Supplementing different daily amounts of energy feedstuff to lactating cows grazing all-day pasture. [German]Original Title Beifutterung von unterschiedlichen Tagesgaben eines energiereichen Kraftfutters an Milchkuhe im System der Vollweide.

摘要

The amount of supplementary feeding and the type of concentrate are key factors for the success of a pasture based milk production with dairy cows. A grazing experiment was undertaken to examine the influence of different quantities of grain maize supplementation to dairy cows on parameters of animal health and performance. For the comparison, an all-day pasture with continuous stocking at 2.9 cows/ha was used. The experiment lasted eight weeks during the main vegetation period 2009. Sixteen grazing Simmental dairy cows, averaging 31 kg/d of milk at the start of the experiment, were allotted to two groups of comparable age and milk yield. Group 1 was supplemented with 1 kg/d grain maize (KM-niedrig) and group 2 with 3 kg/d (KM-hoch). Grain maize was offered twice a day immediately after milking in the stall to ensure a 21 hours long grazing period per day. Quantity of grain maize had no significant effect on milk yield (24.9 vs. 24.8 kg FCM/day). Milk urea content was tendentially lower in KM-hoch. Milk fat content in KM-hoch was lower (3.50%) than in KM-niedrig (3.85%). Back fat thickness decreased in both groups whereas the decrease in KM-niedrig was stronger. Glutamate dehydrogenase (GLDH) in blood was especially high for KM-niedrig at the beginning and for KM-hoch in the middle of the experiment. Aspartat-aminotransferase (ASAT) increased in KM-hoch after four weeks of the experiment and decreased again to the end of the experiment. This, in combination with the low milk fat content in group KM-hoch, may indicate a disorder in metabolism. In conclusion, an enhancement of grain maize supplementation to grazing from 1 to 3 kg/day did not improve animal performance and health.