Pre-synchronization of ovulation timing and delayed fixed-time artificial insemination increases pregnancy rates when sex-sorted semen is used for insemination of heifers.
Anim Reprod Sci
; 226: 106699, 2021 Mar.
Article
in En
| MEDLINE
| ID: mdl-33517066
ABSTRACT
This study was conducted to determine effects of pre-synchronization of ovulation timing among heifers and delayed fixed-time artificial insemination (TAI) with sex-sorted semen on proportion of heifers pregnant after TAI (PR/AI). Heifers were assigned to one of eight treatments 1 and 2), 7-d CO-Synchâ¯+â¯CIDR treatment regimen with administration of gonadotropin-releasing hormone and a CIDR insert on Day 0, prostaglandin F2α (PGF) at CIDR removal on Day 7, and TAI occurring 54â¯h later with conventionally processed (CTRL54-CNV) or sex-sorted semen (CTRL54-SEX); 3 and 4), same as CTRL54 but TAI delayed to 72â¯h with conventionally processed (CTRL72-CNV) or sex-sorted semen (CTRL72-SEX); 5 and 6), same as CTRL54 but additional administration of PGF on Day -7 and TAI with conventionally processed (PRE54-CNV) or sex-sorted semen (PRE54-SEX); 7 and 8), same as PRE54 treatments but TAI delayed to 72â¯h with conventionally processed (PRE72-CNV) or sex-sorted semen (PRE72-SEX). Proportion of heifers pregnant after TAI was greater (Pâ¯≤⯠0.02) with conventionally processed semen compared with sex-sorted semen, yet PR/AI did not differ (Pâ¯=⯠0.14) between heifers in PRE72-CNV and PRE72-SEX groups. There were greater PR/AI in the PRE72-SEX (Pâ¯=⯠0.03) than CTRL54-SEX group (46.1 % and 36.9 %) and there was no difference (Pâ¯=⯠0.31) in PR/AI between CTRL54-CNV and PRE72-SEX groups (50.4 % and 46.1 %). In conclusion, pre-synchronization of ovulation timing among heifers combined with delayed TAI resulted in increased PR/AI with sex-sorted semen compared with the 7-d CO-Synch+CIDR treatment regimen.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ovulation
/
Sex Preselection
/
Cattle
/
Insemination, Artificial
/
Estrus Synchronization
Limits:
Animals
/
Pregnancy
Language:
En
Journal:
Anim Reprod Sci
Year:
2021
Type:
Article