The urinary excretion of oestrogens in cows treated with a synthetic gestagen (chlormadinone-acetate, CAP) for the control of oestrus
Lunaas, T.; Onstad, O.
Nordisk Veterinaermedicin 25(1): 28-32
1973
ISSN/ISBN: 0029-1579 PMID: 4133324 Document Number: 62134
The patterns of excretion of oestrogens were established by daily analyses of urine from two cows during spontaneous oestrus, during subsequent administration of CAP for three weeks and during about 5 weeks after gestagen withdrawal. A dose of 10 mg CAP per day administered to one of the cows was too low to prevent development of follicles as judged from a transient increment of oestrogen excretion during the treatment period. The increased oestrogen secretion did not induce behavioural oestrus presumably because of gestagen inhibition. At the dose of 10 mg CAP per day the first as well as the second oestrus after withdrawal were associated with patterns of oestrogen excretion considered to be normal. In the other cow, which received 20 mg CAP per day, the oestrogen excretion stayed low throughout the period of treatment. At withdrawal the animal showed heat symptoms 5 days later after a steep rise in the oestrogen excretion. However, the excretion was subsequently maintained at a high level indicating a derangement of the ovarian function of long duration.