Banca de QUALIFICAÇÃO: EDUARDO KOHL

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : EDUARDO KOHL
DATE: 02/12/2023
TIME: 10:40
LOCAL: Web Conferência - Google Meet: meet.google.com/cym-bqcs-vot.
TITLE:

Reproductive efficiency in female grandparent roosters.

KEY WORDS:

Reproduction; poultry farming; genetics; selection pressure; fertility.

PAGES: 45
BIG AREA: Ciências Agrárias
AREA: Medicina Veterinária
SUMMARY:

Genetic improvement programs are essential for the expansion of modern poultry farming. The productive capacity of a batch of breeders is directly related to the reproductive efficiency of the male, as it is the agent that modifies the productivity of a herd. Better knowledge of the current reproductive profile of grandparent roosters of female broilers makes it possible to improve the reproductive efficiency of commercial flocks through the selection of reproductively superior roosters. The aim of the study was to evaluate the reproductive efficiency of males raised in different weight curves up to the fifth week and the correlation with herd fertility rates. The data were selected from parent stock of 48 lots, distributed under two different weight gain curves and selection ages by weight and phenotypic characteristics., Group I was comprised with 25 lots with a selection age of 36 days (Group I), whereas Group II had 23 lots with a selection age of 36 days All roosters were from batches of chicken grandparents from a single lineage, considering a slaughter age of 60 weeks, and data were collected from May 2019 to April 2023. Variables such as selection age of phenotypic characteristics, average weight and coefficient of variation of males, average weight and coefficient of variation of females, percentage of males in the flock in relation to females, type of shed (fully-climated poultry houses X conventional poultry houses), period of the year (seasonal batches - housed between July and December X out-of-season batches - housed between January and June) and the correlation with fertility indices generated weekly through candoscopy evaluation of a sample of 240 eggs per batch, with 5 days of laying, after 12 days of incubation. The reproductive data from the evaluated batches were subjected to exploratory analysis, using descriptive statistics and stem and leaf diagrams and box-plots to ensure the robustness of the data. The average weight at seven weeks of males selected at 43 days was 28.85% greater than the weight of males selected at 36 days and the average weight at 22 weeks did not vary significantly between treatments. For fertility indices, the roosters selected with 36 and 43 days did not show a significant difference in the general accumulated average between the groups (Group I = 77.07%, Group II=76.58%). The greatest difference in fertility was associated with type of housing. Flocks raised in conventional poultry houses had average accumulated fertility rates of 80.24%, whereas in fully-climated poultry houses showed 74.25% of fertility. In the next step, logistic regression analysis will be applied to evaluate the effect of the explanatory variables on the fertility rate, since the response variable has a binomial distribution, that is, the number of fertile eggs in relation to the number of eggs evaluated. The “stepwise” method will be used to select the explanatory variables that will compose the mathematical model, assuming a significance level of 5%. In other words, only explanatory variables that are significant (p≤0.05) will be included in the model.

COMMITTEE MEMBERS:
Interno - 2613308 - DELANO DIAS SCHLEDER
Interna - 1046884 - ELIZABETH SCHWEGLER
Interno - 1810731 - JULIANO SANTOS GUERETZ
Interno - 1755182 - MARIO LETTIERI TEIXEIRA
Interna - 2408296 - SORAYA REGINA SACCO
Presidente - 1081425 - TEANE MILAGRES AUGUSTO GOMES