Cows with a high genetic milk yield potential achieve highest yields with both low and high concentrate rations

Ulrik T. Brenøe&Erling Thuen

In a three-year trial using Norwegian Red (NRF) cows with milk yield indexes between 80 and 110, several milk traits were compared. The cows were divided into four groups and fed concentrate rations according to their lactation stage.

NRF-ku på beite Foto: Liv Lønne Dille

The groups were given 4, 8, 12 and 16 kg concentrates, respectively, as the maximum ration one month after calving. After day 30 of lactation, concentrate rations were gradually decreased at a rate of one kilo per 30 days. Cows with a high milk yield index were equally superior with regard to milk performance at both low- and high-concentrate regimes, measured as kg milk and kg protein per day. However, there was a clear trend towards lower lactose and fat percentages in the milk of cows with a high yield index than in the milk of cows with a moderate yield index. This trend was observed at all four concentrate levels. As a result, yields expressed as energy-corrected milk yields were not higher for cows with a high yield index than for those with a moderate yield index. The trials thus show that NRF cows can be suitable for use in less intensive dairy farming systems, e.g., in organic dairy operations.

Updated: 27.02.06
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