Productivity of Intensive Grazing Systems Based upon Irrigated Pangola Pastures in the French West Indies

This work deals with the comparison of the productivity of intensive grazing systems (IGS) in the French West Indies, used for meat production with cattle, goat and sheep. IGS are based upon the use of irrigated, fertilized, and high stocked (1.8 to 1.4 t live weight/ha/year) and rotational grazing Digitaria decumbens pastures. They lie upon good performance levels of local breeds, Creole cattle and Creole goats of Guadeloupe and Martinik ewes, and upon improved general husbandry. Both sheep and goat in IGS exhibit high levels of productivity. They reached up to 1000 kg LW of weaned offsprings and 1400 kg LW of fattened offsprings per ha and per year. Results for cattle were 522 and 1061 kg LW, respectively. The relative interests of species are presented with the aim of increasing meat production in the tropical zone and in limited land resource conditions

FR 41. Intensive production of « Martinik » hair sheep at grazing in Martinique (F.W.I.)

Local hair sheep are the main small ruminants in Martinique (F.W.I.) with more than 37 000 heads. This paper reports an overview of the performances of «Martinik» hair sheep recorded from 1978 to 1996 in an experimental and extension farm belonging to the local council, located in southern dry region of Martinique. The rainfall ranges between 1250 to 1500 mm/year with a marked dry season during 7 months. The reproduction was conducted in 3 mating per 2 years with 3 seasons of mating: dry season (April), mild season (August) and wet season (December). Lambs were weaned at 85 days of age. Two flocks of ewes were reared during 5 years on irrigated or not irrigated grazing systems based on Digitaria decumbens (Dd). The irrigation increased the fertility rate (P<.05); the prolificacy rate (P<.01); annual productivity of ewes, and surface productivity. Two flocks of ewes were reared during 4 years in two grazing systems: Digitaria decumbens vs Cynodon nlemfuensis (Cn). Herbage mass availability on Cn paddocks was higher than on the Dd paddocks (P<.01). Fertility and prolicacy rates were not affected by the type of forage. The mortality rate from birth to weaning was higher for Cn flock than for the Dd flock (P<.01). The milk production in 70 day of lactation reared on Dd was higher than for Cn (P<.01). The daily weight gain (DWG) 10-30 and 30-70 days of age adjusted for sex, litter size and lambing season were 175 vs 147 g/d (P<.01) and 137 vs 120 g/d , respectively for lambs reared on Dd and Cn. However, in our conditions, it appeared that Cn is not adapted to sheep grazing. The third trial was carried out to set up system that will decrease adverse effects of intensification. The association of cattle to growing lambs increased by 23 % the total meat production per ha (P<.01). Mix grazing decreased the infection risk of sheep by H. contortus, so that it is was assumed that it would be possible to decrease drenching rate. It also decreases herbage mass and improve nutritive value of available forage

SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

Formaldehyde (HCHO) is an important intermediate compound in the degradation of volatile organic compounds (VOCs) in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1) the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2×10<sup>15</sup> molecule/cm<sup>2</sup> and the model performances evaluated using surface measurements are satisfactory (~13%); (2) the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa) to a factor of 2 (Poland, the United Kingdom) depending on the regions

SA 06. Integrated control of Strongylosis of small ruminants in the humid tropics: a component of animal production system that required a pluridiciplinary approach

Internal parasitosis, mainly due to nematodes is well known to induce important economic losses in small ruminant production in tropical areas. Strongyloses are the more frequent diseases and became one of the main constraints in small ruminant production in the Caribbean. Research works are generally conducted with a disciplinary approach in Latin America: veterinarians focus on parasitology whereas animal production scientists focus on breeding systems. However, there are now sufficient data that emphasized the need for a global approach to set up efficient plans of integrated control for animal production in sustainable systems. This paper reviews the main research results obtained in the F.W.I. on these parasitizes and describes the pluridiciplinary research that is developed locally in the Animal Production Research Unit (APRU) to improved small ruminant grazing systems taking into account the inevitable gastrointestinal (GI) nematodes, as a component of the production systems

GM 23. Creole goat performances and main constraints in Guadeloupe

This global revision describes productive potential and of resistance to diseases of the bred Creole goat in the 15 last years in experimental conditions at INRA, Guadalupe. Data on reproductive performances of 1 904 kiddings; 145 individual lactations; regular animal performances upon 6 375 kids, were used to estimate the preweaning performances and of postweaning performances upon 1 097 kids. The genetic variation of the resistance of 13 sires to internal parasites was assessed by the mean postweaning performances of their 489 offsprings (both sex). Data were analyzed by different linear models. Fertility average was of 90 % (3 mating times in two years); with 2.1 kid/kidding. Its borning weight was 1.73 kg and the weaning weight of 7.8 kg. Significant effects of the age of kidding, childbirths type and sex on results. Nutritional levels affected yields of milk averaging 792 g/d. The infection by internal parasites were permanent with a prevalence of Haemonchus which is responsible of 80 % of mortality preweans. A significant genetic variability in favourable and unfavourable environments was shown for the 6 month old goats. On the other hand, a genetic resistance to the heartwater was clear. We conclude that Creole goat, a local tropical breed, has high productive capacities provided husbandry conditions are adequate. Thus there exists scope for improvement for the goat breeders. Different traits based on reproductive and maternal performances as well as resistance to internal parasitism will be included in the genetic improvement program of the guadeloupean Creole goat

Explicit modeling of organic chemistry and secondary organic aerosol partitioning for Mexico City and its outflow plume

The evolution of organic aerosols (OA) in Mexico City and its outflow is investigated with the nearly explicit gas phase photochemistry model GECKO-A (Generator of Explicit Chemistry and Kinetics of Organics in the Atmosphere), wherein precursor hydrocarbons are oxidized to numerous intermediate species for which vapor pressures are computed and used to determine gas/particle partitioning in a chemical box model. Precursor emissions included observed C3-10 alkanes, alkenes, and light aromatics, as well as larger <i>n</i>-alkanes (up to C25) not directly observed but estimated by scaling to particulate emissions according to their volatility. Conditions were selected for comparison with observations made in March 2006 (MILAGRO). The model successfully reproduces the magnitude and diurnal shape for both primary (POA) and secondary (SOA) organic aerosols, with POA peaking in the early morning at 15–20 μg m<sup>−3</sup>, and SOA peaking at 10–15 μg m<sup>−3</sup> during mid-day. The majority (≥75%) of the model SOA stems from reaction products of the large <i>n</i>-alkanes, used here as surrogates for all emitted hydrocarbons of similar volatility, with the remaining SOA originating mostly from the light aromatics. Simulated OA elemental composition reproduces observed H/C and O/C ratios reasonably well, although modeled ratios develop more slowly than observations suggest. SOA chemical composition is initially dominated by δ-hydroxy ketones and nitrates from the large alkanes, with contributions from peroxy acyl nitrates and, at later times when NOx is lower, organic hydroperoxides. The simulated plume-integrated OA mass continues to increase for several days downwind despite dilution-induced particle evaporation, since oxidation chemistry leading to SOA formation remains strong. In this model, the plume SOA burden several days downwind exceeds that leaving the city by a factor of >3. These results suggest significant regional radiative impacts of SOA