Proceedings of the New Zealand Society of Animal Production. 1993,
53: 267-270
Proceedings of the New Zealand Society of Animal Production. 1993,
53: 267-270
In the process of attempting to improve synchrony and fertility, a series of four trials was completed with dairy heifers. Each trial was based on the use of a CIDR-B device for 7 to 10 days with or without 10 mg ODB in a gelatin capsule and with an injection of PGF from 2 to 4 days before device removal or at device removal.
The results of these trials showed that injecting PGF before device removal could improve synchrony (in terms of animals inseminated at 48 h after device removal) but reduced pregnancy rates to first insemination by 5% to 10%. Incorporating ODB delayed the post-treatment interval to oestrus and insemination with a 7-day CIDR regime but improved synchrony with a 9 or 10 day CIDR regime. If the use of ODB was combined with an injection of PGF 4 days before CIDR device removal as part of a 10-day CIDR programme, the 48 h post-treatment synchrony rate was 93% and the pregnancy rate was 56%. Excluding the ODB from this programme reduced the 48 h synchrony rate to 87% and the pregnancy rate to 45%.
These results are additional evidence that combing ODB with P4 is altering ovarian follicle wave patterns with consequent effects on synchrony patterns and fertility.
Keywords: NZSAPAB; oestrus synchrony; progesterone; oestradiol benzoate; prostaglandin F2a, CIDR-B; dairy heifers.
