Effects of sward structure on the diet selected by guanacos (Lama guanicoe) and sheep (Ovis aries) grazing a perennial ryegrass-dominated sward

1998 ◽  
Vol 53 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Bakker ◽  
Gordon ◽  
Milne
1998 ◽  
Vol 67 (3) ◽  
pp. 567-572 ◽  
Author(s):  
M. D. Fraser ◽  
D. H. Baker

AbstractAn experiment was conducted to compare the voluntary intake and in vivo digestion for guanacos and sheep when offered perennial ryegrass at three different growth stages: vegetative growth (VG), emerging inflorescence (El) and mature inflorescence (MI). Dry-matter (DM) intake ranged from 1·19 to 2·12 kg/day for the guanacos and 0·79 to 1·52 kg/day for the sheep. When expressed on a metabolic live-weight (M0·75) basis, the intake of the guanacos (55·8, 43·1 and 44·1 g DM per kg M0·75 daily on the VG, El and MI grasses respectively) and the sheep (54·4, 45·7 and 47·4g DM per kg M0·75 daily respectively) were similar (s.e.d. = 3·70). Apparent digestibilities of all food constituents were also similar. In terms of food choice, the response of the two species to grass stem differed; the guanacos selected (El) or tolerated (MI) this fraction, while the sheep tolerated (El) or avoided (MI) it.


Arqueología ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 171-195
Author(s):  
Ailín Guillermo ◽  
Fernando Fernández ◽  
José Cordero

Se presenta el estudio zooarqueológico del sitio Casa de Piedra de Ortega, ubicado en la cuenca superior del río Limay (Río Negro, Argentina). Se analizan los conjuntos del componente prehispánico inmediatamente anterior al contacto (Período III, 1490 ± 70 AP) y del componente posthispánico (Período IV-V, 280 ± 50 AP). Se determinó una baja incidencia de meteorización, erosión y acción de carnívoros, lo que indicó buena conservación y rápido enterramiento de los conjuntos. Gran parte de los restos se depositaron por actividad humana, incluyendo la explotación de fauna autóctona y exótica para alimentación y uso de las pieles. A lo largo de toda la secuencia (Períodos III a V) se explotaron Lama guanicoe, Rhea pennata y Conepatus chinga, aunque L. guanicoe se configura como el principal recurso. En el Período IV, Lycalopex griseus, Lycalopex culpaeus y Chaetophractus villosus se incorporan a los recursos. En el Período V, se registró la utilización de Equus caballus, Bos taurus y, mayormente, de Ovis aries. Si bien se observó una diversificación taxonómica en las ocupaciones posthispánicas, también se registró una mayor intensidad en la explotación de L. guanicoe. Ello demuestra que no hubo un reemplazo de la explotación de la fauna autóctona con la llegada de la fauna exótica doméstica. Para contextualizar la investigación se utilizó la información procedente de fuentes documentales y se compararon los resultados con los obtenidos en análisis arqueofaunísticos realizados en sitios arqueológicos del área de estudio.


Author(s):  
C. Guy ◽  
T. J. Gilliland ◽  
D. Hennessy ◽  
F. Coughlan ◽  
B. McCarthy

White clover (Trifolium repens L.) is at a disadvantage to perennial ryegrass (Lolium perenne L.; PRG) due to its limited cold tolerance and low growth rates at colder temperatures, which can affect subsequent spring herbage dry matter (DM) availability. The effect of PRG ploidy on white clover morphology and growth over winter, and its subsequent recovery in spring and the following growing season, is poorly understood. The objective of this study was to compare the effect of white clover inclusion and PRG ploidy on sward structure, plant morphology and growth of PRG–white clover swards over winter. Four swards (diploid PRG only, tetraploid PRG only, diploid PRG–white clover and tetraploid PRG–white clover) were evaluated over a full winter period (November–February) at a farmlet scale. The PRG ploidy had no effect on herbage DM production, white clover content or tissue turnover (P > 0.05) over winter. However, white clover inclusion caused a significant decrease in herbage DM production (P < 0.001; −254 kg DM/ha) and tiller density (P < 0.001; −1,953 tillers/m2) over winter. Stolon mass was not affected by PRG ploidy (P > 0.05); however, stolon length and number of leaves per stolon were affected by PRG ploidy (P < 0.05). Including white clover in PRG swards can alter winter sward dynamics, potentially causing difficulties in subsequent spring management and performance due to the reduced over-winter growth rate when compared with PRG.


Agronomie ◽  
2003 ◽  
Vol 23 (5-6) ◽  
pp. 503-510 ◽  
Author(s):  
Florence Paynel ◽  
Jean Bernard Cliquet

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