Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during a 6-day storage period

The effects of a 6-day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid compound diets were: liquid grower diet (LGD) and liquid finisher diet (LFD). The loss of corrected dry matter after a 6-day storage, expressed in relation to the initial content, was 1.9, 6.2, 9.6, 4.6 and 4.2% for LWS, PSP, CW, LGD and LFD, respectively. During storage, the total amount of starch decreased 2.7, 24.0, 28.1 and 33.3% for LWS, PSP, LGD and LFD, respectively. The total amount of lactose decreased 23.5% for CW. The gross energy value of the products did not change remarkably during the 6-day storage period; gross energy losses being less than 3% of the initial gross energy content.     

Interpretation of cloud-climate feedback as produced by 14 atmospheric general circulation models

Understanding the cause of differences among general circulation model projections of carbon dioxide-induced climatic change is a necessary step toward improving the models. An intercomparison of 14 atmospheric general circulation models, for which sea surface temperature perturbations were used as a surrogate climate change, showed that there was a roughly threefold variation in global climate sensitivity. Most of this variation is attributable to differences in the models' depictions of cloud-climate feedback, a result that emphasizes the need for improvements in the treatment of clouds in these models if they are ultimately to be used as climatic predictors.     

Detection ofCorynebacterium sepedonicum in potato cultivars with different propensities to express ring rot symptoms

Various potato cultivars were grown in field plots from seed pieces inoculated withCoryneacterium sepedanicum by vacuum infiltration. Foliage symptoms were recorded during the growing season and tuber symptoms at harvest. Cultivars were ranked according to the frequency with which the progeny tubers expressed external bacterial ring rot symptoms. Those that yielded 50–100% symptomatic tubers were placed in symptom expression class (SEC) 1; those that produced 25–49%, 10–24%, and ≤9% symptomatic tubers were placed, respectively, in SEC 2,3, and 4. The incidence of latent ring rot infections in stems and tubers were similar among cultivars in the different SEC classes. Bacterial population densities, quantified by immunofluorescence, were as high as 10¹⁰ cells/g in stems from cultivars of all SEC classes. Mean populations in tubers ranged from 10⁶ – 10⁷ cells/g and did not differ significantly among cultivars.     

Serogroups ofErwinia carotovora involved in systemic infection of potato plants and infestation of progeny tubers

Enrichment techniques and serological strain typing methods were used to determine the source of stem and progeny tuber populations ofErwinia carotovora (Ec) in 1980 and 1981. Plots were established in a field that had been planted with potatoes since 1972. Seed tubers of cultivars Russet Burbank and Norgold Russet were assayed forErwinia carotovora pv.carotovora (Ecc) andErwinia carotovora pv.atroseptica (Eca) by tuber peeling and direct plating and plating following enrichment in a pectate-based broth. Levels of seed tuber infestation ranged from undetectable to 2.4 × 10⁴ colony-forming units per g peel tissue. Prior to planting Ecc was detected in soil samples from field plots by enrichment in a pectate-based broth. Ec was isolated from symptomless plants with increasing frequencies from 8 weeks following planting regardless of the level of Ec populations in seed tubers. At harvest progeny tuber recontamination was low and not related to levels of seed tuber Ec populations. In 1980, serological typing of representative Ecc isolates indicated serogroups III, XXIX, and unknown strains isolated from the soil but not the seed tubers prior to planting were isolated from stems and progeny tubers. Serogroup XXIX was isolated from soil, seed, stems and progeny tubers in 1981. Throughout both years, Ecc was isolated more frequently than Eca from seed, soil, stems, and progeny tubers. These data emphasize the potential for reinfestation of seed stocks and infection of plants by populations of Ecc that overwinter in soil under Wisconsin conditions.     

Some biochemical parameters for qualification of bull semen

Summary

Since the macroscopical and microscopical examination of bull semen does not in all cases appear to give conclusive indications concerning the fertilizing capacity, an investigation of some biochemical parameters was undertaken. It was shown that the following biochemical examination could furnish some more information about the quality of the semen: 1. Determination of the phenylalanine‐ α‐ketoglutarate transaminase activity both in the seminal plasma and in the whole semen. A high transaminase activity in the plasma points to leakage out of the spermatozoa, thus indicating an affection of the spermatozoa. In that case larger amounts of basic amino acids and of leucine were often found in the seminal plasma than would normally be observed.

2. Gas chromatographic examination of the steroids occurring both in the seminal plasma and in the spermatozoa. In a number of infertile bulls small peaks of progesterone were found together with those of other, unidentified compounds.

3. Investigation of the carbohydrate metabolism in the semen. In a number of fertile bulls the following deviations were found: a. the presence of quite a lot of fructose in the spermatozoa;

b. the presence of glucuronic acid and / of other foreign compounds in the spermatozoa or in the plasma;

c. an elevated pH in the seminal plasma some 2 to 3 hours after ejaculation;

d. a low phenylalanine‐α ‐ketoglutarate transaminase activity in the whole semen (the spermatozoa had been disrupted by freezing).

4. Investigation of the presence of reducing aldehydes (glycolaldehyde and glyceraldehyde) inside the spermatozoa.

The determinations mentioned under 1, 3c and 3d can easily be carried out in the laboratories of each District Animal Health Service and of the A.I. stations; the same is true of the occurrence of amino acids in the seminal plasma and of fructose and aldehydes inside the spermatozoa if facilities are available for electrophoresis and chromatography.     

Soil organic matter pools and carbon-protection mechanisms in aggregate classes influenced by surface liming in a no-till system

The stabilisation of soil organic matter (SOM) is the result of the simultaneous action of three mechanisms: chemical stabilisation, biochemical stabilisation and physical protection. The objectives of this study were (i) to evaluate carbon-protection mechanisms in different SOM pools in soil aggregates and (ii) to identify the association of Ca^2 + with total organic carbon (TOC) under the influence of surface liming in a medium-textured Oxisol in a long-term experiment under no-till system (NTS) in southern Brazil (25° 10′ S, 50° 05′ W). The treatments consisted of application of zero or 6 tons ha^? 1 of dolomitic lime on the soil surface in 1993 and a reapplication of zero or 3 tons ha^? 1 of dolomitic lime in 2000 to plots with or without previous lime application. Soil samples collected at depths of 0–2.5, 2.5–5, 5–10 and 10–20 cm were separated into seven aggregate classes. In each of these classes, TOC, particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) were analysed. The 8–19 mm sized aggregates from the 0–2.5 cm layer were assessed by energy-dispersive X-ray spectroscopy (EDS) for the elemental analysis of carbon (C) and calcium (Ca). The liming caused an accumulation of TOC in the aggregates, mainly at a depth of 0–2.5 cm. The aggregates from soils treated with lime had a higher mean weight diameter (MWD) that resulted in the accumulation of TOC, especially in the 8–19 mm aggregate class, that was linear and closely related with C input (R² = 0.99). The proportion of large aggregates in the treatments with lime was closely correlated with the TOC content of the whole sample. The largest dose of lime (9 tons ha^? 1) resulted in higher TOC, POC and MAOC values, mainly in the 8–19 mm aggregate class. The elemental analyses for C and Ca revealed similar spectra between them for the surface-liming treatments in the clay fraction found in the centres of the 8–19 mm aggregates. The surface application of lime to NT fields provided greater stability and protection of the intra-aggregate C, presumably due to Ca^2 + acting as a cationic bridge between OC and the kaolinite in the clay fraction.     

On-farm quantification of sustainability indicators: an application to egg production systems

1. On-farm quantification of sustainability indicators (SI) is an effective way to make sustainable development measurable. The egg production sector was used as a case study to illustrate this approach. 2. The objective was to select SI for economic, ecological and societal issues, and to analyse the performance on selected SI of different production systems. 3. For the case study, we compared 4 egg production systems, characterised by differences in the housing systems which are most common in the Netherlands: the battery-cage system, the deep-litter system with and without outdoor run, and the aviary system with outdoor run. 4. Based on a clear set of criteria, we selected SI for animal welfare, economics, environmental impact, ergonomics and product quality. 5. We showed that on-farm quantification of SI was an appropriate method to identify the strengths and weaknesses of different systems. 6. From this analysis it appears that the aviary system with outdoor run is a good alternative for the battery-cage system, with better scores for the aviary system on animal welfare and economics, but with worse scores on environmental impact.     

Long-term impacts of prescribed burning on regional extent and incidence of wildfires—Evidence from 50 years of active fire management in SW Australian forests

Prescribed burning is advocated for the sustainable management of fire-prone ecosystems for its capacity to reduce fuel loads and mitigate large high-intensity wildfires. However, there is a lack of comprehensive field evidence on which to base predictions of the benefits of prescribed burning for meeting either wildfire hazard reduction or conservation goals. Australian eucalypt forests are among the very few forest types in the world where prescribed burning has been practised long enough and at a large enough spatial scale to quantify its effect on the incidence and extent of unplanned fires. Nevertheless even for Australian forests evidence of the effectiveness of prescribed burning remains fragmented and largely unpublished in the scientific literature.     

A mixed model QTL analysis for a complex cross population consisting of a half diallel of two-way hybrids in Arabidopsis thaliana: analysis of simulated data

To improve QTL detection power for QTL main effects and interactions and QTL mapping resolution, new types of multi-founder crossing populations are created in plants and animals. Some recent examples are complex intercrossed populations in mice and Arabidopsis thaliana. For the latter, a set of eight accessions was intercrossed to produce four two-way hybrids that were subsequently intercrossed again in a half diallel fashion leading to six subpopulations of four-way hybrids, each subpopulation containing 100 individuals. Within each subpopulation, individuals were inbred for four generations via single seed descent. QTL mapping in the complex crosses requires new statistical tools. We present a first sketch of a QTL mapping methodology for the complex cross in Arabidopsis based on mixed model analyses. As experimental data were not yet available, we illustrate our methodology on simulated but realistic data.