Guest essay by Eric Worrall
A press release for a new study suggests milk production in Britain will drop by 18.6% if we don’t mend our wicked ways. But buried in the study itself is an obvious mitigation strategy.
How climate change will affect dairy cows and milk production in the UK – new study
August 22, 2018 10.23pm AEST
The unusually hot summer of 2018 has proved challenging for farmers across the UK. Among other things, the scorching weather and lack of rain has damaged crops, and the grass used to feed farm animals too.
For our recent study, our team looked at how climate change might impact UK milk production, given what we already knew about how it affects dairy cows. In particular, we wanted to quantify the effects of heat stress on milk production.
Using 11 different climate projection models, and 18 different milk production models, we estimated potential milk loss from UK dairy cows as climate conditions change during the 21st century. Given this information, our final climate projection analysis suggests that average ambient temperatures in the UK will increase by up to about 3.5℃ by the end of the century. This means that This during the summer, in some parts of the country, will lead to significant heat stress for cows if nothing is done to alleviate the hot weather’s effects.
However, climate change projections also suggest the UK would experience more heatwaves, and these would lead to even greater losses of milk. For example, the hottest area (south-east England) in the hottest year in the 2090s is predicted to result in an annual milk loss exceeding 1,300kg/cow, which is about 18.6% of annual milk yield.
The abstract of the study;
Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom
Nándor Fodor, Andreas Foskolos, Cairistiona F. E. Topp, Jon M. Moorby, László Pásztor, Christine H. Foyer
Published: May 8, 2018
Dairy farming is one the most important sectors of United Kingdom (UK) agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (<180 kg/cow), the ‘hottest’ 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today’s average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years.
Here’s a thought – even if the predicted warming occurs, why not import heat tolerant dairy cattle from regions which have already had to adapt to warm conditions?
NZ heat-tolerant breed launched in US
06 Jul, 2017 04:00 AM
New Zealand’s Dairy Solutionz launched its Kiwipole breed at the Tulare World Ag Expo event in California earlier this year, in partnership with STGenetics.
Slick Pathos, Slick Eros and its brother Slick Himeros are believed to be the world’s first homozygous slick dairy-type bulls available for export semen sales. The bulls will transmit the heat tolerance associated with the “slick gene” to all of their daughters.
Dairy Solutionz has developed the Kiwipole through natural breeding and introgression of the Senepol slick gene. The aim is a 100 per cent Bos taurus animal that potentially has the same heat tolerance as Bos indicus breeds, but without the negative milkability traits that can be present in the Bos indicus breeds.
The slick genes better regulate body temperature while maintaining milk yield under heat stress. University of Florida research shows the cows can generate up to four litres more milk a day (Dikmen 2014) with a calving interval improvement of almost two months (Ortiz 2015) for cows under heat stress.
The scientists who wrote this handwringing climate study are aware of the potential for importing warm climate varieties of dairy cattle, and the potential of future genetic advances. Not one word of this in their press release, though they mention this possibility in their study.
… These models were used to estimate milk loss in each grid cell without taking into account the type of dairy farming system (at pasture vs indoors). It was assumed that temperature and relative humidity were the same for all systems, and that no mitigation practices were implemented. We also assumed that cattle were not significantly different from the current UK breed types, even though breeding for heat stress tolerance is one of the proposed measures to mitigate effects of climate change on dairy farms …
Availability of milk for children is a serious issue in Britain; between Britain’s green policy inflated energy bills and ongoing housing affordability problems, a lot of people in Britain are having a very tough time.
Why frighten people by exaggerating the problem?