September's storm claimed the lives of a million lambs on Otago and Southland farms, but tough winter and spring weather could potentially have killed double that throughout the country.
Tailing statistics collected by Beef and Lamb New Zealand (BLNZ) reveal the 20-point lambing percentage drop recorded on Southland farms alone from last year to this year, equal to 735,000 fewer lambs, the largest single decline recorded in 40 years of collecting the data.
In Otago, the decline was also significant, but less spectacular at 431,000 lambs, with a dry autumn reducing conception rates and then followed by September's storms.
Nationally, 25.11 million lambs were tailed this spring, 2.78 million fewer than last year, the biggest decline in 21 years, and due mostly to adverse weather.
It will result in the export slaughter of an estimated 19.5 million lambs, a drop of 1.42 million from last season, and the lowest in at least 30 years.
Snow, rain and wind hit much of Southland, South Otago and West Otago in September, killing lambs and an unknown number of ewes, with farmers reporting a drop in lambs tailed of between 6% and 50%.
The most intensively farmed properties in Otago averaged an 18.6% decline and 21% in Southland.
But the North Island was also affected by wet, cold weather during lambing.
A 6.2% lift in the number of lambs born to hoggets, to just over one million nationally, has boosted the overall lamb crop.
BLNZ southern South Island director Leon Black said the storms followed an outbreak of salmonella brandenburg on many Southland farms which reduced the lamb crop before the storm.
Economic service executive director Rob Davison said miserable spring weather meant the lamb killing season was already two to three weeks late and he estimated the kill for the first three months of the season would be 4.2% lower than for the same period last year.
But meat companies were paying more for them and accepting heavier lambs.
A year ago, companies were paying between $5 and $5.20 a kg, but this year they are paying $6.10 to $6.40 a kg.
With lower stock numbers, Mr Davison expected farmers to retain lambs to heavier weights, with an expectation the average weight will be 1% heavier at 17.8kg.
Mr Davison said the decline in southern ewe numbers stabilised last year with 6.93 million going to the ram in autumn, a drop of 1.6%.
Most of that drop was in Otago and the result of the dry summer.
Mr Davison expected ewe lamb retention rates this year to be lower than last season, due to the need to generate cash flow.
The South Island lamb kill was expected to be 784,000 fewer at 10.5 million which follows an 8.8% decrease between 2008-09 and 2009-10.
The expected North Island kill was expected to be nine million, a drop of 638,000
Spring storms take toll
• Southland lambing percentage fell from 133.5% in 2009 to 113.5% in 2010.
• Otago lambing percentage fell from 122.5% to 115%.
• Otago Southland lamb crop estimated to be 1.17 million fewer at 8.25 million.
• New Zealand lamb crop estimated at 25.11 million, a 10% decline.
• Export slaughter estimated at 19.5 million, a fall of 1.42 million.
Source: Beef and Lamb New Zealand.