SUMMARY One-hundred-fourteen cows (30 Guernsey and 84 Holstein), diagnosed as having ovarian cysts via rectal palpation, were treated at randon with a single IM injection of either 50, 100 or 250 /lg synthetic gonadotropin-releas- ing-hormone (GnRH) or a sham injection of the carrier vehicle for GnRH (0 /~g). All animals were from one Guernsey and three Holstein herds maintained on a reproductive herd health program where routine examinations were per- formed at weekly or biweekly intervals. Clinical diagnosis of ovarian cysts was based upon the finding of a single or multiple formation of smooth, fluctuant, rounded structures of 2.5 cm in diameter or larger on one or both ovaries. Response to treatment was recorded as positive if the animal established a normal estrous cycle or conceived and negative if no change in character, size or location of the cystic struc- ture could be determined in a 2- to 4-week period. Positive response to treatment was not significantly different among the groups that received GnRH (50, 100 and 250/ag), but each was different from the animals receiving 0 /lg GnRH (P
This report describes a pregnancy test based on measuring the plasma progesterone level at a fixed time after mating or insemination. The method has been tested on the cow ewe and sow. In 50 Holstein cows blood samples were taken on the first day of estrus and on Days 10 17 and 24 of the cycle. Confirmation of pregnancy was determined 50-60 days after. Ewes were 3-5 years old and had blood samples drawn on day of estrus and on Days 10 and 17. Pregnancy was confirmed when the animals were slaughtered 35-140 days after mating. For pigs 25 Yorkshire gilts 10-12 months old were tested on Days 22 and 24 after estrus. Concentration of progesterone in plasma was determined by a modification of the competitive protein-binding technique. Corticosterone binding globulin (CBG) was obtained from male dogs. In the noninseminated cow the levels of progesterone in the plasma are low from 2 days before until 4 days after estrus. Due to irregular cycles blood samples taken earlier than Day 10 or later than Day 23 after insemination may lead to errors in predicting pregnancy. Pregnancy was determined by a plasma progesterone level greater than 1 ng/ml on Days 10 21 22 23 or 24. Samples taken on Day 19 were 74% accurate while estimates based on samples taken on Days 20-24 were 88-100% accurate. In ewes plasma progesterone is low from 1 day before to 3 days after estrus. A level greater than .5 ng/ml on Day 17 indicated pregnancy pr ovided that the first day serum progesterone level had been low. Accuracy of prediction was 87%. In sows levels were much higher then in cows or ewes. Values of 5 ng/ml or higher indicated pregnancy. Accuracy was 88%. General use of this method is restricted by the necessity of having a liquid scintillation counter. Also blood samples must be taken at a fixed time interval from mating or insemination.