Factors affecting reproductive outcomes in lactating dairy cows that undergo presynchronization-Ovsynch and successive resynchronization programs

Kim, Ill-Hwa; Jeong, Jae-Kwan; Kang, Hyun‐Gu

doi:10.1016/j.theriogenology.2022.04.017

Cited by 4 publications

(1 citation statement)

References 55 publications

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“…To shorten the time until the new insemination of non-conceiving cows that were previously inseminated through a fi xed ovulation and insemination program, estrus and ovulation resynchronization protocols are introduced [17,18]. Moreover, numerous factors affect the pregnancy rate after the resynchronization protocol such as body condition score (BCS), preand postpartum disorders, days after calving, and heat stress [19]. Resynchronization programs continue with the original synchronization programs, thus avoiding estrus detection or insemination of anovulatory cows [20].…”

Section: Introductionmentioning

confidence: 99%

Efficiency of Two Protocols of Resynchronization of Estrus and Ovulation in High-Producing Dairy Cows at Peak Lactation

Đorđević¹,

Blagojević

Radinović

et al. 2022

Acta Veterinaria

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The reproductive efficiency of the cows was monitored after two resynchronization protocols: Ovsynch (OVS) and Double Ovsynch (DOS). The research initially included 70 HF cows who entered the first synchronization protocol – Presynch. Cows that did not conceive after the first synchronization were divided into two groups and introduced to two resynchronization protocols. In the first group of cows (n=35), the DOS protocol began with the application of GnRH on day 22 after the Presynch TAI (Timed Artificial Insemination), and seven days later pregnancy check-up was done and PGF2α was applied only to non-pregnant cows (n=23), which remained in the study. In the second group of cows, the OVS protocol started on day 32 after Presynch TAI only in non-pregnant animals (n=20). Progesterone (P4) concentration was determined at the time of application of GnRH1, PGF2α and GnRH2 in both groups of cows, and then 30 days after Resynch TAI, ultrasound pregnancy diagnosis was done. A higher percentage of pregnant cows were recorded in the OVS group compared to the DOS group (45% and 35%, respectively). The concentration of P4 in the serum of cows in the DOS group during the first measurement (GnRH1) was significantly higher than the value in cows that did not conceive (p<0.05), while in the third measurement (GnRH2) the average concentration of P4 in conceiving cows was significantly lower (p<0.001) compared to cows that did not coincive. The open days period was significantly longer in pregnant cows that were resynchronized using the DOS protocol compared to cows from the OVS protocol. In conclusion, the OVS protocol of estrus resynchronization in dairy cows proved to be more successful than the DOS protocol. However, considering the advantages the OVS, it is needed to determine which day of the sexual cycle is the best to start resynchronization.

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Section: Introductionmentioning

confidence: 99%

Efficiency of Two Protocols of Resynchronization of Estrus and Ovulation in High-Producing Dairy Cows at Peak Lactation

Đorđević¹,

Blagojević

Radinović

et al. 2022

Acta Veterinaria

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Genetic and phenotypic parameters for sexual precocity and parasite resistance traits in Nellore cattle

Moraes,

Gouveia,

Ribeiro

et al. 2023

J Appl Genetics

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Indicator traits of sexual precocity are widely used as selection criteria for the genetic improvement of beef cattle; however, the impact of selection for these traits on resistance to endo-and ectoparasites is unknown. Therefore, this study aimed to estimate the genetic and phenotypic parameters for indicator traits of sexual precocity and parasite resistance in Nellore cattle. The sexual precocity traits evaluated were probability of rst calving (PFC) and scrotal circumference at 12 and 18 months of age (SC12 and SC18). The resistance-related traits included tick (TC), gastrointestinal nematode egg (NEC), and Eimeria spp. oocyst (EOC) counts. (Co)variance components were estimated by Bayesian inference using multitrait animal models. The mean heritabilities for PFC, SC12, SC18, TC, NEC and EOC were 0.23, 0.38, 0.42, 0.14, 0.16, 0.06, respectively, and suggest that selection will change the mean values of these traits over time. The genetic and phenotypic correlations for most pairs formed by a precocity and a resistance trait were not different from zero, suggesting that selection for sexual precocity traits will not result in changes in resistance traits. Thus, selection for indicator traits of sexual precocity does not elicit unfavorable correlated responses in resistance to endo-and ectoparasites and joint selection aimed at improving these traits can be performed using multitrait selection methods, when necessary.

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Clinical management of pregnancy-related problems between days 28 and 60 in the dairy cow

López‐Gatius

Szenci

2023

Theriogenology

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Factors affecting reproductive outcomes in lactating dairy cows that undergo presynchronization-Ovsynch and successive resynchronization programs

Cited by 4 publications

References 55 publications

Efficiency of Two Protocols of Resynchronization of Estrus and Ovulation in High-Producing Dairy Cows at Peak Lactation

Efficiency of Two Protocols of Resynchronization of Estrus and Ovulation in High-Producing Dairy Cows at Peak Lactation

Genetic and phenotypic parameters for sexual precocity and parasite resistance traits in Nellore cattle

Clinical management of pregnancy-related problems between days 28 and 60 in the dairy cow

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