Andean structural control on interseismic coupling in the North Chile subduction zone

Segmentation can influence the extent of earthquake rupture and event magnitude: large megathrust earthquakes result from total rupture of relatively continuous segments of the subduction interface. Segmentation is attributed to variations in the frictional properties of the seismogenic zone or to topographic features on the down-going plate. Structures in the overriding plate may also influence segmentation but their importance has been dismissed. Here, we investigate the links between interface segmentation at the North Chile seismic gap and a crustal-scale fault structure in the overriding plate that forms a coastal scarp of about 1 km in height. We use satellite interferometric synthetic aperture radar (InSAR) and Global Positioning System (GPS) data to measure interseismic surface deformation between 2003 and 2009 and compare the deformation with rupture extent during well-documented earthquakes. From these data we infer the degree of coupling and segmentation at depth. We find that along a 500-km-long segment, the base of the strongly coupled seismogenic zone correlates with the line of the surface coastal scarp and follows the outline of the Mejillones Peninsula. This correlation implies that large-scale structures in the overriding plate can influence the frictional properties of the seismogenic zone at depth. We therefore suggest that the occurrence of megathrust earthquakes in northern Chile is controlled by the surface structures that build Andean topography

In Vitro Gas Production and Dry Matter Degradability of Diets Consumed by Goats with or Without Copper and Zinc Supplementation

An in vitro gas production technique was used to evaluate the effects of copper and zinc supplementation on the amount and rate of gas production, dry matter degradability (IVDMD), utilization of metabolizable energy (ME), and ruminal fermentation patterns using rumen fluid from four Boermale goats as inoculum. The goats were fed twice daily at 07:00 and 19:00 h a total mixed ration containing 10.3 and 22.5 mg/kg DM of Cu and Zn, respectively. This diet was incubated in vitro for 96 h with four treatments being: control, Cu (21.7), Zn (5.6), and Cu–Zn (21.7 and 5.6) which was provided as a mineral premix. Data were analyzed as a completely randomized design. Rates of gas production (RGP) at 4 (RGP4h) and 6 h (RGP6h) and gas production (GP) at 24 (GP24h) and 48 h (GP48h) differed (p<0.01) among treatments. An addition of Cu increased the RGP4h, RGP6h, GP24h, and GP48h (p<0.0001). The Cu treatment had the highest IVDMD and control the lowest (p<0.05), and the Cu treatment was the highest values of ME and SCFA. The addition of Cu to the in vitro ruminal fermentation increased gas production and efficiency of energy use

CONCENTRATION OF SOME ELEMENTS IN BLOOD SERUM OF NONLACTATING GOATS IN A SUBTROPICAL REGION OF SOUTHWEST OF MÉXICO STATE

The objective of this study was to determine the mineral levels in blood serum of nonlactating adult goats in the south of the State of México during the dry and rainy seasons. Eighty four multiparous (>2 calving and non-lactating) does were sampled (LW 39 ± 8 kg). Blood samples were collected by jugular vein punction, followed by separation of blood serum by adding 10% trichloroacetic acid for later laboratory analysis. Data were analyzed as a completely randomized factorial experiment. There was as effect (P<0.05) of season on serum concentrations of P, and there was an interaction (P<0.01) of season*region for Ca, Na, Cu and Zn. Mg was unaffected by treatments. Results suggest possible deficiencies in the diets of P, Ca, Cu and Zn

Zilpaterol hydrochloride improves growth performance and carcass traits without affecting wholesale cut yields of hair sheep finished in feedlot

Growth of the sheep meat industry throughout the world has been slow compared with meat industries of other domestic animals. Therefore, increasing productivity and efficiency of sheep meat production are key factors to enhance the competi- tiveness of this industry (Montossi et al. 2013). The use of β2- adrenergic agonists (β2-AA) as growth promoters has demon- strated to increase sheep meat production by improving protein deposition in muscle (Domínguez-Vara et al. 2013). The use of such technology in the lamb fattening systems could be a nutritional strategy to improve their competitiveness.Fourteen Dorper × Pelibuey ram lambs (initial body weight [BW] = 37.4 ± 1.0 kg and age = 4.5 mo) were housed in individual pens during a 30-d feeding period, and then slaughtered to determine the effects of zilpaterol hydrochloride (ZH) supplementation on productive performance, carcass characteristics and wholesale cut yields. Lambs were assigned under a randomized complete block design (initial BW as blocking factor) to one of two dietary treatments: basal diet without (control) or with 10 mg daily of ZH/lamb. Lambs fed ZH had greater (P ≤ .04) final BW, average daily gain and dry matter intake, but similar (P = .24) feed efficiency compared with control lambs. Hot and cold carcass weight, dressing percentage, longissimus muscle area and leg perimeter were greater (P ≤ .05) for ZH-fed lambs than for control lambs. With exception of blood percentage which decreased (P < .01) with ZH, wholesale cut yields and non-carcass components were unaffected (P ≥ .12) by ZH supplementation. In conclusion, ZH can be used to improve growth rate and dressing percentage, but not to increase wholesale cut yields in feedlot finishing ram lambs.This study was supported by PROMEP-SEP under the thematic network ‘Uso de Promotores de Crecimiento en Ovinos de Pelo (2014–2017

Influence of different levels of dried citrus pulp on in vitro ruminal fermentation kinetics of total mixed ration in goat rumen inocula

Inclusion of dried citrus pulp (DCP) at different levels: 0 (control), 10% (DCP10), 20 (DCP20), and 30% (DCP30) of the total mixed ration (TMR) was evaluated by in vitro gas production (GP), and ruminal fermentation patterns, in a completely randomized design. Rumen fluid was collected before the morning meal from 8 gestating goats (Boer×Saanen, body weight 3±2.3 kg). GP was recorded at 2, 4, 6, 8, 10, 12, 24, 48, 72, and 96 h of incubation. Ruminal fermentation parameters such as 96 h partitioning factor (PF96), in vitro organic matter digestibility (IVOMD), metabolizable energy (ME), short-chain fatty acids (SCFA), and metabolizable energy (ME) were also estimated. Inclusion of DCP linearly increased (P<0.01) cumulative gas production at 24, 48, and 96 h after inoculation, as well as asymptotic gas production (b). Rations at 30% and 10% DCP had the highest values of gas production, whereas control and 20% DCP presented the same values (quadratic effect P<0.01). Lag phase (L) decreased linearly (P<0.001) with DCP addition. IVDMD and IVOMD increased linearly (P<0.01) with the inclusion of DCP in rations. The ration at 30% DCP (DCP30) had the greatest value of ME and SCFA, but no differences were observed in the PF96 among treatments. The data suggest that the DCP30 ration had the best impact on rumen gas production and IVDMD, IVOMD, ME, and SCFA

In vitro gas production of foliage from three browse tree species treated with different dose levels of exogenous fibrolytic enzymes

The aim of this study was to evaluate the effect of different dose levels of exogenous fibrolytic enzymes (EFE) on in vitro ruminal fermentation kinetics and energy utilization of foliages from three browse trees (Pithecellobium dulce, Heliocarpus velutinus and Guazuma ulmifolia). Mixture of EFE product was added to the leaves of the three browse tree species at three dose levels: 0 (control), 3.5 and 7.0 mg/g of DM. Chemical composition of the foliages, including plant secondary metabolites such as total phenolics (TP), saponins (SAP) and aqueous fraction (AF), was determined. In addition, in vitro assaying of ruminal gas production kinetics was determined for the three browse three foliages treated with EFE. P. dulce had the highest crude protein content (p < 0.05), whereas G. ulmifolia had the highest content of neutral detergent fibre and SAP (p < 0.05) and H. velutinus had the lowest content of TP (p < 0.05). The interaction between tree species and dose level of EFE was significant (p < 0.05) for gas production (GP) at 24 h of incubation, parameters b and c of the accumulated GP curve, short-chain fatty acids (SCFA) and metabolizable energy (ME). The lowest (p < 0.01) extent of accumulated GP as well as the b and c values occurred in G. ulmifolia at 0 mg EFE/g DM. P. dulce had the highest (p < 0.05) values for ME and SCFA at the highest dose of EFE. Tree species and dose level had significant (p < 0.05) effects on all parameters describing in vitro ruminal fermentation kinetics and energy utilization. Addition of EFE improved the fermentation kinetics of the browse species considered in this study.UAE

In vitro gas production kinetics and degradability of a diet for growing lambs: effect of fibrolytic enzyme products at different dose levels

The objective of this study was to evaluate the effects of three fibrolytic enzyme products (cellulase (CEL), xylanase (XYL) and a 1:1 mixture of CEL and XYL (MIX)) at three dose levels (0, 1 and 3 lL/0.5 g DM) on the in vitro fermentation of a diet for growing lambs. Bottles were incubated for 96 h at 39 C. A mathematical model was used to estimate the parameters describing the gas production (GP) curve (b, c and L). Dry matter degradability (DMD) and fibre (NDFD and ADFD) degradability were determined at the end of the incubation period. Metabolisable energy (ME) and short chain fatty acids (SCFA) were calculated at 24 h of incubation. The asymptotic GP (parameter b) was affected (p<0.02) by enzyme product and dose level, with a significant linear response (p<0.05). Dose level affected ME and SCFA with a significant linear (p<0.05) and quadratic (p<0.01) response. The interaction between enzyme product and dose level was significant (p<0.05) for cumulative GP up to 72 and 96 h of incubation, pH, ADFD and DMD. The results suggest that application of exogenous cellulases has the potential to alter asymptotic GP and degradability of ADF and DM of a diet for growing lambs, but most of the results depend on the interaction between enzyme product and dose level. Future studies are required to determine the ideal combination between enzyme product and dose level for optimal degradation of ruminant feeds