Milk yield responses by dairy cows in mid-lactation to changes in feeding levels

Abstract

The reduction in milk production following a decrease in feeding level was compared with the increase in milk following an increase in feeding level of cows. Forty cows in their 5th month of lactation were allocated to 2 groups and offered either ad libitum pasture or restricted in their grazing so that, after 32 days, the difference in daily milk yield between the groups averaged 3 L/cow. Cows in each group were then offered cut pasture in stalls for 4 weeks to obtain mean daily intakes of either 14.4 or 10.2 kg DM/ cow The reduction in yield of milk energy (0.133 MJ/MJ metabolisable energy intake) following the decrease of intake from 14.4 to 10.2 kg DM/cow.day was similar to the increase in yield of milk energy (0.140 MJ/MJ metabolisable energy intake) following an increase in intake from 10.2 to 14.4 kg DM/cow.day. We conclude that, for cows in mid-lactation, the decrease in milk production following a decrease in feeding level is similar to the increase in milk production following an increase in feeding level. This implies that increases in milk production due to increased feeding can be predicted from experiments which measured reductions in milk production.