Maize silage particle length modulates feeding patterns and milk composition in loose-housed lactating Holstein cows.

摘要

This study analysed feeding patterns and feed selective consumption by loose-housed lactating dairy cows fed diets based on maize silage (MS) with different particle length (PL) to establish its effects on overall dry matter intake (DMI) and productive performance. Twelve multiparous Holstein cows were offered a total mixed ration (TMR) with three different PL of MS at harvesting (i.e., long, medium, and short). Results demonstrated greater numbers of day-time meals (i.e., 07:30-19:00 h) when PL was decreased from long to medium (P<0.05). Night-time (i.e., 19:00-06:30 h) changes in the feeding pattern included an increased amount of feed per meal (P<0.05) and a tendency to increase eating time per meal (P<0.10) in cows fed the short-PL diet. Lowering the PL of MS also lowered the selective consumption against physically effective fibre larger than 1.18 mm (peNDF; P<0.05) and in favour of fine particles (i.e., particles passing through 1.18 mm screen; P<0.01). Decreasing PL of MS from long to medium and short increased daily DMI as well as the intake of energy and other nutrients contained in the diet including the amount of peNDF (P<0.01). The decrease in the PL of the diet also was associated with increased milk protein and lactose yield and milk urea nitrogen (P<0.05). The actual milk yield and fat-corrected milk were not affected by the diet (P