​Heat load ration research challenges feedlot thinking

Heat load ration research challenges feedlot thinking


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Winner of the lot feeding industry's award for academic work, Communicate Your Research, for 2017 was Stephanie Sammes, from the University of Queensland, with Jessica Tonange, University of New England second and Cameron Steel, Murdoch University, WA, third. With them are sponsors David Frith and Tony Batterham, Quirindi Veterinary Services, Joe McMeniman, MLA and Melissa and Matt George, Bovine Dynamics, Kenmore.

Winner of the lot feeding industry's award for academic work, Communicate Your Research, for 2017 was Stephanie Sammes, from the University of Queensland, with Jessica Tonange, University of New England second and Cameron Steel, Murdoch University, WA, third. With them are sponsors David Frith and Tony Batterham, Quirindi Veterinary Services, Joe McMeniman, MLA and Melissa and Matt George, Bovine Dynamics, Kenmore.

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Stephanie Sammes wins Communicate Your Research program

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UNIVERSITY research which concluded feeding cattle a heat load ration during a simulated heat wave did not influence feed intake or average daily weight gain is challenging standard lot feeding procedures.

The work, carried out by Stephanie Sammes, from the University of Queensland’s School of Agriculture and Food Sciences, involved feeding two groups of purebred Angus yearling steers different diets while they were housed in climate control chambers.

Ms Sammes was the winner of the 2017 Australian Lot Feeders Association’s Communicate Your Research competition, which aims to highlight some of the best academic work underway involving the lot feeding game.

She gave a short presentation of her research at the organisation’s annual conference, SmartBeef 2017, held in Armidale last week.

Feedlot managers said it was fascinating work that raised many more questions.

Indeed, both researchers and industry leaders said there was a lot more academic work happening in the space.

They were keen to express the caveat that data from physiological indicators was still being analysed and may show other advantages to feeding special rations during heat waves.

Management of excessive heat load in feedlots was taken very seriously, industry leaders said.

It is typical practice to take the energy out of rations when a heat wave is predicted to help animals deal with the stressful conditions.

Ms Sammes’ study showed there was limited to no benefit to doing that in terms of two key performance indicators - feed intake (FI) and average daily gain (ADG).

The two groups in her study involved 20 steers overall, which were on feed for 60 days coming into the chambers, where they were housed for 17 days.

The temperature humidity index (THI) was lifted to 91 on the first of the hot days, then gradually dropped back down to 65, Ms Sammes said.

The first group were fed a commercially-available finishing ration and the second a special heat load ration with increased roughage.

“As expected, as soon as the THI increased, feed intake of both groups decreased and did not pick up until THI started to drop off,” Ms Sammes said.

“We found no significant differences between the two groups for FI or ADG.

“ADG was very low but keep in mind the cattle were under different conditions to that of a feedlot and were subjected to a very high heat load.”

Ms Sammes said future studies would look at the efficacy of nutritional supplements to mitigate the effects of head load on feed intake; a variation in timing of heat load ration implementation to alleviate a high load and evaluation of the average heat load on dry matter intake over summer.

Research into the shelf life of vacuum packaged primals earned University of New England student Jessica Tunnage second place in the competition.

Third place went to Cameron Steele, from Western Australia’s Murdoch University, for work on improving marbling predictions in beef using specialised cameras.

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