Integração de recursos nutricionais e genéticos para a produção de carne bovina de qualidade no sistema precoce.

Comissão organizadora: Grácia Maria Soares Rosinha, Alexandra Rocha de Oliveir, Rodrigo Carvalho Alva

Performance and carcass traits of crossbred cattle raised in pastures supplemented or not with virginiamycin.

he aim of this study was to assess performance and carcass traits of crossbred cattle raised grazing tropical grasses, receiving supplement with or without virginiamycin (VM). Steers (n = 49) and heifers (n = 56) produced from matting Nellore, ½ Nellore x ½ Angus and ½ Nellore x ½ Caracu dams with Braford, Charbray and Caracu sires were raised grazing tropical grasses ( Brachiaria brizantha cv. Marandu) from 9 to 20 mo of age. The animals were divided into eight paddocks of eight hectares each, with care to form groups containing individuals of all genetic groups and balanced in age and average body weight (BW). During the dry season (July to October) cattle received protein supplements containing (n = 52) or not VM (n = 53), formulated for intake of 1 g kg -1 of BW and during the rainy season (November to June) cattle received mineral mixtures containing (n = 52) or not VM (n = 53). The VM was included in the supplements to provide an intake of 45 mg 100 kg -1 of BW. Supplements were provided in open troughs ad libitum and intake was evaluated by weighing monthly leftovers

Variações dos níveis de garantia de suplementos minerais para bovinos de corte disponíveis no mercado brasileiro. 1. Macrominerais.

Comissão organizadora: Grácia Maria Soares Rosinha, Alexandra Rocha de Oliveir, Rodrigo Carvalho Alva

Crossbreeding applied to systems of beef cattle production to improve performance traits and carcass quality.

Crossbreeding represents an important technique to improve growth, beef quality and adaptability in beef production systems in tropical countries. The aim of this study was to evaluate sire and dam breed effects on performance and carcass traits of crossbred cattle produced in a tropical environment. Heifers and steers were evaluated during the pre-weaning, the post-weaning (n = 173) and the finishing phase (n = 123). Animals were produced by mating Nellore (N_N), Angus × Nellore (A_N) and Caracu × Nellore (C_N) dams with Braford, Charbray and Caracu sires. After weaning, animals were raised grazing on Marandu grass for 12 months; thereafter they were housed in individual pens and finished in a feedlot, receiving a total mixed ration. Ultrasound carcass evaluations were performed to determine ribeye area (R_A), backfat thickness (B_T) and rump fat thickness (R_T). A_N progeny were heavier at birth than N_N (P 0.05). Progeny of N_N cows had greater B_T (P 0.05). A_N progeny were superior in final B_T compared to C_N (P < 0.01), and Braford progeny had greater R_T at the end of finishing than Charbray (P = 0.05). The use of crossbred dams allows an increase in productivity until weaning, but this is not maintained in the post-weaning and finishing periods. The use of Braford sires produces similar growth performance in the different stages of the production system to those seen with Charbray and Caracu sires but generates animals with higher fat thickness at the end of finishing, which may improve carcass quality and commercial value

Performance of crossbred steers surgically castrated or immunocastrated.

The aim of this study was to assess performance of crossbred steers surgically castrated or immunocastrated. Steers produced along two years from mating Nellore, ½ Nellore x½ Angus and ½ Nellore x ½ Caracu dams with Braford, Charbray and Caracu sires were raised grazing tropical grasses until 20 months of age (n = 80; 40 per treatment) and finished feedlot for 4 months (n = 64; 32 per treatment). The selection of animals that were finished feedlot was performed in order to remove those with more discrepant weights in relation to the mean at the end of backgrounding period, keeping balanced the number of individuals of each evaluated genetic group. Animals were kept in individual pens allowing measuring of daily dry matter intake (DMI) and weight records were taken in the beginning and in the end of the feedlot as well as every 28 days to calculate average daily gain (ADG). Feed conversion ratio (FCR) was used as a measure of feed efficiency

Effect of the pasture supplementation strategy in the growing period on performance and carcass traits of crossbred cattle finished in feedlot.

The aim of this study was to evaluate performance in feedlot and carcass traits at slaughter of crossbred cattle prior raised grazing tropical grasses and receiving supplement with or without virginiamycin (VM). Steers (n = 34) and heifers (n = 31) produced from matting Nellore, ½ Nellore x ½ Angus and ½ Nellore x ½ Caracu dams with Braford, Charbray and Caracu sires were raised grazing tropical grasses (dividedinto eight paddocks of eight hectares each, formed by Brachiaria brizantha cv. Marandu) and received protein and mineral supplementation with or without VM (included in the supplements to provide an intake of 45 mg 100 kg BW-1) on dry (July to October) and rainy seasons (November to June), respectively, from 9 to 20mo of ag

Avaliação de bovinos de diferentes grupos genéticos quanto ao desempenho ponderal do nascimento ao sobreano.

A redução da idade de abate e a utilização de cruzamentos tem sido fundamental na intensificação do sistema de produção de bovinos de corte (5). O cruzamento entre animais de raças europeias adaptadas e não adaptadas com raças zebuínas, permite o aproveitamento da complementaridade entre raças e da heterose, tanto materna quanto individual, incrementando assim, o desempenho dos animais nas fases pré e pós desmama (1) e favorecendo a melhoria da qualidade da carne obtida (4). Sendo assim, o objetivo deste estudo foi avaliar a influência dos grupos genéticos maternos e paternos e o desempenho de diferentes grupos genéticos quanto às variáveis de peso ao nascimento (PN), peso a desmama (P240) e peso ao sobreano (P550)

Effect of sire breed on performance and feed efficiency in feedlot of crossbred cattle.

The aim of this study was to evaluate the effect of sire breed on performance and feed efficiency in feedlot of crossbred cattle. Steers (n=74) and heifers (n=71) produced along two years by breeding Nellore, ½ Nellore x ½ Angus and ½ Nellore x ½ Caracu cows with Braford (BF), Charbray (CC) and Caracu (CR) sires were raised grazing tropical grasses until 20 months (mo) of age and then finished in feedlot for 4 mo. Animals were kept in individual pens allowing measuring of daily dry matter intake (DMI) during finishing phase in feedlot. Weight records were taken in the beginning (BBW) and in the end (EBW) of the feedlot as well as every 28 days to calculate average daily gain (ADG). Feed conversion rate (FCR) was used as a measure of feed efficiency. Data were analyzed using mixed model methodology. There were no differences for BBW and EBW (P>0.05) among progenies of BF (381 and 556 kg), CC (391 and 567 kg) and CR (387 and 549 kg) sires. For ADG, BF progenies were superior to CR (1.45 vs. 1.31 kg dia -1 ; P0.05). Progenies of BF, CC and CR sires did not show any differences for DMI and FCR (P>0.05). All sire breeds present similar feed efficiency in feedlot. Performance in feedlot is affected by sire breed, with Braford and Charbray showing superiority in relation to Caracu.bitstream/item/149809/1/Favero-et-al-2016-sire-breed-performance-feedlot.pd

Crossbreeding applied to systems of beef cattle production to improve performance traits and carcass quality.

Crossbreeding represents an important technique to improve growth, beef quality and adaptability in beef production systems in tropical countries. The aim of this study was to evaluate sire and dam breed effects on performance and carcass traits of crossbred cattle produced in a tropical environment. Heifers and steers were evaluated during the pre-weaning, the post-weaning (n = 173) and the finishing phase (n = 123). Animals were produced by mating Nellore (N_N), Angus × Nellore (A_N) and Caracu × Nellore (C_N) dams with Braford, Charbray and Caracu sires. After weaning, animals were raised grazing on Marandu grass for 12 months; thereafter they were housed in individual pens and finished in a feedlot, receiving a total mixed ration. Ultrasound carcass evaluations were performed to determine ribeye area (R_A), backfat thickness (B_T) and rump fat thickness (R_T). A_N progeny were heavier at birth than N_N (P 0.05). Progeny of N_N cows had greater B_T (P 0.05). A_N progeny were superior in final B_T compared to C_N (P < 0.01), and Braford progeny had greater R_T at the end of finishing than Charbray (P = 0.05). The use of crossbred dams allows an increase in productivity until weaning, but this is not maintained in the post-weaning and finishing periods. The use of Braford sires produces similar growth performance in the different stages of the production system to those seen with Charbray and Caracu sires but generates animals with higher fat thickness at the end of finishing, which may improve carcass quality and commercial value.Made available in DSpace on 2020-01-23T18:06:21Z (GMT). No. of bitstreams: 1 Crossbreedingappliedtosystemsofbeefcattle.pdf: 160676 bytes, checksum: 8974b11d5875715b99317c0649935e93 (MD5) Previous issue date: 2019bitstream/item/209469/1/Crossbreeding-applied-to-systems-of-beef-cattle.pd