EFFECT OF RESTRICTED FEEDING IN THE FAR-OFF PERIOD ON PERFORMANCE AND METABOLIC STATUS OF DAIRY COWS

The aim of the study was to investigate experimentally the effects of restricted or ad libitum feeding in the far-off period on performance of dairy cows. Two groups of Polish Holstein-Friesian cows having 19 animals in each group were allotted to two planes of nutrition in the far-off period from -56 to -22 days. The ADLIB group was fed ad libitum (DMI 12.9 kg) while in the RES group the dry matter intake was restricted by 3 kg DM compared to the average dry matter during the last 7 days in the ADLIB group. Average daily energy intake decreased from 8.90 UFL in the ADLIB to 6.83 UFL in the RES group. In the close-up period and after parturition, the cows of both groups were given the same diet. In restrictively fed cows, there was a tendency to a greater decrease in BCS during both the dry period (P=0.09) and lactation (P=0.07). After parturition milk production, fertility indices and blood concentration of IGF-1, insulin and glucose were not significantly affected by the far-off treatment. In the RES group, lower BHBA 3 days before calving and on day 5 of lactation and lower NEFA on day 28 of lactation were recorded. Also in this group higher levels of glucose 3 days before calving, triiodothyronine (T 3) on days -30 and 5, and thyroxine (T 4) on days -3 and 28 were observed. It is concluded that restricted feeding in the far-off period positively affected blood indicators of lipomobilization during the transition period, but had little effect on performance of lactating cows. In spite of low energy, high-fibre diet offered ad libitum in the far-off period resulted in the energy overfeeding compared to the INRA system recommendation.