Around the Camp: Low lambing? You’re not alone. Plus green date calculator, using scanning, heat stress and a shearing checklist.

  1. Quick picks: green date calculator, using scanning data, heat research, shearing checklist
  2. Deep dive – Low lambing? You’re not alone.
  3. Upcoming events
  4. Podcasts, eBulletins and surveys

Quick picks

New green date calculator:  We’re approaching the middle of the “dry” season, which is a good time to review your forage budget, consider your stocking rate, and determine if feed will last until you expect new pasture growth. A new green date calculator is available to help you determine your budget period, usually 6-8 weeks past your green date. At a minimum, select your region and the amount of rainfall. For those in rangeland environments, the standard 50mm of rainfall might not be appropriate. If you’re not sure what rainfall to use, get in touch with our team!

 

Using your scanning data: If you’ve already scanned, how have you used this information to improve your management? Scanning data can be used to improve management of nutritional requirements of ewes, choose lambing mob sizes, market surplus stock and manage cashflow budgets. The free Lifetime Ewe Management app could be a handy way to record scanning rates, condition scores, determine energy requirements and plan target condition scores or supplementation. Check out the app here.

Could cattle heat research apply to sheep? Preliminary research data from Central Queensland University has found that maximum daily temperatures of 31oC or more significantly reduce rumination in cattle and therefore feed intake and production. It is one of the first studies to explore heat stress in extensively grazed beef cattle and might provide insights into the true costs of heat stress. Read more about the trial here.

Shearing checklist on hand: Save this handy checklist for your next shearing to help with preparation or staff delegation. Australian Wool Innovation has a range of useful resources. Click here to find information on sheep preparation, shed safety, wool clip preparation, shed design and more.

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Deep dive – Low lambing? You’re not alone.

There is evidence of abnormally low scanning and/or lambing rates across Queensland in 2024 from autumn to spring lambing. Given the general distribution of this issue, it lends itself to a seasonal cause, but some tips here might help you to check if there is something else going on in your flock.

What are the seasonal conditions that could have led to low conception or lambing rates, when for some, there has been a reasonable amount of green feed around?

  • Humpy back (heat stress): Whilst many seasoned Queenslanders didn’t find this summer particularly hot temperature wise, there were many complaints about the humidity. The sheep likely felt this humidity effect too. There was discussion about increased incidence of humpy back which is essentially heat stress. Heat can have a drastic effect on reproduction, most significantly around conception. Much of the research on heat stress is done in far milder climates than Queensland. It’s likely our sheep have been naturally selected to be productive under hotter conditions, however they are still susceptible at some point. The important thing to consider with heat is that wind, shade and humidity play a significant role, as well as nighttime temperatures, which need to drop to allow body temperatures to return to normal and provide relief from heat stress.
  • A green drought: When several wet seasons follow consecutively, the nitrogen stored in the soil gets drawn up by the plants each year. Decomposing organic matter restores soil nitrogen and in dry years, with little plant growth, the nitrogen is not depleted. This can mean that after consecutive years of soil nitrogen being depleted, the amount available for plant uptake is low and feed protein levels will not be as high in subsequent years, despite looking lovely and green. This could have been worsened for areas which dried off for most of last year. When the green flush came through it was both low in protein, having not banked up much nitrogen within the year, and high in moisture (moisture dilutes nutrients like energy and protein).
  • Delayed weaning: In areas where the season declined in 2023, some of you may have delayed weaning in order to look after the lamb. Depending on when the season kicked, this might have meant that ewes didn’t have a long time to recover on good feed before being joined. Although a rising plane of nutrition is important for ewes’ cycling, we all know overall condition score is critical.

There are other diseases or issues that could have exacerbated these seasonal and nutritional conditions in your flock. Although sometimes it can be hard to look back after the event.

  • Toxic plants: Nitrate nitrite poisoning from plants like pigweed can occur if stock gorge on these plants. For example, introduced stock, stock released from yards, or where there are limited other options in a dry paddock sprouting green pick. An outbreak of plant poisoning could affect your joining even if the toxins do not affect reproduction directly, but in this situation it’s likely that you would have seen signs such as sick sheep or mortalities.
  • Infectious diseases: Several infectious diseases can affect reproduction from conception through to foetal and neonatal loss. Knowing the timing of your losses (for example, before or after scanning) can be helpful for accurate diagnosis, and some testing can look at immune levels to indicate past infections. Some culprits include campylobacter, leptospirosis, toxoplasmosis, listeria and brucellosis. A general ram check for their overall health is also important as many issues other than brucellosis can affect their fertility.
  • Nutrition: Trace element deficiencies can occur, but it is critical to fix the most limiting nutrients first – by far most commonly these are protein and energy. If protein and energy are the problem, a mineral supplement won’t address the deficiency. If you’re confident that protein and energy are not limiting then it may be worthwhile investigating local or seasonal deficiencies with a nutritionist or veterinarian.

What to do now?

Firstly, have a look back to the time of conception and consider whether the impact of environmental conditions (heat stress, ewes needing to recover condition, not enough time between the season break and joining) could be the leading cause for your flock not performing. Secondly, consider contacting your local Biosecurity Queensland Stock Inspector (call 13 25 23) to conduct free testing. It can be hard to find a cause after the event but it’s worth a shot to rule out some infectious diseases or ongoing plant/mineral issues. Thirdly, consider other low hanging fruit for best practice animal husbandry, such as condition scoring at key times when you have sheep at hand, ram checks, worm egg count testing and vaccinations.

And of course, if you haven’t already, scan. A commercial western merino producer indicated this was the most value scanning had ever brought him as he could now decide what to do with his considerable proportion of dry ewes. He could sell and replace with scanned in-lamb ewes to maintain cashflow, rejoin the dries, or sell and conserve the feed for more productive sheep. It is also highly valuable to narrow down when your reproductive issue occurred and potential causes.

Written by DAF senior extension officer and veterinarian Dr Andrea McKenzie.

Upcoming events

  • 4 July. National Renewables in Agriculture Conference and Expo, Toowoomba. For more information and to register, click here.
  • 25-26 July. Ag Innovation Expo, Longreach. Delivered by GroWQ. For more information and to register, click here.
  • 12-14 August. Breeding EDGE, Longreach. Delivered by Désirée Jackson Livestock Management. For more information and to register, click here.

Podcasts, eBulletins and surveys

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