This was discussed when the editor of Landbouweekblad, ChrisBurges, spoke to senior researcher at the Agricultural Research Council (ARC), Michiel Scholtz. The duo spoke about the impact of climate change on farming as well as livestock genetics in this regard. Here is Burges and Scholtz…

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Burges: “In South Africa, we have incredibly well-adapted livestock genetics, how far are we and what do we have to do to move to a more climate-smart type of farming?”

Scholtz: “Let’s start with selection because everybody is talking about genetic improvement. The problem is, genetic improvement may not necessarily mean improvement in productivity. If I improve cow or calf weight, is it really more productive or do I just increase production? That is why we feel that we should look at breeding objectives that measure output versus input… We came up with the cow-efficiency measure… The second one is that we should look at alternative measures of post-weeding efficiency. Currently, we use [the] feed-conversion ratio, which is feed intake divided by body weight. If you select according to that, you don’t know what you’re changing – are you changing the feed intake, are you changing the growth rate, or are you changing both and in which proportion. That is why the animal breeders have come up with two alternative traits. The one is the residual feed intake.

“With residual feed intake, you keep the growth rate constant but you reduce the amount of feed needed to achieve that growth rate… The advantage is that you keep the cow size constant, but now your cow needs less food to put more weight on so that you can use the extra food to produce a heavier calf. And it’s interesting the reasons for lower residual feed intake, some of it lies in temperament. Animals with a bad temperament [have] a very high residual feed intake because they waste a lot of energy, but it’s also with digestion in the rumen and it seems that the mitochondrial function is more efficient. So, if you select residual feed intake, you select true efficiency.

“The other [option] is the residual daily gain [if you] want the animal to grow faster but don’t have more food. So, the feed intake remains constant but the animal grows faster…My idea is that you combine [these] two in a selection index. Unfortunately, both of these traits require the measurement of individual feed intake, and I think that’s the biggest challenge.”

Burges: “Doesn’t the ARC have the technological capacity to measure individual feed intake?”

Scholtz: “Yes, we have the capacity and there are private testing stations that also have the capacity, but it’s still costly. And that is why we’re now looking at if we use a system [like] a growth save system… we can decrease the test length from 84 days to 49 days and that is the new route we should follow. It is cheaper for the farmer and you can test more bulls.”

Burges: “How good are our adopted genetics in South Africa?”

Scholtz: “We’ve [noticed] in the 2015/16 season, which was the hottest and driest [period] in South Africa… at the Vaalharts Research Station during days of heat stress… the growth rate of exotic breeds decreased by 17% whereas the weight of the Afrikaner and Nguni [decreased] by only 9%. There is also a change in behaviour. We’ve picked up that during periods of heat stress, the Afrikaner eats 22 times per day but every time it only consumes 500 grams of food - it spreads its nutrition over the whole day. The European breed will wait until 20:00 at night and then it will eat 8 kilograms of feed at once. So, there are some adaptive mechanisms in our indigenous breeds.”

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