How to Prevent Sand-Shelled and Soft-Shelled Eggs in Three-Lined Box Turtles

Three-lined box turtles mate and fertilize in March-April each year, and lay and incubate eggs from May to July. A single sexually mature female turtle lays 3-9 eggs per year; the three-lined box turtle has a relatively low egg production among turtles. Improper feeding and management or the influence of other factors can also cause some three-lined box turtles to lay 1-2 eggs, or even a whole clutch, of sand-shelled eggs (with a sandy, non-smooth shell surface) or soft-shelled eggs, affecting the hatch rate and causing certain economic losses to three-lined box turtle farming.

1 Causes of three-lined box turtles laying sand-shelled or soft-shelled eggs

a) Lack of eggshell-producing minerals in the feed, mainly calcium; or lack of vitamin D, making it difficult for the turtle's body to normally absorb enough calcium.

b) Aging of the turtle. Most of the female three-lined box turtles currently kept are wild-caught turtles taken from deep mountains and old forests; such turtles generally lay eggs in nature for more than ten or even several decades. Because they have laid eggs for so long, the function of the eggshell gland declines, and they lay sand-shelled or soft-shelled eggs. According to the author's observations, female turtles with declining eggshell gland function all have laid eggs for more than 30 years of age; externally, the growth rings on the turtle's back are very dense, movement is slow, and food intake is somewhat low. They also have a past history of abnormal egg laying.

c) Inflammation of the female turtle's oviduct causes the eggshell secretory glands to fail to normally secrete calcium.

d) Strong external stimulation causes contraction of the female turtle's oviduct, resulting in the eggshell not being fully formed and soft-shelled eggs being laid.

2 Prevention and control measures

a) Supplement calcium and vitamin D in a timely manner. Some calcium-rich foods can be added to the turtle's feed, such as shrimp shell powder, shell powder, eggshell powder, etc.; at the same time, vitamin D should often be added to the turtle's feed to improve the female turtle's calcium absorption rate; feed with high vitamin D content, such as animal liver, can also be given.

b) Female turtles that are aging due to an excessively long reproductive age should be culled.

c) For female turtles suffering from oviduct inflammation, compound sulfamethoxazole tablets can be mixed into the feed and fed; the dosage per female turtle is 0.25 g, used continuously for 3 d as one course of treatment. Or gentamicin and vitamin B can be injected at one time; the injection amount is 1/5 of the human dosage, used continuously for 3 d as one course of treatment. In addition, Chinese herbal medicine can also be used for treatment: take equal parts of honeysuckle, Phellodendron chinense bark, and licorice, roast them dry and grind them into powder; the dosage per female turtle is 2-4 g, mixed into the feed and fed, used continuously for 3 d as one course of treatment.

d) Keep the turtle pond quiet and avoid startling the female turtles; especially before egg laying, do not easily move the female turtles, and even more so do not transport them over long distances. To reduce the female turtles' stress response to the environment, a certain amount of vitamin C and a small amount of vitamin E can be added to the female turtles' feed. Some feed with high vitamin C content, such as bananas and apples, can also be fed, as well as an appropriate amount of wheat bran, cornmeal, etc., to facilitate the female turtles' intake of vitamin E.