Christian-Albrechts-Universität zu Kiel Agrar- und Ernährungswissenschaftliche Fakultät Institut für Tierzucht und Tierhaltung Effects of energy intake during early postnatal life of Holstein-Friesian calves on later life milk production during first lactation Steffi Wiedemann1, Rebecca Kühl1, Patricia Holz2, Hans-Jürgen Kunz3, Martin Kaske4 1Animal Health, University of Kiel; 2University of Veterinary Medicine Hannover Foundation; 3Chamber of Agriculture of Schleswig-Holstein; 4Department for Farm Animals, University of Zurich Background Results There is evidence that postnatal level of nutrient supply may affect subsequent growth and function of tissues and organs in numerous mammalian species. In calves, research on the effects of an increased supply of nutrients during early life has been intensified during the last years. Recent studies have reported many positive direct effects of an intensified feeding such as higher weight gains in combination with a decrease in abnormal behaviour. Total energy consumption was almost twice as high in AdL calves compared with RES calves until the end of wk 4; no differences were obtained between wk 5 and 10 of life. Average daily gain was higher in AdL-calves compared to RES-calves during the first 4 wk of life (0.72 vs. 0.45 kg/d; p<0.001), Age at first calving did not differ between groups (765 vs. 777 d; p=0.30). Fat-corrected milk yield was higher during the first lactation in AdL animals compared with RES animals (39.2 vs. 28.0 kg/d; p<0.05). No differences in the milk protein and fat concentration were obtained. Roughage intake during first lactation was higher in AdL animals (19.3 kg DM/d vs. 18.8 kg DM/d; p<0.01) Objective The aim of this study was to analyse the long-term effects of intensified feeding of Holstein calves during the first 4 weeks of life compared to an established feeding protocol on subsequent first-lactation milk production and feed intake. Materials and Methods Animals, housing and feeding after birth and supply of at least 3 L colostrum: random assignment of 68 female Holstein-Friesian calves to two groups between d 1 to d 28 of life: ad libitum feeding (AdL, N = 38): wk 1: ad libitum feeding of acidified whole milk (17.3 MJ ME/kg DM); wk 2-4: ad libitum feeding of milk replacer (160 g/L; 21.2 MJ ME/kg DM) restrictive feeding (RES, N = 30): wk 1: 4 L acidified whole milk/day (17.3 MJ ME/kg DM) wk 2-4: 6 L milk replacer/d (120 g/L; 21.2 MJ ME/kg DM) all animals: housing in individual hutches during wk 1 and in group pens during wk 2-4 after d 28: similar feeding and housing of all calves between d 29 and d 70 of life: weaning insemination at approximately 420 kg bodyweight similar feeding and milking management during lactation Acquired data and samples weights birth weights weekly weights up to d 70 of life daily feed intake until d 70 of life: milk and milk replacer intake calf starter intake roughage intake of animals during first lactation daily milk yield monthly milk composition Statistical analyses generalized linear mixed models (MIXED procedure in SAS Version 9.3) Conclusion Intensive rearing during the four three weeks of life results in an enhanced nutrient uptake and body development in comparison with a restrictive rearing protocol. Differences in the milk production and feed intake occurred during the first lactation. The observed results imply that the rearing intensity during the neonatal period has long-term consequences. This result supports the theory of a possible metabolic programming during early life. Contact information: Jun. Prof. Dr. Steffi Wiedemann Animal Health Institute of Animal Breeding and Husbandry Olshausenstr. 40 24098 Kiel, Germany Tel. +49 431 880 4533 Email: swiedemann@tierzucht.uni-kiel.de