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Fecal shedding of Escherichia coli O157:H7 in cattle, except those that shed transiently, is due to the organism's ability to persist in the gut. Site of prevalence in the gut is important for understanding the mechanisms and factors affecting gut persistence and fecal shedding and is a potential target for intervention. The prevalence of E. coli O157:H7 in the rumen, cecum, colon, and rectum was determined with contents collected from slaughtered cattle (n = 815) at an abattoir. Isolation and identification of E. coli O157:H7 were by selective enrichment, immunomagnetic separation, plating on selective medium, agglutination for O157 antigen, and presence of virulence genes. Prevalence in the rumen, cecum, colon, and rectum was 4.9%, 9.9%, 7.6%, and 11.1%, respectively. The overall prevalence of E. coli O157:H7 in the cattle sampled, based on being positive in any one gut location, was 20.3%. E. coli O157:H7 in rectal contents was positively associated (p < 0.01) with presence in the rumen or colon but not in the cecum. Pulsed-field gel electrophoresis (PFGE) was performed to compare the clonal similarity of isolates (n = 144) obtained from the rectum with that of rumen, cecum, or colon within cattle (n = 77). The majority (79-90%) of isolates obtained within the same animal shared a common PFGE type. There were no significant differences in PFGE type between positive samples from the rectum and samples from other locations within the same animal. Acid tolerance for cattle with positive rumen (pregastric) isolates and with at least one other positive hindgut (postgastric) isolate within the same animal was determined. There was no significant difference between gut locations in log reduction following acid challenge. The hindgut was the major site of prevalence of E. coli O157:H7 in cattle, a majority of the isolates within the same animal were clonally similar, and acid tolerance of hindgut isolates were not different from that of ruminal isolates.

Summary In 1987, as part of an embryo transfer programme to produce monozygotic twin foals, mares were flushed during the morning (09:30 to 13:30 h) of Day 6. Of 100 flushes, 48 embryos were recovered half of which were morulae. In 1988, in an attempt to increase the proportion of morulae, various flushing times between 17.00 h on Day 5 and the afternoon of Day 6 were used. For flushes carried out during the morning of Day 6, recovery rates were similar to those of the previous year. However, although the proportion of flushes resulting in the recovery of morulae was not significantly different for times between 23:00 h on Day 5 and 13:00 h on Day 6, the overall recovery rates for flushes on Day 6 were higher than those on Day 5. In addition, a number of mares that did not produce an embryo when flushed before 09:00 h on Day 6, were subsequently found to be pregnant when scanned at Day 18 suggesting that flushing had been carried out before arrival of the embryo in the uterus. To determine whether valid predictions could be made as to when to flush a mare to maximise recovery of morulae, a review of embryo recovery rates and plasma progesterone profiles of a large herd of mares over two breeding seasons was carried out. Mean plasma progesterone levels on the first three days after ovulation were higher for mares that produced embryos when flushed on Day 5 than for all other groups. Comparison of the results of previous flushes with the corresponding plasma progesterone profiles suggested that the characteristics of the post ovulation progesterone rise may have some value in deciding when a mare should be flushed. A review of the effects of uterine flushing, PGF2α and hCG on cycle length and ovulation time was also carried out in order to devise more efficient methods of herd management and ensure a supply of suitably synchronised recipient and donor mares at convenient times for embryo transfer experiments.

Management of transboundary aquifers is a vexing water resources challenge, especially when the aquifers are overexploited. The Hueco Bolson aquifer, which is bisected by the United States–Mexico border and where pumping far exceeds recharge, is an apt example. We conducted a binational, multisector, serious games workshop to explore collaborative solutions for extending the life of the shared aquifer. The value of the serious game workshop was building knowledge, interest, understanding, and constituency among critical stakeholders from both sides of the border. Participants also learned about negotiations and group decision-making while building mutual respect and trust. We did not achieve consensus, but a number of major outcomes emerged, including: (1) participants agreed that action is called for and that completely depleting the freshwater in the shared aquifer could be catastrophic to the region; (2) addressing depletion and prolonging the life of the aquifer will require binational action, because actions on only one side of the border is not enough; and (3) informal binational cooperation will be required to be successful. Agreeing that binational action is called for, the serious games intervention was an important next step toward improving management of this crucial binational resource.

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