Oocyte collection in cattle: Is there a correlation between yield of oocytes and serum insulin-like growth factor-I levels?

Abstract

In 1980, the Bavarian State Agency for Water Research (Bayerische Landesanstalt für Wasserforschung), D-Munich, ran a field test in which the concentrations of hydrocarbons in water were monitored during and after intensive motor boating. The hydrocarbon (HC) detection limit was 0.03 mg/l with an accuracy of 30–50%. The average background level was 0.05 mg HC/1. The test was run in a 100 × 20 m testpond, filled with 4000 m3 fresh water from the river Isar. A 3.3 m long testboat, equipped with a 7 kW mixed lubricated two-stroke outboard motor running at 3500 rev/min, was driven 600 times over the same longitudinal track during a period of 8 h. This is equivalent to very intensive outboard motor usage in the field. For the first half of the test, a synthetic lubricant was used in a 100:1 mixture. In the second half, a mineral oil was used at 50:1. During the whole test, a total of 16.27 1 of fuel was consumed in 345 min of actual operation. As the motor produced 5.9 kW at 3500 rev/min the specific fuel consumption was 0.48 1/kWh. The total environmental surface load was 81.35 1/ha per day. In the first half of the test, the motor was run for a total of 166 min and consumed 7.88 1 fuel. Under the test conditions with this synthetic lubricant, the hydrocarbon concentrations at the surface and at 0.2 m and 1.5 m depth, showed at most an insignificant increase as the average measurements remained well within the statistical dispersion of normal background levels. During the second half of the test, the motor ran for a total of 179 min and consumed 8.39 1 fuel. During this part of the test, there was a clear increase of the hydrocarbon level at the surface. The concentrations were, however, much lower than what might have been expected on the basis of known emission factors. Even under the intensive usage conditions during this test, the hydrocarbon concentrations remained far below known acute toxicity limits of both lubricants. Longterm ecological effects were not investigated in this test. In this field test, speed and direction of the wind were continuously monitored. It was shown that wind effects provide a relatively rapid transit system to transport surface hydrocarbons from up-wind to down-wind areas.