Estimating values for recreational fishing at freshwater dams in Queensland *

In this paper, estimates of value for recreational fishing are reported for three major freshwater impoundments in Queensland, Australia, using both travel cost and contingent valuation methods. Policy analysts often require estimates of value when analysing the importance of recreation against other uses of impoundments, or when considering the potential for further investments, such as with fish stocking programs. Different forms of the travel cost method are used to estimate separate consumer surpluses associated with two key subgroups of recreational anglers: frequent and occasional anglers. A contingent valuation study is used to estimate the marginal values associated with a potential improvement in fishing experience. The results of the travel cost analysis provide strong evidence that recreational values vary between different groups of anglers and across sites, while the contingent valuation estimates provide values for additional marginal benefits of recreational angling. Copyright 2007 The AuthorsJournal Compilation 2007 Australian Agricultural and Resource Economics Society Inc. and Blackwell Publishers Ltd Journal compilation 2007 Australian Agricultural and Resource Economics Society Inc. and Blackwell Publishing Ltd .

Evaluation of models to induce low progesterone during the early luteal phase in cattle

Two experiments were designed to evaluate models for generation of low circulating progesterone concentrations during early pregnancy in cattle. In Experiment 1, 17 crossbred heifers (Bos taurus) were assigned to either prostaglandin F2α (PGF2α) administration on Days 3, 3.5, and 4 (PG3; n = 9) or to control (n = 8). Blood samples were collected from heifers from Days 1 to 9 for progesterone assay. Progesterone concentrations were decreased (P < 0.03) between 18 and 48 h after first PGF2α treatment in heifers assigned to PG3 compared with that of controls. In Experiment 2, 39 crossbred heifers detected in estrus were inseminated (Day 0) and assigned to either (1) PGF2α administration on Days 3, 3.5, and 4 (PG3; n = 10), (2) PGF2α administration on Days 3, 3.5, 4, and 4.5 (PG4; n = 10), (3) Progesterone Releasing Intravaginal Device (PRID) insertion on Day 4.5 with PGF2α administration on Days 5 and 6 (PRID + PGF2α; n = 10), or (4) control (n = 9). Blood samples were collected daily until Day 15, and conceptus survival rate was determined at slaughter on Day 16. Progesterone concentrations during the sampling period in the PG3 and PG4 groups did not differ but were less than that of controls (P < 0.01). After an initial peak, progesterone concentrations in the PRID + PGF2α group were similar to that of controls. More heifers in the PG4 group (6 of 10) had complete luteal regression than did those in the PG3 group (3 of 10). Conceptus survival rate on Day 16 did not differ between groups. There was a significant correlation between progesterone concentration on Days 5 and 6 and conceptus size on Day 16. In summary, treatment with PGF2α on Days 3, 3.5, and 4 postestrus appeared to provide the best model to induce reduced circulating progesterone concentrations during the early luteal phase in cattle.Author has checked copyrightAM