عنوان مقاله [English]
نویسندگان [English]چکیده [English]
To assess the effects of different fat supplements (palm oil, soybean oil or complete roasted soybean) to the transition period diets on Holstein dairy cows, 30 multiparous Holstein cows (fourth parity) with 794±41 kg of body weight and 250±10 days of pregnancy were, randomly, attributed to experimental diets including palm oil (treatment 1), soybean oil (treatment 2) or roasted whole soybean, as on oil containing supplement (treatment 3). following 14 days of adaptation to experimental pens, the animals were started to have free access to experimental diets within a period of 3 weeks following to 3 weeks after calving. Daily Dry Matter Intake (DMI), milk production and composition, animal weight changes, energy balance and nutrient digestibility coefficients of diets were determined. Obtained data were analyzed while applying a completely randomized design. At prepartum, treatment 3 exhibited a higher DMI (14.2 kg) as compared with treatments 1 and 2 (13.5 and 13.7 kg, respectively). At postpartum, DMI for treatment 3 (38.7 kg) was recorded higher (P<0.01) than that for treatment 1 (40.3 kg). The percentages of milk fat and lactose were similar among the experimental groups (P>0.05), but protein was differ (P=0.04). Treatment 1 exhibited a higher gross feed efficiency as compared with treatments 2 and 3 (P<0.01). Apparent digestibility of dry matter, organic matter and NDF were highest in treatment 2, while the lowest in treatment 3 (P<0.01). Overall, feeding diets containing palm oil (in Holstein dairy cows) improved feed intake and energy balance, but caused a higher negative change in body weight. On the other hand, the addition of soybean oil increased diet digestibility as well as feed efficiency and without any negative effect on milk production and composition.