Preparing for lambing

For a successful lamb harvest, it’s necessary to get the system right by understanding the farm’s strengths and weaknesses, Tom Ward writes.

Spring is the most profitable time of the year on sheep breeding farms – it’s the harvest if you like, and the culmination of all the annual actions and environmental effects upon the ewes.

It is also the time of greatest animal risk (weather) and low pasture efficiency (set stocking). It is one of the reasons seasonal dairy farming is so much more profitable than sheep breeding on easy country with sufficient moisture.

Despite all mankind’s collective and clever efforts at manipulating agricultural systems, farming remains determined by weather and topography.

In short, get the system right by understanding the farm’s strengths and weaknesses. Is the farm summer dry or summer moist, and is it reliable? Is the winter cold and long, or relatively warm? What livestock mix is ideal, are the genetics appropriate, and what is the optimum stocking rate?

I listened to a talk by the Christchurch accountant Pita Alexander last month: Pita is in his seventies, has been advising farmers for three generations and was right on point – we grow on capital and survive on cash.

Winter management

The hill country environment is inherently volatile so farmers need to identify key winter targets and the means to achieve these, regardless of pasture conditions. By definition, winter management is a part of the annual plan.

These key winter targets could be:

• Maintain post-grazing winter pasture covers above 1100kg drymatter (DM)/ ha to optimise pasture growth rate, pasture utilisation and liveweight gain in ewes and lambs during lambing.
• Set the farm up in autumn for the winter grazing plan. Monitor feed distribution. Although stocking rate dependent, at May 1 this could be ewes/ewe hoggets on 1400 to 1650kg DM/ha, R1 bulls on 2000kg DM/ha and R2 bulls on 1500kg DM/ha.
• Body condition score (BCS): Ewes minimum 3.0 at May 1. Maintain BCS and increase late winter feeding in line with scanning. Ewe hoggets 41kg liveweight (LW) May 1. A further goal to increase lamb survival could be to target 4kg and 5kg birthweights for triplet and twin lambs respectively.

Preparing for lambing (achieving the targets)

1. The first task is to prepare a feed budget, a document that can be constantly reviewed.
2. Achieving BCS 3.0 to 3.5. Draft into lighter and heavier lines and feed to requirements. Those ewes above 3.0 can be held back until foetus requirements increase.
3. Build flexibility into winter management, i.e: Allow 15% feed wastage in feed budget

• Have a forward store, or otherwise a very saleable class of trading cattle
• Consider grazing the ewe hoggets off, or lamb the hoggets – either way more feed is going into lambing/ lactating sheep. Grazing off should also protect the ewe hoggets’ future.

1.  Leave scrubby gullies, steep sidlings and high tops ungrazed. This “inefficient” grazing management provides useful standing hay when the feed budget gets tight. (It “fans the fire” in the debate over whether the most unproductive hill country should be planted in radiata.)
2. Reduce feed to some livestock classes having analysed the effect of temporary underfeeding on a livestock class, i.e:  Ewe hoggets if well grown – effect will be low

• Ewe hoggets if not well grown – effect will be high
• 5yr ewes – low effect due to imminent culling
• Single bearing ewes – low (maybe)
• Utilise excess condition on both cows and ewes.

6. Assuming there is enough subdivision, from scanning data (or ram harnesses) run separate ewe mobs based on expected lambing date and number of lambs carried. Assess stock weekly in late pregnancy, and delay set stocking until one week from the planned start of lambing. On easy country, rotational grazing can start immediately with singles and from tailing with multiples.
7. Apply nitrogen fertiliser. Despite high prices, this is still a profitable option, providing conditions are conducive to a response, especially where maintaining or gaining BCS through winter is concerned. Spring nitrogen application may seem expensive, but as a short-term fix it can be very effective. If the farm is regularly slow to grow in spring, the nitrogen cycle may be ineffective. Get some legumes growing.

An example of the research showed that on Wakanui soil at Lincoln University, a lucerne stand grew 40kg DM/mm moisture compared to 17kg DM/mm moisture in a cocksfoot-dominated pasture on the same soil. Applying nitrogen to the cocksfoot increased the water use efficiency to 38kg DM/mm moisture.

1. Use supplements where possible – balage, silage, barley grain, maize grain or palm kernel. Palm kernel may be not so attractive now as, due to more oil being extracted, metabolisable energy is a low 9. The best return to supplements is in the autumn when conditions are still growthy, and slowing the round results in maximum grass growth. That is also a time when poorer quality supplements can be used. Running a relatively conservative stocking rate allows the build-up of supplements to be used in difficult seasons.
2. Judicious use of a winter crop. Planting more fodder beet than normally needed allows some ewes to be grazed on crop until the pasture starts to grow. Kale can also be used for sheep. However, too great an area under fodder beet on small farms can put pressure on spring/early summer pasture.
3. Manage the pastures as much as the animals – avoid both under and over grazing, both of which will damage legumes.
4. Consider set stocking ewes based on the number of lambs expected. Sprinkle the triplet-bearing ewes among the twin-bearing ewes to reduce mis-mothering.
5. If lambing the ewe hoggets, draft into heavy and light one month pre-mating. The hoggets should be a minimum 38kg LW and average 41kg. For every 1kg above 36kg, the hogget lambing will increase 2%.
6. As a policy, consider running larger ewes. Bigger lambs at weaning will reduce feed requirements in summer and autumn, and in combination with cattle buying and selling decisions, directly affect the autumn average pasture cover. However, this may require a stocking rate reduction.

There will be different approaches, driven by farm layout, weather, topography and personal preference. For example, some farms have less than desirable lambing country.

• Tom Ward is a Mid-South Canterbury farm consultant.