The variation in heat tolerance in cows is large and varies from farm to farm. The most sensitive cows start to react already when the external temperature exceeds 15ºC, which is reflected, among other things, by a decrease in their milk production likely due to a reduced feed intake. The results come from the project
‘From sensitive to robust athlete - can genomic selection help dairy cows cope with warmer temperatures?’and are a continuation of previous research from SLU that reported that a 7-day average of daily maximum temperatures above 20ºC was associated with sharp declines in milk production.
Another recently published study in the project led by Lena-Mari Tamminen at SLU also shows that fertility is often de-prioritised by dairy farmers in favour of feed production. This neglect is problematic, especially as extended calving intervals and keeping older cows can increase the risk of heat stress and mastitis. The research emphasises the need for greater awareness of uneven calving patterns and the long-term effects of heat stress. In addition, cooling systems in barns need to be re-evaluated. This could involve redesigning existing and future barns to provide a more efficient cooling system, e.g. by utilising cross draughts, fans and sprinklers in the barns, to mitigate the increasing challenges of heat stress.
Part of the project supported by SLU Gigacow is to evaluate breeding objectives to manage heat stress in cows and the possibility to select animals with higher heat tolerance, improved thermoregulation and/or reproductive performance under high temperatures. By taking heat stress into account in breeding selection, it would be possible to obtain a genetic advance that allows production, fertility and health to remain stable even in heat-stressed environments, which will become more common with a warmer climate.
Global methane hub and Nordic work to reduce methane emissions from cows
According to the Global Methane Hub, global methane emissions will increase by 35% by 2030 and by 50% by 2050 compared to 2010 levels. The scientific part of coordinating efforts to reduce emissions from livestock is led by Wageningen University (link). Work is currently underway to allocate donated research funds to strengthen existing projects in the sector. In August, the Global Methane Hub (link) presented a strategy to reduce emissions from ruminant digestion. The report focused on 7 focus areas:
- Inhibitors - Feed additives that inhibit methanogenesis or the microbes that produce methane.
- Genetics - Breeding programmes to develop low-emitting animals.
- Measurement tools - Developing cost-effective tools that measure animal methane emissions.
- Vaccines - Causing the animal's immune system to produce antibodies that suppress methane production.
- Anti-methanogenic feeds - Feeds and forages that contain compounds that reduce methane production.
- Rumen microbiome - Explore the microbes and processes that occur within the rumen ecosystem.
- Physiology and behaviour - Understand the impact of animal behaviour and physiology on the rumen microbial ecosystem.
In Sweden, there is close co-operation between Växa Sverige and SLU in order to prepare our participation in the Nordic breeding work. SLU's infrastructure for cow data, Gigacow, will form the technical backbone for collecting data that will then be analysed in collaboration between researchers at Växa Sverige and SLU. Measuring methane gas emissions from a cow is complex and can be done in three ways. With respiration chambers where the cow is confined for a period of time and the exhaled air is measured, Greenfeeds where cows are lured with concentrated feed and the exhaled air is measured in a controlled air flow and ‘sniffers’ are installed in the feed trough of a milking robot which then measures the exhaled air. SLU has a long history of research in this area (link) and has contributed to the validation of the methods used in the research (link).
DKK 518 million in funding to reduce methane emissions
In Denmark, the government has invested DKK 518 million to finance reduced methane emissions through the use of feed additives (link). In the Nordic breeding work, the aim is to be able to implement low methane production as a breeding goal using cost-effective measurement tools. SimpleScan from C-Lock (link) and MooLoggers from Tecnosens (link) are market leaders in ‘sniffers’, which is the technology deemed cost-effective enough to measure methane emissions from enough animals to be used in a breeding programme. This will be used in combination with calculated values from milk spectra calibrated with data from sniffers or Greenfeeds. To finance the purchase and installation of equipment in Sweden, researchers at SLU and Växa Sverige have written several research applications that are under review. The Swedish Board of Agriculture has also funded adaptations of SLU Gigacow to support the project.
Technically, Växa Sverige staff will install equipment and move it between farms, while SLU Gigacow is responsible for data collection and storing data that is then analysed by researchers at Växa and SLU. Since a sniffer cannot itself identify which cow is breathing on it, data collection from the sniffer needs to be synchronised with registrations in the milk robot. This will be done in SLU Gigacow based on a model developed at Aarhus University (link). At the Nordic level, a research application to the Global Methane Hub is currently being processed, focusing in particular on the red breeds, VikingRed and Norwegian red cattle. In this work, Växa Sverige, SLU, Luke (Finland), Aarhus University (Denmark), Norwegian University of Life Sciences (Norway), Viking Genetics (Denmark) and Geno (Norway) will collaborate to collect and analyse data and share it with colleagues at Scotland's Rural College (Scotland), University of Guelph and Lactanet.
