Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia

Different therapeutic strategies have been used with the objective of improve luteal function to reduce embryonic losses. The objective of this work was to study the effect of the administration of GnRH or hCG at Day 4 post fixed time artificial insemination (FTAI) on reproductive efficiency in Meri...

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Main Authors: Fernandez, Jimena, Bruno Galarraga, Maria Macarena, Soto, Andrés Telésforo, De la Sota, Rodolfo Luzbel, Cueto, Marcela Isabel, Lacau Mengido, Isabel María, Gibbons, Alejandro Eduardo
Format: info:ar-repo/semantics/artículo
Language:Inglés
Published: Elsevier 2018
Subjects:
Online Access:http://hdl.handle.net/20.500.12123/4069
https://www.sciencedirect.com/science/article/pii/S0093691X18303194
https://doi.org/10.1016/j.theriogenology.2018.12.008
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author Fernandez, Jimena
Bruno Galarraga, Maria Macarena
Soto, Andrés Telésforo
De la Sota, Rodolfo Luzbel
Cueto, Marcela Isabel
Lacau Mengido, Isabel María
Gibbons, Alejandro Eduardo
author_browse Bruno Galarraga, Maria Macarena
Cueto, Marcela Isabel
De la Sota, Rodolfo Luzbel
Fernandez, Jimena
Gibbons, Alejandro Eduardo
Lacau Mengido, Isabel María
Soto, Andrés Telésforo
author_facet Fernandez, Jimena
Bruno Galarraga, Maria Macarena
Soto, Andrés Telésforo
De la Sota, Rodolfo Luzbel
Cueto, Marcela Isabel
Lacau Mengido, Isabel María
Gibbons, Alejandro Eduardo
author_sort Fernandez, Jimena
collection INTA Digital
description Different therapeutic strategies have been used with the objective of improve luteal function to reduce embryonic losses. The objective of this work was to study the effect of the administration of GnRH or hCG at Day 4 post fixed time artificial insemination (FTAI) on reproductive efficiency in Merino sheep during the breeding season in North Patagonia. Estrus of multiparous Merino ewes (n ¼ 288) was synchronized by two injections of prostaglandins (PG; 125 mg, Cloprostenol), 14 days apart. Cervical FTAI was performed 53e56 h after the second PG with a dose of fresh semen (100 X 106 spermatozoa) from five Merino rams. In all ewes body condition score (BCS) was determined at FTAI. At 4 days post FTAI ewes were randomly assigned into three experimental groups: GnRH group (4 mg, Buserelin; n ¼ 99), hCG group (300 IU, hCG; n ¼ 92) and Control group (1 ml, saline solution; n ¼ 97). Pregnancy and pregnancy losses were evaluated by ultrasonography on Days 33 and 90 post FTAI. Additionally, embryo crownrump length (CRL) was measured by ultrasonography (n ¼ 12 single-pregnant ewes by experimental group) at the first ultrasound. Date of birth, litter size and lamb weight were recorded (n ¼ 111 pregnant ewes). Pregnancy rate on Days 33 and 90 post FTAI did not differ among treatment groups (P > 0.05). Pregnancy losses at Day 33 post FTAI were lower in the hCG group compared to the GnRH and Control groups (0, 3, 7.2%, respectively; P < 0.05). Pregnancy losses between Days 33 and 90 after FTAI were negligible (P > 0.05). The embryo CRL at Day 33 post FTAI was not increased by the hormonal treatments (P > 0.05). Moreover, it was lower in GnRH group compared to Control group (P < 0.05). Litter size tended to be greater in the GnRH group compared to the hCG and Control groups (P < 0.1). The birth weight of twin lambs tended to be higher in the GnRH group compared to the Control group (P < 0.1). The birth weight of single lambs was not affected by treatments (P > 0.05). Ram fertility and BCS of ewes at FTAI influenced the effect of hormonal treatments on reproductive parameters. In conclusion, administration of hCG or GnRH at Day 4 post FTAI does not improve pregnancy rate but treatment with hCG reduces pregnancy loss on Day 33 post FTAI. GnRH treatment improves litter size and twin lambs birth weight.
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institution Instituto Nacional de Tecnología Agropecuaria (INTA -Argentina)
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spelling INTA40692018-12-13T11:41:07Z Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia Fernandez, Jimena Bruno Galarraga, Maria Macarena Soto, Andrés Telésforo De la Sota, Rodolfo Luzbel Cueto, Marcela Isabel Lacau Mengido, Isabel María Gibbons, Alejandro Eduardo Inseminación Artificial Oveja Artificial Insemination Ewes Breeds (animals) Pregnancy Razas (animales) Gestación Raza Merino Región Patagónica Different therapeutic strategies have been used with the objective of improve luteal function to reduce embryonic losses. The objective of this work was to study the effect of the administration of GnRH or hCG at Day 4 post fixed time artificial insemination (FTAI) on reproductive efficiency in Merino sheep during the breeding season in North Patagonia. Estrus of multiparous Merino ewes (n ¼ 288) was synchronized by two injections of prostaglandins (PG; 125 mg, Cloprostenol), 14 days apart. Cervical FTAI was performed 53e56 h after the second PG with a dose of fresh semen (100 X 106 spermatozoa) from five Merino rams. In all ewes body condition score (BCS) was determined at FTAI. At 4 days post FTAI ewes were randomly assigned into three experimental groups: GnRH group (4 mg, Buserelin; n ¼ 99), hCG group (300 IU, hCG; n ¼ 92) and Control group (1 ml, saline solution; n ¼ 97). Pregnancy and pregnancy losses were evaluated by ultrasonography on Days 33 and 90 post FTAI. Additionally, embryo crownrump length (CRL) was measured by ultrasonography (n ¼ 12 single-pregnant ewes by experimental group) at the first ultrasound. Date of birth, litter size and lamb weight were recorded (n ¼ 111 pregnant ewes). Pregnancy rate on Days 33 and 90 post FTAI did not differ among treatment groups (P > 0.05). Pregnancy losses at Day 33 post FTAI were lower in the hCG group compared to the GnRH and Control groups (0, 3, 7.2%, respectively; P < 0.05). Pregnancy losses between Days 33 and 90 after FTAI were negligible (P > 0.05). The embryo CRL at Day 33 post FTAI was not increased by the hormonal treatments (P > 0.05). Moreover, it was lower in GnRH group compared to Control group (P < 0.05). Litter size tended to be greater in the GnRH group compared to the hCG and Control groups (P < 0.1). The birth weight of twin lambs tended to be higher in the GnRH group compared to the Control group (P < 0.1). The birth weight of single lambs was not affected by treatments (P > 0.05). Ram fertility and BCS of ewes at FTAI influenced the effect of hormonal treatments on reproductive parameters. In conclusion, administration of hCG or GnRH at Day 4 post FTAI does not improve pregnancy rate but treatment with hCG reduces pregnancy loss on Day 33 post FTAI. GnRH treatment improves litter size and twin lambs birth weight. Estación Experimental Agropecuaria Bariloche. Área de Producción Animal. Laboratorio de Reproducción de Rumiantes Menores Fil: Fernández, Jimena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Agropecuaria Bariloche. Laboratorio de Reproducción de Rumiantes Menores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Bruno Galarraga, María Macarena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Agropecuaria Bariloche. Laboratorio de Reproducción de Rumiantes Menores; Argentina Fil: Soto, Andrés Telésforo. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Investigaciones en Reproducción Animal; Argentina Fil: De la Sota, Rodolfo Luzbel. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Cueto, Marcela Isabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Agropecuaria Bariloche. Laboratorio de Reproducción de Rumiantes Menores; Argentina Fil: Lacau Mengido, Isabel María. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Laboratorio de Regulación Hipofisaria; Argentina Fil: Gibbons, Alejandro Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Agropecuaria Bariloche. Área de Producción Animal. Laboratorio de Reproducción de Rumiantes Menores; Argentina 2018-12-13T11:27:23Z 2018-12-13T11:27:23Z 2018-12 info:ar-repo/semantics/artículo info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion http://hdl.handle.net/20.500.12123/4069 https://www.sciencedirect.com/science/article/pii/S0093691X18303194 0093-691X 1879-3231 https://doi.org/10.1016/j.theriogenology.2018.12.008 eng info:eu-repo/semantics/restrictedAccess application/pdf Elsevier Theriogenology 126 : 63-67 (March 2019)
spellingShingle Inseminación Artificial
Oveja
Artificial Insemination
Ewes
Breeds (animals)
Pregnancy
Razas (animales)
Gestación
Raza Merino
Región Patagónica
Fernandez, Jimena
Bruno Galarraga, Maria Macarena
Soto, Andrés Telésforo
De la Sota, Rodolfo Luzbel
Cueto, Marcela Isabel
Lacau Mengido, Isabel María
Gibbons, Alejandro Eduardo
Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title_full Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title_fullStr Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title_full_unstemmed Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title_short Effect of GnRH or hCG administration on Day 4 post insemination on reproductive performance in Merino sheep of North Patagonia
title_sort effect of gnrh or hcg administration on day 4 post insemination on reproductive performance in merino sheep of north patagonia
topic Inseminación Artificial
Oveja
Artificial Insemination
Ewes
Breeds (animals)
Pregnancy
Razas (animales)
Gestación
Raza Merino
Región Patagónica
url http://hdl.handle.net/20.500.12123/4069
https://www.sciencedirect.com/science/article/pii/S0093691X18303194
https://doi.org/10.1016/j.theriogenology.2018.12.008
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