HE said he loved his baby boy and didn't mean to kill him.
Nicholas Arthur also said he didn't mean to crack 19 ribs in his son Seth's body back in 2010.
But Arthur lost his nine-week-old son after he used mild to severe force on his baby's back when he tried to bring up the boy's wind.
Arthur yesterday pleaded guilty in the Rockhampton District Court to two counts of assault causing bodily harm after his son died in late October 2010 from internal injuries.
Arthur sobbed and gave long emotional pauses while giving evidence.
He denied Crown Prosecutor Joshua Phillips' submissions that he intentionally and maliciously beat his son out of frustration.
The court heard that from birth, baby Seth was always unsettled, crying and unable to have a comfortable sleep.
Arthur tried to comfort Seth on the day he died by making the baby bring up wind because burping seemed to relieve the baby's pain, the court heard.
Arthur said he and his former wife Rebecca, who is Seth's mother, made a number of doctor visits after the baby was born in late August.
A number of doctors suggested the baby suffered from reflux and colic, Arthur said.
Crown Prosecutor Phillips submitted that Arthur had used mild force on Seth's back because he was frustrated the baby wasn't showing signs of pain relief.
"No parent likes to see their child in pain," he said.
"I was a little rough on him but it wasn't intentional."
The court heard how Arthur always played with his son, while the latter was on his lap, by performing light and playful boxing manoeuvres on his son.
It wasn't known what injuries were directly related to Seth's death.
Judge Paul Smith sentenced Arthur to three years in prison.
But as he had served 308 days in custody, Arthur was released immediately on parole.
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