Short- and mid-term effects on performance, health and qualitative behavioural assessment of Romane lambs in different milk feeding conditions

The common practice of artificially rearing lambs from prolific meat breeds sheep constitutes a welfare issue due to increased mortality rates and negative health issues. In this multidisciplinary study, we investigated the possible short- mid-term advantages feeding fresh ewe's milk instead commercial replacer on lambs' growth, welfare. Romane were either separated their mothers D3 fed with Lacaune ewes' (LAC, n = 13) or (REP, 15), they reared by (MOT, 15). On D45, weaned, gathered in single-sex groups until end study D150. Lamb performance biomarkers overall assessed measuring: dirtiness perianal area, enteric pathogens faeces, total antioxidant status redox plasma reduced glutathione/oxidised glutathione ratio, immune response after vaccination against chlamydiosis. As an exploratory approach, blood cell transcriptomic profiles also investigated. Last, qualitative behaviour assessment (QBA) was performed as integrated criterion. REP never differed average daily gain but grew less than MOT early suckling period just weaning. No effect detected afterwards. D30, LAC had lower higher did not differ among themselves. cleaner area D21, while faecal pathogen infection vary between treatment groups. After vaccination, stronger D90 compared lambs. Transcriptome analysis D150 showed differential gene expression, mainly relation inflammatory, cycle response, male group those Based QBA, general activity varied only D21; always more agitated conclusion, artificial impaired growth rate, emotional state during at Feeding partly mitigated some effects induced without achieving full benefit being mother.