Preparing for a dry summer

Strong returns for lamb coupled with predictions of a dry summer in many parts of the country are an incentive for farmers to maximise pre-weaning growth rates.
Wednesday, 26 September 2018

NIWA is predicting a moderate El Nino weather pattern will dominate over spring and summer which means drier than normal conditions along the east coast of both islands.

B+LNZ General Manager South Island John Ladley says by utilising spring soil moisture to drive pasture growth, lactation and lamb growth rates, sheep farmers will be able to maximise pre-weaning growth rates and sell lambs and cull ewes before the dry weather kicks in.

Achieving growth rates of 400gms/day – which is possible on high quality pastures or specialist forages – means more lambs are sold prime off the ewe (the most profitable lamb).

He says faster growing lambs use feed more efficiently by partitioning feed into growth rather than maintenance and are less likely to be subject to a parasite challenge – so may never need drenching.

“Selling lambs early allows feed to be partitioned into either capital stock or trading stock.

“In other words, it gives farmers options.”

Careful pasture management can have a huge impact on quality of grass pastures.

Driving pasture quality

  • Run the correct stocking rate so feed supply and demand are closely matched. This minimises surpluses and prevents build-up of dead material.
  • Pre-grazing covers of 2400-2500kg DM/ha and residual covers of 1500kg DM/ha yield the optimum balance of production and pasture growth.
  • Sub-division (permanent or temporary) allows feed to be allocated to high priority stock such as ewes and lambs.

Creep grazing

Creep grazing uses a specially designed gate to allow lambs access to high quality feed while holding the ewes back. Creep grazing trials run throughout New Zealand showed improved weaning weights of up to 5kg in 16 out of 18 experiments.

Making a plan- and sticking to it

John says one of the most effective management practices farmers adopted during the recent Canterbury drought was drawing up management plans and sticking to them.

Prioritising specific actions and ticking them off and setting trigger dates to make decisions ( e.g if it hasn’t rained by November 20 the five-year ewes will be early-weaned) all helped manage feed resources and protect the performance of capital stock.

Early decision making is critical in dryland situations where climate is uncertain.

Early weaning

Early weaning can be a powerful tool, especially when supply of high-quality feed is limited.
In trials run at Massey University, researchers found heavier lambs (over 20 kg) cope best with early weaning, but the quality of the forage on offer is the biggest determinant of how lambs grow post-weaning.

Early weaning (with a minimum weaning weight of 16kg) was found to be most effective in seasons when grass growth was limited (pasture covers of under 900 kgDM/ha), and lambs weaned early were offered a herb clover mix with a minimum pasture cover of seven centimetres.

Early weaning allows cull ewes to be sold early – typically on a higher schedule- which frees up feed for other stock classes.

Selling store

John says farmers could consider selling lambs and cattle as store, rather than struggling to finish stock at the expense of the condition of capital breeding stock.

“It is critical to protect the reproductive performance of your breeding stock. Setting ewes and cows up for a successful lambing and calving next season will help ensure the effects of dry weather are not felt in subsequent seasons.”

Body Condition Scoring

This simple, low-cost management tool allows feed resources to be used efficiently and effectively. It is a powerful tool to ensure feed is partitioned into the animals that actually need it while stock with a higher body Condition Score can be maintained. Again, this protects the reproductive performance of ewes for the following year.

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