The spawning migration and conservation of smelt Osmerus eperlanus in the River Cree, southwest Scotland

The anadromous smelt Osmerus eperlanus population associated with the River Cree on the Solway Coast, southwest Scotland, is the only one remaining from several which previously occurred in that area. Their spawning migration was studied as a basis for conservation and management proposals. The timing and location of the onset of spawning in February/March was determined by regular inspection of the river bed for smelt eggs. The thermal regime in the lower river during preceding weeks is considered the primary factor in initiating spawning, but prevailing temperature, tide and flow conditions determine exactly where and when. Several local factors must be addressed for future conservation and management, e.g. commercial netting, pollution and the present physico-chemical character of the river. The reintroduction of smelt to other rivers on the Solway Coast should now be seriously considered.     

Chronic intermittent colic in a mare attributed to uterine marbles

A 13‐year‐old Quarter Horse mare presented for evaluation of chronic intermittent colic. Following extensive diagnostics, abdominal radiographs revealed two round, radiopaque objects in the caudal abdomen. Palpation per rectum and transrectal ultrasonography of the reproductive tract confirmed that the round objects were uterine marbles. Dinoprost tromethamine (Lutalyse, 5 mg i.m. q. 24 h for 2 days) was administered to bring the mare into oestrus, and both uterine marbles were manually removed from the uterus following digital dilation of the relaxed cervix. Follow‐up with the owner 12 months after discharge revealed that the mare had shown no further signs of abdominal discomfort since having the uterine marbles removed. To the authors' knowledge, this is the first published report of chronic intermittent colic attributed to uterine marbles in a mare.     

An Integrated Modeling Approach to Total Watershed Management: Water Quality and Watershed Assessment of Cheney Reservoir, Kansas, USA

Degradation of water quality is the major health concern for lakes and reservoirs in the central regions of the United States as a result of heavily devoted agricultural production. A vital key to the development of a reservoir management strategy is to identify nutrient loading that describes associated water quality conditions in reservoirs. This study integrated AnnAGNPS watershed and BATHTUB lake models to simulate actual lake water quality conditions of Cheney Reservoir, KS, and demonstrated the use of the coupled model for simulating lake response to changes in different watershed land use and management scenarios. The calibrated current-conditions model simulated in-lake reductions as much as 52% for TN, 48% for TP, and 70% for chlorophyll a due to conversion to native grass, and increases as much as 4% for TN, 9% for TP and 6% for chlorophyll a due to conversion of land from the Conservation Reserve Program (CRP) to cropland (15.5% of watershed). This model also demonstrated an increase in chlorophyll a (19%) as the lake sediment capacity was reached over the next century.     

The effect of temperature regime and substrate Mn on growth and manganese concentrations in rice

Three rice cultivars, IR712, M1–48 and E425 were grown in solution culture for 10 weeks in temperature controlled glasshouses at IRRI, Los Baños, Philippines. Treatments consisted of two Mn levels, 0.5 and 50 μg.cm^‐3 and two temperature regimes, 35/27 and 20/20 (day/night) in °C. Dry matter and Mn concentrations were determined at 2‐week intervals. In a second experiment, the M1–48 cultivar was grown in solutions containing 0.5, 1, 40 and 80 μg.cm^‐3 Mn at 35/27, 29/21 and 20/20 °C (day/night) temperatures.

It was concluded that rice is more sensitive to excess Mn under cool conditions and that the concentration of Mn in the tissue at which toxicity symptoms appear or growth is decreased depends on the age of the tissues and the environmental conditions under which the plant is growing. Growth of two‐day old seedlings exposed to excess Mn was decreased to a greater degree than was that of 2‐week old seedlings. It is suggested that in screening rice cultivars for tolerance to excess Mn the environmental conditions should be rather rigidly controlled.     

Within-field variability of wheat yield and economic implications for spatially variable nutrient management

Economic justification for varying fertiliser inputs to match crop yield potential of different areas or zones in fields is limited by lack of understanding of the relationship between the extent of within-field yield variation and economic gains from zone versus uniform management. We conducted a survey of yield monitor data from 199 fields on the northern sandplain of the wheatbelt in Western Australia in order to document the extent of sub-field yield variation and test if variation is related to attributes such as yield and field area. The economic significance to zone management of the yield variation found in the survey along with variation in size of management zones, costs and prices, and soil fertility status was then assessed using a simple nutrient response model.     

Quantitative trait locus mapping for seed artificial aging traits using an F2:3 population and a recombinant inbred line population crossed from two highly related maize inbreds

Quantitative trait locus (QTL) mapping for seed longevity is essential for breeding modern cultivars with resistance to deterioration during postharvest storage. The inbred lines X178 and I178 showed large differences in seed vigour after artificial aging treatment, while they had similar performances in terms of most agronomic traits. An F_2:3 population and a recombinant inbred line (RIL) population were generated to map QTL after 5 days under artificial aging conditions. Positive correlations were observed among all investigated traits including the aging germination rate, relative aging germination rate, aging simple vigour index, aging primary root length, aging shoot length and aging total length. Thirteen QTL were identified to locate on five chromosome regions: Chr.1:297 Mb (chromosome 1 region 297 Mb), Chr.3:205 Mb, Chr.4:240 Mb, Chr.5:205 Mb and Chr.7:155 Mb, with 2 to 4 QTL co‐located on a region. In each region, 3–8 previously identified aging‐related QTL were located, confirming the importance of these regions for controlling seed longevity in different maize populations. Taken together, the results of this work provide a foundation for further QTL fine mapping and the molecular‐assisted breeding of aging tolerant maize.     

Cryptosporidiosis in a pup

Cryptosporidiosis is a coccidian parasitism which has been implicated as a cause of diarrhea in man and a variety of animals. Cryptosporidiosis was diagnosed in a one-week-old pup which had a history of acute diarrhea. Organisms, 2 to 3 mm in diameter, covered the microvillous border of intestinal epithelium. Ultrastructurally, the cryptosporidia had one or more nuclei with prominent nucleoli and abundant cytoplasmic endoplasmic reticulum. Cryptosporidia may have played a role in the enteritis seen in this pup but further studies are needed to establish its pathogenicity.     

Sperm quality during extra‐gonadal sperm reserve depletion in stallions

To estimate when, during stallions’ extra‐gonadal reserves (EGR) depletion period, sperm quality would reach its highest quality, six light breed sexually rested stallions were collected daily for 7 days to deplete EGR. On collection days 1, 3, 5, and 7, sperm output, total (TM) and progressive (PM) motility, morphology, and plasma membrane (PLM) integrity were evaluated. Sperm output decreased as EGR depletion advanced, stabilizing on days 5–7. Sperm motility (TM and PM) and morphology were not different during EGR depletion. Plasma membrane integrity improved from day 1 to 3; however, no further improvement observed on days 5 and 7. Sperm of sexually rested stallions reach the highest quality on day 3 of the EGR depletion period.