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Biblioteca(s): | INIA Treinta y Tres.
Fecha corriente: | 05/04/2019
Fecha de la última actualización: | 15/10/2019
Autoria: | HERD, R. M.; VELAZCO, J.I.; SMITH, H.; ARTHUR, P. F.; HINE, B.; ODDY, H.; DOBOS, R. C.; HEGARTY, R. S.
Afiliación: | ROBERT M. HERD, NSW Department of Primary Industries, Livestock Industries Centre. Environmental and Rural Science, University of New England; JOSÉ IGNACIO VELAZCO DE LOS REYES, INIA (Instituto Nacional de Investigación Agropecuaria), Uruguay. Environmental and Rural Science, University of New England.; HELEN SMITH, Local Land Services Agency; PAUL F. ARTHUR, NSW Department of Primary Industries; BRAD HINE, CSIRO Agriculture and Food, F.D McMaster Laboratory; HUTTON ODDY, NSW Department of Primary Industries, Livestock Industries Centre; ROBIN C. DOBOS, NSW Department of Primary Industries, Livestock Industries Centre; ROGER S. HEGARTY, Environmental and Rural Science, University of New England.
Título: | Genetic variation in residual feed intake is associated with body composition, behavior, rumen, heat production, hematology, and immune competence traits in Angus cattle.
Año de publicación: | 2019
Fuente/Imprenta: | Journal of Animal Science: 2019, skz077, Corrected Proof, Available online 20 february 2019. In Press.
DOI: | 10.1093/jas/skz077
Idioma: | Inglés
Notas: | Article history: Received: 05 November 2018//Revision Received: 04 February 2019// Accepted: 20 February 2019.
Contenido: | This experiment was to evaluate a suite of biological traits likely to be associated with genetic variation in residual feed intake (RFI) in Angus cattle. Twenty nine steers and 30 heifers bred to be divergent in postweaning RFI (RFIp) and that differed in midparent RFIp-EBV (RFIp-EBVmp) by more than 2 kg DMI/d were used in this study. A 1-unit (1 kg DM/d) decrease in RFIp-EBVmp was accompanied by a 0.08 kg (SE = 0.03; P < 0.05) increase in ADG, a 0.58 kg/d (0.17; P < 0.01) decrease in DMI, a 0.89 kg/kg (0.22; P < 0.001) decrease in FCR, and a 0.62 kg/d (0.12; P < 0.001) decrease in feedlot RFI (RFIf). Ultrasonically scanned depths of subcutaneous fat at the rib and rump sites, measured at the start and end of the RFI test, all had strong positive correlations with RFIp-EBVmp, DMI, and RFIf (all r values ?0.5 and P < 0.001). Variation in RFIp-EBVmp was significantly correlated (P < 0.05) with flight speed (r = ?0.32), number of visits to feed bins (r = 0.45), and visits to exhaled-emission monitors (r = ?0.27), as well as the concentrations of propionate (r = ?0.32) and valerate (r = ?0.31) in rumen fluid, white blood cell (r = ?0.51), lymphocyte (r = ?0.43), and neutrophil (r = ?0.31) counts in blood. RFIp-EBVmp was also correlated with the cellular immune response to vaccination (r = 0.25; P < 0.1) and heat production in fasted cattle (r = ?0.46; P < 0.001). Traits that explained significant variation (P < 0.05) in DMI over the RFI test were midtest metabolic-BW (44.7%), rib fat depth at the end of test (an additional 18%), number of feeder visits (additional 5.7%), apparent digestibility of the ration by animals (additional 2.4%) and white blood-cell count (2.1%), and the cellular immune response to vaccine injection (additional 1.1%; P < 0.1), leaving ~23% of the variation in DMI unexplained. The same traits (BW excluded) explained 33%, 12%, 3.6%, 3.7%, and 3.1%, and together explained 57% of the variation in RFIf. This experiment showed that genetic variation in RFI was accompanied by variation in estimated body composition, behavior, rumen, fasted heat production, hematology, and immune competence traits, and that variation in feedlot DMI and RFIf was due to differences in BW, scanned fatness, and many other factors in these cattle fed ad libitum and able to display any innate differences in appetite, temperament, feeding behavior, and activity.
Palabras-Clave: | BODY COMPOSITION; CATTLE; DIGESTIBILITY; FEED EFFICIENCY; IMMUNE COMPETENCE.
Thesagro: | PRODUCCIÓN ANIMAL.
Categoría del tema: | L51 Fisiología Animal - Nutrición
Registro original: | INIA Treinta y Tres (TT)
Ejemplares: | TT - (102740-1) - PXI - AP - DD - JAS/2019/VELAZCO -  -  - DIS