Weigh up hogget mating gains

01-04-2009 | Gerard Hall

One question on many sheep farmers' minds right now is whether to mate or not to mate-ewe hoggets that is.

Lamb prices this season are up and farmers have growing confidence they will stay that way in the medium term.

During the past few months, lambs have done well. Carcase­weights are ahead of last year, suggesting ewe lambs will be heavier and in better condition by the time the rams are due to go out.

Mating ewe hoggets and keeping ewes an extra year are two options for farmers to consider if they want to expand their sheep enterprise.

Spring, not autumn, is the most critical period feed wise when mating ewe hoggets. However, with good rains falling at the right time, soil moisture levels have been recharged. On many properties this should result in adequate pasture covers going into the winter.

In recent years, a combination of factors, including changing land use, drought, poor lamb returns, and a lack of enthusiasm for farming sheep, have all contributed to mating ewe hoggets taking a back seat on many farms.

Many farmers decided it was not worthwhile financially and they could do without the extra hassle.

However, a turnaround is expected and more ewe hoggets are being mated this year.

To help farmers decide whether to put the ram with the hoggets, Country-Wide posed the same questions to Rural Solutions' Graham Butcher. We also asked the Gore-based registered farm management consultant to crunch the numbers.

Using Stockpol, Butcher looked at the decision of a Southland sheep farmer to mate at least half his ewe hoggets because they were up to the 42kg LW target weight.

The model farm winters 2558 ewes and 716 ewe lambs. The ewes are consistently weaning 140%, (lambs weaned: ewes mated), no hoggets are mated and all surplus lambs are slaughtered.

After taking into account the additional costs incurred and a 4% drop in stocking rate if done well, Butcher's analysis suggests this farmer will better off by a little under $16,500.

Stockpol is a decision support tool that takes a ‘whole of farm' approach. It can be of immense value when seeking answers to some of the ‘what if' questions.

Butcher says experience shows that under Southland conditions, spring stocking rates need to be reduced by about 4% when half the ewe hoggets pregnancy scanned in-lamb.

As a result, the first thing to drop out is the 102 ewes and 28 ewe lambs. If sold, they generate about $12,000 in revenue which could pay for a 10-day Pacific Island family holiday. There's a few brownie points already.

On this farm the decision to mate ewe hoggets lifts the potential carcaseweight sold from 46,303kg CW to 50,026kg CW. At $5.20kg CW the revenue from an additional 3723kg CW is $19,359.

The increase in carcaseweight sold is achieved while consuming the same amount of total feed, but there is a small difference in the feed supply-feed demand curves. A little less feed is required in winter and a little more through the spring-summer period.

In terms of the change in the flock's feed profile, Butcher suggests if done well, the decision to mate ewe hoggets has the potential to create something from nothing. The model flock used in this example is better off simply by using available feed a little differently.

He says the need to drop spring stocking rates could be reduced by applying urea or lambing the hoggets quite a bit later. In Southland, like many other areas of the country, the spring is the most critical period feed-wise. If the weather is rough a high price can be paid.

"It is important both ewe and hogget lambing dates are closely matched with feed supply. That way, ewes and their lambs can get off to good start."

Butcher says lambing a proportion of the ewe hogget flock might also mean shearing patterns need tweaking. In-lamb hoggets may need to be shorn in mid-pregnancy instead of shearing them with lambs at foot at the usual October shearing.

One cost not included in Butcher's analysis is the potential for a drop in the two-tooth lambing performance of those that have lambed as hoggets.

It's simply a liveweight response; Butcher says if two-tooth lambing performance suffers the extent will vary depending on the farm and the farmer.

Research shows if two-tooth ewes are 6kg lighter at mating compared to their un-mated counterparts, they are likely to rear 12% fewer lambs.

If that is the case, on this farm it is likely 46 fewer lambs will be available for sale. At $80/lamb this equates to about $3800 and the likelihood of it happening needs to be considered when determining the financial gains from lambing hoggets.

One option to lessen this risk is weaning lambs at 10-weeks and then preferentially feeding the hoggets through the summer. This will ensure they continue growing out and their two-tooth mating weights and subsequent lambing performances are on target.

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