Auswirkungen der Weidehaltung tragender Jungrinder in einer auf ein Erstkalbealter von 24 Monaten ausgerichteten intensiven Aufzucht auf Körperentwicklung, Abkalbung und Milchleistung

Abstract. Title of the paper: Effect of grazing intensively reared pregnant replacement German Holstein heifers on body development, calving and milk performance
The influence of grazing intensively reared pregnant Holstein heifers on body development; calving and milk performance was tested in a farm experiment. 51 heifers were kept on pasture after insemination (VGW) and 70 heifers were continuously reared in a barn (VGS) aimed at an age at first calving of 24 month. Grazing was realized at a periodically renewed low moor pasture. Insemination began when animals reached life weight of 400 kg. Included were only heifers pregnant before 530th day of life. Life weight gain from birth to 15th month was about 850 g/day in both groups. In contrast to the continuously gaining barn reared heifers the heifers of VG pasture suffered a decrease of life weight up to 1300 g/day after starting pasture. At the same time body condition score and heart girth decreased but increased hip height. Later on pasture life weight gain as well as heart girth turned to increase up to 800 g/day and 3.5 cm/month respectively whereas body condition score tended to be constant at about 3.5. The initially decrease in life weight gain is not discussed as depression of body development but as reduction of an excessive obesity. Statistically calving problems (score 1…4) were positively related with body condition score. Furthermore calving problems influenced milk yield in first 100 days of lactation negatively. Therefore the milk yield of VGW was significant higher than VGS.