حَسِبتُمُyou reckoned وَلَدَoffspring البَرشاءِal-Barshāʾ قاطِبَةًall together
حَسِبتُمُ وَلَدَ البَرشاءِ قاطِبَةً
نَقلَhauling السَمادِthe manure وَتَسليكاًand threading غَفاdry plant refuse الغِيَرِthe ghiyar (meaning uncertain here)
نَقلَ السَمادِ وَتَسليكاً غَفا الغِيَرِ
You reckoned all the offspring of al-Barshāʾ
You thought the son of Barshaa was ungrateful,
Fit for hauling manure and threading the dry plant refuse of the ghiyar (an uncertain term).
carrying dung and serving others while asleep