Relationships of feedlot performance, feeding behavior, rumen morphometrics, and carcass characteristics of Nellore cattle differing in phenotypic residual feed intake1

Abstract

The objective of this study was to examine the relationship of DMI fluctuation, feedlot performance, feeding behavior, rumen morphometrics, and carcass characteristics in Nellore cattle classified by residual feed intake (RFI). One experiment was conducted in 2 consecutive years using individual pens (1.0 × 7.0 m) at the São Paulo State University feedlot, Dracena campus, Brazil. The experiment in year 1 started in June of 2012 with forty-eight 20-mo-old Nellore yearling bulls with an initial BW of 358.2 ± 19.4 kg. The experiment in year 2 started in January of 2013 with sixty 20-mo-old Nellore yearling bulls with an initial BW of 402.5 ± 33.0 kg. Experiments in years 1 and 2 lasted 94 and 84 d, respectively. All yearling bulls were categorized as high RFI (>0.5 SD above the mean, = 25), medium RFI (±0.5 SD from the mean, = 56), and low RFI (<0.5 SD below the mean, = 27). Visual appraisal to collect behavior data was made on d 40 (finishing period) of both years. Yearling bulls were harvested when average across treatment groups achieved a fat thickness of 4 mm at the 12th rib. Low-RFI yearling bulls had lower daily DMI, expressed either in kilograms ( < 0.01) or as percentage of BW ( < 0.01), and improved G:F ( < 0.01) when compared to high-RFI animals. No differences were observed ( > 0.10) for ADG, final BW, or HCW among RFI groups. Also, low-RFI yearling bulls had thinner final 12th rib ( < 0.01) and biceps femoris (P8) fat thickness ( < 0.01). Low-RFI yearling bulls were slower to consume ( = 0.03) and ruminate ( < 0.01) 1 kg of either DM or NDF. No significant ( > 0.10) RFI effect was observed for any ruminal morphometrics variables evaluated, with the exception of papillae area, in which low-RFI Nellore yearling bulls tended to have smaller ( = 0.07) papillae area than medium-RFI animals. In general, low-RFI Nellore yearling bulls consumed more particles larger than 19 and 8 mm and had a similar performance when compared to both medium- and high-RFI bulls; however, carcass fat composition was negatively impacted.

Effects of alternative feed additives and flint maize grain particle size on growth performance, carcass traits and nutrient digestibility of finishing beef cattle

“…(2009), using the same commercially available BEO as was used in the current trial, reported that total VFA concentration were greater compared with monensin even though no differences were detected in the molar proportion of propionate agreeing with findings of the current study. Reduced overall DMI and DMI fluctuation is usually observed in finishing steers fed diets containing sodium monensin, which is associated with greater growth performance (Stock et al ., 1995; Pereira et al ., 2016). According to Duffield et al .…”

Impacts of adding functional oils or sodium monensin in high-concentrate diets on performance, feeding behaviour and rumen morphometrics of finishing Nellore cattle

“…The DMI and NDF intake per meal in kilograms was calculated by dividing DMI and NDF by the number of meals per day. Eating rate of DM, rumination rate of DM, eating rate of NDF and rumination rate of NDF were calculated according to Pereira et al (2016). Samples of diets and orts were also collected for determination of particle-size distribution, which was performed by sieving using the Penn State Particle Size Separator and reported on an as-fed basis as described by Heinrichs (1996).…”

Relação entre diferentes índices de eficiência alimentar e características de desempenho, carcaça e termografia em bovinos Nelore confinados

“…Esses resultados estão de acordo com os apresentados por Lucila Sobrinho et al 2011, Nkrumah et al (2004) e Pereira et al (2016), que relataram correlações próximos de zero entre essas duas variáveis (r= -0,02; r= -0,03 e r= 0,03, respectivamente).…”

“…Esse resultado era esperado em virtude da independência dessa medida em relação ao crescimento e tamanho do animal adulto, corroborando com dados de Koch et al (1963) e relatados por Pereira et al (2016).…”

“…correlação de (r= 0,44) entre o CAR e o CMS relatada porPereira et al, (2016), foi inferior a encontrada neste trabalho porém, também foi significativa, confirmando que ocorre o aumento do consumo com o aumento do valor de CAR.…”