Objective. Evaluate the effects of supplementation with different protein sources (soybean meal and wheat bran with urea) on the productive performance, intake, digestibility, microbial protein synthesis, and metabolic profile of grazing beef heifers. Materials and methods. Were used twenty Nellore heifers at 8.5±0.06 months of age, with an initial average body weight of 241.5±4.71 kg. The animals were distributed in a completely randomized deseing with two treatments and ten replicates. Two protein sources in the supplements were evaluated: 1) Soybean meal (SBM), and 2) Soybean meal + Wheat bran + Urea (SBM+WB+U). Results. Crude protein (CP) and organic matter intakes were higher (p<0.05) for heifers from SBM compared with SBM+WB+U. The CP digestibility was increased (p<0.05) with SBM supplementation. Mean blood concentrations of glucose, cholesterol, serum urea nitrogen, and total proteins were not affected (p>0.10) by protein sources. In the same way, daily weight gain and final body weight were not influenced (p>0.10) by protein sources. Conclusions. The supplementation with soybean meal or wheat bran with urea in association with soybean meal in multiple supplements for grazing cattle provides similar productive and nutritional performance and metabolic profile in beef heifers.

The objective of this study was to evaluate the inclusion of coffee pulp silage (CPS) on the performance and profitability of crossbred cows in the middle tropics. The research took place at the Villa Marina Experimental Farm of the University of Pamplona, Pamplonita, Colombia. Four lactating multiparous bovines with a body weight of 380 ± 10 kg, 6 ± 0.03 years of age and a body condition of 3.8 on a scale of 1 to 5. The animals were distributed in a balanced 4 × 4 Latin square for residual effect. The experiment consisted of four subperiods of 21 days each, being the first 14 days of adaptation to the experimental diet and 7 days for taking samples. The base diet consisted of Pennisetum sp. forage, concentrated in a proportion of 0.2% of body weight, water, and mineralized salt at will. The inclusion of the CPS was included in levels of 4, 8, and 12% of the dry matter (DM) intake. DM intake parameters, nutrient digestibility, milk production and composition, blood parameters, and economic analysis were evaluated. Treatments were compared using orthogonal contrasts; contrasts were constructed in order to evaluate the effects of inclusion of CPS, and the linear and quadratic effects of level inclusion in the DM of the diet. For the variables which did not present inclusion of CPS effect but a linear or quadratic effect was significant, a Dunnett’s test was performed to identify whether a supplemented treatment differed from the control. Significance was considered at P < 0.05 and tendencies when 0.05 < P ≤ 0.10. The inclusion of CPS in the diet increases (P < 0.05) the voluntary intake in kg day−1 of DM, organic matter (OM), CP, ethereal extract (EE), non-fiber carbohydrates (NFC), digested OM (DM), neutral detergent fiber corrected for ash and protein (NDFap), DNDF and dietary NTD concentration, the total digestibility of DM and OM, and dietary DOM content. The production and chemical composition of milk was not affected (P > 0.10) by the inclusion of EPC in the diet. The inclusion of CPS increased (P < 0.05) the concentration of albumin and globulins in the blood. The inclusion of CPS in the diet improved the productive efficiency of dairy cattle. The inclusion of 4% CPS in the DM of the diet is a nutritional strategy, which improves the nutritional characteristics and the concentration of albumin and globulins in the blood of crossed dairy cows in the middle tropics and benefit: cost ratio without affecting milk production.