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چکیده
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The objective of this study was to evaluate the effectsof preweaning total plane of milk intake and weaningage on intake, growth performance, and blood metabolitesof dairy calves. A total of 48 Holstein calves (40 ±1.6 kg of body weight) were used in a 2 × 2 factorial arrangementwith the factors of weaning age (d 60 vs. 75)and the total plane of milk intake (medium vs. high)during the preweaning period. Calves were assigned to1 of 4 treatments: (1) calves fed medium plane of milk(MPM) intake and weaned on d 60 of age (MPM-60d, 4L/d of milk from d 3 to 10, 6 L/d of milk from d 11 to55, and 3 L/d of milk from d 56 to 60 of age; total milkintake = 317 L), (2) calves fed MPM intake and weanedon d 75 of age (MPM-75d, 4 L/d of milk from d 3 to 10and 4.5 L/d of milk from d 11 to 70 of age followed byfeeding 2.25 L/d of milk from d 71 to 75 of age; totalmilk intake = 313 L), (3) calves fed high plane of milk(HPM) intake and weaned on d 60 of age (HPM-60d,4 L/d of milk from d 3 to 10, 6 L/d of milk from d 11to 20, and 8.5 L/d of milk from d 21 to 55 followed byfeeding 4.25 L/d of milk from d 56 to 60 of age; totalmilk intake = ~411 L); and (4) calves fed HPM intakeand weaned on d 75 (HPM-75d, 4 L/d of milk from d 3to 10, and 6 L/d of milk from d 11 to 70 of age followedby feeding 3 L/d of milk from d 71 to 75 of age; totalmilk intake = 407 L) with no milk refusals. All of thecalves were monitored up to d 90 of age. Regardlessof weaning age, starter feed intake and dry matter intake (% of body weight) were lower in calves fed HPMcompared with those receiving MPM. A tendency forthe plane of milk intake × weaning age interaction wasobserved for metabolizable energy intake with the highestvalue was recorded with the HPM-75d calves. Thelowest efficiency of metabolizable energy intake andaverage feed efficiency was observed in HPM-60d calvesthroughout the experimental period as compared withthe other groups. An interaction was found between thetotal plane of milk intake and weanin
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