Integrated crop-livestock systems (ICLS) can be an alternative to increase the productivity of agroecosystems by enhancing nutrient cycling via grazing animals. Despite the holistic approach that bears the designing of ICLS, fertilization practices are proceeded in a conventional crop basis, disregarding nutrient fluxes at the appropriate spatial and temporal dynamics. We argue that fertilization practices in ICLS must follow the same integrated approach. To test this, we compared a conventional crop fertilization strategy versus a system fertilization approach applied to two production systems being a conventional cropping system and ICLS. The conventional cropping system consisted of a soybean crop succeeded by a non-grazed Italian ryegrass cover crop. The ICLS model consisted of a soybean-Italian ryegrass rotation grazed by sheep. In the conventional crop fertilization strategy phosphorus and potassium were applied at soybean sowing and nitrogen at the Italian ryegrass establishment. The system fertilization consisted of the application of all nutrients during the Italian ryegrass establishment. Accordingly, treatments were fertilization strategies in a factorial framework with production systems randomly distributed in a complete block design with four replicates. Results indicated for the first time greater daily herbage accumulation rate (24%; P < 0.01) and total herbage production (18%; P < 0.05) in the system fertilization compared with conventional crop fertilization. Consequently, system fertilization allowed for greater stocking rates in the pasture phase (17%; P < 0.05). The ICLS presented greater equivalent soybean yield (P < 0.001), energy production (P < 0.01), and system productivity (P < 0.05) compared with the cropping system, regardless of fertilization strategies. Soybean yield was not affected by fertilization strategies or grazing. In conclusion, the adoption of system fertilization strategy and crop-livestock integration enhance the production without jeopardizing soybean grain yields, so that land use is optimized by a greater energy production per unit of nutrient applied.

Assessment of carcass bruises in steers and cull females, classified during unloading at the slaughterhouse according to genetic dominance in zebu and taurine cattle, and the presence of horns, including polled, horned and mixed batches. We considered horned the batches that included more than 20% of horned animals and mixed the batches that included less than 20% horned animals. The data were collected in a commercial slaughterhouse and included 93 batches, with a total of 2,520 animals, from different regions in Rio Grande do Sul. After evisceration, the bruises were identified and recorded in the different carcass regions: hip, round, ribs, forequarter and loin area per animal and batch. The weights of the removed tissue due to bruising was based on the average weights of various samples of bruises according to their degree of severity. Regarding the number of bruises per animal, no differences (P > 0.05) were observed between genetic groups, however, when comparing the total bruises per batch, differences were observed in all carcass regions, except for the forequarter, with a greater number of injuries in zebu than in taurine carcasses. The individual assessments showed 86.2% (P < .05) more bruises in the ribs region in horned than in polled animals carcasses. Horned batches had higher bruises mean (P < .05) compared to the polled, with increases of 65.1; 131.7 e 132.8 % in total bruises in the carcass, ribs and forequarter, respectively. The mixed batches did not differ from polled and horned batches. Zebu animals were responsible for higher industry loss totaling 1.21 kg, resulting in a economic loss of R $ 15.48 per carcass. The presence of horns resulted in greater carcass loss, 1.13 kg, with economic loss of R $ 16.11 per carcass. The bruises on carcasses are affected by the breed group and presence of horns, with zebu and horned groups leading to greater economic losses for the meat production chain. Key words: Animal welfare. Carcass cuts. Taurine. Zebu. ResumoFoi realizado um estudo para avaliar as contusões na carcaça de machos castrados e fêmeas de descarte, classificados ao desembarque no frigorífico segundo a predominância genética em taurinos e zebuínos, e a presença de chifres, incluindo mochos, aspados e mistos. Foram considerados aspados os lotes que incluíam mais de 20% de animais aspados, e mistos menos de 20% de animais aspados. coletados em uma empresa frigorífica do RS, por intermédio da análise de 93 lotes, totalizando 2.520 animais, provenientes de diferentes regiões do estado. Após a evisceração, na linha de abate, foram identificadas as contusões e contabilizadas de acordo com as regiões da carcaça: quadril, traseiro, costela, dianteiro e lombo, por animal e total do lote. Os pesos dos tecidos removidos devido às contusões foi baseado nos pesos médios de várias amostragens das contusões de acordo com o grau de severidade das mesmas. Não houve diferenças (P > 0,05) no número de contusões por animal entre os grupos genéticos, porém, quando comparados os totais por lote, observ...

This study was developed to evaluate productive efficiency during the lactation period of cows with predominant Nellore genetic composition based on their body size. Cows were divided into the following categories: light (≤ 316 kg), moderate (≥ 317 and ≤ 400 kg), or heavy (≥ 401 kg). Body weight change and total gain from birth to 210 days of age of calves born from heavy cows (0.155±0.03 and 111.6±5.1 kg) were higher than those of calves born from light (0.064±0.03 and 91.0±4.3 kg) and moderate (0.144±0.03 and 97.7±4.0 kg) cows. Calf production index differed (p < 0.05) with the herd of heavy cows (93.5±3.2 kg), producing 57.4 and 19.7% more kilograms of calf than light (59.4±2.7 kg) and moderate (78.1±2.4 kg) cows, respectively. Heavy Nellore cows produce heavier calves and have a better reproductive performance, which lead to a better calf production index. However, they require a larger area for the same herbage allowance. Calves born from heavier Nellore cows gain more weight from birth to 210 days of age and are heavier from 210 to 270 days of age.

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