Morphological and molecular analysis of androgenetic, selfed and backcrossed plants produced from a Hordeum vulgare x H, bulbosum hybrid

Anther culture (AC) was carried out on a fertile triploid hybrid between Hordeum vulgare L. (cultivated barley) and H. bulbosum L, (bulbous barley grass) to determine whether AC-derived regenerants differed from progeny obtained through selfing and backcrossing. Chromosome counts were carried out on all plants and DNA was extracted from them to prepare Southern blots for molecular analysis. To identify true recombinants, the blots were probed with rye repetitive sequence probes (pSc119.1 and pScl19.2). which hybridize strongly and specifically to H. bulbosum DNA. Twenty probes that detect single- or low-copy sequences were hybridized with Southern blots containing restricted DNA extracted from 25 AC-derived plants, 11 selfed and six backcrossed progeny that showed hybridizations with pScll9. Although restriction fragment length polymorphisms (RFLPs) were only observed using probes that map to four of the possible 14 chromosome arms, an introgression associated with chromosome 6HS was frequently observed among plants derived from AC. selfing and backcrossing. Plants from AC differed from selfed and backcrossed progeny in their chromosome number; unique RFLP bands that were occasionally observed may indicate chromosomal rearrangements.     

Recycling Newsprint on Agricultural Land with the Aid of Poultry Litter

The large volume of cellulose products, primarily newsprint and yard waste, that are disposed of in landfills and the resistance of these products to decomposition led to an evaluation of the disposal of ground newsprint on agricultural land. A field study was conducted with cotton to evaluate the effects of trenching and mixing the excavated soil with ground newsprint and/or poultry litter. Decomposition rate of newsprint and potential for environmental contamination were investigated in a Cahaba-Wickham-Bassfield sandy loam (Typic Hapludult) soil. The experimental variables included different ratios of soil, ground newsprint, and/or poultry litter applied on the soil surface and in trenches 0.61 m or 1.22 m deep. When ground newsprint and excavated soil were mixed without adjusting the C:N ratio of the backfill, the newsprint was still present seven months after application. However, adjusting the C.N ratio of the excavated soil and ground newsprint with poultry litter provided the nitrogen necessary to completely decompose the ground newsprint within seven months. Soil surface application of ground newsprint required adjusting the C:N ratio to control the occurrence of plant pathogenic organisms. Extractable soil nutrients were increased when poultry litter was added, including P and K which are of concern with respect to surface and groundwater contamination. Extractable Zn, Cu, and Mn levels were increased by the addition of poultry litter, but their levels were in the ranges that most row crops will tolerate. The metals Cr and Pb, found in some printer's ink, may be of concern if repeated application of newsprint is made to the same site. Soil organic matter content was increased from 11.9 g kg-1 to 23.8 g kg-1 in the 50:40:10 backfill mixture of soil, newsprint, and poultry litter seven months after application.     

Development of diets for the intensive culture of Pacific lamprey

The Pacific lamprey Entosphenus tridentatus is an ancestral species of critical importance to the ecosystem and indigenous cultures in the Pacific Northwest. Conservation aquaculture has been proposed as a potential technique to restore Pacific lamprey populations. Intensive culture methods and diets for this species have not been developed. A sixteen week feeding trial tested the effects of seven diet treatments on the survival, growth, fatty acid profile and whole body lipid content of Pacific lamprey ammocoetes. Dietary treatments were: active dry yeast, yeast plus fish oil emulsion, micro‐algae, micro‐algae plus fish oil emulsion, yeast with micro‐algae, yeast with micro‐algae plus fish oil emulsion and yeast with larval fish diet. Each diet was offered to five replicate tanks stocked with 20 ammocoetes that were 51 days post hatch. Survival during the trial was not affected by diet. The greatest length and weight increases were in fish fed diets containing yeast. Growth decreased as the amount of algae in the diet was increased. Lipid retention was significantly higher in fish fed yeast with larval fish diet relative to the other treatments. Feed conversion ratio was lowest in fish fed diets containing yeast. Whole body fatty acid profiles tended to reflect the fatty acid profile of the diet. Percentages of 20:5n‐3 and 22:6n‐3 were significantly higher in fish fed diets containing fish oil emulsion. Overall, yeast with larval fish diet provided the best growth performance in larval Pacific lamprey.     

Characterisation of major and minor Dermatophagoides allergens in canine atopic dermatitis

Atopic dermatitis is a well-recognised chronic inflammatory skin disease of humans and dogs. Most atopic dogs are sensitised to Dermatophagoides mites. The aim of this study was to characterise allergens in different Dermatophagoides species using polyclonal and monoclonal antibodies to canine IgE. Western blots were prepared from crude extracts of D farinae, D pteronyssinus and D microceras, and purified group 1 and 2 allergens under reducing and non-reducing conditions. They were probed with sera from atopic (n = 33) and healthy (n = 27) dogs. There was no significant difference in the sensitivity or specificity between the polyclonal and monoclonal sera in detecting Dermatophagoides -specific IgE. Major allergens common to both D farinae and D pteronyssinus were detected at 97-98 kDa, 103-104 kDa and 134-139 kDa on both reducing and non-reducing blots. Major allergens at 84-85 kDa, 65-69 kDa and 44-45 kDa were only recognised on reducing blots, suggesting that these are fragments of the larger allergens. Only a few sera recognised group 1 or 2 allergens on blots of crude extracts or purified allergens. These results confirm that, in atopic dogs, high molecular weight allergens are the most important Dermatophagoides allergens, rather than the low molecular weight group 1 and 2 proteins.     

Factors affecting the variability in cracked and dirty eggs and egg production profitability on an integrated poultry operation

1. A number of factors causing variability in the percentages of cracked, and dirty eggs and weekly standard margin (WSM) of returns from eggs over production costs were examined on an integrated commercial poultry plant in Scotland.

2. As the bird aged, the percentage of cracked eggs increased (P <0.01) and the percentage of grade A eggs and WSM decreased (P <0.01). Cracks in dirty eggs (10.1%) were more than double those in all eggs laid (4.9%).

3. Seasonal effects on percentage cracked eggs and percentage grade A eggs were one‐third the magnitude of those due to age but were significant (P <0.05).

4. Variability in percentage cracked eggs, dirty eggs and WSM accounted for by the factors measured, were 72, 64 and 92% respectively.

5. The variability in WSM was significantly affected by percentage lay, food consumption and age but not by percentage cracked eggs, originally dirty and grade A eggs.

6. Flock management and climate inside the laying house each increased the amount of variability accounted for in the percentage cracked eggs and dirty eggs by at least 10%.     

Key Factors Affecting Reproductive Success of Thoroughbred Mares and Stallions on a Commercial Stud Farm

To evaluate factors contributing to fertility of thoroughbred mares, data from 3743 oestrous periods of 2385 mares were collected on a large thoroughbred farm in Ireland. Fourteen stallions (mean age 8.3 years; range 4–15 years) had bred 2385 mares (mean age 9.4 years; range 3–24 years). Maiden mares accounted for 12%, mares with a foal at foot for 64%, and barren, slipped or rested mares for 24% of the total. The mean pregnancy rate per cycle was 67.8% (68.6% in year 1 and 66.9% in year 2). Backward stepwise multivariable logistic regression analysis was utilized to develop two models to evaluate mare factors, including mare age, reproductive status, month of foaling, dystocia, month of cover, foal heat, cycle number, treatments, walk‐in status and stallion factors including stallion identity, stallion age, shuttle status, time elapsed between covers and high stallion usage on the per cycle pregnancy rate and pregnancy loss. Old age (p < 0.001) and cover within 20 days post‐partum (p < 0.003) were associated with lowered pregnancy rates. High mare age (p < 0.05) and barren, slipped or rested reproductive status (p = 0.05) increased the likelihood of pregnancy loss. Uterine inflammation or infection, if appropriately treated, did not affect fertility. Only high usage of stallions (used more than 21 times in previous week) was associated with lowered (p = 0.009) pregnancy rates. However, shuttle stallions were more likely to have increased (p = 0.035) pregnancy survival, perhaps reflecting a bias in stallion selection. In conclusion, mare age exerted the greatest influence on fertility; nonetheless, thoroughbreds can be effectively managed to achieve high reproductive performance in a commercial setting.     

Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge

Vaccination of cows with rough Escherichia coli mutants fails to protect against experimental intramammary bacterial challenge. Vaccine A, a heat-killed Re mutant of strain K12, (UB 1574), was administered as a single parenteral and local dose to 5 cows with 3 control animals and Vaccine B, a heat-killed mutant of O111:B4 (J5) was administered as three parenteral doses into 5 cows with 5 control animals. Following intramammary challenge with a smooth wild-type strain (P4), an acute, severe clinical mastitis developed in all 14 quarters (9 vaccine A and 5 vaccine B) of the vaccinated animals which was indistinguishable from that in the 11 quarters of the control animals. Following vaccine B there was an elevation in serum IgG1 and IgG2 antibody to the common core antigen of endotoxin which, in contrast to the control animals, showed a further increase after intramammary infection.