Pregnancy rate in dairy cows treated with human chorionic gonadotropin five days after insemination

Abstract

ABSTRACT. This study tested whether the administration of hCG five days after insemination increased progesterone concentration and pregnancy rate (PR) in dairy cows. A total of 989 lactating Holstein cows with different parity and number of prior services were used. Cows were inseminated after overt estrus or at a fixed-time. Five days post-insemination, cows were randomly assigned to two treatment groups: hCG (n=482), which received 3500 IU of hCG by intramuscular injection; and the control group (n=507), which did not receive any treatment. Pregnancy was diagnosed by ultrasound on day 30 post-insemination, and gestation was confirmed on day 60 post-insemination by rectal palpation. In 15 cows from each treatment group, plasma progesterone concentration was determined on days 5, 11, and 15 post-insemination. Pregnancy rate was analysed using logistic regression. Variations in progesterone concentration between treatments were tested by ANOVA for repeated measurements. Progesterone concentration was higher on days 11 and 15 in cows treated with hCG, compared to the control group (P<0.05). Treatment with hCG increased pregnancy rate (47.5 vs. 37.4%. Odds ratio 1.3; P<0.05). No interaction was observed between treatment and body condition, prior services, milk production, parity, or insemination type (overt estrus or fixed time). Treatment with hCG did not reduce pregnancy losses between day 30 and 60 post-insemination (P>0.1). We conclude that injection of hCG five days after insemination increased progesterone concentration and pregnancy rate in dairy cows.Key words: hCG, fertility, progesterone, dairy cows. RESUMEN.Este estudio evaluó si la administración de hCG cinco días después de la inseminación incrementa la concentración de progesterona y la tasa de preñez (TP) en vacas lecheras. Se utilizaron 989 vacas Holstein de diferente número de parto y servicio. Las vacas se inseminaron después de la detección del estro o a tiempo fijo. El día cinco postinseminación las vacas se asignaron aleatoriamente a dos tratamientos: hCG (n=482), donde recibieron 3500 UI de hCG vía im; y control (n=507), donde no recibieron tratamiento. Se diagnosticó la gestación mediante ecografía el día 30 posinseminación y se confirmó el día 60 por palpación transrectal. En 15 vacas de cada tratamiento se determinó la concentración plasmática de progesterona los días 5, 11 y 15 postinseminación. Se analizó la TP mediante regresión logística y la concentración de progesterona mediante análisis de varianza. La concentración de progesterona fue más alta los días 11 y 15 en las vacas tratadas con hCG que en las control (P<0,05). El tratamiento con hCG incrementó la TP en comparación con sus controles (47,5 vs. 37,4%; odds ratio 1,3; P<0,05). No se observó interacción entre el tratamiento con la condición corporal, número de servicios, producción láctea, número de partos y el tipo de inseminación (detección de estro o tiempo fijo). El tratamiento con hCG no disminuyó la pérdida de gestaciones entre los días 30 y 60 postinseminación (P>0.1). S...

Cattle Artificial Insemination Service in Developing Countries: Efficiency, Major Challenges and Economic Loss: A Review

“…Müller-Sepúlveda et al [45] in Chile reported a higher CR 1 (75.6%) in dairy and beef cows. Urzúa et al [46] in Mexico also reported CR 1 on human chorionic gonadotropin (hCG) five-day post-insemination treated group (47.5%) and control group (37.4%) of Holstein cows, and overall CR 1 (48.4%) was reported. There were many actions done to improve the CR 1 of dairy cows in different countries of the globe, for example, Hamid and Kamruzzaman [47] in Bangladesh reported on gonadotropin releasing hormone (GnRH) of one hour before, during or after AI treated group (71.1%) and control group (55.6%) of Holstein Friesian and local crossbred cows.…”

Ovarian luteal category at the time of exogenous progesterone treatment alters pre-ovulatory follicle size and pregnancy outcome but not initial GnRH treatment in repeat-breeder crossbred dairy heifers submitted to the 7-day fixed-time AI protocol

“…On days 32 and 60 after fixed-time AI, all heifers were subjected to pregnancy diagnosis by transrectal ultrasonography. We followed the calculations of PR and embryonic loss based on previous reports ( Urzúa Gonzáleza et al., 2017 ) as follows. The PRs were defined as the proportion of heifers that were diagnosed as pregnant on days 32 or 60 after fixed-time AI, divided by the total number of bred heifers at fixed-time AI.…”

“…(2008) , and Sahu et al. (2014) , treatment of first GnRH irrespective of oestrous cycle stage resulted in an ovulation rate of only 31–49% and depends on the maturation stage of the follicles ( Colazo & Mapletoft, 2014 ) and ovarian structure ( Urzúa Gonzáleza et al., 2017 ) at the time of programme initiation. Because of the importance of ovarian structure, dairy cows with a functional CL at the time of first GnRH tretment had more pregnancy outcome than cows lacking a functional CL at first GnRH injection regardless of their ovulatory response to the first GnRH treatment ( Carvalho et al., 2018 ).…”