre utilization. Milton et al. (1993) fed termites (Microhodotermes viator) to ostrich chicks aged 3-9 weeks as protein source. The benefits of coprophagy have been described as adding useful gut microflora to help chick digestion (Cooper, 2000). There are conflicting reports in the literature on the utilization of fibre by young ostrich chicks. Angel (1996) reported that ostrich chicks can move and forage for feed within the first 48 h after hatching. However, ostriches are born without gut bacteria, but some of the microbes appear after 10 days born (Mead, 2000). Ostriches (body weight between 5-50 kg) can digest 66% and 38% of dietary hemicellulose and cellulose respectively (Swart et al., 1993a). This may be because the microflora of the caecum and large intestine are similar to that of the rumen when an ostrich is 3-6 weeks old (Janssens et al., 1996). In addition, fermentation occurs at the age of 55 days since gas production from the hind gut is rapid at this age (P. Iji, per. comm.). However, at age of 3 weeks, the digestibility of fibre is only 6.5% i (Angel, 1993). High fibre feed can result in intestinal obstruction in young chicks. Ad libitum exposure to lucerne from 7 days of age results in decreased growth and lower body weight at 28 days of age compared to birds on pelleted diets (Schiavone et al., 1999). The performance of ostrich chicks on low energy/high fibre diets was studied by Salih et al. (1998). They found that there was no significant difference in DM intake (817, 818 and 773 g/d respectively) of ostriches fed three experimental diets (high energy (14.5MJ/kg); medium energy (12.0MJ/kg) and low energy (9.5MJ/kg)). However, chicks on medium-energy diet had a higher average daily gain (392g/d) compared to the high-energy (368g/d) and low-energy diets (321g/day). There was no significant difference in feed conversion rate of birds consuming the high energy/low fibre diet (2.09kg DM/kg gain) and the medium energy/medium fibre diet (2.02kg DM/kg gain). Both were lower than the low energy/high fibre diet (2.42kg DM/kg gain). Farrell et al. (2000) compared cockerels (2kg) to ostriches (10-20kg) in fibre utilization. They found higher DM digestibility (84%) and AME (16.26MJ/kg DM) in ostriches for diets which included 20% of milled wheat straw than in cockerels (61%, 12.63MJ/kg DM) and concluded that ostrich have a much better capacity to digest fibre than adult cockerels for feedstuffs high in fibre. There is lack of information on effect of enzyme added in diets to improve health of younger ostriches. More research is needed for fibre feeding such as quantity of fibre and source of fibres, which can be included in the diets for young ostriches.

Preventing infection Ostrich chicks normally lose 10% of their hatch weight by 5-7 days of age then they gain weight continually. If chicks continue to lose weight the fading chick syndrome can develop due to infections. Chicks born with poor health or are severely stressed will have abnormal cloacal bursas and thymuses. It is essential to give these birds individual attention and to remove any potential stressors from their environment. Once they develop clinical symptoms, they can seldom be saved (Glatz 2000a). Naval infection can result in death of chicks. The navel should be checked to ensure it is closed before a chick leaves the hatcher at 7 days. A 7% iodine solution can be applied to novel to prevent infection. A second treatment may be necessary in 2 or 3 days. If a dried umbilical attachment is still present (looking like a large coarse hair) it should be pulled from the navel and the area treated with iodine. This procedure can reduce the risk of yolk sac infections (Berry http://www.osuextra.com). Yolk sac infection is one of major factors causing early death of ostrich chicks. Most chicks die within 14-21 days after hatch (Deeming et al. 1996). Yolk sac infection is commonly attributed to poor hygiene during egg handling and incubation (Deeming 1997; Speer 1996) or navel infections after hatch (Huchzermeyer 1999). Other factors such as incorrect brooding temperature (too cold or too hot), cold concrete brooder floors, insufficient water intake and a delayed start to feeding can cause yolk-sac infection (Huchzermeyer 1999). A uniform environment and less stress rearing conditions can help yolk absorption (Verwoerd et al. 1999). Surgical removal of the infected yolk sac has been practiced (Kenny and Cambre 1992) or use can be made of a large needle and syringe to suck the

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contents of yolk sac followed by injection of a small amount of antibiotic solution into the yolk sac (Huchzermeyer 1999).

Toe trimming Over 50% of ratite skin processed are being downgraded due to damage on farm, during transport, in the lairage and during processing (Glatz 2005a). Toe trimming is one way to minimize this damage (Glatz 2005c). The claws should be trimmed at day old by removing the distal phalangeal joint with a red hot blade using a Lyon beak trimming machine (Glatz 2005b). The big argument against toe trimming is the concern that birds will die soon after the process due to stress or will suffer chronic pain in the toe stump (Lunam and Glatz 2000). In addition when the bird is walking or running on wet ground or hilly ground it is difficult for the toe trimmed birds to maintain footing. If toe trimming is not done according to best practice chick mortality may occur. When toe-trimming is done correctly ostrich chick behaviour is modified and reduces the potential for skin damage in the first two weeks after hatching (Glatz 2003; Glatz 2007).

Stocking rate Stocking densities used for young ostriches varies from 16 to 40m2/bird (Verwoerd et al. 1999). Over stocking can cause death in chicks from suffocation. Optimum stocking levels have not been clearly defined as outlined below. The chick body weight is often used to calculate stocking density. Deeming et al. (1996) recommended a minimum floor space of 0.125 m2/kg while Wade (1995) suggested 0.3-1.4m2 in the brooding area with 18.5-37m2/bird in the outdoor run. In Zimbabwe the space requirement suggested for day old chicks is 0.16m2/chick increasing by 10% per week (Hallam 1992). In South Africa, young chicks are normally kept inside the shelter (2-3 chicks/m2) in groups of 30-50 at night and allowed to run outside during the day according to the weather conditions. The outside run can be 2-3m by 10-15m in dimension for chicks from hatch up to 4-6 months of age (Verwoerd et al. 1999). In Israel, 50-60 chicks (