Preference of dairy cows for ryegrass, white clover and red clover, and its effects on nutrient supply and milk quality

Abstract

Two experiments were conducted with 30 dairy cows each, to study the preference for fresh (Experiment 1) and ensiled (Experiment 2) ryegrass, white and red clover. Both experiments consisted of three choice diets with white or red clover or both, offered with ryegrass, and two diets with ryegrass mixed with white or red clover (40% clover). Cows consumed diets with 37.7% fresh white and 45.9% red clover, and no preference was observed when the cows were offered all three forages. By contrast, cows preferred white and red clover silage (73.0 and 69.2%, respectively) over ryegrass silage (of lower nutritive quality). When offered three forages, cows preferred white (59.8%) over red clover (17.5%) and ryegrass (22.7%). Choice diets resulted in diets similar (fresh forages) or higher in nutrient content and digestibility (silages). Treatments did not affect feed intake and performance. Choices compared to mixed diets with red clover silage were preferable regarding the fatty acid composition of the milk fat. Obviously, only large differences in nutrient and energy concentration facilitate preferences for clovers over ryegrass, which could, depending on clover type, be beneficial in terms of the milk's fatty acid composition.

Keywords:

• Preference
• legume
• forage
• omega-3 fatty acid
• conjugated linoleic acid

Acknowledgements

We thank Tina Leuenberger and the staff of the ETH Research Station Chamau for their assistance in conducting the experiments. Carmen Kunz, Muna Mergani, William Moses, Karin Bartl, and Debora Santschi are acknowledged for assisting in the laboratory. This study was supported by the State Secretariat for Education and Research, Berne (SER) and is part of the COST Action 852 ‘Quality Legume-Based Forage Systems for Contrasting Environments’.