TEREKEKA, South Sudan —When the girl was 16, her uncle told her he was taking her to the family village.

Excited about the trip, she packed the few things she had. She thought the plan was to meet relatives and see the birthplace of her father, who died when she was 10.

She didn’t understand yet that in South Sudan, being “taken to village” has another meaning: She would be married off, against her will, to an elderly man she had never met. She would be the newest of his six wives.

“My uncle needed cows,” she said.

In many communities in South Sudan, one of the world’s poorest nations, girls grow up with a single purpose: to be sold into marriage for cows to expand a family’s herd – the closest thing most people have to a bank account – and to buy wives for her brothers.

OFTEN STILL CHILDREN

Because it makes financial sense to marry off a daughter quickly, the brides are often children.

Independence for South Sudan in 2011 brought widespread hopes for prosperity, an end to years of civil war and rudimentary rights for the new country’s 11.3 million people. But little of that has materialized.

A wave of killings and sexual assaults has accompanied a new outbreak of fighting, and much of the nation remains trapped in deep poverty. Though South Sudan’s assembly even before independence passed a law in 2008 limiting the marriage age to 18 and over, it is rarely enforced, particularly in rural areas.

Across much of the troubled country, young girls remain as much a commodity for marriage as they ever were.

Roughly 17 percent of girls marry before they are 15, and nearly a quarter marry between 15 and 17, according to a 2010 government survey. The vast majority of those marriages are thought to be families trading their daughters for cows.

The bride price is typically 20 to 40 cows, each worth up to $500. A girl who is seen as beautiful, fertile and of high social rank can bring as many as 200 cows.

The United Nations, which says the country has the world’s fifth-highest prevalence of child marriage, has attacked the practice as a violation of human rights, a serious impediment to literacy and a major cause of persistent poverty.

But attempts to wipe it out have faltered because under customary law here and elsewhere in Africa, women have fewer rights than men. The 8-year-old marriage law is resisted in many communities because it demands that impoverished rural families put at risk their biggest potential commodity: their daughters.

Once a girl is taken to village, there is no way back. Schools empty. Friends and sisters are suddenly gone. Some remain, kicking the dusty path to school, dreams still singing in their heads.

Some girls go meekly, melting away to a distant village to haul water and firewood, sweep, clean, wash, cook, give birth, work a lifetime.

HE NEEDED THE COWS

Not Agnes Keji.

When her father informed her that she would be married to a man who was about 70, “I refused,” she said. She had fallen in love with another man when she was 13 – but the romance was unthinkable because he had no cows.

“If you want to kill me, kill me now because I don’t want to go to a man I don’t know,” she said she told her father.

So he beat her. Her brother did worse: He needed the cows she would bring so he could marry the girl he wanted. So he took his machete, Keji said, and found her in the village square.

“He slashed me, and he cut my throat,” she said. “The cut was deep, and I was taken to hospital.”

Neither her brother nor father could be reached for an interview. The left side of her neck has a scar about an inch long.

Keji tried running away to the capital of Juba, 53 miles and a three-hour drive on cratered dirt roads from her town of Terekeka on the Nile River. But her brother caught her and brought her back, she said.

Now 19, she was expecting to soon be married to the older man: “I don’t have power. I’m finished. There’s nowhere to go. There’s nothing I can do.”

The price of a daughter in cows is determined in a negotiation between her father and would-be husband. Many daughters are married off to elderly suitors because those men tend to have the most cows.

Once girls are married, they are expected to work and bear many children, especially daughters, who are seen as assets to acquire more cattle. They obey their husbands or face violence.

Some families have shunned the tradition of collecting a bride price and instead have sent their daughters to school. But in a culture in which the value of a woman is measured in cows, those families are in the minority.

Just 7 percent of girls finish primary school, and fewer than 2 percent go to high school. Girls are three times more likely to die in childbirth than complete their studies, according to the U.N.

“As a girl, from a young age, you will be told to focus on being a good wife,” said Lily Akol, a former deputy agriculture minister and one of the few women to earn a university degree. “Once you go and get educated, you are not seen as a good traditional African or South Sudanese girl.”

Educated women are seen as arrogant, disrespectful and promiscuous, she said.

Phuong Nguyen, the UNICEF representative in South Sudan, said some families worry that sending girls to school exposes them to dangers such as sexual assault that could lower their value when it comes time to look for marriage offers.

“You have some communities that are very anti-education because they don’t understand the value of it,” she said. “Girls are considered a commodity. The earlier they’re married off, the less the burden.”

In March, the U.N. announced a campaign to eliminate child marriage worldwide by 2030. “This type of culture takes time to change,” Nguyen said.

For some girls, running away is the only escape.

In a shelter for vulnerable children in the capital, a 16-year-old girl told the story of how she had fled three years earlier after her father died and her brothers planned to marry her off.

A more likely fate for girls who fled to Juba are the brothels.