Evaluation of treatment with a 5-day versus 7-day controlled internal drug-release insert on reproductive outcomes of beef heifers using a modified timed–artificial insemination protocol

Ahmadzadeh, A.; Gunn, Deidre; Hall, J.B.; Glaze, J.B.

doi:10.15232/pas.2014-01378

Cited by 6 publications

(8 citation statements)

References 23 publications

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“…Moreover, dairy heifers show a comparable ovarian physiology to beef heifers [ 20 , 21 ]. Likewise, a conception rate around 60% was obtained in beef heifers, comparable to that achieved in other studies with the protocol Co-synch 72 and 56 h [ 9 , 10 , 13 , 14 , 16 , 18 , 24 , 27 , 28 , 29 , 30 , 31 ].…”

Section: Discussionsupporting

confidence: 85%

“…In GnRH-based protocols, the initial GnRH is intended to induce LH release and ovulation, with emergence of a new follicular wave approximately 2 d later and luteinization of the follicle present at administration guaranteeing an appropriate level of progesterone during follicle growth. The 5d Co-synch protocol, in which FTAI is performed 72 h after the first prostaglandin administration, shortens the follicular dominance by two days and lengthens the proestrus phase by 16–24 h, ultimately leading to higher mean conception rate (CR) [ 8 , 11 , 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

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Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-Synch Protocol in Heifers

Fernández-Novo

Santos-Lopez

Pesantez-Pacheco

et al. 2021

Animals

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In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. We explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72-h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In experiment 1, we examined the total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56-h protocol (5dCo56; n = 10), 5d Co-synch 72-h (5dCo72; n = 17), or the modified 5d Co-synch 72-h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). In experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72-h or 6-d Co-synch 48-h protocol and conception rate (CR) studied. In experiment 1, the three protocols led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72), and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (p = 0.907). Therefore, delaying removal by 24 h provides satisfactory results without reducing reproductive efficiency of heifers.

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Section: Discussionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-Synch Protocol in Heifers

Fernández-Novo

Santos-Lopez

Pesantez-Pacheco

et al. 2021

Animals

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“…Estos últimos autores estimaron un coste económico 7$ superior para cada novilla en el caso del protocolo 7-d, sobre todo debido a costes de semen, recría y remplazo. Posteriormente, Ahmadzadeh et al (2015) también describieron una tendencia a mejorar la tasa de preñez en novillas de carne con el protocolo de 5-d + CIDR, frente al protocolo convencional de 7-d + CIDR (53 vs. 64%, para 7 y 5 días, P = 0,07). al momento de administrar la PGF, comparado con los protocolos de 7 días.…”

Section: Duración Del Tratamiento Con Progesterona En Los Protocolos unclassified

“…En el estudio de Colazo y Ambrose (2011), la tasa de preñez fue superior en las novillas lecheras que ovularon dentro de las 24 horas posteriores a la IATF, sugiriendo que dichos animales ovularon después de una liberación endógena de LH. Estudios posteriores han descrito mejoras en las tasas de preñez de los lotes de novillas que habían expresado celo, desde un 18% en novillas de carne (Ahmadzadeh et al, 2015) hasta un 27% en vacas de carne (Richardson et al, 2014), frente a los lotes de animales que no lo habían mostrado. (2017), trabajando en novillas de leche, incluyeron tres controles visuales de celos al día, durante 30 minutos cada uno.…”

Section: Inclusión De La Detección De Celo En Los Protocolos Ovsynch/unclassified

Revisión de los programas de sincronización ovárica basados en el uso de hormona liberadora de gonadotropinas y prostaglandina F2α para novillas de leche y de carne

Sanz¹,

Macmillan²,

Colazo³

2019

ITEA

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ResumenLa inseminación artificial lleva décadas implantada en las explotaciones de vacuno de leche, no tanto en el vacuno de carne. Los protocolos de sincronización ovárica que permiten realizar la inseminación artificial a tiempo fijo son muy interesantes, debido a que no dependen exclusivamente de la detección de celos, por lo que se han convertido en una herramienta muy útil para planificar y mejorar la eficiencia reproductiva de las explotaciones comerciales. El ganadero que quiera implementar estas técnicas reproductivas en su explotación deberá asesorarse por un especialista, que le recomiende los protocolos más adecuados para cada tipo de animal y para cada rebaño, teniendo en cuenta que los resultados obtenidos en novillas han sido más variables que en las vacas adultas. En este trabajo se revisan los protocolos de sincronización ovárica basados en el uso de hormona liberadora de gonadotropinas (GnRH) y prostaglandina F2α (PGF) utilizados en novillas, así como los diversos ajustes que se han ido proponiendo, para tratar de unificar y mejorar las tasas de preñez.Palabras clave: Recría, vacuno, reproducción, tratamientos, inseminación artificial a tiempo fijo. A review of the ovarian synchronization programs based on the use of gonadotrophin releasing hormone and prostaglandin F2α for dairy and beef heifers AbstractArtificial insemination has been utilized in dairy cattle for decades, but the adoption of this technique has been low in the beef industry. Ovarian synchronization protocols that allow for timed artificial insemination are attractive because estrus detection is not required, becoming a very useful tool to improve the overall reproductive efficiency of commercial herds. Producers should seek advice from a specialist, who can recommend the most appropriate protocols for each category of animal and for each herd, taking into account that the results obtained in heifers have been more variable than in adult cows. In this publication, we review the ovarian synchronization protocols based on gonadotrophin releasing hormone (GnRH) and prostaglandin F2α (PGF) for dairy and beef heifers, as well as several modifications that have been proposed, to enhance pregnancy rates.

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“…In GnRH-based protocols, the initial GnRH is intended to induce LH release and ovulation, with emergence of a new follicular wave approximately 2 d later. The 5d Co-synch protocol, in which FTAI is performed 72 h after the rst prostaglandin administration, shortens the follicular dominance by two days and lengthens the proestrus phase by 16-24 hours, ultimately leading to higher mean conception rate (CR) [8,[11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Effects of delaying the removal of the intravaginal progesterone device by 24 h in the 5d Co-synch protocol in heifers

Fernández-Novo¹,

Santos-Lopez

Pesantez-Pacheco

et al. 2021

Preprint

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Background In beef herds, increasing animal welfare, improving reproductive performance and easing animal management are key goals in farm economics. This study explored whether delaying the removal of the intravaginal progesterone device by 24 h in heifers synchronized with a 5d Co-synch 72 h protocol could improve reproductive efficiency of fixed-time artificial insemination (FTAI). In Experiment 1, we examined whether such a modified protocol would provide an acceptable, total synchronization rate (TSR) in cycling Holstein heifers. Heifers (13.4 ± 0.69 mo.) were randomly assigned to the standard 5d Co-synch 56 h protocol (5dCo56; n = 10), the standard 5d Co-synch 72 h protocol (5dCo72; n = 17), or the modified 5d Co-synch 72 h protocol, in which removal of the progesterone device was delayed by 24 h (6dCo48; n = 19). Heifers were considered synchronized (TSR) if serum progesterone value > 1.0 ng/mL and the corpus luteus (CL) was detectable by ultrasonography on Day 5, if progesterone < 1.0 ng/mL and at least one follicle had a diameter > 8 mm on Day 7.5, and if progesterone > 1.0 ng/mL and CL was detectable on Day 15. In Experiment 2, 309 cycling beef heifers on 18 commercial farms were subjected to the 5d Co-synch 72 h or 6d Co-synch 48 h protocol and conception rate (CR) studied. Results In experiment 1, the three protocols in dairy heifers led no differences on TSRs of 80.0% (5dCo56), 88.2% (5dCo72) and 89.5% (6dCo48). In experiment 2, the CR from the beef heifers, observed during two consecutive reproductive seasons did not differ: 59.7% for 5dCo72 and 62.0% for 6dCo48 (P = 0.907). Heifer age, body condition score or stress score did not significantly affect conception rate. Conclusions These results suggest that delaying removal of the intravaginal progesterone device by 24 h during the standard 5d Co-synch 72 h protocol provides satisfactory results without reducing reproductive efficiency of heifers.

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Evaluation of treatment with a 5-day versus 7-day controlled internal drug-release insert on reproductive outcomes of beef heifers using a modified timed–artificial insemination protocol

Cited by 6 publications

References 23 publications

Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-Synch Protocol in Heifers

Effects on Synchronization and Reproductive Efficiency of Delaying the Removal of the Intravaginal Progesterone Device by 24 h in the 5d Co-Synch Protocol in Heifers

Revisión de los programas de sincronización ovárica basados en el uso de hormona liberadora de gonadotropinas y prostaglandina F2α para novillas de leche y de carne

Effects of delaying the removal of the intravaginal progesterone device by 24 h in the 5d Co-synch protocol in heifers

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