Banca de QUALIFICAÇÃO: RAFAELLA SOBRINHO VIDAL

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : RAFAELLA SOBRINHO VIDAL
DATE: 24/01/2026
TIME: 08:00
LOCAL: Online
TITLE:

Effect of postpartum interval on conception rate of Nellore cows submitted to fixed-time artificial insemination (FTAI)

 

 

KEY WORDS:

Bovine fertility, calving-conception interval, strategic management, beef cattle farming.

PAGES: 15
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Reproductive efficiency is one of the main pillars of productivity in beef cattle farming systems, especially in extensive management herds.In this context, understanding the factors that influence the conception rate is essential to optimize reproductive results.The objective of this study will be to evaluate the influence of the number of days postpartum (DPP) based on the timing of fixed-time artificial insemination (FTAI) on the conception rate in Nelore cows raised in an extensive system.For this, 3,000 multiparous females, raised on pasture and with an average body condition score (BCS) of 3.0, will be previously selected by gynecological evaluation, will undergo a 10-day ovulation synchronization protocol and FTAI.The animals will be separated into 8 groups according to the number of DPP (days after postpartum), with the groups having a 10-day interval (except group 8, which is from 91 to 129 days), starting with a minimum of 21 days.The gynecological evaluation and pregnancy diagnosis to confirm pregnancy (performed 30 days after AI) will be carried out with the aid of an ultrasound device.The pregnancy rate (pregnant = 1; not pregnant = 0) will be analyzed by generalized linear mixed models in the GLIMMIX procedure of SAS (v9.4), with binomial distribution and logit link function.The following will be considered as fixed effects: DPP, cyclicity, BCS, bull (semen) and their interactions.The bull effect may be treated as random, depending on data repetition.Variable selection will be based on the Wald test, keeping those with P ≤ 0.20, except for the main factors such as DPP.Comparisons between adjusted means of the DPP groups will follow a significance level of 5% (P < 0.05), with Tukey correction or equivalent method.The quality of the model will be verified by residual analysis and criteria such as AIC.

COMMITTEE MEMBERS:
Interna - 2932766 - ANDRESSA FERREIRA DA SILVA
Interno - 387015 - FERNANDO QUEIROZ DE ALMEIDA
Presidente - ***.517.028-** - MARCO ROBERTO BOURG DE MELLO - UFJF