A woman who wheeled her 17-month-old baby into a desert and left her their to die has been jailed for 20 years.

Ashley Denise Attson, 23, from Arizona, put her daughter in a pushchair before leaving her in the Navajo Nation for four days and four nights in September last year.

“Over the next few days she met friends for ice cream and posted pictures of herself on Facebook,” the US Attorney’s office for Arizona said in a statement on Tuesday.

She then retrieved the baby’s body and buried it in an animal hole, the statement read.

The child, who has not been named as she was a juvenile and is referred to in court documents as ‘Jane Doe’, was born with methamphetamine in her system and was in the custody of tribal social services for the majority of her life.

Attson regained custody of her daughter around two months before her death, according to prosecutors.

The mother pleaded guilty to second-degree murder. US attorney spokesman Cosme Lopez did not comment on the motive for the killing.

US District Judge David Campbell said Attlee committed an “intentional, cold-hearted, horrendous killing of an innocent child”.

According to a plea agreement reached with prosecutors, the maximum punishment that could be given to Attson was a life sentence.

A former tribal prosecutor told the Associated Press she was troubled that Attson had instead received a 20-year sentence.

Bernadine Martin, a former chief prosecutor for the Navajo Nation, said the child would have been afraid, in physical distress and “needing the one person who is supposed to care for her the most, that being the mother”.

“And 20 years is simply not enough.”