Some cows are naturally more efficient at converting the food they eat into weight gain, so does that ability mean they might also be better at weathering climate change?
It’s a question University of Alberta beef researcher Gleise M. Silva hopes to answer for cattle producers, who face increasingly common, extreme temperature swings that can grip the province year-round.
Silva and a small team of graduate students are monitoring 49 head of cattle at the U of A’s Roy Berg Kinsella Research Ranch for a full year, measuring the animals’ bodily and behavioural reactions to temperature changes.
The Alberta study will be one of the first to compare cold and heat extremes using the same animals in naturally occurring conditions.
When the project wraps up in March 2023, Silva, an assistant professor in the Faculty of Agricultural, Life & Environmental Sciences, hopes to have new insight into whether cattle that are good at converting calories can also successfully cope with climate change.
The issue is a pressing one, considering Alberta is home to 40 per cent of Canada’s beef herds — and to big temperature swings, says Silva, the university’s first BCRC - Hays Chair in Beef Production Systems.
“Significant extremes have become more noticeable,” with 2021 temperatures topping 36 C in June 2021. In December of that year, they plummeted below -45 C.
Adjusting to extremely hot or cold weather requires cattle to make stressful behavioural, physiological and metabolic changes, she notes.
“All of these changes have a cost to the animal, yet we need to have animals that are able to perform well in both summer and winter temperatures.”
Beef producers also pay a price when the thermometer changes drastically — for example, having to provide more winter feed or seeing herd reproduction rates fall due to heat exhaustion.
As a possible way to improve herd resiliency, Silva’s research will test the theory that feed-efficient cattle — those that eat less than expected but still gain the same weight as other cows — are also better at burning less energy to stay warm or cool.
To find out, Silva and her team will track temperatures recorded by the ranch’s weather station, at the same time measuring what changes the cattle make to cope.
The results will show whether the heifers maintain their weight, immunity level and breeding success compared with their less efficient herdmates.
The findings can build more overall knowledge about the relationship between feed intake and weather resilience, adding to a similar study Silva did in Florida, showing that heifers that tolerated tropical temperatures better also happened to be feed-efficient.
The work will help fulfil a growing need for data that can help livestock producers find the most effective ways to care for their animals in the face of climate change, Silva suggests.
“It’s going to be important to improve animal well-being and production to keep sectors such as beef production even more sustainable.”
Knowing that their feed-efficient cows are also weather-resilient would confirm to producers which animals to retain for breeding, building in herd sustainability and resilience.
“It would mean the animals don’t need to change their behaviours a lot, that they can live in a constant way throughout the year,” Silva says. “This is especially important in cow-calf operations where cows are kept in the herd for years.”
“Having animals that can maintain and sustain more productivity, regardless of what’s going on outdoors, would be great for the industry.”
The information could also help producers plan “stress abatement strategies” like providing more shade and water supply in summer and windbreaks in winter in their pastures, she adds.
The project is funded by the Alberta Beef Producers.