Oestrus response of cows treated with various doses of Prostaglandin F2a

Abstract

The oestrus response o various doses of Prostaglandin F2a in dairy cows was investigated to determine the effectiveness of doses lower than the recommended dose. Prostaglandin analogues are used in reproductive management to induce oestrus in cows. They also have pharmacological application in the correction of a number of reproductive disorders in cows. While prescription of a therapeutic dose is expected for the correction of reproductive disorder , the dose for inducing oestrus and associated ovulation is expected to be comparatively lower. However, the current dose recommendation prescribes a blanket application re e of the hormone for all these purposes. The implication of this is the use of pharmacolgical doses of Prostaglandin F2a where physiological dose should surfice. Consequenth , costs that would otherwise be eliminated through the use of a minimum required do .e are incurred. In an experiment with the objective of lowering the Prostaglandin Faa dost used in oestrus synchronization, the effectiveness of lower doses in inducing oestrus in d; iry cows was investigated. Four (4) Friesian cows were randomly allocated to receive e; her 2.0 mL (recommended dose and positive control), 1.5 mL, 1.0 mL or 0.5 mL of Alfa ^landin, an analogue of Prostaglandin F2a, given intramuscularly on day seven of the oestr lus cycle. There were no differences in response to various doses of Alfaglandin administered (x^ = 3.1, df = 3, P = 0.4). There was 100% oestrus response among cows treated \ ith 2.0 or 0.5 mL, 50% at 1.5 mL, and 66.7% at 1.0 mL. A l l the cows that responded positively to treatment did so within a period of 2.5-3.5 days {P>0.05). In conclusion, lower doses of Prostaglandin F2u were just as effective as those recommended for oesi 'us synchronization in cows. Additionally, the time taken to oestrus was unaffected by the lose of Prostaglandin F2a administered.