oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Photostimulation of male broiler breeders to different photoperiods
MH Floyd, NC Tyler
South African Journal of Animal Science , 2011,
Abstract: The effect of photostimulation of male broiler breeders (n = 144) to different photoperiods (8-h control and 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 14 and 18 h) applied at 20 weeks of age, on age at first semen production, testis weights, as predicted by comb area, and semen characteristics at the reported age at first egg of females provided the same photostimulation photoperiods, as well as semen characteristics during the production cycle and comb area and testis weights at 51 weeks, was investigated. Photostimulation photoperiod did not affect age at first semen production, sperm motility, morphology or predicted testis weights. Sperm concentration, at the reported age at first egg of females on the same photostimulation photoperiod, decreased with increasing photostimulation photoperiod. Large variation in the male response to photostimulation was observed, however, photostimulation to 12 h or higher resulted in reduced variation in the age at first semen production. Males provided with the longer photostimulatory photoperiods had smaller testis weights at 51 weeks of age, although this was not associated with decreased sperm concentration, increased abnormal sperm morphology or reduced comb area. When male and female broiler breeders are reared on the same lighting regimen, initial male reproductive potential is not adversely affected, provided that the photostimulation photoperiod does not exceed the saturation daylength of 13 h, above which, sperm concentration is lower at the reported female age at first egg, which could negatively affect egg fertility near peak production, and the onset of adult photorefractoriness appears to be advanced, which could negatively affect egg fertility towards the end of production.
Abrupt or gradual increases in photoperiod for broiler breeders
PD Lewis, RM Gous
South African Journal of Animal Science , 2006,
Abstract: Cobb 500 broiler breeder females (n = 832), which had been raised to achieve a typical 20-week body weight of 2.1 kg, were subjected to an abrupt or gradual increase in photoperiod to determine the effects on reproductive performance. One group (n = 416) was reared on 8-h photoperiods till 19 weeks and abruptly transferred to 16-h photoperiods. Another group (n = 416) was reared on 8-h photoperiods and given an initial increase to 12 h at 19 weeks, then weekly increments of 1 h to reach 16 h at 23 weeks. Both groups were reared in light-proofed facilities to 23 weeks and then moved to curtain-sided housing and maintained on 16-h daylengths to 60 weeks. There were no significant differences between the two lighting groups for age at sexual maturity, total egg production, egg mass output, mean egg weight to or body weight at 60 weeks. However, the birds given a single abrupt increment had a higher peak rate of lay whilst those given a gradual increase in daylength had better egg production at the end of the laying cycle. Broiler breeders transferred from closed rearing to curtain-sided adult accommodation (similar to that in which a large proportion of broiler breeders are housed) respond similarly to abrupt and gradual increases in daylength as do birds maintained throughout in controlled environment accommodation, and modern genotypes have similar responses to early genotypes. South African Journal of Animal Science Vol. 36(1) 2006: 45-49
Effect of Probiotic on Some Physiological Parameters in Broiler Breeders  [PDF]
Khalid H. Sultan,Saeb Y. Abdul- Rahman
International Journal of Poultry Science , 2011,
Abstract: The study was conducted to evaluate the effect of probiotic diet supplementation on some physiological parameters in Broiler Breeders. 30 Cobb Breeder hens were used (46 week aged), divided into 3 groups (10 hens each). The 1st group was reared on standard ration (control), the 2nd and the 3rd groups were given 10 and 20 gm of probiotic/kg ration for 4 weeks. The results revealed that the probiotic treatment causes a significant increase in LH and FSH serum levels (3rd group) and in T3 levels in (2nd and 3rd group) as compared with control group at p<0.05. Also the probiotic treatment causes a significant decrease in serum triglyceride levels and a significant increase in serum Uric acid level as compared with control. The above effects reflected in improvement of the egg weight, yolk weight and egg production % as compared with control. In conclusion, the probiotic supplementation of Broiler Breeders diet will improve the hormonal status and enhance the productivity.
The Influence of Density and a Partially Shadowed Layer on the Behaviour and Welfare of Broiler Breeders in Battery Cages During Laying
饲养密度和鸡笼局部遮光对肉种鸡产蛋期行为与福利的影响

ZHAO Yang,ZHAO Ya-jun,LI Bao-ming,SHI Zheng-xiang,
赵阳

动物学研究 , 2006,
Abstract: This study compared the behavioural differences of broiler breeders reared under two different densities (Singly-caged: 1 600 cm2 per hen; Paired: 800 cm2 per hen),and in shadowed cages with a half-covering layer on their tops versus controls in order to evaluate the laying preferences of the species in dark versus light regions. The results showed that singly-caged broiler breeders displayed turn-around and head-scratch behaviours more than paired breeders,while singly-caged breeders presented wing-flap behaviours less than paired breeders. Single and paired breeders spent both more time eating in cages which were partially covered than those in control cages. Singly-caged breeders were more likely to lay in the dark region in shadowed cages than paired breeders. These results suggested that broiler breeders exhibited normal behaviours more often when raised in a larger living space and in shadowed cages. Although stocking density has more impact on behaviour and welfare for broiler layers than light environment,being shadowed can reduce overcrowding effect and may alleviate the worse welfare appearance for caged broiler breeders.
Persistence and Transmission Pattern of Avian Adenovirus-4 in Broiler Breeders  [PDF]
S. Ashraf,S. A. Malik,K. Naeem
Pakistan Journal of Biological Sciences , 2000,
Abstract: This study was undertaken to investigate the persistence of Avian Adenovirus-4 (AAV-4) in broiler breeders after the infection of Angara Disease (AD) and also to study its transmission pattern in the progeny. In the affected breeders the presence of AAV-4 was detected in organs of embryonated eggs and egg albumen derived from breeders at 30, 37 and 44 weeks of age, using Dot- ELISA. Shedding of the virus was found to be at its peak at the start of the laying period, decreasing successively thereafter. It has been proposed to vaccinate the breeders against AD to protect the progeny and eliminating the carriers so as to prevent the virus from circulating in the population.
Effect of dietary levels of methionine + cystine on performance of broiler breeders
Gomes, Paulo Cezar;Lima, Cristina Amorim Ribeiro de;Calderano, Arele Arlindo;Rostagno, Horacio Santiago;Albino, Luiz Fernando Teixeira;
Revista Brasileira de Zootecnia , 2011, DOI: 10.1590/S1516-35982011000500011
Abstract: the objective of this experiment was to evaluate levels of methionine + cystine levels for broiler breeders from 40 to 60 weeks of age. it was used 288 cobb broiler breeders, distributed in a randomized experimental design with six levels of methionine+ cystine in the diets (0.39; 0.47; 0.55; 0.63; 0.71 and 0.79%), eight repetitions and six breeders per experimental unit. the diets were isocaloric and isoprotein (2,850 kcal me/kg and 12.58% cp) and oferred at a fixed amount (155 g) per bird. for the entire studied period, by using polynomial analysis, it was observed a quadratic effect of methionine + cystine levels on the percentage of egg production, on number of eggs per hen housed, on number of eggs per hen and egg weight. there was also a linear effect on shell weight when it was calculated in relation to egg weight. the total methionine + cystine requirement for broiler breeders was calculated at 0.521% for percentage of egg production and number of eggs per hen, which corresponds to a daily intake of 808 mg of methionine + cystine/day. the digestible methionine + cystine requirement for broiler breeders was estimated at 727 mg for laying percentage and number of eggs per hen.
Factors Affecting Egg Production in Broiler Breeders from Start to Peak of Production
M. Elahi Torshizi,F. Eftekhari Shahroudi,H. Kermanshahi
Research Journal of Biological Sciences , 2012,
Abstract: A study was conducted to determine the effect of environment, nutrition and management on egg production of broiler breeders from start to peak of production. Rearing and production records of 11 Arian broiler breeder flocks, in 3 farms between 1993 and 2000, including age of broiler breeder, age of maturity, flock number, farm number, density, feeder space/hen, body weight at 20, 22 and 24 weeks, protein and energy intake/day and week, cumulative feed intake in each age, weekly body weight, season effect, diet energy and presence or lack of canal under waterers were used. All records processed in excel software and transferred to JMP 3.1.2 software for analysis. Records tested for normality and then analyzed with multiple regression analysis procedure. The results of the current study indicated that, age of broiler breeders has a dramatic effect on egg production. By delaying age of maturity after 24 weeks, uniformity and egg production in Arian broiler breeders increased. Canals under waterer in some of the farms had a negative effect on mean egg production (63 vs 52%). In the seasons of spring and autumn, mean egg production was higher than those of summer and winter (80.03, 81.08, 50.16 and 60%, respectively). The result showed that body weight at 24 weeks is a better indication of subsequent flock performance than body weight at 20 or 22 weeks. By increasing age and protein intake from 23 to 27 g/hen/day, egg production decreased. Conversely, by increasing age and energy intake, egg production increased. Under the conditions of this study, it was concluded that protein intake should not be increased from 23g/hen/day at this period. Heavier broiler breeders, who get more energy intake/day, may produce more eggs too.
Factors Affecting Egg Production in Broiler Breeders from Start to Peak of Production
M. Elahi Torshizi,F. Eftekhari Shahroudi,H. Kermanshahi
Research Journal of Biological Sciences , 2008,
Abstract: A study was conducted to determine the effect of environment, nutrition and management on egg production of broiler breeders from start to peak of production. Rearing and production records of 11 Arian broiler breeder flocks, in 3 farms between 1993 and 2000, including age of broiler breeder, age of maturity, flock number, farm number, density, feeder space/hen, body weight at 20, 22 and 24 weeks, protein and energy intake/day and week, cumulative feed intake in each age, weekly body weight, season effect, diet energy and presence or lack of canal under waterers were used. All records processed in excel software and transferred to JMP 3.1.2 software for analysis. Records tested for normality and then analyzed with multiple regression analysis procedure. The results of the current study indicated that, age of broiler breeders has a dramatic effect on egg production. By delaying age of maturity after 24 weeks, uniformity and egg production in Arian broiler breeders increased. Canals under waterer in some of the farms had a negative effect on mean egg production (63 vs 52%). In the seasons of spring and autumn, mean egg production was higher than those of summer and winter (80.03, 81.08, 50.16 and 60%, respectively). The result showed that body weight at 24 weeks is a better indication of subsequent flock performance than body weight at 20 or 22 weeks. By increasing age and protein intake from 23 to 27 g/hen/day, egg production decreased. Conversely, by increasing age and energy intake, egg production increased. Under the conditions of this study, it was concluded that protein intake should not be increased from 23g/hen/day at this period. Heavier broiler breeders, who get more energy intake/day, may produce more eggs too.
Modeling energy utilization in broiler breeders, laying hens and broilers
Sakomura, NK;
Revista Brasileira de Ciência Avícola , 2004, DOI: 10.1590/S1516-635X2004000100001
Abstract: the factorial approach has been used to partition the energy requirements into maintenance, growth, and production. the coefficients determined for these purposes can be used to elaborate energy requirement models. these models consider the body weight, weight gain, egg production, and environmental temperature to determine the energy requirements for poultry. predicting daily energy requirement models can help to establish better and more profitable feeding programs for poultry. studies were conducted at unesp-jaboticabal to determine metabolizable energy (me) requirement models for broiler breeders, laying hens, and broilers. these models were evaluated in performance trials and provided good adjustments. therefore, they could be used to establish nutritional programs. this review aims to outline the results found at unesp studies and to show the application of models in nutritional programs for broiler breeders, laying hens, and broilers.
Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages
Almeida, JG;Vieira, SL;Reis, RN;Berres, J;Barros, R;Ferreira, AK;Furtado, FVF;
Revista Brasileira de Ciência Avícola , 2008, DOI: 10.1590/S1516-635X2008000200003
Abstract: this study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. eggs were incubated in a single-stage experimental incubator. a number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. after each count, hatched chicks were removed from the hatcher. data were submitted to analysis of variance using measures repeated. a significant interaction between breeder age and incubation time was found. the total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. eggs from old breeders hatched later as compared to young and intermediate-age breeders. more than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.