scholarly journals Responses to Individual, Family or Index Selection for Short Term Rate of Egg Production in Chickens

1970 ◽  
Vol 49 (4) ◽  
pp. 1052-1064 ◽  
Author(s):  
T.B. Kinney ◽  
B.B. Bohren ◽  
J.V. Craig ◽  
P.C. Lowe
Keyword(s):  
Egg Production ◽  
Index Selection ◽  
Short Term ◽  
Individual Family ◽  
Selection For

Continuous selection for egg production using short-term records

1963 ◽  
Vol 14 (6) ◽  
pp. 909 ◽  
Author(s):  
JA Morris
Keyword(s):  
Genetic Correlation ◽  
Egg Production ◽  
Continuous Selection ◽  
Total Production ◽  
White Leghorn ◽  
Short Term ◽  
Selection For ◽  
Residual Performance ◽  
Actual Response ◽  
Selection Differentials

A closed flock of White Leghorn has been selected for high egg production, since 1947. Selection has always been based on performance achieved from date of first egg until May 31 (part-period test). Selection has been effective in providing gains of approximately three eggs per generation for the part-period and, at the end of the experiment, there is no evidence that the rate of gain has lessened. Total 72-weeks egg production increased during the earlier years of selection but seems to have plateaued subsequently. This leveling off of total production is due to a decline in performance for the period June 1 to 72 weeks of age. The magnitude of this decline is sufficient to offset the gain in the part-period. Annual selection differentials were calculated for the later years, and generally the realized selection differentials were the same size as that intended, which indicated that natural selection was not opposed to the direction of artificial selection. The estimates of heritability of part-period production index show no decline as a result of selection; the actual response observed during the last years of selection supports the contention of absence of such a decline. Although it cannot be statistically confirmed, there are indications that the genetic correlation between part-period and residual performance has decreased in value with the progression of selection. The size of the correlated decline in the residual production suggests not only a reduction in value of the genetic correlation but also a change of sign. The results obtained imply that continuous selection, based on egg production for the part-period, may be an unrewarding procedure; and that selection based on other characters, favourably correlated genetically with total production, might be more effective in providing genetic gain in total production.

scholarly journals Genetic response to short-term index selection in females and mass selection in males of the Nigerian heavy local chicken ecotype

2020 ◽  
Vol 44 (2) ◽  
pp. 1-17
Author(s):  
C. C. Ogbu ◽  
C. C. Nwosu
Keyword(s):  
Body Weight ◽  
Genetic Gain ◽  
Egg Production ◽  
Index Selection ◽  
Mass Selection ◽  
Indigenous Chicken ◽  
Multiple Trait ◽  
Breeding Values ◽  
Expected Gain ◽  
Selection For

The study aimed to determine genetic gain in growth and egg production in the Nigerian indigenous chicken (NIC) subjected to multiple trait index selection for females and mass selection for males. The experimental birds (G generation) were generated from a reference 0 population of NIC and reared according to sire families from hatch. At point of lay, females were housed individually in laying cages for egg production. Hens were selected based on index scores calculated using an index of weighted breeding values constructed from own performance in body weight at first egg (BWFE), egg weight (EW) and egg production (EN), trait heritabilities and relative economic weights while cocks were selected based on own performance in body weight at 39 weeks of age (BW ). Selected parents were mated to 39 generate the G generation which in turn yielded the parents of the G generation. A control 1 2 population was used to measure environmental effects. Data were analyzed using the Restricted Maximum Likelihood (REML) computer programme. For hens, expected average direct genetic gain per generation was 12.58, 2.98g and 25.04g for EN, EW and BWFE, respectively while realized genetic gain was 2.19 and 1.59 for EN, 1.65 and 0.26g for EW, and -25.60 and 123.64g for BWFE for G and G generations, respectively. The corresponding 0 1 values for ratio of realized to expected genetic gains were 2.27 and 1.22, 3.15 and 0.24, and 0.95 and 2.21, respectively. Heritability (h2) ranged from 0.12 to 0.24 for EN, 0.34 to 0.43 for EW and 0.57 to 0.69 for BWFE, across the three generations. Similar improvements in BW 39 were observed in males with an average expected gain of 508.50g per generation. In conclusion, growth and egg production in the NIC can be improved using mass selection for cocks and index of weighted breeding values for hens.

scholarly journals The Effects of Short Term Feeding of Aflatoxin on Egg Production and Some Plasma Constituents of the Laying Hen ,

1973 ◽  
Vol 52 (6) ◽  
pp. 2206-2211 ◽  
Author(s):  
J.D. Garlich ◽  
Hsi-Tang Tung ◽  
P.B. Hamilton
Keyword(s):  
Egg Production ◽  
Laying Hen ◽  
Short Term

A Novel Quantum Neural Network Model with Variable Selection for Short Term Load Forecasting

2010 ◽  
Vol 20-23 ◽  
pp. 612-617 ◽  
Author(s):  
Wei Sun ◽  
Yu Jun He ◽  
Ming Meng
Keyword(s):  
Neural Network ◽  
Variable Selection ◽  
Network Model ◽  
Neural Network Model ◽  
Load Forecasting ◽  
Short Term ◽  
Bp Network ◽  
Quantum Neural Network ◽  
Short Term Load Forecasting ◽  
Selection For

The paper presents a novel quantum neural network (QNN) model with variable selection for short term load forecasting. In the proposed QNN model, first, the combiniation of maximum conditonal entropy theory and principal component analysis method is used to select main influential factors with maximum correlation degree to power load index, thus getting effective input variables set. Then the quantum neural network forecating model is constructed. The proposed QNN forecastig model is tested for certain province load data. The experiments and the performance with QNN neural network model are given, and the results showed the method could provide a satisfactory improvement of the forecasting accuracy compared with traditional BP network model.

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