Initiation of Puberty in Heifers

Estill, Charles T.

doi:10.1002/9781118833971.ch22

Cited by 6 publications

(5 citation statements)

References 82 publications

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“…The onset of reproductive activity is indicated by puberty which is dependent of several factors such as race, environmental, food availability, and body weight. Regarding body weight, females of zebu cattle tend to reach the maturity of their reproductive system when the body weight is around half of the adult weight (Estill, 2014).…”

Section: Introductionmentioning

confidence: 99%

Polymorphisms Related to Bovine Leptin Gene and Association with Productive and Reproductive Traits in Nellore Heifers

Fernandes¹,

Crispim²,

Seno³

et al. 2020

Trop. Anim. Sci. J.

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The identification of genes and polymorphisms in female zebu related to the leptin gene that may be involved in better productive and reproductive performances is relevant to the livestock and economic sector. Thus, the objective of this study was to evaluate the SNP markers (T954M and C305T) and the BM1500 microsatellite and to analyze their associations with the traits of body weight, age at first calving (AFC), calving interval (CI), and reproductive efficiency (RE) in Nellore heifers. DNA extraction was performed, followed by the amplification of all markers. Association analyses were carried out with each marker and each traits separately. The result showed that no significant association was found between the reproductive traits and all markers and between body weight and both SNP markers. For the BM1500 microsatellite, the effect of the allele 138 (p=0.0383) on body weight was observed, with the growth curve for this allele being related to the lower asymptotic weight. Therefore, the BM1500 microsatellite marker was the only one with a significant association with a productive trait providing information about the condition of body weight in Nellore heifers.

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Section: Introductionmentioning

confidence: 99%

Polymorphisms Related to Bovine Leptin Gene and Association with Productive and Reproductive Traits in Nellore Heifers

Fernandes¹,

Crispim²,

Seno³

et al. 2020

Trop. Anim. Sci. J.

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“…3). Even though the impact of feeding on growth and puberty has already been demonstrated, 19,[28][29][30] the idea that in grazing conditions a short fasting period could delay puberty attainment needs to be tested.…”

Section: Discussionmentioning

confidence: 99%

Application of longitudinal data analysis allows to detect differences in pre‐breeding growing curves of 24‐month calving Angus heifers under two pasture‐based systems with differential puberty onset

et al. 2019

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BACKGROUND Longitudinal data analysis contributes to detect differences in the growing curve by exploiting all the information involved in repeated measurements, allowing to distinguish changes over time within individuals, from differences in the baseline levels among groups. In this research, longitudinal and cross‐sectional analysis were compared to evaluate differences in growth in Angus heifers under two different grazing conditions, ad libitum (AG) and controlled (CG) to gain 0.5 kg day−1. RESULTS Longitudinal mixed models show differences in growing curve parameters between grazing conditions, that were not detected by cross‐sectional analysis. Differences (P < 0.05) in first derivative of growth curves (daily gain) until 289 days were observed between treatments, AG being higher than CG. Correspondingly, pubertal heifer proportion was also higher in AG at the end of rearing (AG, 0.94; CG, 0.67). CONCLUSION In longitudinal studies, the power to detect differences between groups increases by exploiting the whole information of repeated measures, modelling the relation between measurements performed on the same individual. Under a proper analysis, valid conclusion can be drawn with fewer animals in the trial, improving animal welfare and reducing investigation costs. © 2019 Society of Chemical Industry

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“…The DPCPS is characterized by having low productive and reproductive indices compared to the specialized animal production systems (beef and dairy cattle). One of these indices is the age at puberty, which can be defined as the moment when females physiologically start the capacity to reproduce (Estill, 2014). The onset of puberty is determined by age, and this process also depends on an undefined order of physiological conditions that result from a specific critical weight (Kenny et al, 2018), for others, body development and nutrition are more important (Grajales et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Factors Associated with the Onset of Ovarian Activity of Cattle Commonly Reared in the Huasteca Veracruzana, Mexico

Olivares-Sixto

Silva-Martínez

Vite-Cristóbal

et al. 2021

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Objective: To identify the factors that affect the onset of ovarian activity in prepuberal heifers in the Huasteca Veracruzana of Mexico.Design/Methodology/Approach: Samples were taken from animal production units of the municipality of Tantoyuca, Veracruz. The onset of ovarian activity was determined by the presence of ovarian follicles andncorpus luteum by ultrasonography technique. Zoometric indices and body condition were calculated at them same time, and the zootechnical practices that were applied to the animals in the last six months before thesampling day were registered. A survey was applied to characterize the management of animal productionunits; the main topics in the survey were: health, reproduction, nutrition, and suckling. All animals available within selection criteria in the production units were sampled. A multiple linear regression (Statistical Analysis Software Version 9.4) and cluster analysis (R Studio Version 1.1.419) were used to identify the main categorical variables that affected the model.Results: The onset of ovarian activity depends mainly on the anatomical development of the heifers. The biostimulation (male effect) on the heifers has an important effect on reducing the age at puberty.Study Limitations/Implications: The study was developed during a long drought period in the region.Findings/Conclusions: The genetic mosaic of the evaluated animals in the production units did not affect the onset of ovarian activity of the heifers; however crossbred heifers (Bos taurus ? Bos indicus) begin the ovarian activity younger.

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Initiation of Puberty in Heifers

Cited by 6 publications

References 82 publications

Polymorphisms Related to Bovine Leptin Gene and Association with Productive and Reproductive Traits in Nellore Heifers

Polymorphisms Related to Bovine Leptin Gene and Association with Productive and Reproductive Traits in Nellore Heifers

Application of longitudinal data analysis allows to detect differences in pre‐breeding growing curves of 24‐month calving Angus heifers under two pasture‐based systems with differential puberty onset

Factors Associated with the Onset of Ovarian Activity of Cattle Commonly Reared in the Huasteca Veracruzana, Mexico

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