Introduction: During oviposition (the process of laying an egg) the shell gland (the lower part of the hen�s reproductive tract where the egg shell is formed) is temporarily everted (turned inside out) along with the egg. This allows the hen to lay a very clean egg. Sometimes the oviduct will not immediately retract once the egg has been laid. This condition is known as prolapse. The longer the oviduct remains outside the body, the greater the chance other birds will peck at the material, which could cause irreversible damage. If not noticed immediately, other birds will pick at the protruding material, often causing hemorrhage, infection, and death if quick action is not taken. CAUSANTS:
- Over or underweight Birds:
- Overweight birds are more prone to prolapse due to general muscle weakness and a tendency to lay larger eggs. Too much fat around the reproductive organs can also lead to prolapse.
- Birds that are underweight: when the birds begin lay are more likely to suffer prolapse because they may begin laying before the reproductive tract has completely matured.
- Early Photostimulation (increasing day length to stimulate sexual maturity):
- Birds that are exposed to increasing day length before the reproductive tract has fully matured are more likely to prolapse, because the reproductive tract may not be fully matured when they begin lay.
- Unbalanced feed rations:
- Insufficient calcium and other nutrients like Manganese, D3 and Choline in the diet will cause problems with eggshell formation but can also result in poor muscle tone. Poor muscle tone may cause problems with oviduct retraction once the egg has been laid.
- Reproductive age of the flock:
- Prolapse is more likely to occur at peak production and peak egg mass, simply because of the large demand placed on the birds metabolism.
- Laying double yolked eggs :
- The excessive size of these eggs will stretch and possibly weaken cloacal muscles. Weakened cloacal muscles will lead to an increase in the amount of time the oviduct is outside the body.
- High light intensity:
- Under high light intensity conditions, birds are more likely to see and be attracted to the everted oviduct and thus more likely to peck at it and cause damage.
TO AVOID DAMAGE:
- If the flock is laying a lot (more than 4%) double-yolked eggs, gently restrict feed intake (about 5-10% less than they eat ad libitum).
- Observe vent-pecking behaviour and isolate them from the flock.
- Reduce the lighting
- Round or blunt the beaks of the aggressive hens by using a hot cauterizing blade.
- Consider a very low wattage red-colored bulb. If birds can not distinguish the color of the everted shell gland from the background of colors, they may not be as prone to cause damage.
TREATMENT: Treatment of prolapsed hens with estradiol benzoate resulted in 89% of the birds recovering within 3 weeks compared to a 4% recovery rate in the controls. (Shemesh M, Shore L, Lavi S, Ailenberg M, Bendheim U, Totach A, Weisman Y; SUGGESTED LEVEL: 20 ml/100 birds for 7 days