Luteolytic effect of Estrumate in cattle as a function of the estrus phase and its suitability for estrus regulation
Dobeli, M.; Risi, J.; Zerobin, K.
Schweizer Archiv für Tierheilkunde 123(11): 587-595
1981
ISSN/ISBN: 0036-7281 PMID: 6950517 Document Number: 176178
In this excerpt from a dissertation, data on 200 herdbook Swiss Brown cows, aged 19-30 months, were analysed. In the 1st series of experiments, single intramuscular injections of the synthetic progestogen Estrumate (500 mu g cloprostenol) given on day 3, 5, 7, 11, 15, 17 or 19 of the oestrous cycle were compared; only those given on day 7 or later induced luteolysis followed by oestrus. In the 2nd series of experiments, 156 cows were given a single PG injection between the 5th and 18th days of the cycle; 141 came into oestrus, 129 of those 2-3 days after treatment. Their CR to 1st insemination was 67.4% vs. 70.2 for untreated controls. In the 3rd series of experiments, 51 cows were given 2 PG injections at 11-day intervals, irrespective of stage of the oestrous cycle. This had the effect of almost completely synchronising oestrus in the entire herd, but reduced the CR to 1st insemination (62.7 vs. 68.2% for untreated controls).