EFFECT OF FEEDING PROTEIN ACCORDING TO ARC AND NRC RECOMMENDATIONS ONDRY-MATTER INTAKE, DIGESTIBILITY AND PRODUCTION PERFORMANCE IN CROSSBRED COWS IN LATE LACTATION

The effect of feeding protein according to the ARC (1984) and NRC (198 9) recommendations on dry matter intake, digestibility, N balance, mil k yield and milk composition was studied in crossbred dairy cows in la te lactation. The study included a feeding trial and a metabolism tria l. The feeding trial was conducted using eight multiparous cows in lat e lactation in a switch over design. The cows were divided into two gr oups of four cows. Group I (Gp I) received an ARC protein diet and Gro up II (Gp II) an NRC protein diet. The duration of the trial was fourt een weeks, each period lasting for seven weeks. The diet consisted of mixed straw of finger millet and paddy (FM-P) and a compound feed mixt ure (CFM). The roughage dry matter intake for Gp I and Gp II was 3.87 and 3.69 kg d(-1), respectively. The 4% FCM yield (kg d(-1)) for the c orresponding two groups was 6.44 and 6,75, The fat, SNF and protein co ntents (%) for Gp I and Gp II were, respectively 4.69, 8.82, 3.93 and 4.95, 9.04, 4.28. The difference between the two groups in roughage DM I. body condition score, milk yield and milk composition was not signi ficant (P>0,05). ?he DOMD of the two diets was similar. However, N bal ance (g d(-1)) in Gp II (39) was significantly (P<0.01) higher than in Gp I (4). The results indicated that although N balance improved with feeding higher UDP level according to MIG, it had no beneficial effec t on roughage DMI, milk yield, milk composition and body condition sco re. Therefore, it is concluded that in crossbred cows in late lactatio n, with low levels of production, feeding protein according to the ARC recommendations is adequate. (C) 1998 Elsevier Science B.V.