Effects of Feeding a Little Amount of the Concentrate on Holstein Cows

It is common to feed a moderate amount of a concentrate to cows to maintain good milk production, but it is useful to confirm how the feeding none or a little amount of the concentrate affects cow herds which have high milk performances. Therefore we investigated the effects of restricted feeding of a concentrate (1 kg/head/day) on Holstein cows in comparison with usual feeding in our Experiment Farm, Tokyo Univ., by using 24 cows in the same Farm and using change-over design. As roughages, self-sufficed grasses, forages and silages of them were principally fed, and on days when it was impossible to harvest them, commercial feed as hay-cube, beet-pulp etc. were fed. Through the test period, body weights (every 2 months), milk yields (every 1 week), milk fat and solid contents (every 1 or so month) were scaled on each cow, and states of parturition, postpartum returns of estrus, and fertilities were also investigated. Feeding a little amount of the concentrate to cows had a tendancy to suppress the deseases at partritions and hence to improve the fertilities of cows. Body weights were a little lower with cows fed on the less amount of the concentrate (significant at 5%), and a variation was also recognized between years tested. Milk yields were largely decreased by feeding a little amount of the concentrate (significant at 0.5%), and especially in obseration in short periods, they were affected by the sorts and qualities of roughages. Milk fat and solid contents were compared by using 3 pairs (6 cows) which had the same calving numbers and the same calving seasons respectively. They considerably varied, therefore it was impossible to distinguish the differences between treatments. Because of gaps in measuring times, it was not proper to calculate fat corrected milk (FCM), nevertheless it was assumed that FCM would considerably decrease by feeding a little amount of the concentrate.