Spring has been slow to arrive at many New Zealand farms, according to the latest BNZ Rural Wrap.
Wet weather had been unhelpful for many farmers, the report said, lamb number estimates and expected milk production have both dropped, and the export growth outlook has been lowered.
Beef + Lamb New Zealand estimates the 2017 spring lamb crop is 23 million head. That is 1.3 per cent down on last season.
"This drop is in contrast to previous indications that the lamb crop might be up around 1.1 per cent," the Rural Wrap said. "The drop equates to around 300,000 fewer lambs this spring compared to last year and about 500,000 fewer lambs than what was being factored in for the new season a couple of months ago."
Fewer lambs result from the fall in breeding ewe numbers. At the end of June, there were estimated to be 17.8 million, down 1.9 per cent from a year earlier.
"The expected small lift in lambing percentage is not enough to offset the drop in breeding ewe numbers, hence the now expected decline in lamb numbers. After accounting for retentions, it all suggests there will be around 19.3 million lambs available for export, similar to the season just ended.
"Meanwhile, lower sheep numbers is expected to see export mutton production in 2017-18 fall by as much as 9 per cent from the 2016-17 season. All this sees us tab down our overall meat export volume growth forecasts for the 2017-18 season."
A smaller supply of lambs could improve their prices.
"Reports of very little inventory held through the supply chain supports this view, although, as ever, actual pricing at the farm gate will also depend on the weather and currency levels."
B+LNZ expected export production would to be marginally lower in 2017-18.