Luminosity indicators in dusty photoionized environments

The luminosity of the central source in ionizing radiation is an essential parameter in a photoionized environment, and one of the most fundamental physical quantities one can measure. We outline a method of determining luminosity for any emission-line region using only infrared data. In dusty environments, grains compete with hydrogen in absorbing continuum radiation. Grains produce infrared emission, and hydrogen produces recombination lines. We have computed a very large variety of photoionization models, using ranges of abundances, grain mixtures, ionizing continua, densities, and ionization parameters. The conditions were appropriate for such diverse objects as H II regions, planetary nebulae, starburst galaxies, and the narrow and broad line regions of active nuclei. The ratio of the total thermal grain emission relative to H$\beta$ (IR/H$\beta$) is the primary indicator of whether the cloud behaves as a classical Str\"{o}mgren sphere (a hydrogen-bounded nebula) or whether grains absorb most of the incident continuum (a dust-bounded nebula). We find two global limits: when $IR/H\beta<100$ infrared recombination lines determine the source luminosity in ionizing photons; when $IR/H\beta\gg100$ the grains act as a bolometer to measure the luminosity.Comment: 12 pages 3 figures. Accepted ASP Sept.9

Adaptive capacity of female rabbits submitted to a change in breeding practices

[EN] The aim of this study was to test the consequences of a change in breeding practices on 219 multiparous rabbit does over 2 reproductive cycles (5th and 6th insemination). Three rabbit breeding systems were defined I: intensive, S: semi-intensive and E: extensive), which varied for the females in terms of reproductive rhythm (RR: 35, 42 and 49 d, respectively) and age at first insemination (20.6, 19.6 and 16.6 wk, respectively), and for kits in terms of age at weaning (32, 35 and 30 d, respectively) and age at slaughter (63, 70 and 70 d, respectively). Females were submitted to one of the 3 systems from the 1st to the 4th artificial insemination (AI), and to another system from the 5th to the 6th AI, before returning to the initial system at the 7th AI. Consequently, they were allocated to 4 groups: I-S-I, S-I-S, S-E-S and E-S-E. Because of poor reproductive performance in the I system and despite a high growth of kits before weaning due to a more energetic diet for does, a sudden change from an I system to an S system significantly increased productivity at 28 d, from 3.37 to 5.04 kg/AI. Conversely, in the S and E systems, the females were not very sensitive to an intensification (groups S-I-S and E-S-E) or an extensification (S-E-S) of the breeding system, leading to similar productivity at 63 d (14.4 and 14.3 kg/AI, 14.4 and 13.5 kg/AI, 16.5 and 16.2 kg/AI, respectively, for groups S-I-S, E-S-E and S-E-S). The consequences of a return to the initial system deserve to be tested over a longer period.This work was supported by the CAS DAR (Cunipalm n° 9023) and by the French rabbit Interprofessional Association (CLIPP).Theau.clément, M.; Galliot, P.; Souchet, C.; Bignon, L.; Fortun-Lamothe, L. (2016). Adaptive capacity of female rabbits submitted to a change in breeding practices. World Rabbit Science. 24(4):267-273. https://doi.org/10.4995/wrs.2016.5155SWORD267273244Blanc F., Dumont B., Brunschwig G., Bocquier F., Agabriel J. 2010. Extensive ruminant farming systems highlight animal coping processes based on robustness, flexibility and plasticity. In: Robustesse, rusticité, flexibilité, plasticité, résilience, les nouveaux critères de qualité des animaux et des systèmes d'élevage. Sauvant D., Perez J.M. (Eds). Dossier INRA Prod. Anim., 23, 65-80.Maertens, L., Perez, J.M., Villamide, M., Cervera, C., Gidenne, T., Xiccato, G., 2002. Nutritive value of raw materials for rabbits: EGRAN tables 2002. World Rabbit Sci., 10: 157-166.Theau-Clément M., Boiti C., Mercier P., Falières J. 2000. Description of the ovarian status and fertilising ability of primiparous rabbit does at different lactation stage, In Proc.: 7th World Rabbit Congress, 4-7 July 2000, Valencia, Spain, Vol A: 259-266

High plasmatic progesterone levels at insemination depress reproductive performances of rabbit does

The aim of this experiment was to quantify the frequency of the high progesterone syndrome at the moment of insemination and to study the influence of progesterone level (P4) on receptivity and reproductive performances of primiparous and secondiparous rabbit does. A total of 422 primiparous INRA 0067 were inseminated twice at an interval of 42 days. Prior to artificial insemination (AI), sexual receptivity of the does was tested in the presence of a vasectomised buck and, just after AI, blood samples were collected to determine progesterone concentration by RIA. The mean plasma progesterone concentration was 1.8\ub13.4 ng/ml and significantly depended on parity (primiparous: 2.2\ub13.7 ng/ml, secondiparous: 0.9\ub12.2 ng/ml, P&lt;0.001). At the following AI, 78% of pseudopregnant rabbit does returned to the basal level of oestrous condition, demonstrating that the pseudopregnancy is a reversible process. The overall percentage of pseudopregnant does (P4 651 ng/ml) was 25.9%, but it was differently (P&lt;0.001) distributed between primiparous (31.2%) and secondiparous does (12.2%). Moreover, primiparous lactating females were more frequently pseudopregnant than non-lactating ones (36.5 vs. 18.9% respectively, P&lt;0.001). The progesterone level of primiparous does was related to the lactation status (2.5\ub13.8 vs. 1.5\ub13.2 ng/ml, respectively for lactating and non-lactating, P&lt;0.001). The receptivity was highly related to the level of progesterone (P4&lt;1: 74.1%, 1 64P4&lt;6: 79.1% vs. P4&gt;6: 56.3%, P=0.006). Also the kindling rate was significantly influenced by progesterone concentrations. Non-pseudopregnant does (P&lt;1 ng/ml) had the highest fertility rate (79.0%) but when the progesterone concentration increased from 1 64P4&lt;6 to P4&gt;6 ng/ml, the fertility decreased from 68.1 to 37.4%, respectively (P&lt;0.001). Consequently, the productivity at birth was highly depressed when the progesterone level was over 6 ng/ml (9.5 and 8.6 vs. 4.5 number of born alive rabbits/AI, for P4&lt;1, 1 64P4&lt;6 and P4&gt;6 respectively, P&lt;0.001). The productivity of pseudopregnant and nonreceptive females was very poor in comparison with pseudopregnant receptive does (0.4 vs. 9.5 born alive rabbits/AI). The productivity at birth was also highly (P&lt;0.001) influenced by the physiological status of the does. Primiparous non-lactating does produced the highest number of born alive rabbits/AI, whereas primiparous lactating does had the lowest productivity at birth (9.9 vs. 5.6), secondiparous lactating being intermediate (7.1). In conclusion, the high progesterone syndrome evaluated at the moment of insemination occurred in 25.9% of females and had a strong negative impact on receptivity and reproductive performance of rabbit does

Urinary Allantoin as an Estimate of Microbial Protein Synthesis

Allantoin excretion in the urine was evaluated as a marker for bacterial protein production in lactating and dry cows grazing Sandhills range and meadows. Allantoin excretion declined with season as diet digestibility declined. Bacterial protein predicted from allantoin was significantly related (R2 = .62) to bacterial protein predicted by NRC. Urinary allantoin has potential as a tool to predict bacterial protein production in grazing cattle

Microbial Protein Synthesis and Efficiency in Nursing Calves

Microbial protein synthesis and efficiency were estimated in springborn nursing calves grazing native range and subirrigated meadow. Forage intake increased from 1.5 lb/ day (0.6% BW) in June to 5.9 lb/day (1.2% BW) in September while milk intake decreased over the same period. Microbial protein (MCP) synthesis increased from 67 g/day in May to 278 g/day right before weaning in September. Urinary allantoin was used as a marker. Efficiency of MCP synthesis was approximately 19% of forage digestible organic matter (OM) intake

Review: Towards the agroecological management of ruminants, pigs and poultry through the development of sustainable breeding programmes. II. Breeding strategies

Agroecology uses ecological processes and local resources rather than chemical inputs to develop productive and resilient livestock and crop production systems. In this context, breeding innovations are necessary to obtain animals that are both productive and adapted to a broad range of local contexts and diversity of systems. Breeding strategies to promote agroecological systems are similar for different animal species. However, current practices differ regarding the breeding of ruminants, pigs and poultry. Ruminant breeding is still an open system where farmers continue to choose their own breeds and strategies. Conversely, pig and poultry breeding is more or less the exclusive domain of international breeding companies which supply farmers with hybrid animals. Innovations in breeding strategies must therefore be adapted to the different species. In developed countries, reorienting current breeding programmes seems to be more effective than developing programmes dedicated to agroecological systems that will struggle to be really effective because of the small size of the populations currently concerned by such systems. Particular attention needs to be paid to determining the respective usefulness of cross-breeding v. straight breeding strategies of well-adapted local breeds. While cross-breeding may offer some immediate benefits in terms of improving certain traits that enable the animals to adapt well to local environmental conditions, it may be difficult to sustain these benefits in the longer term and could also induce an important loss of genetic diversity if the initial pure-bred populations are no longer produced. As well as supporting the value of within-breed diversity, we must preserve between-breed diversity in order to maintain numerous options for adaptation to a variety of production environments and contexts. This may involve specific public policies to maintain and characterize local breeds (in terms of both phenotypes and genotypes), which could be used more effectively if they benefited from the scientific and technical resources currently available for more common breeds. Last but not least, public policies need to enable improved information concerning the genetic resources and breeding tools available for the agroecological management of livestock production systems, and facilitate its assimilation by farmers and farm technicians

A log analysis study of 10 years of ebook consumption in academic library collections

Even though libraries have been offering eBooks for more than a decade, very little is known about eBook access and consumption in academic library collections. This paper addresses this gap with a log analysis study of eBook access at the library of the University of Waikato. This in-depth analysis covers a period spanning 10 years of eBook use at this university. We draw conclusions about the use of eBooks at this institution and compare the results with other published studies of eBook usage at tertiary institutes

Effect of late weaning and use of alternative cages on performance of does, suckling and fattening rabbits under extensive reproductive management

The effects of the combined use of long lactation periods (46 days) with alternative cages on the reproductive and growth performance of 104 rabbit does and their litters during five consecutive reproductive cycles were studied. Half of does were housed in conventional polyvalent cages (39 cm×100 cm×30 cm) and the other half in alternative polyvalent cages (39 cm×100 cm×60 cm), with a raised platform. Half of the rabbit does in each type of cage were weaned at 32 and the other half at 46 days after parturition. Longer lactation negatively affected the body weight (P<0.001), fat and energy content (P<0.05) of rabbit does at the end of the lactation period, but this effect decreased with the number of parturitions. Fertility, prolificacy and doe mortality were not affected by lactation length. Late weaning led to higher litter size (by 8.9%) and litter weight (by 11.3%) at the end of growing period (P<0.001) and lower feed conversion ratio per cage during the experimental period (13.5%) than weaning at 32 day (P<0.001). These results were paralleled by lower mortality (12.6 vs. 17.6%; P<0.01) of young rabbits weaned later during the overall experimental period. Differences in performance as a result of different weaning ages were only observed during cycles with worst health status (third and fifth cycles) in which late weaning decreased mortality. Type of cage did not affect doe body weight and body condition, mortality, fertility, prolificacy and litter size during the five reproductive cycles. Nevertheless, at day 21 litter weight and feed conversion ratio between 3 and 21 day were 4.2% higher (P<0.01) and 5.0% lower (P<0.05), respectively, in animals housed in alternative rather than in conventional cages. Alternative cages also led to heavier litters at 59 days (P<0.01). It was concluded that the combined use of longer lactations and cages with higher available surface with a raised platform could be alternatives to improve animal welfare in farmed rabbit