Effect of Amounts of Feed Offered to Eating of Lactating Cows Fed a Total Mixed Ration

Abstract

Four Holstein cows during early lactation were used to find out changes in feed intake, composition of residuals, and meal and rumination patterns with increasing amounts of feed offered. Feeding trials were designed as 4² Latin squares, in which rows, columns, and treatments were represented by periods, cows, and levels of amounts of feed offered. A total mixed ration (TMR), consising of 30% of grass silage, 5% of grass hay and beet pulp, 15% of alfalfa pellet and 45% of concentrate on a DM basis, was offered twice daily at 9:15 and 19:45. The results were as follows: (1) Dry matter intake (DMI) tended to increase when higher amounts of feed were offered; DMI for feeds offered averaged 24.7kg for 25.1kg, 26.6kg for 28.1kg, 27.1kg for 31.1kg and for 34.1kg. (2) Milk production in levels was not improved. (3) Body weights tended to increase when higher amounts of feed were offered. (4) When higher amounts of feed were offered, the length of the first meal after feeding decreased, but spontaneous meals and length increased. (5) Ruminating time, ruminating time/kg DMI and chewing time/kg DMI were almost not affected by the amounts offered. (6) When higher amounts of feed were offered, the amounts of residuals increased and their chemical composition approximated those of the TMR offered. From the results mentioned above, when there were large differences in quality between feed offered and its residuals or small amounts of residuals, caused by lowered amounts offered, voluntary DMI was observed to be influenced more by the control of amounts of feed offered rather than by the physiologi-cal control of animals. The method to get voluntary DMI should be tested with 10-15% as the ratio of residuals to intake.