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Understanding the contribution of cattle behaviour to variations in feed efficiency and greenhouse gas emissions and the welfare consequences of improving environmental sustainability

Final Report Summary - BEHENT (Understanding the contribution of cattle behaviour to variations in feed efficiency and greenhouse gas emissions and the welfare consequences of improving environmental sustainability)

Summary of the results
We assessed the impact of different diets and additives and the effect of breed on feed efficiency and methane emissions. Residual Feed Intake (RFI) as a measure of feed efficiency and the individual methane emissions were estimated. The first was assessed after contrasting the weekly weight gain with the actual feed intake during 8 weeks. After that, animals were moved to respiratory chambers to measure the methane emissions during 4 days. The results show that RFI was strongly influenced by diet and breed. According to this, concentrate diets resulted in more efficient animals compared to forage. On the other hand, Charolais steers were more efficient than Luing (a breed developed for extensive production in the UK). Methane emissions were influenced by the diet and animals fed with concentrate diets emitted less methane than forage diets. The tested additives (Nitrates and fatty acids) showed a similar reduction of methane emissions without impacting feed efficiency. When contrasting RFI with methane emissions it was surprising to discover that, contrarily to our hypothesis, they showed no correlation between them. In the same animals, we identified and quantified the behaviours potentially impacting on RFI or methane emissions. Animal temperament (temperament tests and infrared thermography as a measure of peripheral vascular changes in response to stress) and stress sensitivity (using heart rate monitors and serum biomarkers like cortisol, creatine kinase and free fatty acids) were measured after a commercially relevant stressor. We also measured social behaviour (aggression during feeding), feeding behaviour and activity (using locomotor sensors). During the characterisation we found that changes of skin temperature can predict the behavioural stress response during handling. This finding has never been demonstrated before and constitutes a novel methodology to assess temperament.
When the results of feed efficiency and methane were contrasted with temperament and stress response we found that more temperamental animals showed reduced fed efficiency. On the other hand, animals showing higher serum cortisol emitted more methane (Figure 1).
In a second phase of the project, we compared some behaviour (feeding and social) as well as activity with feed intake. A higher proportion of contacts during feeding was associated with reduced efficiency (greater RFI). Also, increased activity represented by higher Motion Index was indicative of increased methane emissions.
In addition, we carried out a literature review about potential consequences of key strategies to mitigate greenhouse gas emissions on animal welfare. Increasing productivity is one of the most promising strategies to reduce the livestock carbon footprint which in many cases is likely to be achieved at the cost of welfare. Other strategies can effectively reduce GHG emissions whilst simultaneously improving animal welfare (e.g. feed supplementation or enhanced health status). These win-win strategies should be strongly supported.
In conclusion, GHG are influenced by diet and breed. Changes in behaviour and metabolism due to stress responsiveness may affect feed efficiency and CH4 emissions per unit of feed consumed in beef cattle highlighting a potential route for breeding and management strategies to mitigate climate change. This highlights that improved welfare can help to promote both animal efficiency and GHG emission mitigation.

Impact on society and economy
Animal agriculture needs smart development at all levels, integrating economic, social and environmental aspects and recognizing their interlinkages, so as to achieve sustainable development in all its dimensions. A key goal of the project was not only to determine the effects of diet and welfare on economic and environmental sustainability in cattle, but to provide the necessary understanding to allow the industry to prepare in advance for future social, economic and environmental contexts.
This is the first time that the behavioural mechanisms underlying improved RFI and the behavioural and physiological competence of efficient cattle to respond to routine stressors have ever been studied. The results of this project have the potential to help breeding companies to develop strategies to breed cattle for more resilience to stress which may increase the feed efficiency and mitigate enteric methane emissions. If this goal is achieved it may improve the welfare of the majority of commercially produced beef cattle which can be promoted by the industry to improve consumer’s attitudes towards this agricultural sector.
Although the focus of this proposal is on beef cattle, the results obtained are likely to benefit also the dairy cattle industry as well as other livestock species. All the above benefits help to protect the viability of one of the most important industries in rural regions within Europe.

Societal implications
This project addresses major societal concerns such as improvement of livestock welfare and reducing its impact on the environment (through improved efficiency and reduced production of greenhouse gases). Research findings are of interest to inform society about the welfare challenges for livestock in a future climate change scenario. For example, we envisage that in a context of future global warming cattle will be subjected to an increase in heat stress, which according to the findings of this project, may have implication for production efficiency and climate change mitigation. Notably, evidence from this project will inform policy makers of future actions to tackle estimated climate change in livestock agriculture.
Futhermore, the findings about trade offs of anticipated benefits in environmental sustainability on animal welfare are key to identify which strategies are beneficial for both climate change mitigation and animal welfare and should be promoted.