Quantifying the animal welfare and production benefits of shade structures in southern feedlots has been the focus of a research project funded by Meat & Livestock Australia in 2021-22 (MLA).
It involved trials carried out by the University of New England (UNE) at its Tullimba feedlot research facility, led by Dr Angela Lees and Dr Peter McGilchrist.
Researchers are investigating the impacts of two different types of shade on feedlot cattle - compared to no shade - and are following the cattle through to slaughter.
One part of the feedlot had a shade structure installed in a two-tiered design, comprising 290/300 GSM knitted Monofilament polyethylene 80 per cent UV solar block shade.
Another part of the feedlot had a shade structure installed in a similar two-tiered design, comprising a translucent waterproof 340 GSM high UV polyethylene.
The two-tiered shade and shelter systems, designed and supplied by Architex Fabric Structures - a subsidiary of Polytex - featured a large vented apex to allow air flow through the structures.
The north-south orientation, combined with reducing rainfall into the pens under the waterproof shade, helped to manage pen surface conditions.
Dr Lees, who has been involved in previous shade and shelter research projects in Queensland, said while Tullimba is in the temperate New England climate, the researchers anticipated cattle would seek shade and experience production benefits similar to northern shade trials.
"Most people would consider the New England summer to be relatively mild," she said.
"But we've seen cattle here in the December to March period expressing heat stress behaviours.
"The high elevation of the New England region means there is a trade-off between 'cooler' summer conditions and solar load.
"Some of our colleagues in the United States have defined that, in locations such as Nebraska, there seems to be solar load effect, meaning that feedlots in higher locations tend to experience heat stress at a lower threshold.
"We're confident we'll see the welfare and production benefits from these shade structures, similar to northern trials, but we need the data to quantify it."
The research involves Bos taurus pregnancy-tested empty heifers, fed for 100 to 110 days.
The summer trial started in January 2021 and cattle were split into two cohorts.
Ms Lees said this enabled them to measure the difference between early summer conditions and late summer conditions on different components of the feeding term.
"The December cattle will come off having been through summer their entire feeding period," she said.
"The later cattle will come off when conditions here are starting to cool off a little bit.
"We will follow them to slaughter and get a Meat Standards Australia (MSA) grade on them so we can see the carcase characteristics.
"We're also collecting the adrenal glands as an indicator of chronic stress.
"The project will really help quantify the impacts of shade from a science perspective, while still giving a real world outcome for the Australian feedlot industry."
Another cohort of cattle entered the feedlot in winter 2021 to help quantify the benefits of the waterproof shade structures as a shelter during winter conditions.
"Keeping cattle and pens dry in winter by preventing rainfall from impacting the pen could also reduce the amount of energy each animal uses to stay warm, therefore allowing more energy for growth," Dr Lees said.
The productivity results from the summer trial included:
The gain to feed ratio of feed efficiency of cattle in the two tier waterproof treatment was 0.153 compared to the unshaded of 0.147 and the conventional shade cloth of 0.148.
The results translated to a significant increase in carcase weight (HSCW) for cattle in the two tiered waterproof treatment - of 7.2 kg compared to the unshaded and conventional shadecloth treatments
Assuming a conservative carcase weight (HSCW) price of $7.50 /kg HSCW, this translates to an economic benefit of $54 /hd for cattle provided waterproof shelter at 4.0 m2/animal compared to no shade or conventional shadecloth construction.
The winter trial concluded in mid-November 2021. The results are still being analysed and will be available in mid 2022.
For more information contact: firstname.lastname@example.org
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