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e factors causing variation in birth date and birth weight were analysed from the data from an experimental reindeer herd consisting of 1136 calves with parental information. e traits had coe cient of variation of 37 and 14%, respectively. e variation in both traits was a ected by year and sex (male calves heavier) and by management factors, such as the age distribution of females and males. Early calving results from the use of older breeding males and is most apparent in prime age females. In both traits the heritability was moderate (0.23 and 0.24) with a high proportion of maternal genetic variation (0.23) in birth weight. e North Atlantic Oscillation (NAO) indices, summarizing the major weather conditions prior to rut, explained part of the annual variation in the traits. e amount of total genetic variation in relation to trait mean, or the evolvability, was 21% in birth date and 10% in birth weight indicating that selection could successfully be used to improve herd productivity and that the traits have substantial potential for adapting to possible changing environmental conditions. e results on genetic correlations imply that selection on calf 's birth weight leads on one hand to calves being born earlier and on the other hand to dams with later parturition.

Selection of breeding animals is a tool to improve the revenues in animal production. Information about selection practices and criteria are essential in assessing the possibilities for systematic selection schemes. Attitudes of reindeer herders towards use of selection in improving production were investigated by means of interviews. We interviewed the managers of reindeer herding cooperatives concerning their selection decisions. Fortyfive out of 56 managers answered to the semi-structured questionnaire. Among herding operations, selection of breeding animals was regarded by managers as critical for calf 's autumn weight and survival. The main selection criteria were calf 's health, vigour, body size and muscularity, dam or dam line, and maternal care. Hair quality and hair length were important as well, while such often quoted traits as antler characteristics, e.g. early shedding of antler velvet and thick antler bases, were unimportant. The results show that reindeer herders i) acknowledge the importance and effects of selective breeding, and ii) have empirical knowledge to list the most important selection criteria.

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In reindeer husbandry, animal breeding could o er tools for improving productivity by selection. e traits a ecting meat production e ciency are primarily related to calf growth and survival, and to dam's longevity and lifetime ability to raise heavy calves. Information on genetic (co)variation in these traits is scarce but needed in estimating the potential and e ectiveness of selection as well as biological constraints. e objectives of the study were to estimate these genetic parameters from the data of an experimental reindeer herd at Kutuharju (Inari, Finland).Heritabilities (h 2 ) and genetic correlations (r g ) among the average daily gain of calves (ADG), dams' age at maturity, individual tness ( ind ) and the cumulative sum of her calves' weaning weight over seven years (WW7) were studied with AS-Reml software using the dataset from the experimental herd. e pedigree included also sire information to allow the separation of the maternal e ects.Direct and maternal heritabilities of ADG were moderate (0.24±0.09 and 0.18±0.05, respectively) and the directmaternal correlation was highly negative (-0.73±0.17). Indeed, selection on growth necessitates information on both calf and dam. e genetic correlation of growth with birth date and birth weight could not be detected with the data. e age at maturity and ind had a small heritable component (0.07±0.12 and 0.10±0.06, respectively), whereas the heritability value of WW7 was 0.23±0.07. Reindeer herders' empirical selection on calf 's autumn weight favours fast growth (r g between growth and autumn weight = 0.35±0.24). Dam's weight in her rst autumn was strongly correlated with her lifetime production expressed by her individual tness (r g = 0.71±0.23) and the cumulative sum of her calves' weaning weight (r g = 0.63±0.12). Hence, the early information on the dam (her weight in her rst autumn or her rst calf 's autumn weight) works as useful selection criteria for the traits related to lifetime production.