The Effect of Selection for Shank Length on Sexual Maturity and Early Egg Weight in Single Comb White Leghorn Pullets

Lerner, I. Michael

doi:10.3382/ps.0250204

Cited by 15 publications

(8 citation statements)

References 11 publications

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“…These differences between sexes in response to selection reflect, in part, the there was a slight reduction in shank length of the index selected birds (line 630). It is interesting to note in this connection that the reverse selection process, selection for The length of shank (tarso metatarsus) was not affected by selection for heavy body weights (lines 610 and 620, Table 4); but long shanks, in chickens (Lerner, 1946) markedly increased body weight. Thus, the genetic correlation between the two characteristics may vary, depending on which one of the two is selected.…”

Section: Resultsmentioning

confidence: 97%

Influence of selection for body weight at different ages on growth of Turkeys

Abplanalp¹,

Ogasawara²,

Asmundson³

1963

British Poultry Science

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Section: Resultsmentioning

confidence: 97%

Influence of selection for body weight at different ages on growth of Turkeys

Abplanalp¹,

Ogasawara²,

Asmundson³

1963

British Poultry Science

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“…In SCWL, the problem is.not attaininlg early sexual maturify but achieving adequate skeletal size io accommodate early maturity (Lerner 1945). Leeson et al (1990) have shown thar total egg mass increases significantly with increases in mature body weight.…”

Section: Ggg)mentioning

confidence: 99%

Effects of age at photostimulation on reproductive efficiency and carcass characteristics. 2. Egg-type hens

Robinson¹,

Wautier²,

Hardin³

et al. 1996

Can. J. Anim. Sci.

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Increasing day length is the primary cue for the timing of sexual maturation in poultry. Typically, Single Comb White Leghorn (SCWL) pullets are reared under conditions of short days (8L:16D) until 18 wk of age. In this study, the effects of varying the age at photostimulation from 16, 18 or 20 wk of age were studied in terms of carcass composition at photostimulation and at sexual maturity, as well as reproductive performance.A flock of 1600 SCWL pullets (Shaver 288 strain) were housed in floor pens in light-tight facilities (8L:16D). All birds were provided with ad-libitum access to both feed and water. At 16 wk, 18 wk and 20 wk, 50 birds per treatment were moved to laying cages and provided to a photoperiod of 14L: 10D. An additional 288 birds per treatment were housed two birds per cage, and group egg production and feed consumption data were collected to 64 wk of age. At photostimulation (n = 20 birds per treatment) and on the day following the first oviposition, (n = 20 birds per treatment) birds were killed by cervical dislocation. All surviving hens were killed at 64 wk of age. All carcasses were studied in terms of selected organ weights and reproductive organ morphology. Birds killed at photostimulation and at sexual maturity were further studied for whole body carcass composition.Significant differences were found in dry matter, water, lipid and ash content among treatment groups at the age of photostimulation. As age at photostimulation increased, absolute weight of carcass fat, protein and ash increased. The percent carcass lipid content increased for all groups between photostimulation and sexual maturity with the 16 wk treatment group showing the largest increase. The time required to reach sexual maturity from the age of photostimulation decreased as the age at photostimulation increased. No significant differences were found in total egg production. The 16 wk group laid significantly smaller eggs. Delaying sexual maturity until 20 wk of age resulted in an increased prime sequence length and fewer pause days to produce approximately the same number of eggs as birds that were photostimulated at 16 wk of age. Key words: Chicken, egg-type hens, sexual maturity, egg production, carcass composition

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“…However, selection for egg weight in the 11W and LW lines was not effective in changing egg number. This situation is somewhat analogous to that reported by Lerner (1946) in which body size (or sexual maturity) appeared to limit the expression of genes for egg weight. In the present case, both characters are manifestations of metabolic efficiency, or the capacity of the bird for the production of total egg mass.…”

Section: Resultsmentioning

confidence: 47%

“…The relationships between November egg weight and shank length has not been specifically studied. Lerner (1946) found that the phenotypic correlations of shank length with beginning egg weight (mean weight of the first io eggs laid) and January egg weight were o29 and o3o respectively, while the phenotypic correlation between shank length and December body weight was o52.…”

Section: Characters Studiedmentioning

confidence: 99%

Concurrent inbreeding and selection in the domestic fowl

Shultz

1953

Heredity

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The Effect of Selection for Shank Length on Sexual Maturity and Early Egg Weight in Single Comb White Leghorn Pullets

Cited by 15 publications

References 11 publications

Influence of selection for body weight at different ages on growth of Turkeys

Influence of selection for body weight at different ages on growth of Turkeys

Effects of age at photostimulation on reproductive efficiency and carcass characteristics. 2. Egg-type hens

Concurrent inbreeding and selection in the domestic fowl

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