Improving management of dry land sheep farms lessons from Silverwood.

August 2008
Now in the second year of a series of trials supported by SFF, there have been some mistakes made and lessons learnt in the quest for more productive systems for farming dry land. The findings are relevant to farmers in the district, and the principles if not the detail may apply to many other dry land farmers.

The main lessons so far are partly because the units were in transition to the management regime and stock type:

Winter feed needed to allocate 10-12% of units to winter fodder rather than the 6% which was there

Switch pastures (permanent clover direct drilled with annual rye in autumn to provide winter grass) need to be grazed out hard mid-summer and sown in February.

Tall fescue and Cocksfoot are of questionable value in the grass system

In the legume system feed is tightest in autumn, but this can be covered with the use of lucerne as long as it is free of disease and damage otherwise oestrogen levels will reduce conception rates.

Underfeeding in winter because of poor pasture performance and inadequate area set aside led to higher than expected perinatal deaths of older ewes

Worm problem with lambs on grass may be ameliorated if they are weaned onto lucerne

When finishing feed is short, need to favour any lamb that will finish quickly. It was a mistake to favour twins rather than advanced singles.

Silverwood farm is 418 hectares of light land at Hororata, farmed by the late Frank White until 1985 when he established it as a charitable trust for education and research in sheep and cattle breeding and husbandry, and forestry. Lincoln University leased the property from the Silverwood Trust in 1999 and established a farmer reference group to assist in defining research priorities for the farm.

The group was awarded a Sustainable Farming Fund grant in 2006 to establish two research and demonstration units at Silverwood. The research intention is to look for ways of pushing the boundaries of productivity on dry land farms using high numbers of low body weight high fecundity ewes plus some cattle to give a stocking rate of 14su/ha on the two systems:

An 85ha traditional grass based system with strict grazing management to maintain pastures in an active growing state during peak growth periods and encourage clover growth.

An 87ha legume based system with a combination of traditional grass pastures, lucerne and switch pastures (perennial clover pastures, direct drilled each autumn with annual ryegrass)

To reduce risk, flexible stocking and management was to include:

Early lambing of older ewes to allow early weaning and sale

2 yr old cattle on the grass unit to assist in maintaining residuals in sheep pastures and as a readily saleable stock class

2 yr ewes instead of cattle on the legume unit, the majority lambed early

A paddock of lucerne on the grass farm to extend feed supply in dry conditions

All sale stock sold before the end of the year

Use of supplements and grains when absolutely necessary

The Grass Unit

At establishment, the grass farm had:

13 Pdks of grass based pastures, primarily ryegrass with 2 pdks each of cocksfoot and tall fescue and 3 of Bareno grazing brome (69.7 ha, 81.9%)

1 Pdk of kale (4.7 ha, 5.5%)

2 of lucerne (9.4 ha, 11%).

The unit was stocked with 858 mixed age Coopworth ewes and 55 R2yr cattle, equivalent to 14SU/ha.

30 kg N as urea were applied to all grass paddocks, except the cocksfoot and tall fescue at the beginning of August. 60 kg N was applied to cocksfoot paddocks and a further 30 kg N to all other grass paddocks in late spring; 40 kg N wasto be applied to any bailage paddock (there were none).

The Legume Unit

At establishment, the legume farm had:

4 Pdks grass pastures (25.7 ha, 30.2%)

2 Pdks turnips (9.4 ha, 11.0%)

5 Pdks switch pasture (25.5 ha, 30.0%)

5 Pdks lucerne (24.5 ha, 28.8%)

Switch paddocks were established as rape undersown with clover in November 2006 and grazed off by February 2007. They were direct drilled with annual ryegrass in early March 2007.

The unit was stocked with 832 mixed aged Coopworth ewes, plus 242 2yr ewes, equivalent to 13.9 SU/ha.30 kg N as urea were applied to all grass paddocks, including the switch paddocks at the beginning of August with a further 30 kg N applied to grass pastures only in late spring.

Lessons so far

1. The experimental areas are relatively large not a plot trial so they couldnt re-establish the whole farmlet in the pasture types wanted, so pastures ended being a little different to what was anticipated. Also some pastures were past their best and didnt perform to expectation. A crop of turnips on the legume farmlet was sown late and did not perform well. The result was lack of winter feed. So the first lesson is that we really need about 10-12% of the farm in winter feed, and we had only about 6%.

2. We ended up going onto pasture on the legume farmlet earlier that expected, and a third of the farm had been sown in switch (permanent mixed clover sward with annual direct drilling of annual ryegrasses). The second lesson was that the switch pastures should have been grazed out hard in January and sown earlier, preferably February to take advantage of any rains. That was done this year with Tama, the preferred ryegrass.

3. The Bareno pastures were run out, but we also should have maintained higher covers. This year we have kept above 1500kgDM. However, Bareno does not seem to thrive in this hard dry land environment. The tall fescue and cocksfoot paddocks probably dont have a place in this system either because we need the feed earlier than they provide it. We can use the lucerne more effectively to provide high quality feed later in the season or cover feed shortfalls in dry seasons.

4. On the lucerne farmlet the tightest period for feed is autumn. Lucerne is available but it needs to be free from disease or damage otherwise its oestrogen levels will be too high and could affect conception rates.

5. We are using replacement ewes from the Lincoln Ashley Dene Coopworth flock, which are have been selected for high fecundity and low body weight. They are doing about 155% lambing with tupping body weights around 64kg. However, at establishment, there were a number of older ewes that are not from that blood line, they were larger composites, and when the feed crunch came they did not stand up well and we had death rates around 10%.

6. We had a major worm problem, particularly on the legume farm, so because feed situation and the worms, fewer lambs were finished and we had to sell more as stores. In general its is better to graze the lambs on lucerne because worm survival is lower on the dryer tops of lucerne and also because it is higher in protein and so ameliorates some of the effects of a worm burden. In this case, the level of contamination must have been high enough to effect the lambs.

7. When feed became short we tightened up the ewes with single lambs, reasoning that they didnt need so much feed. However, this slowed the growth of the single lambs so in retrospect we would have been better to feed the more advanced lambs best and quit them as early as possible.

This year to provide winter feed we have put two paddocks in kale on each farmlet. We are also making sure we have at least two paddocks with higher pasture masses going into autumn so that they will provide feed for earlier lambing ewes in spring, and that we have paddocks of clean lucerne for the lambs to go onto (two on the legume farm, 1 on the grass farm).