Inter-specific hybrids of Lilium lankongense Franchet produced by embryo-culture

Summary Lilium lankongense crossed with some related species of Lilium produced seeds without endosperm and with very small embryos which would not germinate in soil. Hybrid plants have been obtained from a number of these crosses by culturing excised embryos on sterile nutrient medium. It is suggested that the technique may prove useful in the production of hybrids from other lily species-combinations which are not normally viable.     

Pressure Induced Triploidy in Hybrid Lepomis

Worldwide expansion of aquaculture will require identification of species more adapted to localized conditions and less likely to affect genetic diversity of natural populations in the event of escape. Hybrids of Lepomis sunfish have the potential as an alternative for aquaculture in regions of North America where the growing season is unsuitable for production of traditional coldwater and warm-water species. Triploidy was induced in hybrids of green sunfish Lepomis cyanellus males and bluegill L. macrochirus females using hydrostatic pressure shocks. A total of 27 combinations of pressure (41,369, 48,264, and 55,158 kPa), duration (2, 3, 4 min), and post-fertilization time of shock initiation (2, 3, 4 min) were tested to identify those which were most efficient for inducing triploidy. Several of the shock regimes produced 100% triploid hybrid sunfish with at least 90% survival relative to unshocked controls. The two shock treatments deemed best overall were: 1) 48,264 kPa for 4 min begun 2 min after fertilization; and 2) 41,369 kPa for 2 min begun 3 min after fertilization.     

Aboveground vegetation effects on the deposition and cycling of atmospheric sulfur: Chemical and stable isotope evidence

Up to 60% of the sulfate in upland forest throughfall and stemflow at Plastic Lake in central Ontario is non-precipitation by origin, but is derived from aboveground vegetation. The sources of this aboveground vegetation sulfate include dry deposited aerosols and SO₂, and mineralized plant organic S. σ³⁴S data indicate that atmospheric S dominates the upland forest ecosystems of southern and central Ontario, with little S isotope fractionation. Seasonal σ³⁴S variations in precipitation sulfate may be due to mixing of bacteriogenic and anthropogenic S. σ¹⁸O and concentration data indicate that oxidation of dry-deposited SO₂, and mineralization of organic S on vegetation surfaces may contribute one third or more of throughfall sulfate in summer and autumn, but less in late spring, perhaps due to foliar uptake of S during this season. Oxidized SO₂, or mineralized organic S contributes one third or more of stemflow sulfate during these seasons.     

Energy metabolites in pre- and postpartum dairy cattle as predictors of reproductive disorders

This study aimed to determine values for selected energy metabolites (non-esterified fatty acid [NEFA], β-hydroxybutyrate [BHB], urea or urea:BHB ratio), together with a body condition score, associated with an increased risk of cows developing a reproductive disorder and to investigate temporal relationships between predictors and reproductive outcome. A cohort of 98 cows on one farm was monitored weekly from four weeks before to 10 weeks after calving; 89 cows provided sufficient data to calculate commencement of luteal activity (C-LA). Cows with high NEFA × urea (Nu; product of NEFA and urea) values one and three weeks after calving were twice as likely to develop cystic ovarian disease (risk ratio 2). Cows that developed endometritis had high NEFA values one (P=0.02) or four weeks (P=0.04) before calving, or low urea:BHB ratios two weeks before calving, at calving or three weeks after calving (P=0.024, P=0.031 and P=0.001, respectively). Cows that had delayed C-LA had high NEFA values one week after calving (P=0.05) or low urea:BHB ratios three or four weeks after calving (P=0.004 and P=0.003, respectively).     

Risk Factors Associated with Detection of Salmonella in Broiler Litter at the Time of New Flock Placement

In this study, we investigated risk factors associated with the probability to detect Salmonella in samples of litter collected within 2 h prior to new flock placement in 76 grow‐out houses on 38 conventional broiler farms located in the US states of Mississippi, Alabama and Texas. We evaluated characteristics of location and layout of the farm; area adjacent to and surrounding the house; house construction; condition and type of equipment in the house; litter management and other production, sanitation, visitation and biosecurity practices; non‐broiler animal species on the farm; and weather conditions on the 3 days leading up to flock placement. Logistic regression was used to model the relationships between probability to detect Salmonella in litter and potential risk factors. In the screening process, each risk factor was evaluated as a single fixed effects factor in a multilevel model that accounted for variability among the sampled farms and their production complexes and companies. Of almost 370 risk factors screened, 24 were associated with the probability to detect Salmonella in litter. These were characteristics of the surroundings of the house, house construction and conditions, litter management, length of downtimes between flocks in the house, biosecurity and farm location. After investigation of collinearity between these variables and building of models for important risk factor categories, the list of candidate variables for the final model was refined to eight factors. The final model demonstrated that a higher probability of detecting Salmonella in litter was strongly associated with the use of wood to construct the base of the walls or to cover the inside of the broiler house foundation, and with the use of fresh wood shavings to top‐dress or completely replace the litter between flocks.     

Chlamydia psittaci infection in horses: results of a prevalence survey and experimental challenge.

Nasal and conjunctival swabs were obtained from 300 horses and Chlamydia psittaci was isolated from 15 of them (5 per cent). Eleven nasal swabs and six conjunctival swabs were positive on culture, but there was no association between the isolation of the organism and the presence of clinical ocular or respiratory disease. Six ponies were challenged with an equine isolate of C psittaci into the eye, nasal cavity or bronchial tree. The organism could be isolated from nasal and conjunctival swabs taken from the ponies for up to 17 days after challenge, but there was no clinical evidence of disease.     

Uptake of drugs from topically applied anti-inflammatory preparations applied to racing animals

Objective To determine whether a drug detected in the blood or urine of a racing animal could have penetrated through the skin from a topically applied preparation.
Design Blood and urine of dogs and horses were analysed after topical administration of three common nonsteroidal anti-inflammatory preparations.
Experimental method Dimethylsulphoxide was analysed using a gas chromatograph with a flame photometric detector. Phenylbutazone, its metabolites and lignocaine were analysed using a gas chromatograph with a mass selective detector.
Results Dimethylsulphoxide, phenylbutazone and ligno-caine were detected in dog urine after muliple applications of the preparations. The maximum concentration of dimethyl-sulphoxide in dog urine correlated with the concentration of dimethylsulphoxide in the preparation. Phenylbutazone penetrated the skin more effectively from the cream than from the solution or gel preparations. This penetration was independent of the concentration of dimethylsulphoxide.
Conclusion The superior penetration of phenylbutazone from the cream can be explained by it being present as a neutral molecule in an hydrophobic medium. It is proposed that phenylbutazone penetrates the skin of greyhounds most effectively by a hydrophobic lipid route which is likely to be different from the path by which dimethylsulphoxide penetrates the skin.     

Liquid chromatography, microfluorometry, and dye-titration determination of vitamin C in fresh fruit and vegetables

The vitamin C content of several fresh fruit and vegetables was determined by a liquid chromatographic (LC) method which gave simultaneous separate values for ascorbic acid and dehydroascorbic acid (DHA) and by the official AOAC methods of microfluorometry and dye-titration. The levels of ascorbic acid obtained by LC and dye-titration were in good agreement, except for a few colored products where it was difficult to determine the end point of the titration. The combined values for ascorbic acid and DHA obtained by LC and microfluorometry were in agreement for most produce, but for about one-third of the samples, the values obtained by microfluorometry were significantly higher.     

Diarrhea in growing-finishing swine.

Regardless of the etiology of an enteric disease in nursery age to finisher swine, making a prompt and accurate diagnosis is crucial. Eliciting a complete history, assessing clinical signs and pathology, and selecting and interpreting laboratory tests are essential components in achieving this. Early detection and diagnosis of enteric disease is particularly critical in the nursery through finisher phase because of economic impacts. Recurrent topics when discussing control and prevention of enteric diseases are reducing stress and improving pig comfort and reducing or eliminating exposure through sanitation and biosecurity. These are not new concepts; in fact, prior to the advent of antimicrobials, they were the mainstay of treatment of enteric diseases. With concern over the use of antimicrobials in food animal production increasing, exploiting disease ecology to control enteric diseases is increasing in importance. New vaccines and bacterins for postweaning swine enteric diseases are needed tools to exploit the pig's immune system. Recent advances in diagnostic capabilities allow an increase in understanding and exploitation of disease ecology.