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An evaluation of timing of AI with frozen sex-sorted semen in lactating dairy cows in pasture-based seasonal-calving herds
Authors
Evelyn Drake (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); Victoria Aublet (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); ShaunaA. Holden (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); Chloe Millar (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); Stephen G. Moore (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); Clio Maicas (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork); Andrew R. Cromie (Irish Cattle Breeding Federation); Federico Randi (Ceva Sante Animale. Libourne France); Patrick Lonergan (School of Agriculture and Food Science, University College Dublin); Stephen T. Butler (Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork)
Publication information
World Buiatric Congress 2022.
OBJECTIVES
The objective was to use ovulation synchronization with a PRID-Ovsynchprotocol for timed artificial insemination (TAI), to evaluate the effect of timing of insemination (16 h or 22 h after the second GnRH) with frozen sex-sorted semen on fertility performance in pasture-based seasonal calving herds.
MATERIALS AND METHODS
- Ejaculates from 3 different bulls were split and processed to provide frozen sex-sorted semen at 4×106 sperm per straw (SexedUltra-4M; SS) and frozen conventional semen at 15×106
spermper straw (CONV). - A modified PRID-Ovsynch protocol was used for estrous synchronization (Fig1).
- TAI occurred 16 h after the second GnRH injection for cows assigned to CONV and 16 h sexed semen(SS-16) treatment, cows in (SS-22) received TAI with sexed semen 22 h following the
second GnRH injection. - Pregnancy diagnosis was conducted by ultrasound scanning 35-40 d after FTAI (n=2175records available for analysis).
RESULTS
- P/AI was greater for CONV compared to both SS-16 and SS-22 (Fig.2).
- The relative P/AI for SS-16 and SS-22 vs. CONV were 81% and 84%, respectively.
- There were significant bull and treatment by bull interaction effects.
- The study identified a marked herd to herd variation (the relative P/AI for the combined SS treatments vs. CONV rangedfrom 50.9% to 116.8%).
- The best third of herds achieved a mean relative P/AI of 101.5% (range=93.9% to 116.8%), indicating that P/AI equivalent to CONV is achievable with SS.
- Conversely, the lower third of herds achieved a mean relative P/AI of 67.4% (range=50.9% to 76.9%).
- Interestingly, the third of herds with the poorest relative P/AI had greater P/AI with CONV than the third of herds with the best relative P/AI, indicating a satisfactory response to the synchronization protocol on the induction of a fertile ovulation event in these herds.
CONCLUSIONS
The use of PRID-Ovsynch protocol for FTAI allowed for satisfactory P/AI varying between 60% for CONV to ~50% for SS.
Marked variation existed between herds ,however, with one third of herds achieving P/AI results equal to CONVENTIONAL
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