Economic evaluation of alternative crossbreeding systems involving four breeds of swine. I. The simulation model

A static, deterministic computer model, programmed in Microsoft Basic for IBM PC and Apple Macintosh computers, was developed to calculate production efficiency (cost per kg of product) for nine alternative types of crossbreeding system involving four breeds of swine. The model simulates efficiencies for four purebred and 60 alternative two-, three- and four-breed rotation, rotaterminal, backcross and static cross systems. Crossbreeding systems were defined as including all purebred, crossbred and commercial matings necessary to maintain a total of 10,000 farrowings. Driving variables for the model are mean conception rate at first service and for an 8-wk breeding season, litter size born, preweaning survival rate, postweaning average daily gain, feed-to-gain ratio and carcass backfat. Predictions are computed using breed direct genetic and maternal effects for the four breeds, plus individual, maternal and paternal specific heterosis values, input by the user. Inputs required to calculate the number of females farrowing in each sub-system include the proportion of males and females replaced each breeding cycle in purebred and crossbred populations, the proportion of male and female offspring in seedstock herds that become breeding animals, and the number of females per boar. Inputs required to calculate the efficiency of terminal production (cost-to-product ratio) for each sub-system include breeding herd feed intake, gilt development costs, feed costs and labor and overhead costs. Crossbreeding system efficiency is calculated as the weighted average of sub-system cost-to-product ratio values, weighting by the number of females farrowing in each sub-system.     

terraGIS – a web GIS for delivery of digital soil maps in cotton‐growing areas of Australia

Effective management of soil requires the spatial distribution of its various physical, chemical and hydrological properties. This is because properties, for example clay content, determine the ability of soil to hold cations and retain water. However, data acquisition is labour intensive and time‐consuming. To add value to the limited soil data, remote sensing (e.g. airborne gamma‐ray spectrometry) and proximal sensing, such as electromagnetic (EM) induction, are being used as ancillary data. Here, we provide examples of developing Digital Soil Maps (DSM) of soil physical, chemical and hydrological properties, for seven cotton‐growing areas of southeastern Australia, by coupling soil data with remote and proximal sensed ancillary data. A greater challenge is how to get these DSM to a stakeholder in a way that is useful for practical soil use and management. This study describes how we facilitate access to the DSMs, using a simple‐to‐use web GIS platform, called terraGIS. The platform is underpinned by Google Maps API, which is an open‐source development environment for building spatially enabled Internet applications. In conclusion, we consider that terraGIS and the supporting information, available on the sister web page ( http://www.terragis.bees.unsw.edu.au/ ), allow easy access to explanation of DSM of soil properties, which are relevant to cotton growers, farm managers, consultants, extension staff, researchers, state and federal government agency personnel and policy analysts. Future work should be aimed at developing error budget maps to identify where additional soil and/or ancillary data is required to improve the accuracy of the DSMs.     

Crocin and geniposide profiles and radical scavenging activity of gardenia fruits (Gardenia jasminoides Ellis) from different cultivars and at the various stages of maturation

The major components of gardenia fruits are geniposide and water soluble pigment crocins. In this study, we investigate crocins and geniposide profiles of gardenia fruits from different cultivars and at the various stages of maturation. DPPH scavenging activity of gardenia fruits from different cultivars and at the various stages of fruit maturation was also assayed. Quantitative determination of crocins in the gardenia at the various stages of maturation revealed a significant increase when ripening. However, geniposide content was negatively correlated with ripening stages. A significant difference was observed when comparing crocin content of different gardenia from various cultivars and geniposide content also showed marked variety. Current study indicated no relationship between crocin and geniposide content in gardenia fruits at the various stages of maturation and DPPH radical scavenging activity. Data showed that, although crocins feature markedly less DPPH scavenging activity than gardenia ethanol extract, total crocin content of gardenias collected in various cultivars correlate, to a certain degree, with radical scavenging effects of the Chinese traditional medicine (r = 0.75).     

Seasonal fluctuations in soil microbial biomass carbon,phosphorus, and activity in no-till and reduced-chemical-input maize agroecosystems

Summary The soil microbial biomass contains important labile pools of C, N, P, and S, and fluctuations in its size and activity can significantly influence crop productivity. In cropping systems where fertilizer use is reduced or eliminated and green-manure legumes are used, nutrient availability is more directly linked to C-cycle dynamics. We observed the fluctuations in microbial biomass C and P, and in microbial biomass activity over three cropping seasons in continuous maize and 2-year maize-wheat-soybean rotation agroecosystems under no-till and reduced-chemical-input management. We estimated the concentrations of microbial C and P using fumigation-incubation and fumigation-extraction techniques for the surface 20 cm of Cecil and Appling series soils (clayey, kaolinitic, thermic, Typic Kanhapludults). There were significant seasonal fluctuations in microbial C and P under all cropping systems. Generally, the magnitude of fluxes and the quantity of microbial C and P tended to be higher in reduced-chemical-input systems due to tillage and incorporation of crop, weed, and legume residues. Over 3 years, the means for microbial C were 435 under reduced-input maize; 289 under no-till maize; 374 und the reduced-input crop rotation; and 288 mg kg^-1 soil under the no-till rotation. The means for microbial P were 5.2 under reduced-input maize; 3.5 under no-till maize; 5.0 under the reduced-input rotation; and 3.5 mg kg^-1 soil under the no-till rotation. Estimates of microbial activity, derived from CO₂–C evolution and specific respiratory activity (mg CO₂–C per mg biomass C), suggest that reduced-chemical-input management may cause a larger fraction of the biomass to be relatively inactive but may also increase the activity of the remaining fraction over that in no-till. Thus in these specific systems, the turnover of C and P through the microbial biomass with a reduced chemical input to the soil may be higher than under a no-till system.     

Comparison of crossbred cows containing various proportions of Brahman in spring or fall calving systems: II. Milk production

Monthly estimates of 24-h milk yield were obtained on 160 spring-calving and 153 fall-calving crossbred cows containing various proportions (0, 1/4 or 1/2) of Brahman breeding, all bred to Limousin sires. Milk production was measured using weigh-suckle-weigh procedures. Interactions between crossbred group and season of calving were not significant. Across seasons, milk production rarely was affected by proportion of Brahman breeding; however, milk yield, averaged over six monthly measurements, was greater (P less than .10) for cows out of Hereford dams than for cows out of Angus dams. Averaged over six monthly measurements, estimated 24-h milk yield ranged from 5.3 kg for Hereford x Angus to 6.2 kg for Brahman x Hereford cows. Season of calving affected milk yield during the first and fourth measurement periods. Fall-calving cows produced more (P less than .01) milk during the first period whereas spring-calving cows produced more milk during the fourth period. Lactation patterns for the two seasons differed. Spring-calving cows had a more typical lactation curve, whereas the curve for fall-calving cows showed more variability in milk yield throughout lactation. Phenotypic correlations between monthly measurements of 24-h milk yield and calf performance tended to be moderate and positive within the spring group. Correlations for the fall group, although positive, tended to be weaker than those found in the spring group.     

Gross Morphometry of the Bovine Placentome during Gestation

Forty-seven pregnant uteri were collected from an abattoir at eight chronological stages of gestation. Assessments were made of placentome number, weight, length shape and ratio of foetal to maternal tissue by weight. The study showed that there was a great variation in number, size, weight and shape of placentomes. There was no significant change in the total number of placentomes during gestation. Both mean weight and length increased significantly during gestation, but there was a significant change in the relationship between the two as gestation progressed. There was no correlation between the number of placentomes and the mean weight or length of the placentomes. The development of the placenta in the non-pregnant horn was significantly different from that of the pregnant horn, with fewer, smaller, lighter placentomes. However, there was no evidence that placentome development in the non-pregnant horn was affected by placentome development in the pregnant horn. The proportion of the placentome that was maternal tissue increased during gestation, but there was no significant effect of placentome number, or individual placentome weight or length on this proportion. Two placentome shapes were identified, but no effect on foeto-maternal proportion or relationship between shape and total placentome number or weight was identified.     

Recovery of microorganisms from synovial and pleural fluids of animals using hyperosmolar media

L-phase (CWD) broth and plate media were used in parallel with conventional microbiological media during a 3-year period for culturing synovial and pleural fluids of animals. Two kinds of recoveries were obtained where parallel conventional methods were negative: (1) parent or normal bacteria, in very low numbers; and (2) Type B CWD variants in equally low numbers. Organisms in group 1 were: Streptococcus zooepidemicus from horses (2X); β-hemolytic streptococci, Lancefield Gp. G (2X); Staphylococcus aureus; Actinobacillus, and Actinomyces viscosus. Group 2 consisted of Bacteroides sp., Propionibacterium acnes, and three “Nocardia-like” sp. Catalase + Actinomyces was not recovered equally well on CWD plates as on conventional media with fluids obtained during ampicillin treatment. This occurred in spite of the fact that the CWD media was shown to support growth and reversion of laboratory induced L-phase variants of Nocardia caviae and N. asteroides, and had facilitated recovery of a Bacteroides L-phase variant from a pleural fluid. The nature of this fault in the media is under investigation in this laboratory.     

Economic evaluation of alternative crossbreeding systems involving four breeds of swine. II. System efficiency

A static, deterministic computer model was used to calculate production efficiency (cost per kg of product) for four purebred and 69 alternative crossbreeding systems involving the Duroc, Yorkshire, Landrace and Spotted breeds of swine. Crossbreeding systems were defined as including all purebred, crossbred and commercial matings necessary to maintain a total of 10,000 farrowings. Driving variables for the model were predicted mean conception rates, litter size born, preweaning survival rate, postweaning average daily gain, feed-to-gain ratio and carcass backfat. Predictions were computed using breed effect and heterosis estimates obtained from experimental data involving the four breeds collected at the Oklahoma Agricultural Experiment Station between 1976 and 1979. The most efficient breed combinations for each of the nine types of crossbreeding systems evaluated were predicted to reduce cost per kg of product by 6.7 to 10.5%, relative to the most efficient purebred (Duroc). The Duroc X (Yorkshire, Landrace, Spotted) four-breed rotaterminal was predicted to be the most efficient system, followed by the Duroc X (Yorkshire, Landrace) rotaterminal. Duroc X (Spotted X Landrace) and Duroc X (Spotted X Yorkshire) static systems ranked third and fourth overall, respectively. Sensitivity analysis indicated that ranking of systems predicted to be most efficient under the default model was reasonably robust to varying input economic, genetic and management parameter values. Results of this study suggested that three- or four-breed rotaterminal or static systems should maximize effective use of heterosis and breed complementarity in swine production systems.