Hormone test aid precise panda reproduction

 XTAN-A female panda who has discovered a newfound fondness for playing in the water caught the attention of its keepers at the Qin-ling Panda Research Center in Northwest China's Shaanxi province who believed she might be in heat.

Researchers at the center, which houses a total of 32 giant pandas, are busy monitoring and studying the animal's breeding activities, especially verifying whether or not the pandas have initiated their estrus cycle.

Giant pandas come into estrus between February and May, with April usually being the peak of the cycle. To create the best conditions for the pandas to mate, the keepers must track the

The precise time of the cycle.

However, there are many challenges: The cycle only occurs once a year for pandas in captivity, lasting for only one or two weeks. To make matters worse, the mating window often lasts less than a day, and sometimes only for a few hours.

Currently, there are two methods to determine whether the animals are in heat. One method is the traditional means of observation, and the others are testing their reproductive hormones, according to Zhang Danhui, an assistant veterinarian at the center.

The conventional method can be an arduous task for the researchers, as they have to watch the pandas around the clock, in shifts, recording their condition and conducting analysis.

It is not an easy task for a lone keeper to follow two potential mates around with a flashlight into the early morning hours.

"We would pay attention to certain behaviors, such as if their tails are up and if they are paddling or taking a cold bath," says Zhang.

However, in recent years science has come to the rescue of exhausted researchers by way of the aforementioned reproductive hormone testing.

They no longer have to rely on their instincts and experience alone to determine the brief window of time for mating.

Once the hormones of the pandas are set to change, the center will collect urine samples and gradually increase the sampling frequency, says Zhao Pengpeng, a senior veterinarian.

"It is like a race against time when multiple pandas enter their rutting periods during the peak season. It is often the case that their previous urine samples are still being tested when the latest urine samples are collected and sent to us, "says Shen Jimena, an assistant engineer there.

"Every single minute or second matters, since the best mating period may only last several hours. Once you miss the window, you have to wait for the following year," she adds.

After identifying the best mating time, the center will then help giant pandas conduct breeding activities through natural mating or assisted reproduction.

In 2020, four giant pandas were born at the center, the world's third-largest breeding base for the animal.

"We spare no effort to help every female panda that is suitable for breeding to have cubs. When they give birth to new cubs, it is a happy moment for us as well," Zhang says.