Temporal patterns of ovulation,oviposition and feeding of laying hens under skeleton photoperiods

1. The ovulation, oviposition and eating pattern of laying hens showed that the second light period in the 2L:12D:2L:8D skeleton photo‐period is interpreted as the start of the subjective day.

2. This interpretation is independent of the light period during which the animals are serviced.

3. During each of the 2L periods about one‐third of the total food is eaten, the other third is eaten during the 8D period: little or nothing is eaten during the 12D period.     

Alterations in uterine contractility during the oviposition cycle in domestic hens

1. The potencies of several neurohypophysial hormones were examined at different times during the oviposition cycle in an in vitro fowl oxytocic assay.

2. Uterine tissues were removed 2 h before (—2h‐OP), immediately after (Oh‐OP) and 5 h after (+5h‐OP) spontaneous oviposition. In addition, uterine tissue was removed immediately after oviposition was induced, by administering prostaglandin E₂ 2 h before an expected oviposition (Induced‐OP).

3. The rank order of oxytocic potencies for the peptides was arginine vasotocin=vasopressin>oxytocin>mesotocin. The sensitivity of the uterus to the hormones was Oh‐OP = Induced‐OP> — 2h‐OP= +5‐OP.

4. These results suggest that uterine sensitivity to neurohypophysial hormones changes during the oviposition cycle in domestic fowls.     

Effect of photoperiod on the mean oviposition time of two breeds of laying hen

1. Oviposition times were recorded for brown and white egg‐laying hybrids under 8, 10, 13 and 18 h photoperiods.

2. Mean oviposition time for both breeds was advanced relative to dusk by approximately 0.5 h for each 1 h extension of photoperiod.

3. Mean oviposition time for the brown egg hybrid was 1.2 to 1.4 h earlier than that of the white egg hybrid under each lighting regimen.

4. A genetic difference in phase setting of the Open Period for Luteinising Hormone (LH) release is the likely reason for the difference in mean time of lay of the two breeds. The difference is possibly one between brown and white hybrids generally, rather than between the particular varieties of hen used in this trial.

5. The proportion of the day in which eggs are laid is shorter under long photoperiods presumably because light at the end of the photoperiod inhibits the pre‐ovulatory surge of LH.     

Stress-induced oviposition delays in laying hens: duration and consequences for eggshell quality

1. This study investigated relationships between the timing of stress, duration of oviposition delays and consequences for eggshell quality, in 2 experiments with ISA Brown hens. 2. Periods of up to 6 h of environmental stress (relocation from an individual cage to a larger one containing 3 unfamiliar hens), commencing up to 4.5 h before predicted oviposition time, reliably induced oviposition delays. Many hens still retained their egg when stress ended. 3. Ovipositions that occurred during stress were never delayed for more than 3.0 h beyond the expected time. Ovipositions that occurred after the period of stress ended usually did so after <1 h if the delay at the end of stress was less than about 2.4 h. Delays that ended either during stress or <2 h after stress ended were classified as short-term. 4. If an oviposition delay was more than about 2.4 h when stress ended, the egg concerned was usually laid much later, after a delay of 7 to 15 h. Delays that ended >5 h after stress ended were classified as long-term. 5. Eggs delayed long-term were white-banded and the subsequent egg was slab-sided, or occasionally soft-shelled. Short-term delays often caused eggshell dusting with varying amounts of superficial calcification. Hence, duration of oviposition delay affects both the number of abnormal eggshells and the degree of abnormality. 6. The present findings are of potential importance to both the egg industry and breeders, because abnormal eggshells cause downgrading and can impair embryonic development. Also, numbers of abnormal eggshells and degree of abnormality can be used as indicators of environmental stress.     

Effect of calcium with and without probiotic,lactose, or both on organ and body weights,immune response and caecal microbiota in moulted laying hens

A total of 72 laying hens were used to investigate the effect of probiotic and lactose on body weight loss, tibia ash, antibody production against sheep red blood cell (SRBC), heterophile‐to‐lymphocyte (H/L) ratio and gut microbiota in a common moulting method for 14 d. Hens were randomly allocated to 6 experimental groups consisting of (i) full feed (FF), (ii) feed withdrawal (FW), (iii) FW with calcium (Ca), (iv) FW with Ca and offering 7 g/lit lactose in drinking water (CaL), (v) FW with Ca and offering 1 g/lit probiotic in drinking water (CaP), and (vi) FW with Ca and offering a mixture of lactose and probiotic in drinking water (CaLP). The results showed body weight loss in all FW groups were more than 25% that was significantly higher than FF group (p < 0.05). The relative organ weights of hens in FW groups were lower than FF group; especially, it was significant for liver and ovary (p < 0.05). No significant difference was observed between all groups for tibia ash. The highest H/L ratio was related to FW group and offering Ca and lactose numerically and probiotic alone significantly resulted in decrease of this ratio (p < 0.05). The results also showed no significant difference for antibody production against SRBC among experimental groups. The highest coliform bacteria numeration observed in FW group and lactose could significantly reduce this population (p < 0.05). Lactic acid bacteria (LAB) numeration demonstrated a significant difference among treatments, so that FF hens had higher LAB than others (p < 0.05). In addition, FW moulted hens had significantly lower LAB compared to other moulted hens (p < 0.05), except for Ca group. In conclusion, probiotic and lactose was effective in maintaining caecal microbiota balance and improving immunity in hens exposed to moulting.     

合生素对蛋鸡生产性能的影响

选择49周龄海兰褐蛋鸡1275只,随机分成5组,设3个正对照组、1个负对照组和1个试验组。试验组饲喂负对照组日粮（未加微生态制剂）基础中添加0．05％合生素,3个正对照组分别饲喂负对照组日粮基础中依次添加其他微生态产品M100、NW和GEK（营养标准相对负对照组低6％蛋白）的日粮。预试期30d,试验期30d,考察不同添加剂产品对蛋鸡生产性能的影响。结果表明,合生素添加组与M100添加组、负对照组、NW添加组和GEK添加组的生产性能相比．产蛋率分别提高4．82％、1．01％、1．78％和5．55％;蛋质量分别提高2．79％、3．77％、2．61％和3．82％。统计上均差异显著。合生素添加组和正负对照组的料蛋比分别是2．331、2．471、2．369、2、400和2．441。鸡蛋的平均合格率统计上均无显著差异。这表明,饲料中添加0．05％合生素可达到较理想的效果。     

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.     

Nesting and floor laying by domestic hens in a commercial flock

1. The nesting behaviour of broiler breeders was studied in a commercial flock of nearly 4000 birds kept on deep litter by tagging a sample of 200 hens. Use of nest boxes by tagged birds was recorded on 52 d over 34 weeks.

2. Forty hens were never observed in nest boxes and 33 others were recorded only in ground‐level boxes. These 73 birds were recorded significantly less often in nest boxes and more often apparently laying on the floor than others. Fewer of them perched during observations and they started doing so later than birds which used raised nest boxes.

3. These results suggested that there were consistent floor layers, which had difficulty reaching raised nest boxes, as found previously in experimental conditions. Many or all floor layers may, however, have used ground‐level boxes sometimes.

4. Hens were inconsistent in their use of particular nest boxes, and some even nested in two distinct areas.

5. Most individuals were, however, consistent in their reaction to one or more features of the nest boxes, including height, aspect and area. Individual choices for these features varied, so no boxes were used particularly heavily, with the exception of those at ground level.     

Genetic and phenotypic parameters for oviposition pattern traits in three selection lines of laying hens

1. Oviposition pattern and egg production traits were recorded in 471 hens from three selection lines. The lines, named according to their selection criteria, were egg number (EN), egg mass (EM) and egg mass, food consumption (EMFC).

2. Mean oviposition intervals within sequences were 24.9, 26.0 and 25.3 h, respectively in the EN, EM and EMFC lines. Corresponding heritability estimates were 0.52, 0.55 and 0.42.

3. The mean oviposition interval within sequences showed a positive genetic correlation with mean oviposition time.

4. Egg weight decreased significantly as the serial number within sequences increased, but only for sequences containing less than 18 eggs.     

甪里艾叶粉对蛋鸡产蛋性能与蛋品质的影响

为了研究甪里艾叶粉对蛋鸡产蛋性能与蛋品质的影响,试验选用50周龄健康状况良好、生产性能相近的海兰褐蛋鸡288只,随机分为四组,一个对照组,三个试验组,各组甪里艾叶粉分别添加0、1%、2%、3%,每组6个重复,每个重复12只鸡,预试期为7 d,试验时间为42 d。结果显示:(1)甪里艾叶粉对产蛋性能的影响:试验各组的平均日产蛋重均高于对照组(P0.05),分别提高了2.62%、3.58%、2.41%;随着艾叶粉添加量的增加,平均日采食量显著减少(P0.05),分别减少了2.76%、3.29%、3.62%;试验各组料重比均显著低于对照组(P0.05),分别降低了5.10%、6.63%、5.61%;随着甪里艾叶粉添加量的增加,产蛋率分别提高了2.85%(P0.05)、3.99%(P0.01)、5.93%(P0.01)。试验各组的蛋重与对照组均无显著差异(P0.05)。(2)甪里艾叶粉对蛋品质的影响:甪里艾叶粉可显著提高蛋的比重(P0.05),其中添加量为2%时差异极显著(P0.01)。各组间的蛋形指数、哈氏单位、蛋黄颜色差异均不显著(P0.05)。但试验各组的蛋白高度分别提高了8.92%(P0.05)、11.29%(P0.05)、10.21%(P0.05),哈氏单位则相应提高了4.51%、5.67%、5.69%。各组间的蛋壳指标差异不显著(P0.05)。试验各组的蛋白比率、蛋黄比率差异不显著(P0.05),随着甪里艾叶粉添加量的增加,蛋壳比率逐渐降低,其中添加2%和3%的甪里艾叶粉可显著降低蛋壳比率(P0.05)。甪里艾叶粉可以改善海兰褐蛋鸡的产蛋性能,蛋的比重和蛋白高度显著提高,蛋壳比率呈降低的趋势。     

Restricted feeding time and the behaviour of caged laying hens

1. Layers housed as pairs in cages were denied access to food from 07.30 to 15.30 h each day. Analyses of video records of daily activity patterns showed several behaviour changes compared with the patterns shown by similar birds allowed ad libitum (AL) access to food. 2. Birds given restricted access (RA) to food spent more time sitting and cage pecking while unable to feed than those feeding ad libitum during the same period. They also engaged in less agonistic pecking and the lengths of bouts of drinking were reduced during the period of food denial compared with the AL treatment. 3. After the food troughs were uncovered birds on the RA treatment showed fewer bouts of feather pecking but more bouts of drinking than the AL treatment. 4. Improvements previously reported in the efficiency of food utilisation of birds on the RA treatment may have been the result of additional sitting, although other activities requiring energy expenditure were performed. 5. It is concluded that restricting access to food on a time basis has both positive and negative effects on the welfare of caged layers.     

海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性及生长的影响

试验研究了在蛋鸡饲粮中添加不同剂量的海藻饲料添加剂对蛋鸡产蛋性能、血清抗氧化性、生长及营养物质消化率等的影响。选取360只26周龄体重相近的海兰褐蛋鸡,随机分为6组(每组3个重复,每个重复20只鸡),1组为空白对照组,饲喂基础饲粮;2组为抗生素对照组,在基础饲粮中添加0.005%的杆菌肽锌;3~6组为试验组,分别在基础饲粮中添加0.02%、0.04%、0.06%、0.08%的菊粉,0.025%、0.050%、0.100%、0.150%的大西洋海藻粉及相同剂量的铜藻粉(以下简称低、中、较高、高剂量海藻复合物),预试期7 d,正式试验期63 d。结果表明:海藻饲料添加剂对蛋鸡的产蛋性能有明显的剂量-效应关系,添加量为中等剂量海藻复合物(4组)时最佳且差异显著(P<0.05)。此添加量下,蛋鸡血清中超氧化物歧化酶活性最高(P<0.05)。试验中粗纤维的表观消化率随添加剂量的增加而增加(P<0.05)。低剂量试验组体重增长最多且差异显著(P<0.05)。试验结果表明,基础饲粮中添加中剂量海藻复合物作为蛋鸡饲料添加剂,能够显著提升蛋鸡产蛋性能及血清抗氧化性。     

复合微生态制剂对蛋鸡产蛋性能、蛋品质、血清生化指标和肠道形态的影响

试验在基础饲粮中添加由丁酸梭菌和屎肠球菌组成的复合微生态制剂,研究其对产蛋高峰期蛋鸡的产蛋性能、蛋品质、血清生化指标、肠道形态的影响.选取产蛋率和体重接近的40周龄健康的海兰褐蛋鸡400只,随机分成4组,每组5个重复,每个重复20只鸡.对照组蛋鸡饲喂基础饲粮,抗生素组在基础饲粮中添加200 g/t金霉素,试验1组、2组...     

Estimation of total genetic effects for survival time in crossbred laying hens showing cannibalism,using pedigree or genomic information

Mortality of laying hens due to cannibalism is a major problem in the egg‐laying industry. Survival depends on two genetic effects: the direct genetic effect of the individual itself (DGE) and the indirect genetic effects of its group mates (IGE). For hens housed in sire‐family groups, DGE and IGE cannot be estimated using pedigree information, but the combined effect of DGE and IGE is estimated in the total breeding value (TBV). Genomic information provides information on actual genetic relationships between individuals and might be a tool to improve TBV accuracy. We investigated whether genomic information of the sire increased TBV accuracy compared with pedigree information, and we estimated genetic parameters for survival time. A sire model with pedigree information (BLUP) and a sire model with genomic information (ssGBLUP) were used. We used survival time records of 7290 crossbred offspring with intact beaks from four crosses. Cross‐validation was used to compare the models. Using ssGBLUP did not improve TBV accuracy compared with BLUP which is probably due to the limited number of sires available per cross (~50). Genetic parameter estimates were similar for BLUP and ssGBLUP. For both BLUP and ssGBLUP, total heritable variance (T²), expressed as a proportion of phenotypic variance, ranged from 0.03 ± 0.04 to 0.25 ± 0.09. Further research is needed on breeding value estimation for socially affected traits measured on individuals kept in single‐family groups.     

Effect of dietary fibre on the performance of laying hens

1. In tests to determine whether gizzard weight could be influenced by dietary fibre concentrations, caged layers were fed on diets containing 15, 30 or 60 g pine shavings/kg diet.

2. As dietary fibre content increased, gizzard weight increased, but there was no effect on body weight, hen‐day production, egg weight, efficiency of food conversion, mortality, percentage of liver ether extract or egg shell breaking strength. Percentage of body ether extract tended to be lower when pine shavings were fed.     

脂肪粉对蛋鸡生产性能及相关理化指标的影响

为探讨饲料中添加脂肪对蛋鸡生产性能的影响,选择300日龄褐壳蛋鸡720只,随机分为3个处理,每个处理分为6个重复;试验组分别添加1％、2％脂肪粉,观测其对蛋鸡生产性能、生理变化及经济效益的影响。结果表明：添加脂肪,可以明显提高（P〈0．05）蛋鸡产蛋率（3．51～5．23％）和蛋重（6．03～8．69％）,降低采食量（3．63～3．67％）,改善饲料报酬（13．08～16．03％）;生理指标检测结果显示,试验组血清T3、T4含量显著提高（P〈0．05）,并且有提高GH、IGF－1含量趋势（P〉0．05）;综合经济效益分析,添加脂肪可以提高蛋鸡养殖效益（16．67～26．98％）。因此,杂粕型蛋鸡饲料中添加脂肪有实际意义。     

Effect of cross-wise perch designs on perch use in laying hens

1. The use of cross-wise perches by laying hens was investigated in 8 groups of 6 hens. During a period of 5 weeks each group was exposed to 4 different perch arrangements: a single straight perch of 60 cm (P60), a 30-cm perch crossing the middle of another 30-cm perch (P30 + 30), crossing a 45-cm (P45 + 30) or crossing a 60-cm perch (P60 + 30). 2. Perch arrangement influenced perch use. Perch occupancy (the mean number of hens using the perches) was lowest in the P30 + 30 treatment during daytime, evening and night. Perch occupancy was lower for P45 + 30 than for P60 + 30 during daytime and for P60 during evening and night. Perch occupancy did not differ between P60 and P60 + 30. 3. Perch utilisation (perch use per unit of total perch length provided) was lower for the three cross-wise perch arrangements than for P60, indicating that the area near the crossing was not used optimally. 4. There were indications that the process of taking roosting positions was more disturbed with cross-wise perches. 5. Legislation and guidelines about the minimal perch length per hen should be refined to take into account the arrangement of the perches. A perch of 30 cm cross-wise to another perch should not be included in the total amount of perch length provided to the hens. For longer cross-wise perches, the precise distance near the cross that should be excluded remains to be determined.     

合生素对蛋鸡生产性能及蛋品质的影响

在我国传统养殖生产中,抗生素一直被用作饲料添加剂来控制畜禽疾病和提高生产性能。但随着抗生素的大量使用,其带来的负面影响日趋严重。药物残留和耐药菌株的产生及畜禽产品质量的下降,已对畜牧业可持续发展和人类健康带来严重的影响。研制开发无公害和无残留的饲料添加剂替代     

Distribution of oviposition times of hens in continuous darkness or continuous illumination

The pattern of oviposition in continuous illumination or continuous darkness was investigated. In continuous darkness the mean time of all ovipositions was at 05.00 h and the mean time of the first oviposition of a sequence (C1) was 01.00 h. There was considerable variation and some ovipositions occurred throughout the 24 h. In contrast, the mean time of all ovipositions under continuous illumination was at 15.00 h and the mean time of C1 ovipositions was 12.30 h. When a diurnal rhythm of bird noise was audible during the light period (photoperiod 06.00 to 18.00 h or 18.00 to 06.00 h) in adjoining rooms, the birds in continuous illumination showed a mean time of oviposition at 09.30 h with mean time of C1 ovipositions at 06.30 h. For birds in continuous dark the corresponding mean values for the two treatments were 04.00 and 03.00 h for all ovipositions and 00.30 and 23.00 h for the first oviposition of a sequence. When continuous illumination was changed to continuous darkness and vice versa and the 12L:12D lighting treatments in the adjoining rooms were correspondingly reversed, the mean times of oviposition under continuous darkness occurred at 05.00 and 06.30 h, which was earlier by 3 and 4.5 h than the mean time of oviposition at 09.30 h under continuous lighting. The tendency of birds kept in constant darkness to lay eggs in the early morning hours was found to be persistent and repeatable. It is concluded that the findings are best explained by the entrainment of the circadian rhythm to an unidentified synchronising Zeitgeber, but only in continuous darkness.     

Effect of novelty and restraint on catecholamines in plasma of laying hens

1. The present study describes the effects of novelty (experiment 1) and restraint (experiment 2) on the catecholamine responses in laying hens.

2. Manual restraint caused a higher catecholamine response than mere visual exposure to a human being wearing yellow gloves and swinging his hand in the bird's home cage.

3. A relationship could be shown between adrenaline concentrations in plasma after a novel stimulus and the duration of tonic immobility.