Feed intake and eating characteristics of lactating cows fed silage mixture and supplemental concentrates in free-stall housing

Abstract Studies were conducted of the estimated feed intake and eating behavioral characteristics of individual cows fed SM (Silage Mixture) and concentrates via CFS (Concentrates Feed Station) on an average of 14.1 deg C by using 15 lactating Holstein cows kept in a barn with two rows of eight free stalls each. Daily eating time, bouts (visits) to bunk-fed SM and CFS, and meals of SM for each cow were measured for two periods of 3d each. Ten minutes was adopted as the minimum inter-meal interval. Load cells were attached to measure the feed intake in 2 of 15 feed troughs. Those two measured the opening and shutting time of the door feeders and the intervening feed weight in each cow. The eating rate of each cow was calculated from the daily feed intake and the daily eating time of the cows in the two troughs that were monitored in this way. The daily voluntary DMI (Dry Matter Intake) of SM in each cow was estimated by multiplying the eating rate by the daily total eating time. The daily total eating time of SM averaged 221 minutes, which seemed to be shorter than that in tie stalls and to imply a higher eating rate. Shifts between feed troughs per meal were observed 6 times on average because the number of SM meals per day averaged 8 while the number of daily bouts to SM averaged 49. Older cows had a higher DV (Dominance Value), shorter daily distance traveled, fewer visits to SM and CFS, and also showed a tendency toward a larger meal size and longer meal duration. Heavier cows tended to have a shorter daily total eating time and a higher eating rate. Neither milk production nor DV influenced eating behavior aside from a significantly positive correlation between milk production and DMI in SM and CFS. The ratio of TDN (Total Digestible Nutrients) intake to TDN requirements varied from 86-126% with an average of 103%.