scholarly journals Influence of selection for increased body weight, egg production, and shank width on the length of the incubation period of turkeys

2000 ◽  
Vol 79 (5) ◽  
pp. 613-618 ◽  
Author(s):  
V.L. Christensen ◽  
D.O. Noble ◽  
K.E. Nestort
Keyword(s):  
Body Weight ◽  
Incubation Period ◽  
Egg Production ◽  
Selection For

Effect of long term selection for juvenile body weight and egg production on semen quality in broiler breeder dam line

2017 ◽  
Vol 52 (2) ◽  
pp. 222
Author(s):  
M. Shanmugam ◽  
M. Niranjan ◽  
K. Rakesh ◽  
T.K. Bhattacharya ◽  
B.L.N. Reddy ◽  
...  
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Semen Quality ◽  
Broiler Breeder ◽  
Term Selection ◽  
Selection For

SELECTION LIMITS: HAVE THEY BEEN REACHED IN THE POULTRY INDUSTRY?

1984 ◽  
Vol 64 (2) ◽  
pp. 217-221 ◽  
Author(s):  
PETER HUNTON
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Multiple Objectives ◽  
Shell Quality ◽  
Key Words Genetics ◽  
Physiological Limit ◽  
Selection For ◽  
Hatching Eggs ◽  
Almost All ◽  
Commercial Turkey

Present emphasis is on the heavy turkey, grown to relatively heavy body weight and subsequently jointed and further processed. Rapid selection for broad-breasted conformation led to problems in natural mating; hence the fertilization of almost all commercial turkey hatching eggs by artificial insemination. Meat chickens have experienced similar selection for growth and conformation. While reproductive performance has not been affected as much as with turkeys, rate of lay, fertility and hatchability of meat chickens has room for improvement. Increased feed intake, in response to selection for growth improvements has led to increased fat deposition, an unwanted feature. Breeding programs for egg production stocks differ fundamentally from those for meat stocks because they are concerned with multiple objectives. Many of these are of low heritibility and some are antagonistic to others. Because of this, selection intensity for any one trait has not been as high as among meat chickens and turkeys. Selection for increased rate of egg production has often been based on "part record;" since this is measured at a time of maximum lay, this trait approaches what may be regarded as a physiological limit, but not necessarily a genetic one. Persistency of lay, on the other hand, shows potential for further improvement. Egg weight and body weight, as they determine feed efficiency, are discussed, as are egg interval and shell quality. No genetic limit has been reached for any of these traits. The application of genetic disease resistance to Marek's disease, for example, affords considerable scope for future improvements. The large resevoir of genetic diversity, coupled with the use of multiple objectives, suggests that even after 40 years of relatively intense selection, genetic variation does not appear to be exhausted. Key words: Genetics, selection, egg production, broilers, turkeys

Genetic parameters for a heavy female turkey line

2005 ◽  
Vol 2005 ◽  
pp. 9-9
Author(s):  
A. D. Kranis ◽  
J. A. Woolliams ◽  
W. G. Hill ◽  
P. M. Hocking
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Genetic Parameters ◽  
Selection Criterion ◽  
Breast Muscle ◽  
Commercial Company ◽  
Egg Number ◽  
Research Population ◽  
Simultaneous Selection ◽  
Selection For

The major selection criterion in the turkey breeding industry is increased breast muscle and body weight in order to adapt to market demands. In female lines a dual selection for both body weight and egg production is performed. However, most published estimates indicate a variable correlation between growth and egg number (Nestor et al., 1996) and so the challenge posed is how to best to select for those opposing goals. The objective of this study was to investigate the effects of simultaneous selection for body weight and egg number by estimating the genetic parameters for a research population held by a commercial company in two different locations.

scholarly journals Direct and Correlated Responses to Long-Term Selection for Increased Body Weight and Egg Production in Turkeys

1996 ◽  
Vol 75 (10) ◽  
pp. 1180-1191 ◽  
Author(s):  
KARL E. NESTOR ◽  
D.O. NOBLE ◽  
J. ZHU ◽  
Y. MORITSU
Keyword(s):  
Body Weight ◽  
Egg Production ◽  
Correlated Responses ◽  
Term Selection ◽  
Selection For

scholarly journals Genetic analysis of body weights of Japanese quails (Coturnix japonica) in a semi-arid area of Nigeria

2020 ◽  
Vol 44 (1) ◽  
pp. 30-38
Author(s):  
A. O. Raji ◽  
S. T. Mbap
Keyword(s):  
Body Weight ◽  
Japanese Quail ◽  
Egg Production ◽  
Arid Area ◽  
Final Body Weight ◽  
Environmental Correlations ◽  
Japanese Quails ◽  
Body Weights ◽  
Selection For ◽  
Semi Arid

Production and management of Japanese quail is relatively new in Nigeria but the birds have been attracting national attention in the recent times. This study on Japanese quail was conducted to estimate genetic parameters of egg production traits of Japanese quails in a semi-arid area of Nigeria. In a study that lasted for 40 weeks, 40 sires and 120 dams that produced 1267 progenies (743 females and 524) in three batches were used. The mixed model least squares and maximum likelihood programme of Harvey was used to estimate heritability, genetic, phenotypic and environmental correlations for body weights of Japanese quails from 0 – 40 weeks of age. Heritability estimates from sire, dam and, sire plus dam variance components from 0 to 36 weeks were low to moderate ranging from 0.071 to 0.569. Genetic correlations between body weights at the different ages were positive but varied widely from low (0.02) to high (0.977). However, the genetic relationships between body weights from hatch to 8 weeks were high (0.921 to 0.992). This may suggest that selection for final body weight may be based on early weight records. The phenotypic and environmental correlations were generally high, positive and ranged from 0.572 to 0.995 and 0.776 to 0.999, respectively. Though, the magnitude of genetic and phenotypic correlations of body weights decreased with increase in age of Japanese quails. Thus, rapid progress in selection for improvement of body weight of the Japanese quail may be

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.

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