Effect of crude protein level in high grain diets on calf growth and feed utilization





calves, early weaning, growth, intake, N utilization


This study assessed the effect of crude protein level in the diet on animal performance, feed conversion ratio and N utilization, in early-weaned lot-fed calves. Four iso-energetic rations were formulated (ME: 12.0 MJ/kg dm) differing in the crude protein content (CP: 12%, 15%, 17% and 21%, DM basis), and offered in a random experimental design to 24 Hereford calves (107.2 ± 21.5 kg). Animals were individually housed and fed ad libitum twice a day for 84 days. Increasing CP levels in the diet promoted a quadratic response (P<0.01) for dry matter intake (kg/d) and liveweight gain (LWG, kg/d), with maximum LWG of 1.36 kg/d for CP= 17.5%, without differences in subcutaneous back fat thickness (3.70 ± 0.73 mm, P = 0.25) or feed conversion ratio (4.44 ± 0.26, P> 0.10). As CP increased in the diet, N consumption increased quadratically (P <0.01), and an improvement was observed for CP (P = 0.053) and ndf (P = 0.020) apparent digestibility. Daily excretion of N in feces tended to decrease (P = 0.06), while urea-N concentration both in blood (P = 0.013) and urine (P = 0.046) increased. These results show that a level of 17% CP in the diet would optimize the performance of lot-fed early-weaned beef calves while controlling the excretion of N to the environment.


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How to Cite

Beretta V, Simeone A, Morteiro I, Young I. Effect of crude protein level in high grain diets on calf growth and feed utilization. Agrocienc Urug [Internet]. 2020 Nov. 16 [cited 2024 Feb. 21];24(2):e111. Available from: https://agrocienciauruguay.uy/index.php/agrociencia/article/view/111



Animal production and pastures
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