Cesar graduated from La Molina National Agricultural University, Lima, Peru, where he served as lecturer/researcher with the Pastures and Grasslands Research Program. While in Peru, his work was mostly focused on the improvement of Andean agricultural systems, especially grazing systems. In 1994, Cesar was awarded a scholarship by the New Zealand Government for postgraduate studies in pastoral livestock systems, obtaining his Master and PhD degrees in animal science from Massey University. His PhD studies, conducted at AgResearch Grasslands, pioneered the efforts to understand methane production by grazed ruminants. Cesar had postdoctoral positions at the Goat Research Institute - La Garza (Oklahoma, USA) and in the Herbivore Nutrition Division of INRA (France). In both positions, Cesar continued investigating methane emissions from ruminant animals. In 2003, Cesar returned to AgResearch New Zealand as a postdoctoral funded by the New Zealand Foundation for Science and Technology to continue research on reducing methane emissions using the animal selection approach. Once positioned in New Zealand, Cesar became the leader and then the co-leader of the world’s first successful research program (funded by PGGRC and MPI New Zealand) on methane emission reduction using animal breeding. There, he led a team to commission the New Zealand Ruminant Methane Measurement Centre. In 2013, Cesar was awarded a GRASS scholarship from the Global Research Alliance on Agricultural Greenhouse Gases for a Sabbatical tenure at MTT Finland, where he collaborated with the European Ruminomics project aimed at understanding the interrelationships between animal host, ruminal microbiology, methanogenesis and feed efficiency. In 2014, Cesar was hired by CSIRO Australia to lead research on winter forage systems to support the forage base of livestock systems. Between 2016 and 2020, Cesar was the International Coordinator for the New Zealand Peru Dairy Support Project, where resilience and transformative adaptation of the smallholder Andean dairying to climate change was supported. In March 2021 Cesar joined Mazingira Centre.