"South Island numbers dropped 3.3 per cent to 9.5 million, also affected significantly by drought. Reducing capital stock numbers is often the least preferred option for farmers so it does reflect a very challenging year."
The largest drop in breeding ewes was in Marlborough and Canterbury, where numbers dropped 6.5 per cent due to ongoing drought conditions.
The lamb crop estimate will be updated in November.
Beef + Lamb noted that land use change towards dairy farming had slowed considerably over the past year, underpinned by a low farmgate milk price and increasing concerns over future environmental regulations for the sector. However, strong returns for beef cattle increased the lure of cattle production.
The country's beef cattle herd increased 2.8 per cent to 3.7 million, following a 3.3 per cent decline the previous season.
The largest contributor to the increase in cattle numbers was an 8.2 per cent lift in weaner cattle as farmers responded to good returns and to offset selling of adult cattle in some regions, the organisation said.
While dairy cattle numbers aren't measured by the survey, the Economic Service expects the total herd to be almost unchanged, down about 0.9 per cent to 6.43 million as at June 30.
The Economic Service noted that farming practices were more efficient than in the 1930s, with lamb production 1.7 times greater, mutton production 60 per cent greater, and the average lamb slaughter weight up 23 per cent.