The objective of this study was to evaluate the carcass and meat traits, and the non-carcass components of crossbred Dorper lambs fed diets with increasing levels of urea (0.0, 0.5, 1.0, and 1.5% of dry matter – DM). The experimental design was completely randomized with four treatments (urea inclusion levels) and six replicates per treatment. Lambs were fed ad libitum for 56 days and slaughtered at 37.9 ± 5.1 kg of body weight (BW). The weight and yield of carcass before and after cooling were not influenced by urea levels, with average values of 16.9 kg and 44.6% for cold carcass weight and yield. Urea levels did not affect the morphometric measurements, the fat deposition on the carcass, the weight of carcass cuts and the weight of non-carcass components. There was a quadratic effect of urea levels on the loin yield, which may achieve maximum value of 11.31% with the inclusion of 0.84% DM urea in the feed. The pH and the color coordinates L* (brightness), a* (red intensity) and C* (saturation) of the meat also showed quadratic response to the urea levels, where in the minimum value of 5.53 for pH, maximum value of 48.67 for L* and minimum values of 14.04 and 16.21 for a* and C* may be obtained by including 0.53 to 0.70% DM urea in the ration. The inclusion of 0.84% DM urea in the ration is recommended to obtain maximum yield of loin and meat with attractive characteristics to the consumer, which is characterized by high red intensity and brightness. If consumers have preference for lamb meat with a more intense red color, the inclusion of 1.5% DM urea should be considered in the ration formulation.

Residual feed intake (RFI) and its relationship with reproductive traits was evaluated in growing bulls. Fifty-two growing Purunã bulls (11 mo initial age) were fed ad libitum in individual feedlot pens for 112 d. The animals were ranked for RFI and assigned to 3 feed efficiency groups: efficient (low RFI), intermediate (medium RFI), and inefficient (high RFI). Initial and final BW and ADG did not differ ( > 0.10) among the efficiency groups and were mean values of 254.6 (SD 44), 373.0 (SD 62), and 1.06 kg (SD 0.25), respectively. Mean values of 7.12 ± 0.28, 7.78 ± 0.28, and 8.04 ± 0.28 kg/d for DMI and -0.38 ± 0.04, -0.02 ± 0.04, and 0.51 ± 0.04 kg of DM/d for RFI were observed in the efficient, intermediate, and inefficient groups, respectively. Crude protein and ME intake were strongly correlated ( = 0.74, < 0.001 for both variables) with RFI and were lower ( < 0.10) in the efficient group (13.6 ± 0.2 g DM/kg BW∙d and 0.252 ± 0.003 Mcal/kg BW∙d, respectively) and greater ( < 0.10) in the inefficient group (15.3 ± 0.2 g DM/kg BW∙d and 0.282 ± 0.003 Mcal/kg BW∙d, respectively). Testicular measures (width, length, volume, ultrasonogram pixel intensity, and scrotum perimeter) and serum testosterone were not correlated with RFI ( > 0.10) but showed moderate to strong correlations with initial BW ( ranged from 0.36 to 0.51, ≤ 0.01), final BW ( ranged from 0.36 to 0.64, ≤ 0.01), and ADG ( ranged from 0.29 to 0.53, < 0.05). All the reproductive traits (testicular measurements and concentrations of serum testosterone) showed similar values among the efficiency groups. During the growth phase, feed intake and protein and energy requirements were decreased in more efficient bulls in terms of RFI. However, both groups maintained similar BW and ADG. Regardless of their RFI classification, Purunã bulls had the same reproductive traits during the growth phase.

The objective of this study was to evaluate the carcass and meat traits, and the non-carcass components of crossbred Dorper lambs fed diets with increasing levels of urea (0.0, 0.5, 1.0, and 1.5% of dry matter – DM). The experimental design was completely randomized with four treatments (urea inclusion levels) and six replicates per treatment. Lambs were fed ad libitum for 56 days and slaughtered at 37.9 ± 5.1 kg of body weight (BW). The weight and yield of carcass before and after cooling were not influenced by urea levels, with average values of 16.9 kg and 44.6% for cold carcass weight and yield. Urea levels did not affect the morphometric measurements, the fat deposition on the carcass, the weight of carcass cuts and the weight of non-carcass components. There was a quadratic effect of urea levels on the loin yield, which may achieve maximum value of 11.31% with the inclusion of 0.84% DM urea in the feed. The pH and the color coordinates L* (brightness), a* (red intensity) and C* (saturation) of the meat also showed quadratic response to the urea levels, where in the minimum value of 5.53 for pH, maximum value of 48.67 for L* and minimum values of 14.04 and 16.21 for a* and C* may be obtained by including 0.53 to 0.70% DM urea in the ration. The inclusion of 0.84% DM urea in the ration is recommended to obtain maximum yield of loin and meat with attractive characteristics to the consumer, which is characterized by high red intensity and brightness. If consumers have preference for lamb meat with a more intense red color, the inclusion of 1.5% DM urea should be considered in the ration formulation.

This study assessed production performance, carcass characteristics, serum parameters, residue depletion of meat, and economic performance during the finishing period of steers in feedlots using salinomycin in their diet. A total of 32 steers were finished in a feedlot on a diet comprising corn silage and concentrate (50:50), with or without added salinomycin (120 mg per animal day -1 ). Study design was completely randomized, with eight repetitions. Results indicated that the use of salinomycin increased both weight gain (1.582 vs. 1.304 kg) and feed conversion (6.16 vs. 7.25 kg kg -1 ). No significant alterations were observed in feed intake (9.52 vs. 9.25 kg animal day -1 ), serum parameters, or apparent diet digestibility. The withdrawal period of 16 h prior to slaughter promoted a lower salinomycin concentration (0.25 µg kg -1 ) in organs and edible tissues, which is below the levels allowed by legislation. Animals finished with salinomycin also exhibited greater warm carcass weight (287.76 vs. 275.81 kg) and better economic performance (profit margin increments of R$ 84.20 per animal). Salinomycin use in feedlot-finished steers promoted both production and economic performance improvements without added implications to either animal or consumer health since there were no significant residues found in any edible tissues. Key words: Growth promotion additives. Feed conversion. Ionophores. Withdrawal period. ResumoObjetivou-se avaliar o desempenho produtivo, as características de carcaça, os parâmetros séricos, a depleção residual na carne e a economicidade da terminação de novilhos em confinamento com salinomicina na dieta. Foram confinados 32 animais com dieta constituída de silagem de milho e concentrado (50:50), adicionada ou não de salinomicina (120 mg por animal dia -1 de alimento (9,52 vs 9,25 kg animal dia -1 ), nos parâmetros séricos e na digestibilidade aparente da dieta. O período de carência de 16 h antes do abate promoveu concentrações de salinomicina inferiores a 0,25 µg kg -1 nos órgãos e tecidos comestíveis, cujos valores estão abaixo dos permitidos na legislação. Animais terminados com salinomicina apresentaram maior peso de carcaça quente (287,76 vs 275,81 kg) e melhor resultado econômico, com incremento de R$ 84,20 por animal na margem de lucro. O uso de salinomicina para novilhos em confinamento promoveu melhorias no desempenho produtivo e econômico, sem prejudicar a saúde dos animais e dos consumidores, pois não houve resíduos significantes nos tecidos comestíveis. Palavras-chave: Aditivo promotor de crescimento. Conversão alimentar. Ionóforo. Período de carência.

-This study intended to evaluate three identification devices for adult goats reared in semi-intensive system. They were (1) the ruminal bolus, electronic identification device composed of non-toxic ceramic and weighing 74.4 g; (2) small ear tag on left ear, visual identification device with dimensions of 50 × 15mm; and (3) big ear tag on right ear, also a visual identification device with dimensions of 42 × 48 mm. Twenty-two crossbred Boer female goats with mean age of 4 years and mean body weight (BW) of 52.6 kg were used. The identification devices were applied on all animals. Time spent for administration/application, readability and retention rate of devices were assessed. Problems during and after the application of devices, as well as device losses were recorded. Evaluations were performed one day and one week after application, then, monthly, for six months. The time spent for administration/application of the devices showed mean of 21 s and was similar between the evaluated devices. One big ear tag was lost, which decreased the retention rate of this device to 95.5%. The other devices showed retention rate of 100%. The readability was 100% for all studied devices. Small ear tags and ruminal boluses used in this study are recommended for adult goats. Production systems, environment, and ear tags with large dimensions may affect the retention rates of these visual identification devices.

The aim of this study was to evaluate the economic viability of the inclusion of urea in the ration provided to feedlot lambs. Twenty-four non-castrated male lambs, crossbred Dorper, with 2-5 months of age and a body weight (BW) of 25.0 ± 4.3 kg were used. A completely randomized design with four treatments and six replicates was adopted, in which the treatments were urea levels of 0.0, 0.5, 1.0 and 1.5% in the ration, on a dry matter (DM) basis. Lambs were fed ad libitum for 56 days and slaughtered at a BW of37.9 ± 5.1 kg. The analyzed economic indexes were the cost of the rations, cost of marginal factor (CMF), revenue of marginal factor (RMF), net revenue (NR) and benefit: cost ratio (BCR). The ration without urea presented the highest cost (0.30 US$/kg DM) and the ration with 1.0% DM of urea had the lowest cost (0.23 US$/kg DM). The CMF had a quadratic response to the urea level, reaching the lowest value (0.28 US$/day) with the addition of 0.9 to 1.0% DM of urea. The lowest and the highest NR values were obtained from the rations without and with 1.5% DM of urea, respectively (0.26 and 0.34 US$/day). The ration without urea had a worse BCR (1.74), whereas the ration with 1.0% DM of urea resulted in a better BCR (2.09). A better economic return for lambs finishing in feedlots is obtained with rations containing 1.0 to 1.5% DM of urea.

Residual feed intake (RFI) and its relationship with reproductive traits was evaluated in growing bulls. Fifty-two growing Purunã bulls (11 mo initial age) were fed ad libitum in individual feedlot pens for 112 d. The animals were ranked for RFI and assigned to 3 feed efficiency groups: efficient (low RFI), intermediate (medium RFI), and inefficient (high RFI). Initial and final BW and ADG did not differ ( > 0.10) among the efficiency groups and were mean values of 254.6 (SD 44), 373.0 (SD 62), and 1.06 kg (SD 0.25), respectively. Mean values of 7.12 ± 0.28, 7.78 ± 0.28, and 8.04 ± 0.28 kg/d for DMI and -0.38 ± 0.04, -0.02 ± 0.04, and 0.51 ± 0.04 kg of DM/d for RFI were observed in the efficient, intermediate, and inefficient groups, respectively. Crude protein and ME intake were strongly correlated ( = 0.74, < 0.001 for both variables) with RFI and were lower ( < 0.10) in the efficient group (13.6 ± 0.2 g DM/kg BW∙d and 0.252 ± 0.003 Mcal/kg BW∙d, respectively) and greater ( < 0.10) in the inefficient group (15.3 ± 0.2 g DM/kg BW∙d and 0.282 ± 0.003 Mcal/kg BW∙d, respectively). Testicular measures (width, length, volume, ultrasonogram pixel intensity, and scrotum perimeter) and serum testosterone were not correlated with RFI ( > 0.10) but showed moderate to strong correlations with initial BW ( ranged from 0.36 to 0.51, ≤ 0.01), final BW ( ranged from 0.36 to 0.64, ≤ 0.01), and ADG ( ranged from 0.29 to 0.53, < 0.05). All the reproductive traits (testicular measurements and concentrations of serum testosterone) showed similar values among the efficiency groups. During the growth phase, feed intake and protein and energy requirements were decreased in more efficient bulls in terms of RFI. However, both groups maintained similar BW and ADG. Regardless of their RFI classification, Purunã bulls had the same reproductive traits during the growth phase.

Resumo O objetivo deste estudo foi caracterizar a dinâmica de alguns parâmetros hematológicos em cordeiros recém-nascidos sadios, antes e após a ingestão de colostro. Foram coletadas amostras sanguíneas de 28 cordeiros recém-nascidos, determinando-se o eritroleucograma, as concentrações de proteína plasmática total (PPT) e de fibrinogênio nos momentos pré e pós-colostro. Os dados foram analisados comparando-se a variabilidade dos parâmetros entre os dois momentos. O hematócrito (P<0,001), a concentração de hemoglobina (P<0,05) e o volume globular médio (VGM) (P<0,05) diminuíram após a ingestão de colostro, enquanto a concentração de hemoglobina globular média (CHGM) aumentou (P<0,01) no momento pós-colostro. Houve aumento no número de leucócitos totais (P<0,001) e nas contagens absolutas de neutrófilos segmentados (P<0,05) e de linfócitos (P<0,01) após a ingestão de colostro. As concentrações de PPT e de fibrinogênio também aumentaram no momento pós-colostro (P<0,001 e P<0,01, respectivamente). O eritroleucograma, as concentrações de PPT e de fibrinogênio variam consideravelmente antes e após a ingestão de colostro, sendo modificados em função da própria ingestão do colostro e/ou da adaptação dos processos fisiológicos do animal à vida extrauterina. Portanto, recomenda-se que a interpretação de hemogramas realizados em cordeiros recém-nascidos seja feita com base em intervalos de referência específicos para o período neonatal.