Scientists have been tracking cattle movements on a virtually treeless Barkly Tablelands station to discover whether shade from the Northern Territory sun might reduce calf mortality.
The "Reducing calf loss from exposure" project was tested at Australian Agricultural Company's Avon Downs Station on the NT/Qld border to see whether providing shade might reduce calf mortality in relatively treeless Mitchell grass plains.
Calf loss is a major economic cost to the massive beef cattle herds of northern Australia.
The pilot study, overseen by Katherine senior livestock scientist Kieren McCosker, involved 150 pregnant purebred Wagyu heifers.
The heifers were predicted to calve between October and December last year and were randomly allocated to either a paddock which had a shade structure near the watering point or a paddock with no shade.
Pregnant heifers were put into the enormous trial paddocks for approximately seven months and mustered in April this year.
Heifers observed to be lactating beyond their expected calving date were considered to have successfully weaned a calf.
The level of calf loss experienced by first-lactation heifers with access to shade was comparable to the no shade group.
Five heifers from each paddock were fitted with GPS collars to track their movements.
Four of the collars were also able to record temperatures.
Location data was summarised by generating daily counts for each collar of GPS locations within 500m of water and total number of GPS locations recorded over a single day and between 10am and 3pm.
"These preliminary results appear to indicate that the provision of shade near watering points does not have a large impact on either incidence of calf loss, average GPS collar-recorded temperature or time spent near the shade for heifers during summer when considered across an entire day," NT Department of Primary Industry and Resources researchers said.
Although there was no evidence of heifers spending more time resting in the installed shade near water, researchers found the daily average collar-recorded temperature for shade was 0.5°C lower than for no shade.
This calf loss research is ongoing.
In late August, with the help of station staff, 214 GPS collars were fitted to the next cohort of pregnant first-calf heifers grazing these trial paddocks for the next round of testing.
An assessment of the available natural shade in paddocks using satellite imagery is planned.
More information on the Future Beef project here.
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