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Farm Tech
In The Paddock – Seasonal sheep flock management tips
‘In The Paddock’ is a monthly column that gives seasonal sheep
flock management tips. It is emailed each month to growers who have provided
their email address to Meat & Wool Innovation. Email us if you want to go on
the emailing list.
- Feed budgets can be used to help improve anilmal performance and profitability
- They enable farmers to plan for impending feed shortages and surpluses
- Key parts of the budget are calculations of feed available and animal
requirements
- Feed budgets can be done on the whole farm and/or a paddock by paddock
basis
- An expert should be consulted for training when starting out
- A computer makes the job a lot easier and quicker
- ME levels are usually the best basis for assessing the quality of
supplementary feeds
- High quality feed is needed to assure ewe or lamb liveweight gains
- Specialist forage crops have MEs of 12–13 MJ ME/kg DM if grazed
at the correct growth stage
- Grains have MEs of 12–13.5 ME/kg DM
- Pasture silages and hay have MEs of 8.5–10.5. Most are suitable
for maintenance feeding only
- For supplementary feeding to be economic, feed planning or budgeting
is essential
- Put the rams out near the peak of the breeding season
- Lambing date should coincide with the onset of the spring pasture
growth flush
- Ewes should have a condition score of 3 or better
- Avoid taking weight off ewes between weaning and mating
- Androvax can increase lambing percentages by about 20 per cent
- Vaccinate against the abortion diseases toxoplasmosis and campylobacter
- Rams must be fit and healthy
- Absorbent yeast and clay compounds may reduce ryegrass staggers and
improve stock health.
- Reducing intake of toxic ryegrass by grazing management or offering
supplements, crops etc is beneficial.
- Replace toxic ryegrass with AR1 ryegrass or a similar safe endophyte
cultivar where possible.
- Spraying/cropping or double spray/fallow reduces toxic ryegrass seed
in the soil and ensures a safe pure sward is established. This could
take two years.
- Prevent the invasion of wild-type seed via hay/silage, dung, fleeces
and machinery.
- Selection for animal resistance to staggers may be a good long-term
strategy.
- Endophytes are fungi that exist inside plants
- They produce a wide range of compounds. The main ones are peramine,
lolitrem B and ergovaline
- Peramine helps protect plants from insect attack, especially Argentine
stem weevil
- Lolitrem B is a neurotoxin that causes ryegrass staggers in animals
- Ergovaline lowers blood prolactin levels and causes heat stress
- Some of these chemicals, in combination with other as yet unidentified
compounds, depress intake and liveweight gain, and cause scouring and
dags in sheep
- Non-toxic strains of endophyte have been identified
- The most promising, AR1, produces peramine and is commercially available.
It protects the plant from insect attack and has no ill-effects on grazing
animals
- For control puroses there are two types of thistle - Californians
and the rest
- Annual and biennial thistles are best controlled by pasture management
practices that encourage the maintenance of a tight sward
- Topping, grubbing and herbicides also have a place in thistle control
- Californian thistle can be controlled by regular rotational grazing,
associated with the use of either topping or herbicides to deplete root
reserves and weaken the plant
- Select rams which will produce profitable lambs
- Performance recording is the only way to accurately identify genetic
merit
- Breeding values describe individual traits
- Indexes describe the total genetic package
- Genetic trend graphs indicate whether your ram breeder has adopted
good selection practices
- Select rams on index first, then on structure and appearance
- 50–70 per cent of the year's pasture growth normally occurs
during spring/early summer.
- To maximise profit, as much of this pasture as possible should be
converted into liveweight gain. To achieve this, the pasture should
be of high quality.
- Pasture surpluses need to be managed so the build up of low quality
dead material is minimised. If pasture has a lot of dead material in
it, lambs may not gain any weight.
- The aim of grazing management should be to keep average cover from
1400–1800 kgDM/ha, or 4–6 cm, and to enhance clover growth.
- Surplus late-spring pasture can be conserved as hay or silage, topped,
controlled with low rates of herbicide, or grazed with cattle or weaned
ewes.
- In high fecundity flocks, about 25 per cent of triplets are either
born dead or die before they are 12 weeks of age.
- In severe storms, losses due to exposure and mis-mothering can be
higher than this.
- Orphan and triplet lambs, which otherwise would have died, can be
successfully reared on fortified cow colostrum and meal.
- The total cost is around $30/lamb (excluding labour). With prime lambs
worth around $65/head, it is clearly economic to artificially rear such
lambs.
- It is not economic to remove small triplet lambs for rearing. If a
ewe is capable of rearing its lambs it should be allowed to do so.
- Artificial rearing requires good animal husbandry skills, and careful
attention to hygiene and animal health.
- Monitoring pasture growth is a key to better livestock nutrition and
greatly improved farm productivity
- There are effective tools available for measuring pasture cover and
these are now being calibrated for sheep pastures
- By measuring how much pasture is present in a paddock, we can make
accurate feed budgets, plan feed requirements and make better grazing
management decisions
- Pasture cover estimates need to be adjusted for seasonal differences
in the amount of dead matter in the sward
- Meat & Wool Innovation has set up PasturePlan, a nation-wide pasture
measurement programme which will help farmers become familiar with pasture
measurement
- Ryegrass/white clover pastures are productive and tough
- Optimum growing temperature ranges are 15–20 deg C for ryegrass
and 20–25 deg C for white clover
- Large regional differences in total pasture production are mainly
due to climate
- Seasonal growth patterns vary little between regions, with a peak
in spring/summer
- Optimum pasture growth occurs at pasture masses of 1000–2250
kg DM/ha
- Careful planning is needed to get the correct pasture covers for lambing.
- Too little cover at lambing will lead to underfeeding of ewes, low
milk production and poor lamb growth rates.
- Too much cover will result in an early decline in feed quality, and
a drop-off in milk production and lamb growth.
- To achieve target covers, you need to have adequate pre-winter cover
and to adopt a slow (60–120 day) winter rotation. Strategic nitrogen
use may also have a place.
- Ideal target covers vary between regions, but in most cases pre-lambing
covers of 1100–1400 kg DM/ha are appropriate. This equates to 2–3
cm pasture height.
- Ewes with twins or triplets should be offered pasture at the high
end of the range.
- Ewes with singles can be offered pasture at the low end of the range.
If pasture supplies are limited, feed for these ewes can be supplemented
with grain.
- Mid-pregnancy shearing of crossbred ewes is becoming common as a means
to increase lamb birth weight, improve lamb survival and wean heavier
lambs.
- Sheep should be shorn with winter combs. Lifters or blades may be
necessary in some environments.
- Shear ewes in mob sizes that can be adequately fed and sheltered.
- Get shorn ewes onto sheltered pasture well before dark.
- Covered yards and/or the woolshed should be available for emergency
shelter.
- Thousands of lambs die soon after birth each year
- By increasing the birth weights of twins and triplets, losses can
be greatly reduced
- Shearing crossbred ewes in mid-pregnancy (around day 70) can increase
the birth weights of their lambs by around 0.4 kg and their weaning
weights by around 1.0 kg
- The birth weight response does not appear to occur in ewes which are
very light (<50 kg) or very heavy (>70 kg). Nor does it occur
in those with very low (<1–1.5) or very high (>4) condition
scores.
- Ewes produce about 0.2 kg more wool a year if they are mid-pregnancy
shorn
- To protect winter-shorn ewes from exposure, they should be shorn (depending
on the region) with genuine winter combs, winter combs with lifters,
or blades
- They also must have good shelter and adequate feed after shearing
- Hogget mating has high management requirements. It should be attempted
only if these requirements can be met.
- Ewes that lambed as hoggets have improved lambing performance as 2-tooths
and for the rest of their lives.
- Breed and/or strain of sheep has a significant impact.
- Hoggets should be mated at around 40 kg at a condition score of 3
or better, using 2 rams per 100 hoggets.
- Good growth rates after weaning are essential in order to achieve
these targets
- Vaccinate hoggets for toxoplasmosis and campylobacter before joining
teasers or entire rams.
- Aim for growth rates of 80–100 g/day from mating until mid-pregnancy
and for a target weight of about 52 kg at lambing.
- NZ pastures have a number of fungi that produce toxins that can markedly
reduce productivity. Facial eczema (FE) is the most common.
- While clinical FE is well-known and easily recognised, farmers are
often unaware of major lifetime losses due to sub-clinical FE.
- FE outbreaks can be predicted from weather patterns and FE levels
can be easily monitored from pasture or dung samples.
- In FE-prone areas, it is advisable to use rams that have been selected
for FE-tolerance.
- Zinc boluses, while expensive, are effective in reducing the risk
of losses due to FE.
- It is very hard to accurately judge the condition of woolly sheep
visually
- Condition scoring manually is a very useful way to judge the fatness
of sheep
- Ewes should not be losing body condition over the pre-mating and mating
period
- A condition score of 3 to 4 at this time of the year is recommended
- Ewes should be given priority at this time to get good lambing percentages
- They should be rapidly rotated into 5–6 cm pasture and not graze
to lower than 3 cm.
- Protein is the key to achieving a flushing/ovulation response in silage-fed
ewes
- A minimum of 12 per cent true protein is required
- High DM wilted silage is better than low DM silage
- At current lamb prices the use of finishing crops is often profitable
- Specialist forage crops, if grazed at the correct stage of growth,
can provide a bulk of high quality feed when the quality or quantity
of ryegrass pasture is low
- Risks include possible crop failure, the lag time before the crop
can be grazed and potential animal health problems
- Animal health problems can occur with most fodder crops, especially
brassicas
- An acclimatisation period is essential when introducing sheep to brassicas.
- Wean lambs when pastures are grazed below 3 cm or at 10–12 weeks
of age
- Pasture quality is of paramount importance and should be mainly new
green grass leaf and clover
- Such pasture has an ME content of 11–12 MJ ME/kg DM and is more
than 20 per cent protein
- Don't try to utilise too much pasture in each grazing — aim for
25–30 per cent, and a post grazing level of 3–5 cm
- In many areas a crop or special purpose pasture can provide high quality
feed when pasture quality declines in summer
- Optimum quantity and quality of feed is needed for high levels of
animal performance
- Clover and green grass leaf are the quality components in the sward
- Pasture quality declines in late spring
- Grazing management at this time should aim to keep grazed pastures
at 3–4 cm
- Surplus late-spring pasture can be conserved as hay or silage, mechanically
topped, or grazed with lower priority stock like cattle or weaned ewes
- Feeding levels at this time of the year will determine whether productivity
targets are achieved
- Single-suckling ewes should be fed twice maintenance
- Twin-suckling should be fed three times maintenance
- Feed quality is extremely important
- Early weaning or creep grazing should be considered if feed is short
- Late pregnancy is a critical time for breeding ewes
- Priority should be given to feed management so that ewe health is
optimised and to ensure there is enough colostrum and early milk for
lamb viability
- Shearing and ultrasound scanning in mid-pregnancy are useful tools
for improving lamb birth weights and survival. They also lead to other
improvements in lamb production
- After scanning, single- or multiple-carrying ewes can be run in separate
mobs during late pregnancy for differential feeding
- Shearing crossbred ewes with winter combs and lifters in mid-pregnancy
can result in increased lamb birth weights and improved lamb survival.
- Pasture silage is generally cheaper than hay and is usually a higher
quality feed
- Breeding ewes readily eat ryegrass-white clover silage
- Silage intake can be increased by wilting and/or chopping before ensiling
- Baleage is a convenient form of silage
- Good ewe liveweight gain can be achieved on pasture silage
- Silage supplementation has a ‘pasture sparing’ effect, and
helps with feed planning by reducing over-grazing of pastures
- Improvements in wool growth can occur and if silage is used as a flushing
feed, lambing percentages can be improved.
- Start rationing feed by lengthening ewe grazing rotation. Feeding
low quality supplements may help achieve this.
- Feed well-conditioned ewes at maintenance — about 1.1–1.2
kg DM/day intake per head for a 60–65 kg ewe at condition score
3.
- Preferentially feed light, poorly-conditioned ewes at about 1.3–1.5
kg DM/day intake per head.
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