首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 312 毫秒
1.
This study aimed to characterize the local chickens and their production systems and to investigate the opportunities for improvement. The study was carried out in 18 villages in northern Jordan with the participation of 120 households. Data were collected by individual interviews and surveys supported with structured questionnaires. A scoring system was developed to study the effect of different levels of management on chicken performance. The main reasons for keep local chickens were egg production and generation of income. The main features of the production systems were improper housing and inadequate hygiene. Newcastle disease, predators, and parasites were the main causes of flock losses. Purchasing rate was controlled by the chickens’ phenotype, sex and age, and by season of year. The average flock size was 41.6 (±32.9) chickens per household, with a hen:cock ratio of 6.4:1. The average effective population size was 15.35, which indicated a high rate of inbreeding (5.52%). The main selection criterion adopted by farmers was egg production. There were positive significant correlations (p < 0.001) between management level and chickens’ performance. Hatchability, survivability, flock size, number of clutches, egg weight and egg mass were the major parameters that improved significantly with improvement in management level. Local chickens fulfil significant functions in the livelihood of rural smallholders; however, many constraints affected the efficiency of the production systems. Solutions should start with improving the management practices and establishing an effective breeding system.  相似文献   

2.
Three similar flocks of broiler breeder parent chickens that had been given live infections bronchitis (IB) vaccines during rearing were injected at 20 weeks of age with three different oil emulsion vaccines: a commercial monovalent Newcastle disease (ND) vaccine (flock A); an experimental bivalent vaccine containing ND and infectious bursal disease (IBD) components (flock B); and an experimental trivalent vaccine containing ND, IBD and IB components (flock C). One week after vaccination 40 hens from flock A and 40 from flock C were taken to the laboratory and their egg yields individually recorded. At 37 weeks of age they were challenged by aerosol exposure to virulent IB virus. The egg production dropped significantly in the hens from flock A but not in the hens from flock C. On the farm, flock C showed a higher mean IB virus antibody titre four weeks after vaccination but titres rose in all three flocks indicating the presence of active IB virus infection. No differences in egg yields were found between the three farm flocks.  相似文献   

3.
Peracute onset of disease was reported in a 42-wk-old broiler breeder flock that was presented by error with feed containing monensin at approximately seven times the approved level for broiler chickens. Morbidity and mortality were extremely high, and the affected chickens displayed feed refusal, decreased water consumption, and severe paralysis that ranged from abnormal gait to a complete inability to move. During the first 10 days postingestion of the suspect feed, mortality in hens reached 13.7% and 70.9% in the roosters. Hen day production decreased from 67% to 3% in the same period of time. A total of 638 g/ton of monensin was detected in suspect feed samples by one laboratory and 740 g/ton in a second laboratory. Twenty-one days after removal of the suspect feed, the mortality rate returned to normal levels in both hens and roosters, albeit feed consumption and egg production remained extremely low, which prompted the company involved to eliminate the flock.  相似文献   

4.
In humans, metabolic complaints may be associated with a failure in one of the body hormone or enzyme systems, a storage disease related to lack of metabolism of secretory products because of the lack of production of a specific enzyme, or the breakdown or reduced activity of some metabolic function. Some of these disorders also occur in poultry, as do other important conditions such as those associated with increased metabolism, rapid growth or high egg production that result in the failure of a body system because of the increased work-load on an organ or system. These make up the largest group of poultry diseases classified as metabolic disorders and cause more economic loss than infectious agents. Poultry metabolic diseases occur primarily in two body systems: (1) cardiovascular ailments, which in broiler chickens and turkeys are responsible for a major portion of the flock mortality; (2) musculoskeletal disorders, which account for less mortality, but in broilers and turkeys slow down growth (thereby reducing profit), and cause lameness, which remains a major welfare concern. In addition, conditions such as osteoporosis and hypocalcaemia in table-egg chickens reduce egg production and can kill.  相似文献   

5.
A cross-sectional survey investigating the contribution of free-range village chickens to household economies was carried out in four administrative districts within 60km of Accra. Answers were provided by 101 men and 99 women. Nearly all respondents claimed to keep chickens for meat, with a far smaller percentage claiming to keep them for egg production. Over 80% of respondents kept chickens to supplement their incomes. The proportion of the flock eaten varied between administrative areas (p=0.009 and p=0.027), although this was possibly a consequence of differences in consumption patterns between occupation of the respondent, land area cultivated and flock size. The proportion of chickens sold varied as a result of differences in flock size (p=0.013), the proportion sold increasing with number of birds in the flock. Respondents generally agreed that chickens could be sold without difficulty. A majority of chicken sales were from the farm gate, directly to consumers or traders. Sales were on demand or when the owner needed money. Money from the sale was kept by the owner of the chicken and the money was spent on personal needs. The proportion of the flock sold varied between administrative areas (p=0.025) and occupation of the respondent (p=0.040). Respondents describing animal production as their main occupation tended to have greater reliance on chicken sales for their income. Consideration is given to estimating the offtake from the flock and the financial contribution to the household.  相似文献   

6.
Two field occurrences of protein-deficiency disease were reported in turkeys and chickens. The disease caused unthriftiness, poor growth, and the exhibition of pica in flocks of 15-week-old pedigree large white turkeys, and it resulted in a sharp drop (18%) in egg production in a flock of 60-week-old white leghorn layers. In each case, the disease was cured by replacing the protein-deficient diet with a protein-sufficient one.  相似文献   

7.
In each of two trials, 80 commercial leghorn-type pullets were separated into two treatments with four replicates of 10 chickens in each treatment. Forty pullets were designated as controls and received no inoculation, whereas the remaining 40 pullets received the 6/85 vaccine strain of Mycoplasma gallisepticum (MG) at 10 wk of age. Hen-day egg production, egg weight, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded weekly in each trial through an entire laying cycle of 43 wk. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. No significant difference was observed between the treatments for 43-wk means for hen-day egg production, for any of the monitored egg or eggshell quality parameters, or for the number of extra large, large, medium, small, pee wee, or undergrade egg sizes. A significant (P < or = 0.05) difference was observed for the number of jumbo-sized eggs between the two treatments. Results of this study suggest that vaccination of commercial layer chickens at 10 wk of age with 6/85 strain MG does not detrimentally impact egg production, egg size distribution, or ovary/oviduct function as evidenced by selected egg parameters monitored in this study.  相似文献   

8.
1. Production-induced osteoporosis in caged laying hens is thought to represent a major constraint to continued genetic development. 2. The relationship between body weight, egg production, skeletal abnormalities characteristic of osteoporosis, femur calcium and bone histology was examined in a flock of ISA Brown layers from 16 to 68 weeks of age. 3. Experiment 2 examined a flock of Lohmann browns for skeletal abnormalities characteristic of osteoporosis at 45 weeks of age and the severity of abnormalities was then related to body weight and production between 18 and 45 weeks of age. 4. Average body weight declined in the ISA flock between 35 and 45 weeks of age, which correlated with a loss of skeletal calcium reserves (15% to 20%) and with the induction of osteoporosis. Between 42 and 68 weeks of age, birds were able to replenish femur calcium levels. 5. Birds in the Lohmann flock showing severe skeletal abnormalities at 45 weeks of age experienced weight loss between 27 and 31 weeks of age, which was associated with a decrease in egg production of 18%. After 35 weeks of age, egg production of these birds recovered to similar levels as unaffected or mildly affected birds. 6. It seems likely that better standardisation of the equilibrium between growth, skeletal reserves, food intake and egg production can reduce osteoporosis, as well as improving the productive potential of modern laying strains.  相似文献   

9.
Erysipelas was diagnosed in a layer breeder flock in Sweden in 2002. Although vertical transmission of Erysipelothrix rhusiopathiae has not been previously described in chickens, the potential of erysipelas infection to adversely affect hatching eggs was of concern. To clarify the possible impact of erysipelas on hatching eggs and their progeny, an experiment was done using 200 hatching eggs collected from the infected flock. The eggs were incubated for 21 days, and the egg shells, infertile eggs, dead-in-shell embryos, and a sample of day-old hatched chicks and blood samples from 5-day-old chicks were cultured for E. rhusiopathiae. In addition, after 28 days of grow-out, the male chickens were euthanatized and cultured for the bacterium, and the remaining female chickens were placed as a backyard flock and observed over a 4-mo period. Bacteriological test results of the above-mentioned samples were negative for E. rhusiopathiae. Mortality rates were not excessive, and no clinical symptoms of erysipelas were observed during the period of observation. The result of the investigation suggests that in layer breeder chickens, E. rhusiopathiae is not vertically or egg transmitted and that the disease outbreak in the parent stock had no adverse impact on the quality of hatching eggs in terms of increased embryo mortality.  相似文献   

10.
The course of a disease due to Salmonella pullorum in laying chickens is described. The experimental application of enrofloxacin (Baytril) at a dosage of 100 mg/l drinking water for 10 days resulted in a stop of the mortality rate, increment of egg production and reduction of Salmonella excretion. A recurrence of the disease was observed in the fifth week following the end of treatment with high mortality and decreasing egg laying. The treatment lead to a short-dated success but a permanent elimination of the germ from the flock was not achieved.  相似文献   

11.
We determined the flock sizes and rates of loss caused by different factors in broody-hen chicks (BHC) up to 60 days of age on 600 randomly selected smallholdings in Bangladesh. The smallholders were beneficiaries of a village poultry production chain called ‘Smallholder Livestock Development Project-2’ (SLDP-2) which was undertaken with the financial assistance of the Danish International Development Agency (DANIDA). For estimating survival time of BHC, we observed chicks in 80 smallholdings. SLDP-2 aims at ameliorating poverty among women by poultry rearing at village level; in total, 104,000 key rearers, constituting 96% of all of the beneficiaries of the SLDP-2 area, were enrolled in 26 upazilas (a lower administrative unit of Bangladesh). A key rearer is a smallholder who rears at least five ‘Sonali’ (RIR × Fayoumi) and some indigenous (desi) chickens in a semi-scavenging system. Sonali chickens are supplied from the development project, and have higher egg production while the broodiness of the desi hens is exploited to get chicks hatched for future stocks; thus, the chicks hatched and reared to 60 days old at key rearers’ households are called BHC. In this study 32% of the smallholders had BHC each month. At the beginning of a month, the median number of chicks in a flock was 8, and the mean survival time was 50.5 days. Incidence rates of loss of BHC from disease, predation, selling and slaughtering were 0.102, 0.086, 0.009 and 0.002 per chick-month at risk, respectively. The major predators were crows, mongooses and eagles with incidence rates of loss being 0.018, 0.016 and 0.010 per chick-month at risk, respectively. Colibacillosis (both single and mixed infections) contributed to the death of 21% of dead BHC collected; Newcastle disease and salmonellosis contributed to the next highest (14 and 12%) proportional mortalities.  相似文献   

12.
The relationship between delayed onset of oviposition and involution of the bursa of Fabricius is described. Chickens studied were 26 weeks of age and had not come into production. The bursae of nonlaying chickens were compared with those of age-matched chickens that had laid the first egg 1, 9 to 11, or 24 days before. The bursae from the nonlaying chickens were similar in weight and morphology to the functional bursae of immature pullets. Bursae of laying chickens, even on the day of the first egg, were markedly involuted. Age of the chicken was not a factor in determining bursal involution. The onset of egg production was directly related to bursal involution.  相似文献   

13.
试验旨在为北京油鸡品系选育、配套利用和科学养殖提供基础数据。选用北京油鸡纯系母雏534只,开展快慢羽群体的鉴定,并对比快慢羽母鸡羽毛发育、生长和繁殖性能的差异。北京油鸡保种群出雏时按照主翼羽与覆主翼羽的相对长度表型特征鉴别,将其分为快慢羽亚群,其中快羽包括K1（主翼羽长于覆主翼羽5 mm以上）和K2（主翼羽长于覆主翼羽2~5 mm）,慢羽包括M1（主翼羽与覆主翼羽等长或主翼羽长于覆主翼羽2 mm以内）、M2（主翼羽短于覆主翼羽）和M3（主翼羽未长出）。6周龄时通过PCR方法进行再次鉴定快慢羽。7 d内每隔1 d测量1次主翼羽与覆主翼羽羽长;7~42 d每隔1周测量1次;1~8周每周测定体重,9~18周每隔1周测定体重;产蛋期根据个体产蛋记录统计群体开产日龄、个体产蛋数以及连产相关性状等产蛋性能。结果表明,北京油鸡初生雏鸡快慢羽表型鉴定结果与通过PCR方法鉴定的结果一致,快羽鸡占总数的25%,慢羽鸡占75%,慢羽鸡又以M2为主,有少量M1和M3。21日龄以内快羽鸡的主翼羽羽长显著高于慢羽鸡（P<0.05）;28日龄时,M1和M2型慢羽鸡的主翼羽长度与快羽鸡差异不显著（P>0.05）,但是M3仍显著短于快羽鸡（P<0.05）。与慢羽鸡相比,快羽鸡70日龄后体重显著增加（P<0.05）,且开产日龄显著提前（P<0.05）,但是43周产蛋数较低（P<0.05）;快羽鸡除蛋形指数显著高于慢羽鸡外（P<0.05）,其他蛋品质指标均无显著差异。综上,快慢羽北京油鸡在生长和产蛋性能上有一定差异,在选育方向和生产管理中应有所差异化,包括加强慢羽品系早熟性即开产日龄的选育和调整快羽品系育成期饲料能蛋水平等。  相似文献   

14.
Live Mycoplasma gallisepticum (MG) vaccines have been USDA approved and licensed for use in commercial layer chickens since 1988; however, egg production and egg quality data exist only for the F strain of MG. Information pertinent to the effects of ts-11 MG on egg and eggshell quality parameters, as well as egg size distribution, is lacking. In this study, pullets were inoculated at 10 wk of age with ts-11 strain MG and placed in biological isolation units at 10 birds/unit. Hen-day egg production, eggshell strength, Haugh unit score, pimpling incidence, and blood/meat spot incidence were monitored and recorded in each trial through a 45-wk production cycle. Further, eggs from all treatments were collected daily, Monday-Thursday, and individually weighed. Results of this study indicate that no significant difference was observed between the treatments for the parameters measured or for egg size distribution. Therefore, these data should lessen producers' concerns pertaining to the impact of ts-11 strain MG on egg production, egg and eggshell quality parameters, and egg size distribution.  相似文献   

15.
Thirty blood samples were collected randomly from each of the 38 breeder-broiler farms in Jordan. Serum samples were examined using indirect ELISA for specific antibodies to avian influenza virus. The overall true flock-level sero-prevalence of avian influenza was 71% (95% CI: 55,83). Positive flocks had 2-30 sero-positive chickens and half of flocks had >20 sero-positive birds. The number of sero-positive flocks varied in the studied localities with more sero-positives in farms located within the migratory route of migratory wild fowl. The examined broiler-breeder flocks had no clinical signs, or noticeable decrease in egg production; mortalities were within the normal range (0.1-1%). The number of positive sera/flock correlated with flock size. There were a no significant (Pearsons r=0.21, p=0.21) correlation between positive flocks and age. A non-pathogenic AI virus infects broiler-breeder farms in Jordan. Wild local and migrating birds might promote the further spread of this virus in Jordan and other countries.  相似文献   

16.
Reproduction data of 8689 ewe records spread over 40 years (from 1960 to 2000) representing 2952 breeding Barki ewes were used in this study. The flock belonged to the Desert Research Center in Egypt. Flock dynamics of nine age groups (2–10 yrs) were assessed. Two parameters were used to evaluate flock dynamics, net reproduction rate (Ro) (number of ewe- lambs reaching joining age and produced by each ewe during its lifetime in the flock) and intrinsic rate of increase (rm) (flock growth when no resource is limiting). Age of ewe had a highly significant (P < 0.01) effect on number of ewes lambing per ewe joined (EPJ), number of lambs born per ewe joined (LBJ), number of lambs weaned per ewe joined (LWJ) and number of ewe lambs reaching joining age per ewe joined (LEJ.J). All estimates tended to increase with dams age up to four years and decreased thereafter. The results of Ro and rm showed that the studied flock must consist of 5 age groups to maintain its size and replace itself. It may be recommended to cull the breeding ewe at the age of 6 years to accelerate genetic improvement.  相似文献   

17.
不同饲养方式对蛋鸡生产性能和蛋品质的影响   总被引：2，自引：0，他引：2  
本试验旨在研究不同饲养方式对蛋鸡生产性能和蛋品质的影响。选取400只22周龄如皋黄鸡,随机分为两组,分别进行常规笼养和室外林地放养,每组200只,每组4个重复,每个重复50只。试验期为126d（3－7月）,饲养至40周龄时进行蛋品质测定。结果表明,126d饲养期内,放养组产蛋数和产蛋率均显著低于笼养组（98.61vs106.5,78.3%vs84.5%;P〈0.05）;280日龄放养组鸡蛋的蛋形指数为1.35,显著高于笼养组的蛋形指数1.30（P〈0.05）。蛋壳强度、蛋壳厚度方面,放养鸡蛋和笼养鸡蛋差异不显著（P〉0.05）;放养组鸡蛋的哈氏单位和蛋黄颜色显著高于笼养鸡蛋（P〈0.05）。  相似文献   

18.
1. Data from 9 experiments in which broiler breeder pullets had been photostimulated at two or more ages were integrated to produce a model to predict age at 50% egg production following a single increase in photoperiod during rearing. 2. It was clear that the photosexual response in broiler breeders was strongly influenced by the feed allowance and hence the rate of prepubertal growth. Regressions for birds given either a constant photoperiod or a single increase indicated that mean age at 50% lay advances by 2 d for every 100-g increase in body weight at 20 weeks. 3. The general response of broiler breeders was similar to that previously reported for egg-type pullets, but with important changes in the ages at which the birds progressed from one physiological state to the next, depending on body weight. 4. Broiler breeders, unlike modern egg-type pullets, exhibit juvenile photorefractoriness and, depending on their body weight, require up to 20 weeks to dissipate this (faster growth allows quicker dissipation). As a consequence, a group of birds grown to a typical weight of 2.1 kg at 20 weeks do not start to be photoresponsive until about 10 weeks and are not uniformly responsive until 19 or 20 weeks. A transfer to a stimulatory photoperiod before a bird has dissipated photorefractoriness causes a delay of about 3 weeks in its sexual development, and this results in a bimodal distribution of ages at maturity when a flock is photostimulated between 10 and 20 weeks. 5. Once photosensitive, the response of broiler breeders to an increment in photoperiod is between 0.50 and 0.65 of that observed in ISA Brown egg-type pullets. However, a flock of broiler breeders with typical feed restriction starts to mature spontaneously under the influence of the initial photoperiod from about 25 weeks. 6. There is a difference of only 1 to 3 d in age at 50% egg production between a flock transferred to 11 or 12 h followed by further increases to 15 or 16 h and one increased abruptly to one of these photoperiods, and so this model can be used to predict maturity in a commercial flock of birds even though they are likely to be given a stepped, rather than a single, increase in photoperiod.  相似文献   

19.
A pleiotropic effect of a mutant haemoglobin type in chickens   总被引：1，自引：0，他引：1  
The growth rate, viability, and reproductive parameters of a mutant haemoglobin type in chickens were compared with that of normal and heterozygous types. There were no significant differences in the parameters of growth rate, adult body weight or the reproductive parameters of egg weight, fertility, percentage hatch‐ability or sexual maturity. Percentage egg production was significantly depressed in the mutant type compared with normal or heterozygote.  相似文献   

20.
本试验旨在研究饲粮粗蛋白质水平对济宁百日鸡繁殖性能及初生雏鸡器官指数和血清生化指标的影响,以确定41~48周龄济宁百日鸡饲粮粗蛋白质需要量。采用单因素完全随机试验设计,选用40周龄体重接近、产蛋率无显著差异(P0.05)的健康济宁百日鸡产蛋种鸡525只,随机分为5个处理,每个处理5个重复,每个重复21只鸡。各处理分别饲喂粗蛋白质水平为13%、14%、15%、16%和17%的试验饲粮。预试期7 d,试验期56 d。结果表明:1)饲粮粗蛋白质水平极显著影响了平均日粗蛋白质摄入量(P0.01),平均日粗蛋白质摄入量随着饲粮粗蛋白质水平的增加而增加。2)饲粮粗蛋白质水平显著或极显著影响了种鸡的产蛋总数、种蛋合格数和出雏数(P0.05或P0.01)。3)44周龄种蛋孵化的初生雏鸡,种鸡饲粮粗蛋白质水平仅显著影响了心脏指数(P0.05);48周龄种蛋孵化的初生雏鸡,种鸡饲粮粗蛋白质水平显著影响了小肠指数(P0.05),极显著影响了肝脏指数和血清尿酸含量(P0.01)。综合试验结果,满足41~48周龄济宁百日鸡种鸡最佳繁殖性能的饲粮粗蛋白质水平为14.81%。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号