RESUMO

O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos com quatro intervalos de tempo (10, 15, 20 e 30 minutos), para avaliação dos comportamentos comendo, ruminando, em ócio, em pé, apresentados por bovinos confinados individualmente. Foram utilizados 62 machos Nelore desmamados, confinados durante 112 dias. O comportamento foi registrado a cada 28 dias, durante 24h, por observações diretas com rota de amostragem scan e intervalos de registro de 5 minutos, para o cálculo das seguintes características: tempo de alimentação, tempo de ruminação, tempo em ócio, tempo em pé e frequência de alimentação. Foram comparados os intervalos de registro por meio de variâncias, correlações e médias das características. Observou-se para as características, tendência de aumento da variância residual à medida que o intervalo de tempo entre dois registros aumentou, com exceção da frequência alimentar, em que foi observada tendência de diminuição da variância residual com o aumento do intervalo de registro. As médias ajustadas para as medidas de comportamento ingestivo obtidas nos intervalos de registro de 5, 10, 15, 20 e 30 minutos não diferiram significativamente (P>0,05) entre si, com exceção de tempo de alimentação, que apresentou menor valor (P<0,05) no intervalo de registro de 30 minutos em comparação ao intervalo de 5 minutos. Observou-se que até o intervalo de registro de 15 minutos, as correlações com o intervalo de registro de 5 minutos podem ser consideradas altas. Entretanto, acima de 15 minutos de intervalo de registro, a correlação com o intervalo de registro de 5 minutos cai abruptamente, deixando claro que intervalos de registros superiores a 15 minutos são inadequados para estimar as características de comportamento ingestivo de bovinos avaliadas. (AU)

: The objective of this study was to compare five-minute recording intervals with four time intervals (10, 15, 20 and 30 minutes) for estimation of eating, ruminating, idling and standing time, as well as meal frequency, of cattle housed in individual pens. Sixty-two weaned Nellore males housed in individual pens for 112 days were used. Ingestive behavior was evaluated every 28 days for 24 h. Direct observations were made using scan sampling and instantaneous sampling at intervals of 5 minutes. The recording intervals were evaluated using error variance, correlations, and adjusted means. For all traits, the residual variance tended to increase with increasing recording interval, except for meal frequency whose residual variance decreased with increasing recording interva. The adjusted means for the ingestive behavior measurements obtained at intervals of 5, 10, 15, 20 and 30 minutes did not differ significantly (P>0.05), except for meal frequency which was lower (P<0.05) in the 30-minute recording interval. The correlations with the 5-minute recording interval were considered high up to the 15-minute interval. However, for longer recording intervals, the correlation with the 5-minute recording interval decreased abruptly, showing that recording intervals longer than 15 minutes are inadequate to estimate ingestive behavior traits of cattle.(AU)

Assuntos

RESUMO

O objetivo desse trabalho foi comparar o intervalo de tempo de registro de cinco minutos com quatro intervalos de tempo (10, 15, 20 e 30 minutos), para avaliação dos comportamentos comendo, ruminando, em ócio, em pé, apresentados por bovinos confinados individualmente. Foram utilizados 62 machos Nelore desmamados, confinados durante 112 dias. O comportamento foi registrado a cada 28 dias, durante 24h, por observações diretas com rota de amostragem scan e intervalos de registro de 5 minutos, para o cálculo das seguintes características: tempo de alimentação, tempo de ruminação, tempo em ócio, tempo em pé e frequência de alimentação. Foram comparados os intervalos de registro por meio de variâncias, correlações e médias das características. Observou-se para as características, tendência de aumento da variância residual à medida que o intervalo de tempo entre dois registros aumentou, com exceção da frequência alimentar, em que foi observada tendência de diminuição da variância residual com o aumento do intervalo de registro. As médias ajustadas para as medidas de comportamento ingestivo obtidas nos intervalos de registro de 5, 10, 15, 20 e 30 minutos não diferiram significativamente (P>0,05) entre si, com exceção de tempo de alimentação, que apresentou menor valor (P<0,05) no intervalo de registro de 30 minutos em comparação ao intervalo de 5 minutos. Observou-se que até o intervalo de registro de 15 minutos, as correlações com o intervalo de registro de 5 minutos podem ser consideradas altas. Entretanto, acima de 15 minutos de intervalo de registro, a correlação com o intervalo de registro de 5 minutos cai abruptamente, deixando claro que intervalos de registros superiores a 15 minutos são inadequados para estimar as características de comportamento ingestivo de bovinos avaliadas.

: The objective of this study was to compare five-minute recording intervals with four time intervals (10, 15, 20 and 30 minutes) for estimation of eating, ruminating, idling and standing time, as well as meal frequency, of cattle housed in individual pens. Sixty-two weaned Nellore males housed in individual pens for 112 days were used. Ingestive behavior was evaluated every 28 days for 24 h. Direct observations were made using scan sampling and instantaneous sampling at intervals of 5 minutes. The recording intervals were evaluated using error variance, correlations, and adjusted means. For all traits, the residual variance tended to increase with increasing recording interval, except for meal frequency whose residual variance decreased with increasing recording interva. The adjusted means for the ingestive behavior measurements obtained at intervals of 5, 10, 15, 20 and 30 minutes did not differ significantly (P>0.05), except for meal frequency which was lower (P<0.05) in the 30-minute recording interval. The correlations with the 5-minute recording interval were considered high up to the 15-minute interval. However, for longer recording intervals, the correlation with the 5-minute recording interval decreased abruptly, showing that recording intervals longer than 15 minutes are inadequate to estimate ingestive behavior traits of cattle.

Assuntos

RESUMO

Data from 156 Nellore males were used to develop equations for the prediction of retail beef yield and carcass fat content, expressed as kilograms and as a percentage, from live animal and carcass measurements. Longissimus muscle area and backfat and rump fat thickness were measured by ultrasound up to 5 d before slaughter and fasted live weight was determined 1 d before slaughter. The same traits were obtained after slaughter. The carcass edible portion (CEP in kg and CEP% in percentage; n = 116) was calculated by the sum of the edible portions of primal cuts: hindquarter, forequarter, and spare ribs. Trimmable fat from the carcass boning process, with the standardization of about 3 mm of fat on retail beef, was considered to be representative of carcass fat content. Most of the variation in CEP was explained by fasted live weight or carcass weight (R(2) of 0.92 and 0.96); the same occurred for CEP% (R(2) of 0.15 and 0.13), and for CEP, the inclusion of LM area and fat thickness reduced the equation bias (lower value of Mallow's Cp statistics). For trimmable fat, most variation could be explained by weight or rump fat thickness. In general, the equations developed from live animal measurements showed a predictive power similar to the equations using carcass measurements. In all cases, the traits expressed as kilograms were better predicted (R(2) of 0.39 to 0.96) than traits expressed as a percentage (R(2) of 0.08 to 0.42).

Assuntos

RESUMO

Empty body and carcass chemical compositions, expressed as content of water, ether extract, protein, minerals, and energy, were evaluated in Nellore bulls with different residual feed intakes (RFI). Forty-nine not castrated males, with 343 kg of average initial BW and 398 kg of average slaughter BW, were studied. Animals were divided in two subgroups: reference group (RG) and ad libitum feeding group. At the end of the adaptation period, animals of subgroup RG were slaughtered and the other animals were finished in individual pens for approximately 100 d, until they reached a subcutaneous fat thickness over the LM of 4 mm, and were slaughtered at an average age of 540 d. Body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Tissue deposition rates and chemical composition of gain were also measured based on gains estimated by comparative slaughter technique. No significant differences in slaughter BW (P = 0.8639), empty BW (P = 0.7288), HCW (P = 0.6563), or empty body and carcass rates of gain were observed between RFI groups, demonstrating that the low (-0.331 kg DM/d) and high (+0.325 kg DM/d) RFI animals presented similar body sizes and growth rates. No significant differences in empty body or carcass content of water, ether extract, protein, minerals, and energy were observed between the low and high RFI animals. And also there were no significant differences in empty BW or carcass gain, demonstrating that low and high RFI animals had a similar growth potential. More efficient animals (low RFI) consumed less feed than less efficient animals (high RFI) but presented similar body sizes, growth rates, and empty body and carcass chemical composition.

Assuntos