Forage is the main crop in Sweden, however, its restrictive role in feed intake limits the total amount included in the diet of a dairy cow. This study examined the effect of extrusion on grass silage intake, milk production, ingestive behaviour and rumen pH. Eight Swedish Red dairy cows in mid/late lactation were fed grass silage of early or late harvest, extruded or control, in a 4x4 Latin square design with four periods of three weeks. Diets were supplemented with a mix of soybean meal, compound feed and minerals. Extrusion increased daily silage dry matter (DM) intake by 11% (p<0,001), neutral detergent fibre (NDF) intake by 12% (p<0,001) and total DM intake by 7% (p<0,001). Milk yield increased by 4% (p=0,008), Energy corrected milk (ECM) yield increased by 5% (p=0,004), milk protein content increased by 3% (p<0,001) while total daily fat and protein production increased by 5% (p=0,015) and 7% (p<0,001), respectively. Extrusion decreased average rumen pH by 0,1 units (p=0,008) and increased the time rumen pH was below 5,8 by 151% (p=0,038). Rate of intake of silage DM and NDF was increased by 33% (p<0,001), daily silage eating time decreased by 10% (p=0,006) and daily rumination time decreased by 20% (p<0,001). Daily chewing time decreased by 17% (p<0,001), with rumination and chewing time per kg of silage NDF intake decreasing by 29% and 27% (p<0,001). In conclusion, extrusion increased silage intake, eating rate and milk production but decreased chewing activity.
Marcos Managos Animal Science - Master's programme
I am a veterinarian from Greece and I am interested in animal nutrition and management. I am deeply concerned about environmental and sustainability issues and my goal is to follow a career as a researcher focusing on utilizing nutrition and management as a means for improving the health, welfare and longevity of animals. I am searching for future career opportunities.