But instead of waiting for an ambulance baby Richard Royal was rushed to Tauranga Hospital's emergency department.
Despite CPR attempts by hospital medical staff, her son was pronounced dead a short time later, the mother said.
Other prosecution witnesses on Tuesday included a child who, in a videotaped interview by a Child, Youth and Family specialist, said he saw the defendant hit Richard Royal in the face with his hand.
Under later cross-examination by defence lawyer Rob Stevens, the child, who cannot be identified for legal reasons, recanted part of his statement about seeing the defendant hit the baby.
Stevens urged the jury to keep an open mind.
"This is a tragic case."
Stevens said in a brief moment, the defendant reacted in a way that caused the baby's death, and accepted responsibility for inflicting the fatal injuries.
"But he did not mean to kill Richard Royal," he said.
Stevens reminded the jury that the burden of proving the charge beyond reasonable doubt rested with the Crown.
At the end of the trial the jury could find the defendant guilty of manslaughter but not guilty of murder, he said
Acting Crown solicitor Anna Pollett earlier argued the amount of force inflicted on the "defenceless 14-week-old" showed the defendant meant to kill the baby or knowingly "diced with the risk" that the assault was likely to cause his death.
The trial, which is expected to last 6-7 days, continues today.