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| Schmidt,GS; Figueiredo,EAP de; Ledur,MC; Alves,HJ. |
| This study used 300 females and 30 males with 36 weeks of age from the selected PP and control PPc maternal broiler lines. PP has been selected for heavy body weight (PC) and high egg production for eight generations. Fertile eggs were collected and weighed individually for 4 periods of 5 consecutive days at two-week intervals. In each period, a total of 960 eggs/line were identified and separated in groups of 240 eggs, and stored for later incubation. Embryo weight (PE) was evaluated at 9 (P9), 11 (P11), 13 (P13), 15 (P15), 17 (P17) and 21 (P21) days of incubation. The objective was to estimate the effect of selection on embryo development. Egg weight (PO) was similar between the two lines. The differences in PE were significant from P15 on, resulting in... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Correlation; Egg weight; Embryo weight; Genetic gain; Meat lines. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2003000200006 |
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| Avila,VS de; Penz Jr.,AM; Rosa,PS; Brum,PAR de; Guidoni,AL; Ledur,MC. |
| One thousand two hundred and ninety six Arbor Acres females and 144 males were used to study the influence of feeding time on sexual maturity and carcass composition. Treatments were: T1 = feeding at 6:30 am, T2 = 50% feeding at 6:30 am and 50% at 3:30 pm (dual), T3 = feeding at 11:00 am, T4 = feeding at 3:30 pm. Nutrition and management were as recommended to the commercial line. Variables studied were: sexual maturity at 5% production (SM), mean egg production percentage (PEP) body weight (BW), carcass composition, tibia weight (TIBW) and tibia calcium (Ca) and phosphorus (P) contents. Analysis of variance was used, and the means were compared using Student's t test. T2 females reached SM at 25.92 weeks, which was earlier (p<0.01) than the other... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Broiler breeders; Carcass composition; Egg production; Feeding time; Sexual maturity. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2003000300006 |
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| Schmidt,GS; Coutinho,LL; Figueiredo,EAP de; Ledur,MC; Alves,HJ. |
| Two paternal broiler lines (LL and LLc, originated from the same stock in 1998) of Embrapa Suinos e Aves genetic program were used. Line LL had been selected for eight generations for rapid growth while LLc had been mated randomly, without selection, as a control line. In the last generation, 30 males and 240 females were used in hierarchical matings with pedigree control to determine sire effect. The same number of birds were used, but matings were at random for LLc. Eggs of both lines were incubated and embryos were collected in different development stages (40, 45, 50, 55 and 60 hours after setting) in order to determine somite number (NOS). The number of evaluated embryos were 1,967 and 498 for LL and LLc, respectively. This study aimed to determine... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Genetic; Heritability; Selection; Somite. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2003000300003 |
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| Fialho,FB; Ledur,MC; Avila,VS. |
| A segmented polynomial model was used on several egg production curves in an attempt to analyze the differences between the curves in a more descriptive manner. Production curves from different commercial and experimental genetic lines of layers were used. The parameters of the model include the age and level of peak production, rate of decrease in production after the peak and time between start and peak of production. These and other derived variables were compared between the curves using contrasts. The methodology used allowed an easier interpretation of the curves, and the detection of differences in sexual maturity, uniformity and peak of production. This work validates the segmented polynomial model for use in future research dealing with analysis... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Egg production; Layers; Laying hens; Model. |
| Ano: 2001 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-635X2001000300002 |
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