Are early-life lambs’ characteristics and behavioural reactivity related to later survival and growth performance during artificial feeding?

The use of prolific sheep breeds often leads farmers to rear some lambs with an automatic milk feeder improve survival and growth. However, the success these challenging situations could depend on lamb’s early individual characteristics, their behavioural reactivity in a stressful context. study was performed 567 Romane lambs. We tested hypothesis that early-life including behaviour physiology, predict growth performances until weaning. In addition, random subsample one third we assessed whether social isolation unknown human presence further predictor variability rate. Lambs were characterised by birth weight, rectal temperature scores for vigour, handling sucking first bottle arrival at nursing. After three weeks artificial rearing (i.e. halfway weaning age), 202 randomly-chosen studied 2-phase test record reaction novel arena human. Test variables summarised phase-wise principal component analysis. factor lamb general activity phase 1 affinity humans 2. Data examined using descriptive statistics, analysis multivariate regression models identify key factors average daily gain (ADG) Cumulative death rate week 5% global end period 11.6%. There higher hazard ratio weak milk-bottle (P = 0.011), low < 0.05), dam age 4–5 years versus 2–3 0.01). A ADG associated vigour score 0.01), 0.05) weight 0.001). Our data also supports relationship between artificially-reared shown 0.001) lower expressed new 0.05). suggests early-age characteristics but be valuable predictors rearing. results possibly reveal over-dependency such system.