Prevalence of keel bone deformities in Swiss laying hens

The goal of this study was to evaluate the prevalence of keel bone deformities of laying hens in Switzerland. The keel bones of 100 end-of-lay hens from each of 39 flocks (3900 in total) were palpated. On average, 25·4% of the hens had moderately or severely deformed keel bones and the overall prevalence including slight deformities was 55%. 3. Variation between flocks was considerable. Thus, the prevalence of moderately or severely deformed keel bones ranged from 6 to 48%, and the overall prevalence including slight deformities ranged from 20 to 83%. Aviary housing was associated with a higher prevalence of total, and severe or moderate deformations, compared with floor pens. There were no significant differences in the number of deformities between the different plumage colours, hybrids or perch materials.     

Influence of housing system and design on bone strength and keel bone fractures in laying hens

The main objectives of the study were to provide an accurate assessment of current levels of old breaks in end-of-lay hens housed in a variety of system designs and identify the important risk factors. Sixty-seven flocks housed in eight broad subcategories were assessed at the end of the production period. Within each flock, the presence of keel fractures was determined and the tibia, humerus and keel bones dissected for measurement of breaking strength. For each house, variations in internal design and perching provision were categorised and the effective heights of the differing structures recorded. All systems were associated with alarmingly high levels of keel damage although variation in mean prevalence between systems was evident with flocks housed in furnished cages having the lowest prevalence (36 per cent) despite also having significantly weaker bones and flocks housed in all systems equipped with multilevel perches showing the highest levels of damage (over 80 per cent) and the highest severity scores.     

Keel bone condition in laying hens: a histological evaluation of macroscopically assessed keel bones

The objective of the present study was to conduct a corresponding histological analysis of 162 macroscopically assessed keel bones (1: severe, 2: moderate, 3: slight, 4: no deformity). Four layer lines were used and hens were kept in furnished cages, small group systems (both allowing more activities due to the provision of perches) and an aviary system, which fully conformed to the EU standards. Investigations were carried out in the 3rd, 6th, 9th and 12th laying month of two experimental trials. In 97.9% of grade 4 keel bones, no histological deviations were found, whereas in keel bones manifesting deformities of grade 1 and 2, the predominant histological observation was the incidence of fracture callus material (FCM) and new bone in the form of woven bone. FCM was also detected in 50.9% of grade 3 keel bones, whereas in 40.7%, only s-shaped deviations of keel bones were found, which were related to extended pressure loading while perching activities rather than short-duration trauma. Histological analysis showed that keel bones of grade 1 and 2 were mainly attributed to traumatic origin and therefore associated with pain experience in layers. Grade 3 keel bones manifested either FCM as a result of trauma or adaptational deformities without any evidence of a preceding fracture in response to mechanical pressure loading and were most likely not associated with pain. Therefore, histological analysis was found to be a mandatory tool when evaluating grade 3 keel bones with respect to layers'welfare. Furthermore, this analysis corroborates the findings that in aviary systems deformities of keel bones are predominantly caused by painful fractures.     

Use of radiography to identify keel bone fractures in laying hens and assess healing in live birds

The aim of this study was to use radiography to assess and characterise naturally occurring keel bone fractures in laying hens and monitor live birds over several weeks to examine the healing process. Twenty-four Lohmann brown commercial laying hens with varying degrees of keel bone fracture were used in the study. Birds were radiographed regularly over six weeks and the radiographic features and changing appearance of keel bone fractures were evaluated. The radiographic characteristics of old and new fractures were categorised and indicated that 80 per cent of birds entering the study with new fractures had healed after 35 days and five birds had incurred new fractures irrespective of their original fracture status.     

Thermal panting and respiratory alkalosis in the laying hen

1. Changes in respiratory rate (f), rectal temperature (T_r ) and blood acid‐base values were measured in laying hens exposed to ambient temperatures (T_a) of 32, 35, 38 or 41 °G.

2. At T_a 32 °G there was no panting. At T_a 35 °G panting occurred without any increase in T_r but there was a slight alkalosis (pH 7.55).

3. At T_a 38 °G T_r increased and panting was accompanied by moderate alkalosis (pH 7.58).

4. At T_a 41 °G T_r increased considerably and severe alkalosis developed (pH 7.65).

5. From the relation between T_r , f and pH it is concluded that some degree of alkalosis is a normal response to panting in the laying hen.     

微生态益生菌粉在蛋鸡日粮中应用效果

在蛋鸡日粮中加入2～8％生物饲料添加剂——兹生态益生茵粉等量替代豆粕,以61周龄海兰褐鸡群为试验鸡群,通过7周的饲喂试验观察结果如下：饲料成本略有下降;鸡群料蛋比下降2．79～4．57％;能明显改善蛋鸡的产蛋性能,延迟蛋鸡产蛋后期产蛋率的下降速度,使只鸡每周可多盈利0．036～0．06元;能增加鸡蛋壳的颜色和硬度,加深鸡蛋黄的颜色和弹性;对去除鸡舍中的臭味有一定的效果。微生态益菌粉在蛋鸡饲料中的添加量以5～8％为宜。     

产蛋鸡卵母细胞卵黄生成受体(OVR)的研究进展

OVR介导大量的血浆蛋白被产蛋鸡吸收到生长的卵母细胞中,是卵黄前体进入卵母细胞的瓶颈。到目前为止发现它不仅与最丰富、最重要的卵黄前体极低密度脂蛋白(VLDL)、卵黄蛋白原(VTG)结合,还结合丛生蛋白、α2-巨球蛋白(α2-M)、受体相关蛋白(RAP)、乳铁蛋白、核黄素结合蛋白(ribBP)等,这些成分占蛋黄干物质的绝大部分。OVR发生突变的蛋鸡,不能繁殖,并且具有严重的高脂血症。它所内吞的VLDL的数量是蛋黄胆固醇含量的决定因素,因此期望通过调控OVR来控制蛋黄胆固醇的含量。     

The metabolism of labelled progesterone in the laying hen

Eight hours after administering 4–14C‐progesterone to laying hens four radioactive metabolites could be detected in the droppings. Excretion of labelled steroid products was still continuing 192 h after the injection. In blood a relatively high level of labelled progesterone was found 8 to 24 h after application. The last traces disappeared from blood after 72 h. Compared with mammals the hen metabolises progesterone at a slower rate.

Certain tissues were also examined 24 h after treatment. The adrenals showed a high level of labelled progesterone metabolites. The liver contained similar steroids as were found in the droppings. In the ovary, pituitary and skeletal muscle low or trace amounts of radioactive steroids were detected.     

光照与蛋鸡饲养的关系

1 光照的意义 光照是一门科学,要想养好鸡,就必须要懂得这门学问.在蛋鸡饲养上,光照与雏鸡发育、青年鸡生长、成年鸡产蛋等都有着极密切的关系.实践证明,光照的时数与强弱、光照的颜色与波长、光照刺激的起止时间、黑暗期是否连续或间断,都会对蛋鸡的成活率、生长发育、体成熟、性成熟、产蛋率以及繁衍后代的公母交配活动等方面,产生重要的影响.光照是蛋鸡饲养的重要的环境条件之一.换句话说,没有光照条件的环境,是不能进行蛋鸡饲养活动的.     

Voluntary food and calcium intake by the laying hen

Two experiments, each of 40 d duration, are described in which a diet rich in calcium (3.5% Ca) or one deficient in calcium (1% Ca), but with oyster shell offered separately, were fed ad libitum to four laying hens. The voluntary consumption of food and oyster shell was automatically recorded every 2 h. The hourly consumption of the high Ga diet increased during the afternoon while the daily pattern of consumption was modified by the position of the egg in the clutch.

When the low Ca diet was fed with oyster shell, the daily consumption was increased but the effect of the position of the egg in the clutch was reduced. The ingestion of oyster shell was very high between 16.00 and 20.00 h when egg calcification was in progress; after the last oviposition of the clutch this elevated level of intake remained though to a lesser degree. In relation to the stage of egg formation, the voluntary intake of oyster shell increased sharply between 4 and 12 h after the former oviposition.

These results confirm that the laying hen can discriminate between food and calcium intake. It seems that appetite for calcium is firstly related to light‐dark cycles with a modulation of the afternoon peak by ovulation and then egg shell calcification.     

Composition of crop and gizzard contents in the laying hen.

Crop and gizzard contents were analysed at six stages of egg formation. 2. The crop was empty during the day and full during the night while the gizzard contained a constant amount of dry matter. The water content of the crop did not change but that of the gizzard was at a minimum just after the ovulation and at a maximum 18 h later. 3. The osmotic pressure of the gizzard contents remained constant and close to that of the blood; that of the crop contents was almost isotonic at oviposition but hypertonic 18 h later. In both organs the pH of the liquid phase varied cyclicly with the egg formation and was lowest during egg shell deposition. 4. The Na+, K+ and Cl- contents of the crop liquid phase did not vary but Ca2+ increased with decreasing pH.Na+ and K+ were also constant in the gizzard liquid phase but Cl- and Ca2+ increased during shell formation. 5. It is concluded that the amount of HCl secreted by the proventiculus is related to egg shell deposition and that calcium solubilisation depends on microbial fermentation in crop and HCl secretion by proventriculus.     

Genetic variation in the time of oviposition in the laying hen

1. The distribution of oviposition times in modern layers is relatively narrow. Consequently, in management systems where hens have to compete for nestboxes, some eggs will be laid on the floor. 2. The purpose of this study was to investigate the possibility of using genetic methods to change oviposition time while maintaining a high production rate. 3. The mean oviposition times of 464 hens from three selection lines were calculated using time-of-lay records for every egg laid until the hens reached 51 weeks of age. 4. Heritability estimates for mean oviposition time were high for each of the three lines: 0.38, 0.68 and 0.78. 5. The three lines differed in terms of the genetic correlations between mean oviposition time and certain important production traits. It should, however, be possible to shift the mean oviposition time while maintaining a high production rate. 6. It is suggested that the spread in oviposition times be increased by performing divergent selection for mean oviposition time and by mixing the different genotypes in the same commercial flock, kept on the floor or in other non-cage systems.     

蛋鸡应激综合征的分析与应对

2006年7月份丹东市动物疫病预防控制中心接到一养殖大户蛋鸡死亡病例的报告,经现场观察和实验室检验、诊断,确诊为蛋鸡猝死性应激综合征。现将情况报告如下。     

生物鱼粉在蛋鸡生产中的应用

利用角质蛋白质进行氨基酸工业化生产,使废料资源化,保持生态良性循环,作为进口鱼粉的替代品在蛋鸡生产中应用。     

The effect of keel fractures on egg production,feed and water consumption in individual laying hens

1. The impact of keel bone fractures on egg production, egg weight and feed and water consumption in individual laying hens. A total of 165 Lohmann brown laying hens were obtained from a commercial farm that consisted of 105 with keel fractures and 60 without keel fractures.

2. After a 4-d period of acclimatisation, hens were individually housed and provided with ad libitum food and water for a 24-h period. The number of eggs laid, egg weight, feed and water consumption during this period were recorded. Keel bone strength was also assessed.

3. Hens free from keel fractures laid more eggs (91.7% vs. 84.9%) of significantly heavier weight (61.9 g vs. 60.2 g), ate less feed (139 g vs. 151 g) and drank less water (212 ml vs. 237 ml) than hens with fractures.

4. There was a significant positive association between keel fracture severity and water consumption, and a significant negative association between keel fracture severity and egg weight and keel bone strength.

5. This small-scale study on individual birds shows that keel bone fractures may have an impact on the economics of egg production.     

Feed formulation using phytase in laying hen diets

Lohmann LSL-Lite and Classic Brown laying pullets were reared and caged at the Agassiz Research Centre following recommendations of the management guides. At 30 wk of age, these hens were fed 1 of 5 diets per strain following the Lohmann nutrient recommendations. In addition to a control treatment, diets were formulated to contain 300 or 600 U/kg of phytase, with or without enzyme inclusion, where the phytase was assumed to cause the release of P, Ca, energy, and protein. Diets were changed at 45 wk to follow a phase-feeding program, but treatments remained the same. These dietary changes did not result in major changes in measures associated with P deficiency, likely because the management guides suggest P levels that largely exceed the requirements of the birds. Rather than adding high levels of inorganic P to layer feeds, the safety margin currently included in recommended dietary specifications could be provided by the addition of phytase. This would reduce the negative environmental effects of intensive poultry production that are associated with P excretion.