Romeu Fernandes Nardon

Evaluation of carcass characteristics of Bos indicus and tropically adapted Bos taurus breeds selected for postweaning weight

Data from 9 studies were compiled to evaluate the effects of 20 yr of selection for postweaning weight (PWW) on carcass characteristics and meat quality in experimental herds of control Nellore (NeC) and selected Nellore (NeS), Caracu (CaS), Guzerah (GuS), and Gir (GiS) breeds. These studies were conducted with animals from a genetic selection program at the Experimental Station of Sertãozinho, São Paulo State, Brazil. After the performance test (168 d postweaning), bulls (n = 490) from the calf crops born between 1992 and 2000 were finished and slaughtered to evaluate carcass traits and meat quality. Treatments were different across studies. A meta-analysis was conducted with a random coefficients model in which herd was considered a fixed effect and treatments within year and year were considered as random effects. Either calculated maturity degree or initial BW was used interchangeably as the covariate, and least squares means were used in the multiple-comparison analysis. The CaS and NeS had heavier (P = 0.002) carcasses than the NeC and GiS; GuS were intermediate. The CaS had the longest carcass (P < 0.001) and heaviest spare ribs (P < 0.001), striploin (P < 0.001), and beef plate (P = 0.013). Although the body, carcass, and quarter weights of NeS were similar to those of CaS, NeS had more edible meat in the leg region than did CaS bulls. Selection for PWW increased rib-eye area in Nellore bulls. Selected Caracu had the lowest (most favorable) shear force values compared with the NeS (P = 0.003), NeC (P = 0.005), GuS (P = 0.003), and GiS (P = 0.008). Selection for PWW increased body, carcass, and meat retail weights in the Nellore without altering dressing percentage and body fat percentage.

Efeitos de raça e da seleção para peso pós-desmame sobre características de confinamento e de carcaça da 15ª progênie dos rebanhos Zebu e Caracu de Sertãozinho (SP)

Quarenta e quatro machos inteiros provenientes de rebanhos selecionados para peso aos 378 dias (P378), nascidos em 1995, foram confinados na Estacao Experimental de Zootecnia de Sertaozinho, Estado de Sao Paulo. As amostras, representando a media geral de P378 em cada rebanho, foram formadas por oito animais Guzera (GuS) e nove para cada um dos grupos Gir (Gi), Nelore (NeS), Nelore Controle (NeC) e Caracu (Ca). O abate ocorreu aos 580 dias de idade e condicao corporal 8, em uma escala de 1 a 9. As medias minimas e maximas ajustadas, para as principais caracteristicas, envolvendo todos os grupos, foram: ganho medio diario de peso, 817 (NeC) e 1061 g (Ca); peso de abate (PAB), 408,3 (Gi) e 513,6 kg (Ca); peso de carcaca (PCAR), 230,2 (Gi) e 285,0 kg (Ca); rendimento de carcaca, 55,6 (GuS) e 58,1% (NeC). No corte entre a 9a-11a costelas, foram: musculo: 55,7 (NeC) e 64,7% (Ca); gordura: 18,6 (Ca) e 26,9% (NeC); osso: 16,7 (Ca) e 19,2% (Gi); espessura de gordura (ESPGOR): 6,4 (Ca) e 7,5 mm (GuS); area de olho de lombo: 62,8 (Gi) e 76,6 cm2 (Ca); forca de cizalhamento: 4,4 (Ca) e 5,4 kg (Gi) e perdas totais no cozimento: 23,4 (NeC) e 26,1% (Ca). Considerando o grupo Nelore, a selecao para peso provocou maiores PAB e PCAR, sem alterar o rendimento, a composicao fisica da costela ou a qualidade da carcaca e da carne. Animais Ca tiveram maior PAB, porem menor rendimento, maior musculosidade e menores niveis de gordura e espessura de gordura. Ja GuS, com rendimento semelhante ao Ca, apresentou maior ESPGOR. Nao se observaram diferencas entre os grupos geneticos quanto aos indices de maciez e perdas no cozimento da carne.

Efeitos da injeção de cloreto de cálcio pós-morte e tempo de maturação no amaciamento e nas perdas por cozimento do músculo Longissimus dorsi de animais Bos indicus e Bos taurus selecionados para ganho de peso

ABSTRACT - The objective of this study was to evaluate the effect of postmortem calcium chloride (CaCl2) injection and aging time on tenderness and cooking losses of Longissimus dorsi muscle from Bos indicus and Bos taurus animals selected for weight gain. Sixty-four young bulls (16 Caracu, 16 Guzera, 16 Nellore Control and 16 Nellore Selection) were used. Twenty four hours after slaughter a sample from Longissimus dorsi muscle, taken between the 6th and 9th lumbar vertebrae was removed and divided into nine sub-samples. In each sub-samples, randomly selected, an amount correspondent to 10% of sub-sample weight was injected, with one of the following solutions: a) water (control), b) 200 mM CaCl2 or c) 300 mM CaCl2. Each sub-sample was then vacuum-wrapped, cooled to - 2oC and aged for 1, 7 or 14 days until the realization of the shear force and cooking losses (evaporation, drip, and total losses) tests. A completely randomized design with a split-plot arrangement, where breeds corresponded to a whole plots and the combinations among three levels of CaCl2 and three aging times as split-plots, was used. The breed affected the shear force, but did not affected the cooking losses. Higher CaCl2 concentrations resulted on the lowest shear force values and greater evaporation losses although it did not affect either dripping or total losses. The 200 mM CaCl2 concentration showed the best reduction in the shear force. The postmortem injection with CaCl2 hasten the tenderness process without affecting the cooking losses.

Estudo da curva de crescimento de animais da raça Guzerá e seus cruzamentos alimentados a pasto, com e sem suplementação: 1. Análise e seleção das funções não-lineares

ABSTRACT - The objective of this work was to evaluate seven non linear functions to describe Guzera male and female growth curves, and their crossbreds (3/4Guzera-1/4Brown Swiss, 1/2Nellore-1/4Brown Swiss-1/4Guzera, 1/2Guzera-1/2Brown Swiss, 1/2Chianina- 1/4Brown Swiss-1/4Guzera, 1/2Caracu-1/2Guzera, 1/2Caracu-1/4Brown Swiss-1/4Guzera) submitted to three levels of supplementation (without, during the dry period and the whole year), to analize and to select one function which presented lower regression deviation, lower residual sum of squares, higher coefficient of determination, lower variation among animal parameters, higher convergence and assintotic compatible value with the observed mature weight. The function that best express these parameters of selection was the Gompertz, followed by the Von Bertalanffy function. The Richards function showed the high computational difficulty to the adjustment, resulting on lower convergence. Brody functions presented the largest and the modified Gompertz and Logistic functions showed the smallest mature weight.

Chemical composition of whole body and carcass of Bos indicus and tropically adapted Bos taurus breeds

Relationships between the chemical composition of the 9th- to 11th-rib section and the chemical composition of the carcass and empty body were evaluated for Bos indicus (108 Nellore and 36 Guzerah; GuS) and tropically adapted Bos taurus (56 Caracu; CaS) bulls, averaging 20 to 24 mo of age at slaughter. Nellore cattle were represented by 56 animals from the selected herd (NeS) and 52 animals from the control herd (NeC). The CaS and GuS bulls were from selected herds. Selected herds were based on 20 yr of selection for postweaning BW. Carcass composition was obtained after grinding, homogenizing, sampling, and analyzing soft tissue and bones. Similarly, empty body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Bulls were separated into 2 groups. Group 1 was composed of 36 NeS, 36 NeC, 36 CaS, and 36 GuS bulls and had water, ether extract (EE), protein, and ash chemically determined in the 9th- to 11th-rib section and in the carcass. Group 2 was composed of 20 NeS, 16 NeC, and 20 CaS bulls and water, EE, protein, and ash were determined in the 9th- to 11th-rib section, carcass, and empty body. Linear regressions were developed between the carcass and the 9th- to 11th-rib section compositions for group 1 and between carcass and empty body compositions for group 2. The 9th- to 11th-rib section percentages of water (RWt) and EE (RF) predicted the percentages of carcass water (CWt) and carcass fat (CF) with high precision: CWt, % = 29.0806 + 0.4873 × RWt, % (r(2) = 0.813, SE = 1.06) and CF, % = 10.4037 + 0.5179 × RF, % (r(2) = 0.863, SE = 1.26), respectively. Linear regressions between percentage of CWt and CF and empty body water (EBWt) and empty body fat (EBF) were also predicted with high precision: EBWt, % = -9.6821 + 1.1626 × CWt, % (r(2) = 0.878, SE = 1.43) and EBF, % = 0.3739 + 1.0386 × CF, % (r(2) = 0.982, SE = 0.65), respectively. Chemical composition of the 9th- to 11th-rib section precisely estimated carcass percentages of water and EE. These regressions can accurately predict carcass and empty body compositions for Nellore, Guzerah, and Caracu breeds.

Desempenho em Pastagens e Características de Carcaça da 16ª Progênie dos Rebanhos Nelore, Guzerá e Caracu de Sertãozinho (SP)

Forty one young bulls of herds selected for 378 days weight (W378), born in 1996, were finished on pastures of Panicum Maximum (Jacq.), Panicum Maximum (Jaq) cv. Tanzania 1 and Brachiaria brizantha (Hoschst) Stapf cv. Marandu at the Sertaozinho Experimental Station, Sao Paulo State, Brazil. The samples, representing the W378 mean for each herd, were composed by 11 Nellore Selection (NeS) and by 10 of each one of the groups Nelore Control (NeC), Guzera Selection (GuS) and Caracu (Ca). The slaughter was carried out when the animals were 824 days older, with a body condition score averaging 7.6, in a 1-9 scale. The minimum and maximum adjusted means for the main traits, including all groups, were: average weight daily gain, 406 (NeC) and 501 g (NeS); slaughter weight (SW), 446.8 (NeC) and 544.3 kg (NeS); carcass weight (CW), 249.8 (NeC) and 309.7 kg (NeS); dressing percentage (DP), 54.0 (GuS) and 56.3% (NeC and NeS). In the 9th-11th rib section: muscle, 59.6 (NeC) and 65.2% (Ca); fat, 15.6 (Ca) and 21.4% (NeC); bone, 18.9 (NeC) and 20.2% (GuS); fat thickness (FT), 2.0 (Ca) and 4.2 mm (NeC); loin eye area, 65.6 (NeC) and 71.1 cm² (NeS and Ca); Warner-Bratzler shear force (SF), 4.5 (Ca) and 6.6 kg (GuS) and total cooking losses (TCL), 22.5 (NeC) and 24.9% (GuS). The selection for weight promoted higher SW and CW in the NeS group, without changing the DP, the physical composition of the rib, SF and TCL in the meat. However, there was lower FT compared to NeC. The GuS animals had intermediates SW and CW, compared to NeS and Ca and lower DP. The Ca animals presented higher muscle percentage, in the rib section, and also higher meat tenderness compared to the meat of the Zebu animals.

Estimativas da composição física das carcaças e do corpo vazio de amostras da 15ª progênie dos rebanhos Zebu e Caracu de Sertãozinho(SP)

The body composition, in terms of percentages of muscle, fat and bone of carcass or empty body weight (EBW), was estimated in a sample comprised of 44 bulls, born in 1995, from the selected herds for weight at 378 days (W378) at Sertaozinho Experiment Station (SP-Brazil) and finished in a feedlot until slaughter. The sample of each herd, representing its mean for W378, was 9 for each group, Gir (Gi); Nellore (NeS); Control Nellore (NeC), Caracu (Ca) and 8 for Guzera (GuS). The slaughter was at 580 days of age with a body condition score averaging 8 (1-9 scale). The estimates were obtained either by predicting equations of muscle, fat and bone amounts (estimates 1) or percentages (estimates 2) utilizing the information of the 9th-11th rib section and other slaughter traits. Average values for the two estimates for muscle, fat and bone carcass percentages were: Gi (65.9; 18.2 and 15.8); GuS (64.1; 21.3 and 14.6); NeC (63.0; 21.2 and 15.7); NeS (62.6; 21.3 and 16.0) and Ca (64.2; 17.1 and 18.6). Correspondent values for % of EBW were: Gi (41.5; 11.5 and 10.0); GuS (39.1; 13.0 and 8.9); NeC (40.0; 13.5 and 10.0); NeS (39.4; 13.4 and 10.1) and Ca (39.4; 10.5 and 11.4). The selection for post-weaning weights, observed by comparing the two Nellore groups, did not promote any change on body composition of these animals. The muscle proportion for the animals of the other groups were also similar. The percentages of kidney and pelvic fat, related to EBW, were also similar among genetic groups but the carcass and EBW fat percentage were lower for Gi and Ca. The body composition estimates for the two kinds of equations were in agreement except for bone percentages in the Ca group.

Growth curve analysis of Guzera and their crossbreds fed under grazing with or without supplementation: 2. Evaluation of growth curve parameters

This paper evaluated the parameters of Gompertz nonlinear function to describe Guzera male and female growth curve, and their crossbreds (3/4Guzera - 1/4Brown Swiss, 1/2Nellore - 1/4Brown Swiss - 1/4Guzera, 1/2Brown Swiss - 1/2Guzera, 1/2Chianina - 1/4Brown Swiss - 1/4Guzera, 1/2Caracu - 1/2Guzera, 1/2Caracu - 1/4Brown Swiss - 1/4Guzera) submitted to three levels of supplementation: without supplementation, supplementation only during the dry season, and year-round supplementation. There were significant interactions between supplementation and breed, and breed and sex on mature weight and maturing rate; supplementation and sex on maturing rate and integration parameter; and breed effect on integration parameter. The dry season supplementation did not change mature weight. Increasing the energy content of the supplement increased the maturing rate estimates. Supplementation during year-round decreased the estimates of mature weight but increased maturing rate values. Calving status had a significant effect on mature weight and maturing rate estimates. An allometric equation with an r2 of 0.68 was derived to predict maturing rate from mature weight estimates.