Identification of a nasal nematode (Eucoleus boehmi) in greyhounds

Eggs ofEucoleus boehmi were recovered from the faeces of greyhounds from three breeding farms and four racetrack kennels and from those of four greyhounds submitted for necropsy. Diagnosis was dependent on differentiation of the eggs ofE. boehmi, E. aerophilus andTrichuris vulpis. Quantitative fecal examinations conducted weekly for 24 weeks in one greyhound suggested that the egg shedding pattern ofE. boehmi is cyclical. Nasal swabs failed to reveal eggs ofE. boehmi, but nasal washings gave positive results. Because of its small size (15–40 mm) its location within the epithelial lining of the nasal mucosa, turbinates, and sinuses, and difficulty in differentiating the bipolar plugged eggs,E. boehmi probably occurs more often than is currently diagnosed.Abbreviation EPG eggs per gram     

Teladorsagia circumcincta egg output at the onset of natural and induced lactation in ewes

Nineteen ewes maintained under 'worm-free' conditions received anthelmintic and 1 week later were dosed on 5 days each week with 500 Teladorsagia circumcincta larvae for between 10 and 12.5 weeks. Faecal egg counts were determined twice weekly. There were three groups: pregnant (P) ewes (n = 6) which each reared twin lambs, hormone-treated (H) ewes (n = 7) which were not pregnant and were given exogenous hormones (dexamethasone, oestradiol-17 beta, progesterone) for 37 days to induce udder development and milk production, and untreated barren (B) ewes (n = 6). The plasma concentrations of oestradiol-17 beta, prolactin and progesterone were measured. Starting 10-15 days before birth in Group P, there was a biphasic periparturient rise in egg count and the onset of the first peak in egg count preceded the parturient peak in plasma prolactin concentration by several days. Most Group H (5/7) and all Group B ewes remained highly resistant to Teladorsagia infection throughout, despite an induced rise in prolactin concentrations in Group H ewes. It was concluded that factors other than prolactin initiate the periparturient rise but that prolactin is one factor which maintains the response once lactation commences.     

Effectiveness of Commercially Formulated and Fish Baits in Trapping Cambarid Crawfish1

In the USA, cambarid crawfishes are harvested commercially with traps baited with fishes, formulated baits, or a combination of the two. Commercially formulated baits and fish baits, done and in combination, were evaluated to assess their relative effectiveness M attractants for crawfish. Traps baited with a combination of fish and formulated bait generally captured the most crawfish. Traps baited with common carp, the most effective natural bait, captured more crawfish than traps baited with skipjack herring, gizzard shad or channel catfish heads. Crawfish harvest from traps baited with several types of commercially formulated baits was equal to that obtained with traps baited with either gizzard shad or skipjack herring. Population density of crawfish and the availability of natural forage did not appear to influence relative effectiveness of either formulated baits or fish baits.     

Identification of CMS maintainers and restorers for hybrid rice development in Ghana

The cytoplasmic-genetic male sterility is the most widely used system for hybrid rice (Oryza sativa) seed production. It requires three lines: the two hybrid parents (A and R lines) and a third line (maintainer (B line)), which maintains the sterility of the female parent during seed increase. Studies were undertaken to identify maintainers and restorers for introduced cytoplasmic male sterile (CMS) lines using simple sequence repeat (SSR) markers and testcrosses. Molecular screening with SSR marker RM6100 grouped the assembled inbred lines into 30 potential restorers and 55 potential maintainers. One maintainer (WAS 127 -12-1-6-3-1) and 16 restorers were confirmed by testcrosses. WAS 127-12-1-2-3 had higher grain yield per plant in crosses with CMS1 (IR69625A) than the local checks (AgraRice and Jasmine 85) and could be used as a restorer to develop a locally adapted, high-yielding hybrid. Conversion of WAS 127 -12-1-6-3-1 into a local CMS line was stopped because of sterility instability in the BC₁F₁ generation. Continued testcrosses to the set of identified potential maintainers could help identify a stable one that can successfully be converted into a locally adapted CMS line.     

A regional analysis of total nitrogen in an agricultural landscape

Techniques for modeling spatial variability in the loss, gain, and storage of total nitrogen (N) in an agricultural landscape were developed utilizing a geographic information system (GIS) based on the Map Analysis Package (C.D. Tomlin, Yale University). The study area is a well-monitored portion (upper 114.9 km²) of the Little River Watershed, located near Tifton, Georgia, U.S.A. On the basis of measured N in the soil and vegetation, and the gains and losses of N by stream discharge, fertilizer, precipitation, N fixation, crop harvest, etc., it was possible to quantify and map source and sink regions of Total N, and to calculate a mass balance of N for an entire year. Results indicate massive flows of N, especially from anthropogenic sources. However, for the watershed as a whole, the N is virtually in balance with a small accretion occurring mostly in the riparian zones. Stream discharge of total N indicates that this landscape is well-buffered against excessive losses of N despite the large agricultural inputs.