LPM 222: Diversified poultry production and current concepts in poultry management and marketing [Livestock Production Management (Regional Interest)] (1+1)

Ostrich paediatrics

REARING OF YOUNG ONES (OSTRICH PAEDIATRICS)

• Ratite chicks are susceptible to disease and infection, leg deformities, rolled toes, impaction, overstocking and heat and cold stress during the first few weeks of their life. Ratite chicks are very sensitive to cold, leading to poor yolk sac absorption and secondary infections.
• Refusal to eat and drink is a common problem with young ostrich chicks. This problem can be easily alleviated by placing several older chicks (1 to 3 weeks of age) that are already eating with the younger chicks. If older chicks are not available, domestic poultry chicks can be placed with new-hatched ostrich chicks to teach them to eat and drink.
• The importance of maintaining correct relative humidity in the incubator has a bearing on the subsequent normal growth and survival of ostrich chicks. High relative humidity has been attributed to the development of anasarca and myopathy in chicks. Excessive relative humidity also causes reduction in the moisture loss from the egg. This results in undersized air cell; which interfere the chick from penetrating the air cell for pulmonary respiration during hatching. This process allows the embryos to breathe the air few hours before pipping.

Yolk Sac Infection

• It is one of major factors causing early death of ostrich chicks, with most birds dying within 21 days of hatching or it will lead to poor development and growth. This is due to the failure to absorb the yolk sac during the first few days after hatching. This phenomenon has been associated with poor husbandry, high ambient temperatures, energy-rich diets and lack of exercise.
• Yolk sac infection is commonly attributed to poor hygiene during egg handling and incubation, or to post-hatch navel infections. Other factors have been implicated in yolk-sac infection; these include incorrect brooding temperature, heaters on a cold concrete brooder floor, insufficient water intake and a delayed start to feeding.
• Egg hygiene should be aimed to prevent yolk sac infection. This includes keeping nests clean and dry, collecting eggs before they cool down and cleaning eggs properly to prevent bacteria penetrating the shell.
• Poor hygiene and maintenance in incubators and hatchers also result in pathogenic microbial infections, and the post-hatch survivability of chicks is severely reduced.

Fig. 7.18. Unabsorbed yolk due to infection

Yolk Sac Removal

• The removal of the yolk sac in young chicks involves a surgical procedure that totally removes both the yolk sac and the umbilical stump. Although this procedure has been widely used to eliminate yolk sac infections in the past, it is not a common practice now and the overall results of this type of surgery may not be good.
• The removal of the yolk sac should be a last effort since the yolk material is necessary for providing both nutrition and antibody to the young bird. The prevention of this problem by stimulating the chick to use this material is the most beneficial treatment. Surgical procedure usually involves anesthetizing the bird with Isofluorane, Halothane or Metofane.
• The feathers on the entire abdomen are clipped and the area is surgically prepared. An incision of about 2 inches is made completely around the navel, completely removing it (Note that it is still attached to the yolk sac and care should be taken not to rupture the yolk sac). The yolk sac is then tied off next to the intestine and the yolk sac removed.
• The abdomen is sutured with gut and the skin with non-absorbable suture. Flushing the abdominal cavity with warm saline (PBS) is usually helpful in maintaining temperature and antibiotic therapy is recommended. Chicks can be returned to their familiar surroundings as soon as recovered from the anaesthesia.

Umbilical Infections

• These are often one of the most common causes of moralities in chicks up to 2 weeks of age. Many of these infections result from over ambitious handling of chicks, poor sanitation in the hatcher, or contamination of the umbilical area after hatching.
• Proper treatment of newly hatched chicks and proper hatching procedures can reduce losses due to these types of infections Umbilical infections are generally due to the same problems as are yolk sac infections.
• Many times the yolk sac becomes infected as a result of the umbilical area being infected. Proper care and handling of newly hatched chicks can minimize these infections.
• When chicks are 6 to 7 days of age, re-examine the umbilical area to determine if further treatment is needed. At this time, a small "knot" or bump can often be detected at the umbilicus. This is usually what remains of the umbilical vessels and can be the source of bacterial infection that may result in umbilical and yolk sac infections.
• To treat this condition, the umbilical area is palpated and the scab that has formed on the umbilicus is removed. By applying pressure with fingers from the belly outward, infected material can be easily expressed. This area has to be treated with 7% iodine and the bird is returned to its original facility. No further treatment is usually needed.

Leg Problems

• Leg deformities, including twisted or bowed leg bones and swollen or deformed hock joints, commonly occur in young or growing ratites. Rolled toes are common for ostriches. This is normally caused by poor management during hatching and early development of young ratites. Feeding high protein starter diet to birds with a lack of exercise results in rapid growth (bodyweight of over 4.5 kg at 28 days for ostriches) and finally end up in leg problems.
• Housing chicks on cement floors with high stocking density contributes to leg problems as well. Rolled or twisted toes could be caused by deficiency of B-complex vitamin (such as riboflavin deficiency) or an unsuitable surface. Slipped tendons could be caused by deficiency of manganese, while bowed legs could be caused by an imbalance in the Ca and P ratio or low protein levels.

Impaction

• This commonly occurs in ostriches and rheas. In ostriches, impaction is caused by excessive ingestion of material which accumulates in the proventriculus and gizzard. Impaction may be classified into acute (birds become weak in a few days) or chronic (birds become weak in weeks to months), hard (caused by hard materials such as rocks and sand) or soft (caused by fibrous materials such as grass), and partial or complete. Impaction can be prevented by using sand and dirt as floor materials.
• Impaction is not likely to be a major problem under intensive rearing but it can be a significant cause of mortality in young chicks under semi-intensive systems where chicks have access to pastures freely or on restricted basis. Chicks previously confined to concrete and turned out to pastures for the first time usually get excited and tend to eat almost anything which may cause impaction.
• Early treatment with some form of oral lubricant such as vegetable oil can help to breakdown some of this material and get the bird back to a normal diet. When diagnosed early, surgical intervention can be very successful in removing the impacted material. Oral dosing of ¼ teaspoon Epsom salt (magnesium sulphate) in water for a small chick to 2 tablespoons for an adult bird.

Fig.7.19. Impaction

Toe Trimming

• This minimises skin damage and injuries due to fighting, thereby improving the quality of leather. When toe trimming is practiced on day-old ostriches, there is a reduction in trampling behaviour which lowers the potential for skin damage in the first 2 weeks after hatching and improves the percentage of A-grade skins.