Focusing on lamb survival
19 August 2016
Sheep producers have successfully lifted lamb survival rates in the past decade and the industry is on target to achieve further lifts, assisted by outcomes through levy investment in R&D.
To assist producers in further improving lamb survival, sheep industry consultant and researcher Dr Jason Trompf of JT Agri-Source has developed a five-part plan, called ‘Lambs Alive do the Five’, to achieve more kilograms of lambs weaned/hectare, drawing on tools and techniques which underpin industry programs such as Bred Well Fed Well and AWI program Lifetime Ewe Management.
“Lamb survival is all about attention to detail,” Jason said.
“Implementing a balanced strategy across five key components will significantly improve the wellbeing of the breeding ewe and her lambs, and subsequently the productivity of most Australian sheep flocks.”
Jason says the five tips are:
1. Measure to manage
Tools that offer great opportunities to sheep producers, that can still be more widely utilised, include condition scoring and pregnancy scanning for multiples.
For example, pregnancy scanning ewes allowed producers to identify dry, single and twin-bearing ewes and make proactive management decisions such as feed allocation, culling or re-joining. Scanning also measures the overall conception rate (pregnancies/100 ewes) to highlight potential.
2. Fed well
The feed requirements of a dry ewe don’t change, but the energy requirements of pregnant ewes increase from around 10MJ/day at conception to as high as 25-30MJ/day for twin-bearing ewes and 20MJ/day for single ewes, at 20-40 days after lambing (peak lactation). The key practice that programs like Lifetime Ewe Management encourage include coaching producers to adapt to meet these changing energy requirements by reallocating feed resources (paddock feed and supplements) to the ewes that need it most. It is not necessarily about feeding more but ensuring what is offered to the ewe is tailored to her requirements.
Ewe nutrition and the resulting lamb birth weight are the primary drivers of lamb survival. Results from the Sentinel Flock Project (run by Victorian Department of Environment and Primary Industries - DEPI) showed inadequate nutrition and mismothering accounts for the majority of perinatal deaths and the next biggest cause of lamb loss is excess or imbalanced nutrition resulting in dystocia.
The value of hitting condition score (CS) 3 at lambing was significantly higher today than in the past because of increased meat values and a reduced micron premium for wool. Compared to CS 2.5, lambing in CS 3 can lift profit by around $20/ewe through increased ewe wool production, ewe survival and progeny survival.
3. Adapt well
There are four strategies to adapt to seasonal variability:
- Know your enemy – what is the impact of variability on your business?
- Adjust your sights, so you have a flexible strategy for varying seasons.
- Know what targets you want to hit, to improve the likelihood of success.
- Identify tactics for tough years.
These principles are critical for improving the resilience of sheep enterprises to cope with varying seasons and are delivered in a new one-day workshop known as ‘More Lambs More Often’. A key message in the program is CS targets for managing pregnant ewes should not be adjusted in varying seasons, as whole-farm economic modelling shows that at a range of stocking rates and across a range of seasons, for high, medium and low rainfall environments, it is more profitable to maintain ewes in pregnancy.
A loss of 0.3 of a CS can cost $3/ewe profit, while a loss of 0.6 of a CS can cost $7/ewe, so investing in strategies such as extra grain supplementation may be required to meet CS targets to drive flock productivity and profit.
The top performing sheep enterprises have strategies that enable them to be flexible to seasonal variation, including:
- later lambing to prepare paddocks
- higher reproduction rates so they can sell more lambs and recover quicker from dry times
- feed reserves on hand to feed until mid-June
- time shearing for sale sheep for spring/early summer
- sell surplus sheep early before using summer feed reserves
- selecting genetics that are robust so it easier to maintain live weights
4. Bred well
Producers should have a clear breeding objective and use the best visual and objective tools available to produce a balanced, high-performing sheep.
It is critical to breed a ewe that is highly productive and can thrive and survive under varying conditions. The Bred Well Fed Well program coaches producers to use tools including:
- Ram selection: Australian Sheep Breeding Values (ASBVs), sire evaluations, progeny tests, bloodline evaluations, and classing for structural assessment.
- Ewe selection: matching rams to ewes, performance based culling such as wet-drying.
5. Lamb well
To give lambs the best possible chance of survival from birth, select lambing paddocks for adequate feed, water and shelter, freedom from predators and minimal disturbance.
It takes five to six hours post-birth for ewes to bond with their lambs and privacy is critical for this process, particularly with multiple births. Maternal behaviour is influenced by feed-on-offer at the birth site, where an extra 1,000 kg DM/ha available lifts lamb survival by 10%, even at optimum birth weights.
R&D making a difference to lamb survival
Sheep producers have lifted lamb survival in the past decade and the industry is on target to achieve further lifts, according to MLA's Sheep R&D program manager Richard Apps.
"According to the Sheep Industry Stocktake carried out in 2014, lamb marking rates from all ewes (including Merinos) lifted from 80% to 90% in the five years to 2011-12," Richard said.
"MLA has worked with industry to develop an RD&E investment plan to improve lamb survival even further. A suite of projects have been, or are being, developed in four key areas: conception and early embryo mortality, ewe and lamb survival, early reproductive success and weaner performance and genetics and biological mechanisms."
Richard said some of the gains already made by industry were as a direct result of levy investment in research and development programs such as:
* Making More from Sheep: A recent review of this MLA and AWI developed and funded program found more than 50% of practice change by participants was aligned to the ‘Wean More Lambs’ module (see graph).
* Bred Well Fed Well: This one day workshop has been delivered to 3,323 producers and focuses on lifting marking rates via genetics, condition scoring and management of ewes, ewe nutrition and management of twin and single bearing mobs.
* Sheep CRC: In partnership with other industry organisations and research bodies, MLA funds the Sheep CRC to carry out research in areas such as animal wellbeing, genetics, new technologies, on farm management, producer training and nutrition.
* Genetics: MLA and AWI jointly support the development of LAMBPLAN and MERINOSELECT which deliver Australian Sheep Breeding Values (ASBVs) which include reproduction traits. MLA is funding the CSIRO to research immune function and the potential for improvement through genetic selection. Additional projects have investigated genetic selection based on lamb vigour and identifying genetic regions, or SNPS, which influence the robustness of reproductive traits.
* Nutrition: Projects are underway to better understand the links between ewe nutrition and lamb survival. An MLA-funded project is almost complete on addressing mineral and vitamin deficiencies in ewes and lambs to increase immune function.
* Environmental: MLA- and AWI-funded EverGraze research found the use of perennial grass hedgerows can increase twin lamb survival by 15% and overall all survival by 30%.
* Feral animal control: Along with other organisations, MLA funds the Invasive Animals CRC , which offers RD&E on feral animals which prey on sheep, particularly wild dogs and foxes.
Jason Trompf E: J.Trompf@latrobe.edu.au
Richards Apps E: firstname.lastname@example.org
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