The effect of hCG administration five days after insemination on the first service conception rate of anestrous dairy cows.
Theriogenology
; 63(7): 1938-45, 2005 Apr 15.
Article
en En
| MEDLINE
| ID: mdl-15823350
ABSTRACT
The aim of this study was to investigate the effect of treating anovulatory anestrous (AA) dairy cows with 1500 IU of hCG IM, 5 d after insemination, on their first service conception rate. A clinical trial was conducted during the 2003/2004 breeding season involving 442 AA dairy cows in six herds. On Day -8, all cows were treated with a progesterone-containing intravaginal device (Cue-Mate). The devices were removed on Day -2, and on Day -1 all cows received an IM injection of 1mg of estradiol benzoate. Cows in the control group (n=220) received no further treatments. Cows in the treatment group (n=222) which had been inseminated on Days 0 or 1 were treated with 1500 IU of hCG IM 5 d after insemination. Blood was collected from 30 cows (15 in each group) on Days 5 and 12 after AI for analysis of plasma P4 concentration. There was no difference in first service conception rates between the control and treatment groups (46.3% versus 43.6%, respectively; P=0.68), despite the fact that plasma P4 concentrations were higher in the treatment group on Day 12 (4.9+/-1.3 ng/mL versus 6.2+/-2.7 ng/mL for control and treatment groups, respectively; P<0.01). In conclusion, 1500 IU of hCG 5 d after insemination did not improve first service conception rate in AA dairy cows.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Progesterona
/
Bovinos
/
Inseminación Artificial
/
Estradiol
/
Gonadotropina Coriónica
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
/
Pregnancy
Idioma:
En
Revista:
Theriogenology
Año:
2005
Tipo del documento:
Article
País de afiliación:
Nueva Zelanda