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PhD position: Unravelling the role of protein metabolism in animal to animal variation of feed efficiency in growing beef cattle
Deadline for applications
Date of publication


Details on the type of contract
PhD contract
Duration of contract
36 months

Around 1425 euros/month


Name of unit of assignment
UMR1213 UMRH Unité Mixte de Recherche sur les Herbivores
Address of unit of assignment
Region of assignment
Auvergne Rhône-Alpes


Working environment

Research unit:

UMR1213 Herbivores is a joint research unit associating Inra and VetAgro Sup (http://www1.clermont.inra.fr/urh/). It contributes to the design of sustainable farming systems for herbivores that seek to reconcile production efficiency, product quality and socio-economic viability with environmental protection and valuation, and animal welfare. UMR1213 Herbivores assesses both on-farm practices and predominant and alternative systems of herbivore farming, and proposes innovative techniques with high environmental value. To achieve this aim, UMR1213 Herbivores analyses and integrates the underlying biological mechanisms, and establishes laws for animal responses with approaches ranging from high-throughput techniques to modelling and decision support tools for various stakeholders (producers, consumers, citizens, and policy-makers).


Ruminant production is of considerable economic and societal value. Ruminants can transform human-inedible feed (e.g. grasses and forages rich in cellulose) into high-quality human-edible food (e.g. meat, milk). However, this conversion has a low efficiency, especially in growing ruminants (Tolkamp et al., 2010), and is associated with N pollution and greenhouse gas emissions. Given the growing human population, the scarcity of natural resources and the need to preserve our environments, improving the conversion of forage diets into animal products (i.e. animal feed efficiency) is becoming a major challenge for ruminant productions (Makkar and Beever, 2013). To date there has been a huge progress to understand dietary factors influencing the average feed efficiency from an animal group, but there exist important animal-to-animal variations around this average which is still far from being fully understood.
Protein turnover refers to the continuous breakdown (degradation) and replacement (synthesis) of proteins not leading to net changes in protein mass. The protein turnover in growing ruminants is huge compared to the net protein deposition with as high as 94% of the whole body protein synthesis only serving to counterbalance the protein degradation occurring in fattening young bulls (Lobley, 2000). Besides, this huge turnover is accompanied by a high-energy cost for the ruminant, with only protein synthesis accounting for 23% of total energy expenditure in ruminants (Caton et al., 2000). Nevertheless, this dynamic state represents an essential mechanism for life by enabling nonproductive functions such as metabolic regulation, cellular repair and rapid adaptation against environmental changes. This is why animals with a high feed efficiency might adopt a low protein turnover strategy (Cantalapiedra-Hijar et al., 2018) likely in detriment of their robustness (Rauw et al., 1998). In growing beef cattle, despite that protein turnover has been suggested as one of the most important mechanisms explaining the animal-to-animal variation in feed efficiency (Richardson and Herd, 2004) it has not been yet thoroughly studied likely due to the lack of simple and low-invasive methods enabling to phenotype a large number of animals for long periods.

PhD research topic:

The PhD student will evaluate at the individual animal level the link between protein metabolism, with a particular focus on protein turnover, and feed efficiency in cattle fed two contrasting diets (high forage vs high starch). He/she will be in charge of developing and applying new and low-invasive isotopic methods in a large number of animals. During his/her thesis, the PhD student will supervise the animal experiments planned in this project (two big experiments with 50 animals each). The PhD student will be also engaged in the analysis of samples, data processing including statistical analysis, data interpretation and publication.

Training and skills required


o The candidate should have a MSc or equivalent academic degree in biological science
o A background in animal physiology, nutrition and modelling is desirable
o Proficiency in scientific writing in English
o Excellent communication and proactive attitude are expected
o Knowledge in statistics and data analysis
o Good level of conversational French is desirable but not mandatory

Send a motivation letter and a CV to Gonzalo CANTALAPIEDRA-HIJAR and Isabelle ORTIGUES-MARTY


(33) 04 73 62 41 06 (G. Cantalapiedra-Hijar) / (33) 04 73 62 42 29 (I. Ortigues-Marty)