scholarly journals Heritability, Maternal Effects and Nicking in Relation to Sexual Maturity and Body Weight in White Leghorns

1947 ◽  
Vol 26 (5) ◽  
pp. 508-514 ◽  
Author(s):  
L.N. Hazel ◽  
W.F. Lamoreux
Keyword(s):  
Body Weight ◽  
Maternal Effects ◽  
Sexual Maturity ◽  
White Leghorns

Single crossing between White Leghorn and Australorp

1958 ◽  
Vol 9 (6) ◽  
pp. 842 ◽  
Author(s):  
JA Morris ◽  
F Skaller
Keyword(s):  
Body Weight ◽  
Artificial Insemination ◽  
Sexual Maturity ◽  
Egg Production ◽  
The Body ◽  
White Leghorn ◽  
Reciprocal Crosses ◽  
Related Data ◽  
Single Crossing ◽  
White Leghorns

Egg production and related data are presented for 1520 pullets resulting from nine generations of single crossing between White Leghorns and Australorps. Both types of reciprocal crosses were consistently superior to the better of the parental breeds (White Leghorn) in hatchability, chick viability, and egg production. This superiority became still more apparent when pure and crossbred half-sisters were compared. Crossbreeding was not effective in improving the viability of adult birds or the body weight, the latter remaining intermediate between that of the two pure breeds. The number of days required to reach sexual maturity was decreased as a result of crossbreeding. The crossbreds showed less variation in egg production and included in their sample a much smaller percentage of extremely low-producing pullets. A comparison between the two types of crossbreds shoved differences in individual years, but when viewed over the whole period of the experiment the only consistent differences were the superior hatchability and higher fertility, under artificial insemination conditions, when the White Leghorn served as the dam. There were no significant differences in production characters between the two types of crossbreds when housed on deep litter.

scholarly journals DOMINANCE AND EPISTASIS IN HETEROSIS OF WHITE LEGHORN STRAIN CROSSES

1987 ◽  
Vol 67 (3) ◽  
pp. 663-680 ◽  
Author(s):  
R. W. FAIRFULL ◽  
R. S. GOWE ◽  
J. NAGAI
Keyword(s):  
Body Weight ◽  
Sexual Maturity ◽  
Egg Production ◽  
Significant Contribution ◽  
Production Traits ◽  
White Leghorn ◽  
Cross Combination ◽  
Commercial Strain ◽  
Better Than

Four unrelated pure strains of White Leghorns including a grandparent strain from industry and 12 two-strain, 24 three-strain, 24 four-strain and 12 F2 strain crosses produced contemporaneously were used to examine the role of dominance and epistasis in heterosis. A control strain and a commercial strain were also included. For egg weight, the heterosis observed closely approximated that expected due to dominance alone. For sexual maturity and body weight, dominance was the major component of heterosis, but epistasis made a significant contribution — additive by additive (A × A) genetic effects for sexual maturity and 140-d body weight, and parental epistasis for mature body weight. Both dominance and epistasis played a significant role in heterosis for egg production traits. A × A, dominance by dominance (D × D) and additive by dominance (A × D) epistasis were all important for hen-housed egg production and hen-housed egg yield. For hen-day rate of egg production, A × A epistasis was significant only early in the laying year (to 273 d), A × D and D × D were significant to 385 d and in the full year (to 497 d); however, none (A × A, A × D and D × D) was significant near the end of lay (386–497 d). Overall heterosis estimates for full year egg production measured as hen-housed egg production to 497 d or hen-day rate from housing to 497 d clearly showed that on average two-strain crosses were superior to three-strain crosses which were superior to four-strain crosses which in turn exceeded the F2 crosses. Nevertheless, several three-strain crosses had performance for egg production that was equal to or better than the two-strain cross with the highest egg production. Thus, in commerce, where the level of egg production is of great economic importance, the testing and use of a specific three-way cross combination will usually result in a better commercial product. Key words: Heterosis, egg production genetics, epistasis, stocking rate, strain cross, White Leghorn

scholarly journals Occurrence and practical solvent possibility of gilts preinsemination anestrus

2010 ◽  
Vol 26 (1-2) ◽  
pp. 37-46 ◽  
Author(s):  
I. Stancic ◽  
M. Gagrcin ◽  
M. Jovicin ◽  
S. Jovanovic
Keyword(s):  
Body Weight ◽  
Sexual Maturity ◽  
Good Health ◽  
Reproductive Efficiency ◽  
Ovarian Activity ◽  
Genetic Traits ◽  
Paper Review

Gilts reproductive efficiency is one of the primary factors of successful piglets' production. This performance, among other things, is expresses by the number of pregnant gilts, with desirable genetic traits, body weight and age, sexual maturity status, and general good health, provided for the replacement of sows in primary herd. This goal is very difficult to achieve in practical conditions. The main reason is occurrence of prolonged preinsemination anoestrus (oestrus was not detected even after 8 months of age). This paper review the occurrence of prolonged preinsemination anoestrus, based on the results of our and study of other authors. All studies consistently show that, in most of these gilts, pubertal cyclic ovarian activity were established, that silent oestrus occurred in only 4% of the cyclic gilts, and that this problem can be solved by applying appropriate technologies for oestrus detection, and by treatment with adequate hormonal preparations.

scholarly journals Effect of Immediately-After-Birth Weaning on the Development of Goat Kids Born to Small Ruminant Lentivirus-Positive Dams

Animals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 822 ◽  
Author(s):  
Nalbert ◽  
Czopowicz ◽  
Szaluś-Jordanow ◽  
Moroz ◽  
Mickiewicz ◽  
...  
Keyword(s):  
Body Weight ◽  
Sexual Maturity ◽  
Linear Models ◽  
Small Ruminant ◽  
Negative Impact ◽  
Body Weight Gain ◽  
Mixed Linear Models ◽  
Daily Body Weight ◽  
The Mean ◽  
The Difference

A longitudinal study was carried out to investigate the influence of two different rearing systems of young kids on their development to sexual maturity. Kids born to small ruminant lentiviruses-infected (SRLV) female goats were split into two groups: the immediately-after-birth weaned group and the unweaned group. Kids’ body weight (BWT) was measured before the first consumption of colostrum, and then at the age of one week, and one, two, four, and seven months. The relationship between the rearing system and BWT at each age was investigated using mixed linear models adjusted for potential confounders. The mean BWT of kids of the immediately-after-birth weaned group was significantly lower at the age of one week, one month, and two months, and then the difference became insignificant. The mean daily body weight gain (DWG) was significantly lower in the immediately-after-birth weaned group during the whole first month of life, but then DWG in both groups became equal. Crude mortality rate did not differ significantly between groups. This study shows that weaning kids immediately after birth does not appear to have any negative impact on kids’ development except transient growth retardation, which is fully compensated until they reach sexual maturity.

scholarly journals Telomere dynamics from hatching to sexual maturity and maternal effects in the ‘multivariate egg’

2020 ◽  
Vol 223 (23) ◽  
pp. jeb232496 ◽  
Author(s):  
Francois Criscuolo ◽  
Roxanna Torres ◽  
Sandrine Zahn ◽  
Tony D. Williams
Keyword(s):  
Immune Response ◽  
Maternal Effects ◽  
Sexual Maturity ◽  
Negative Relationship ◽  
Individual Quality ◽  
Testosterone Treatment ◽  
Adult Females ◽  
Sexually Mature ◽  
Lps Treatment ◽  
Telomere Dynamics

ABSTRACTAvian eggs contain a large number of molecules deposited by the mother that provide the embryo with energy but also potentially influence its development via the effects of maternally derived hormones and antibodies: the avian egg is thus ‘multivariate’. Multivariate effects on offspring phenotype were evaluated in a study on captive zebra finches, by simultaneously manipulating maternally derived antibodies (MAb) by lipopolysaccharide (LPS) treatment of mothers and injection of testosterone into the egg yolk. LPS treatment had a positive effect on body mass growth at 30 days after hatching and immune response at sexual maturity, while egg testosterone treatment positively influenced immune response at fledging and courtship behaviour in sexually mature male offspring. Maternal effects are known to modulate offspring telomere length (TL). However, the multivariate effects of egg-derived maternal components on offspring telomere dynamics from hatching to sexual maturity are undefined. Here, we tested: (1) the effects of LPS and testosterone treatments on TL from hatching to sexual maturity (day 82); (2) how LPS treatment modulated TL over reproduction in adult females; and (3) the relationship between maternal and offspring TL. We predicted that TL would be shorter in LPS fledglings (as a cost of faster growth) and that TL would be longer in sexually mature adults after yolk testosterone treatment (as a proxy of individual quality). In adult females, there was an overall negative relationship between laying and rearing investments and TL, this relationship was weaker in LPS-treated females. In chicks, there was an overall negative effect of LPS treatment on TL measured at fledging and sexual maturity (day 25–82). In addition, at fledging, there was a Sex×LPS×Testosterone interaction, suggesting the existence of antagonistic effects of our treatments. Our data partially support the hypothesis that telomeres are proxies of individual quality and that individual differences in TL are established very early in life.

Utilization of heterosis in poultry

1958 ◽  
Vol 9 (4) ◽  
pp. 599 ◽  
Author(s):  
FHW Morley
Keyword(s):  
Body Weight ◽  
Genetic Variation ◽  
Genetic Variability ◽  
Sex Chromosome ◽  
Inbred Lines ◽  
White Leghorn ◽  
Egg Weight ◽  
Additive Genetic Variation ◽  
White Leghorns ◽  
Recessive Genes

Records were analysed of 500-day production, egg weight, 11-week and mature body weight, sex maturity, and broodiness of the crossbred progeny of inbred lines of Australorps mated to White Leghorns, and inbred lines of White Leghorns mated to Australorps. Clear differences between lines of both breeds mere found in most characters, indicating the presence of potentially useful amounts of additive genetic variation. Non-additive genetic variation was also found to be present in varying degrees in different characters. Because of the difficulties of developing and maintaining inbred stocks of poultry, and the importance of sex-linked characteristics in some commercial environments, a scheme is proposed which may enable heterosis to be exploited without the use of inbred material. The basis of this scheme is the combination of the White Leghorn sex chromosome, with varying proportions of Australorp and White Leghorn autosomes, in a new breed. Assuming that the heterosis observed in the F1 is due to elimination of certain biochemical blocks determined by recessive genes, the formation of the new breed should enable the methods of closed flock breeding to be used in material at a higher level of production, and likely to contain more genetic variability, than either parent breed.

The effect of feed restriction on sexual maturity and initial reproductive performance of broiler pullets under different light treatments

1969 ◽  
Vol 9 (39) ◽  
pp. 417 ◽  
Author(s):  
RAE Pym ◽  
R Sledge
Keyword(s):  
Body Weight ◽  
Reproductive Performance ◽  
Sexual Maturity ◽  
Feed Restriction ◽  
Restricted Feeding ◽  
Egg Weight ◽  
Laying Performance ◽  
The Mean ◽  
The Difference ◽  
Lighting Systems

An experiment was conducted to examine the effect of restricted feeding under two lighting systems during the rearing period on the initial laying performance of broiler type pullets. The rearing treatments were imposed at nine weeks of age, removed at 22 weeks and the trial was discontinued at 36 weeks of age. The feeding treatments (restricted versus ad lib.) were arranged factorially with the lighting treatments (decreasing versus increasing). Birds reared on restricted feeding reached sexual maturity 16 days later than full fed birds, ate 17 per cent less feed to 22 weeks and gained seven per cent less in body weight to 24 weeks of age and ten per cent less to 36 weeks. Birds reared under the decreasing lighting regime reached sexual maturity at the same age as those reared under increasing lighting, ate five per cent more feed during the rearing and laying periods and gained five per cent more in body weight to 24 weeks. The mean weight of eggs laid between 24 and 34 weeks of age from pullets subjected concurrently to decreasing lighting and restricted feeding was approximately two grams heavier than that of the other three treatment combinations. Mean egg weight was one gram greater in the restricted than in the full fed group, although the difference was not statistically significant. Laying mortality was lower in the restricted fed group than in the full fed group.

Maternal effects and Chicken Growth

1996 ◽  
Vol 1996 ◽  
pp. 20-20
Author(s):  
J. H. Catterall ◽  
G. E. Pollott
Keyword(s):  
Body Weight ◽  
Maternal Effects ◽  
Maternal Effect ◽  
Genetic Effect ◽  
Additive Genetic Effect ◽  
Breeding Lines ◽  
Broiler Production ◽  
Female Line ◽  
Male Line ◽  
Commercial Breeding

Previous research into the genetics of broiler traits in a commercial breeding operation found a significant maternal effect on juvenile body weight, at 32 days of age, in addition to the additive genetic effect (Morris and Pollott, 1995). Since no nurture or imitative behaviour occurs between the dam and offspring in modem broiler production, any maternal effects are likely to be conferred to the offspring via the egg. This study attempts to investigate the nature of these effects.Pedigreed eggs from two separate broiler breeding lines, one experimental male line and one experimental female line, were individually weighed prior to incubation. In total 2871 eggs were weighed, 1887 eggs from the experimental female line and 984 eggs from experimental male line.

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