Peak Egg Production Research Articles

Editorial

IsaBrown pullets were obtained from a commercial breeder at 15 (Expt 1) and 16 (Expt 2) weeks of age and housed in either single-bird or multiple 5-bird cages in a high rise, windowless layer house in which temperatures were maintained below 30˚C by computerised control of fans and evaporative cooling pads. In Expt 1, they were fed either a grower diet or a pre-layer diet consisting of the grower diet containing additional calcium to 18 weeks of age and then maintained during lay to 56 weeks of age on diets containing either 160 or 180 g crude protein (CP)/kg. In Expt 2, they were fed the grower diet to 19 weeks of age and then 1 of 5 diets similar in all ingredients except that the lysine concentration varied between 7.35 and 8.95 g/kg in increments of 0.4 g/kg. The L-lysine HCl supplements were added in lieu of solka floc, an inert cellulose supplement. In Expt 1, mortality was low (2.25%), peak egg production was high (95–98%), and the mean rate of lay at 56 weeks of age was above 88%. The diet fed prior to lay had no significant effect on production during lay. Feed intake and egg production were similar for hens fed both dietary protein levels during lay, and egg weight and egg mass output were greater for hens fed the diet containing 180 g CP/kg. Hens in multiple-bird cages ate significantlyless feed for a significantly smaller daily egg mass output. In Expt 2, increasing the dietary lysine concentration significantly reduced feed intake and significantly increased lysine intake, egg shell breaking strength, and albumen height. Multiple-caged hens had a significantly lower hen-housed egg production as a result of a 7-fold increase in mortality compared with hens in single cages, due mainly to cannibalism. The daily lysine requirement formaximum egg production approximated 940 mg for hens in single cages and 975 mg for hens in multiple-bird cages.

Egg Production, Fertility, and Hatch Success of American Plaice Held in Captivity

The reproductive performance of individual female American plaice Hippoglossoides platessoides was monitored during a spawning season under laboratory conditions. The majority (74%) of females produced eggs at some point in a 2-month period (May–July) during which they were checked every 2 d for ovulated eggs. Most females produced several batches of eggs during an average production period of 26 d. Approximately 12% of the total number of eggs produced by each female were obtained in the first egg batch. There were periodic peaks of egg production for the group in increasing intervals at about 8, 20, and 34 d after the first eggs were collected. The mean relative fecundity was 1.5 × 105 eggs/ kg body weight, but there was no relationship between actual fecundity and either length or weight. The mean percentages of viable and fertile eggs were 44.7% and 13.7%, respectively. A significant decline in the percentage of fertile eggs was observed with time, such that percent of fertile eggs by the sixth batch was significantly (P < 0.05) lower than in the first batch. There was no significant decline in viable eggs with time, although there was a positive correlation (r = 0.72, P < 0.001) between viability and fertility. The number of larvae hatched from viable eggs varied widely during the spawning period with a mean hatch success rate of 23%. A significant positive correlation was observed between the number of larvae hatched and the percentage of fertile eggs (r = 0.82, P < 0.001).

Estudo da capacidade de combinação de linhagens de matrizes de frangos de corte, por meio da análise de fatores. Produção de ovos

Com o objetivo de determinar a capacidade de combinação de linhagens de matrizes de corte, por meio da análise de fatores, cruzamentos (dialelo completo) dentro das linhagens fêmea (PP, KK e VV) foram usados. As características analisadas foram: número de ovos da 24ª - 32ª(P1), 32ª - 40ª(P2), 40ª - 48ª(P3), 48ª - 56ª(P4), 56ª - 64ª(P5), 22ª - 66ª(P6), 32ª - 66ª(P7), 40ª - 66ª(P8), 48ª - 66ª(P9), 24ª - 40ª(P10), 24ª - 48ª (P11) e 24ª - 56ª (P12) semana de idade. Na análise de fatores foram usados dois fatores, sendo os fatores de significado definidos após a rotação. O fator comum 1 apresentou o maior peso para a característica P6, sendo, então, considerado o fator de produção. Na seleção de progenitores superiores com base no valor genético-aditivo, o progenitor VV foi o que mais se destacou. O híbrido superior para as duas características mais importantes, produção no pico de postura e produção total de ovos, envolve os mesmos progenitores, o PP e VV. A análise de fatores forneceu fatores com significado biológico e econômico, possibilitando maiores facilidades de uso e interpretação.

Use of hatch date for broiler breeder production planning

Data on 109 batches of broiler breeders belonging to six strains and bred in conventional sheds were analyzed to determine the possible influence of natural day length cycle phase on age at start of laying, at sexual maturity, and at peak egg production. The dependence of these variables on date of hatching was characterized by polynomial regression analysis. The resulting equations constitute simple, novel empirical models that are in keeping with current theory on the effects of photoperiod on sexual maturation, and should facilitate production planning in broiler breeder farms.

Biological parameters of Trichostrongylus colubriformis in Meriones unguiculatus

In a series of three experiments, 64 jirds, Meriones unguiculatus, were infected with 700 infective larvae of Trichostrongylus colubriformis for the study of several biological parameters of this laboratory host–parasite model. In jirds the third stage larvae of T. colubriformis were shown to reach the fourth larval stage by the Day 6 post-infection (PI). By Day 10 PI, all the worms harvested had reached the immature adult stage. All immature adult stages of T. colubriformis developed to sexually mature adult stage by Day 12 PI when the female worms showed developing eggs in their uteri. Developed eggs were observed in the uteri of females on Days 13 and 14 PI. The first eggs of T. colubriformis appeared in the faeces of jirds on Day 13 PI. The peaks of egg production were recorded between Day 21 and Day 31 PI. Immunosuppression of jirds infected with 700 L 3, by administration of dexamethasone from Day 57 to Day 94 PI led to increased faecal egg count when compared to untreated controls. All the worms were located in the small intestine. The jirds of dexamethasone treated group harboured higher number of adult worms than those of the untreated group. The number of adult worms was significantly higher in the first part of the small intestine than in the three other similar parts of the small intestine. The coefficient of correlation between the faecal egg count and worm number on the day of necropsy of jirds ranged between r = 0.58 and r = 0.89. Patent infections in jirds were maintained till the end of experiment on Day 100 PI, indicating that in this host and unlike other laboratory hosts, T. colubriformis is responsible for long lasting infections similar to what happens in domestic ruminants. The results of the present study suggest that the jird is a suitable laboratory model to study various aspects of this host–parasite relationship.

Variability in Stage I egg production and settlement of plaice Pleuronectes platessa, on the west side of the Isle of Man, Irish Sea

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 189:241-250 (1999) - doi:10.3354/meps189241 Variability in Stage I egg production and settlement of plaice Pleuronectes platessa on the west side of the Isle of Man, Irish Sea Richard D. M. Nash*, Audrey J. Geffen School of Biological Sciences, University of Liverpool, Port Erin Marine Laboratory, Port Erin, Isle of Man IM9 6JA, United Kingdom *E-mail: rdmnash@liv.ac.uk ABSTRACT: The variability in Stage I egg production and subsequent settlement of plaice Pleuronectes platessa L. on the west side of the Isle of Man, Irish Sea, was investigated over the period 1992 to 1998. This small spawning ground contributed approximately 0.6% of the total plaice egg production in the northern Irish Sea for 1995. The timing of peak egg production varied between years from approximately the middle of February to the end of March. The timing of peak egg production was related to the mean autumnal water temperature, with earlier spawning in warmer years. Egg production on the west side of the Isle of Man in 1995 was earlier than in the eastern Irish Sea, probably reflecting the slightly warmer water conditions in the central Irish Sea. The estimated Stage I egg production varied considerably between years, differing by a factor of 2.8 over all years. There was a positive relationship between the annual egg production and the numbers of individuals settling in Port Erin Bay. Interannual variation in abundance was greater at settlement than in either Stage I eggs or the size of the juvenile population in July. Higher inter-annual variability in the pelagic phase is dampened during the nursery ground phase. KEY WORDS: Irish Sea · Plaice · Egg production · Settlement · Variability Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 189. Publication date: November 26, 1999 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1999 Inter-Research.

Welfare and productivity of restricted broiler breeder females fed ad libitum or restricted after the peak of egg production

Welfare and productivity of restricted broiler breeder females fed ad libitum or restricted after the peak of egg production

Plagiorchis muris: recovery, growth and development in albino rats.

Metacercariae of Plagiorchis muris, obtained from naturally infected dragonflies, Sympetrum eroticum, successfully established in 4-week-old albino rats up to 14 days post-infection (p.i.) but by day 28 p.i. the recovery rate had significantly decreased. The genital primordia in excysted metacercariae were differentiated into those of metraterm, Mehlis' gland, ovary and cirrus pouch, with the primordial testes appearing on day 1 p.i. The vitellaria and eggs in the uterus were present in flukes on days 2 and 4 p.i., respectively. Mature flukes were established in the lower part of the small intestine on day 5 p.i., with the peak of egg production occurring on day 14 p.i. Growth of the flukes continued up to day 28 p.i.

Opioid involvement in behavior modifications of mice infected with the parasitic nematode, Nippostrongylus brasiliensis

Several studies have documented the opiate effects of parasitic infection on experimental animals. The current study examined the relationships between infection with the intestinal nematode, Nippostrongylus brasiliensis with analgesia and activity levels. Male white mice infected with N. brasiliensis displayed a significant increase in thermal latency thresholds that rose through the duration of infection and subsided with its termination. Analgesia first became apparent on day three-post infection but did not reach statistical significance (p < 0.05) until day 7 post infection. The maximum analgesia was reached on day 8-post infection and gradually declined. By day 15 post infection, there was no significant difference in the latency times between control and infected mice. The initial significant difference in latency roughly corresponded with the on set of egg production by the parasite. The peak difference in latency times and their subsequent decline also parallels peak egg production and the decline in egg production as the infection subsided. Both naloxone and naltrindole significantly reduced the latency times (p < 0.05) of infected mice. There was also a significant difference in total ambulatory activity levels between infected and control mice. Activity levels began to decline on the second day post infection but did not reach a statistically significant difference (p < 0.05) from the controls until 9th day post infection. Infected mice that were injected with either naloxone or naltrindole had a significantly higher activity level than the infected mice injected with saline.

Effects of Conventional Insecticides and Insect Growth Regulators on Fecundity and Other Life-Table Parameters of Micromus tasmaniae (Neuroptera: Hemerobiidae)

Effects of 3 conventional insecticides (methyl parathion, azinphos-methyl, cyper­ methrin) and 3 insect growth regulators (fenoxycarb, diflubenzuron, and tebufenozide) on life-table parameters of Micromus tasmaniae Walker were determined in adults derived from insecticide-treated larvae. The following parameters were compared with the control: sex ratio, longevity, sterility, and fecundity. Power analysis was used to increase the efficiency and the predictability of the life-table test. Diflubenzuron resulted in a higher proportion female lacewings. Longevity was reduced for females emerging from fenoxycarb- and diflubenzuron­ treated larvae. Total number of eggs was reduced for diflubenzuron- and fenoxycarb-treated lacewings, as weIl as the following generation oftebufenozide-exposed lacewings. Daily number of eggs was reduced for the diflubenzuron treatment. Peak egg production was increased for lacewings exposed to azinphos-methyl and was decreased for the following generation of tebufenozide-exposed lacewings. Diflubenzuron treatment resulted in an extended preovipo­ sition period. Oviposition periods were reduced for lacewings treated with fenoxycarb, di­ flubenzuron or azinphos-methyl as weIl as for the following generation of the tebufenozide treatment. The time to peak egg production was similar for all treatments. Methyl parathion, cypermethrin, and tebufenozide treatments showed no differences in any ofthe tested life-table parameters in the 1st generation. In summary, the insect growth regulators fenoxycarb and diflubenzuron had a more severe impact on life-table parameters than the 2 organophosphates and the pyrethroid. In future research, increased attention should be paid to long-term (e.g., the following generation) effects on life-table parameters.

An immune system switch in T cell lifespan at birth results in extensive loss of naive fetal T cells during the first week of postnatal life : Cahill R.N.P., Kimpton W.G., Washington E.A.,Dudler L., Trnka Z., Laboratory Fetal Neonatal Immunology, The University of Melbourne, Parkville, Victoria 3052, Australia [International Immunology 9(9), 1253–1258; 1997

Parents, and particularly mothers, can influence their offspring's development in non-genetic ways. Maternal effects can occur during the mothering phase as well as during the embryonic phase. Prenatal maternal effects in birds can be mediated by yolk steroid hormones that influence subsequent offspring development. Studies have focused mainly on the influence of laying females' living conditions on yolk hormonal contents, and rarely on the effects of individual characteristics. Here, we investigated prenatal influence of parent age on yolk steroid levels and on offspring phenotype. We compared Japanese quail at two different ages: at the beginning of their reproductive cycle (11 weeks old: age 1) and six months later, after egg production peak (37 weeks old: age 2). Egg composition, reproductive outcomes, and offspring growth, sexual development and behaviour were studied at both ages. We found that laying rate, fertility and chick survival rates declined between age 1 and age 2. Age 2 eggs had relatively lighter shells and higher yolk plus albumen contents; they also had lower testosterone contents. Age 2 offspring weighed more at hatching than did age 1 offspring; subsequently their growth patterns differed and their sexual development was more precocious. Age 2 offspring were less emotional than age 1 offspring when encountering a novel environment, and they appeared more sensitive to social separation. Our study shows, for the first time in a bird species, a strong impact of parental age on offspring phenotype, and especially on behaviour, an impact that is possibly mediated via modulation of yolk testosterone content.

The epidemiology of fasciolosis in the inter-Andean valley of Cajamarca, Peru

Fasciolosis is recognised as a major problem in dairy cattle in parts of Peru. A longitudinal study of dairy cattle in Cajamarca, Peru was used to determine the annual pattern of infection with Fasciola hepatica. After a gradual increase from January, peak egg production occurred in August/September and then dropped rapidly. Indirect indicators of infection, eosinophil counts and serum liver-enzyme activities, indicated that the major period of new infection in cattle occurred from December to May each year. Examination of snails demonstrated that, although there was no clear annual cycle in snail abundance, the majority of snails infected with cercariae were found between January and March. Climatological data indicated that there was sufficient moisture for development of the parasite during a limited period each year, coinciding with the period of maximum abundance of cercaria-infected snails, but that irrigation could substantially alter the amount of water available. Infections in tracer-calves decreased from December to September, with little or no infection occurring between June and August, but suggesting that there could be significant infection prior to December. Thus a defined annual cycle of infection was observed, where cattle acquired infection from December to May and this infection matured to produce peak egg counts in August/September which were then available to infect the intermediate host for the next cycle of infection.

Application of Non-linear Models to Egg Production Curves in Chickens.

Four mathematical models (compartmental (C), modified compartmental (MC), Wood (W), and Adams-Bell (AB)) were fitted to different patterns of egg production data in laying hens to compare the fits of these models.The egg production data were obtained from the two lines which were founded on a basis of divergent selection for egg quality traits. Egg production data of individual hens were classified in six patterns. The average hen-day rates of lay were calculated for every 10 days from the first egg for each pattern. The comparison of fits was based on the R2 adjusted for degrees of freedom and Akaike's information criterion (AIC).The fits of C, MC and AB models were similar for the egg production data showing a general pattern of curve. However, the model parameters could not be estimated by these three models for the data whose patterns showed abrupt decreases after the peak of egg production. The data in which the period from the first egg to the peak of egg production was short and linearly decreased after reaching the peak showed poor fits of the models. The parameters of all patterns could be estimated by the W model, but the fits were lower than those of the others.

A test for photorefractoriness in high‐producing stocks of laying pullets

1. Pullets of 2 high-producing commercial stocks (both brown-egg layers) were exposed to 5 different lighting patterns between 18 and 72 weeks to test the hypothesis that photoperiods used in commercial lighting programmes early in the laying year may be unnecessarily long and, by accelerating the development of photorefractoriness, may contribute to the decline in egg production observed after the initial peak. Two rooms of 288 pullets were allocated to each treatment. 2. The rate of lay observed with a Step-Up treatment which gave increases in photoperiod from 8L:16D at 18 weeks to 15L:9D at 27 weeks of age was not significantly different from that of treatments which held the birds on 11L:13D during peak egg production but gave increments up to 15L:9D later in the laying year. 3. A control group maintained on 11L:13D from 20 to 72 weeks laid 295 eggs per bird housed and a further group held on 8L:16D from 0 to 72 weeks laid 284 eggs per bird. These yields were lower than the Step-Up treatment (299 eggs) but show the potential of modern hybrid stocks to lay prolifically even without light stimulation. 4. It is concluded that the stocks tested in this experiment showed no advantage when given lighting programmes in the first laying year which were designed to minimise the adverse effects of photorefractoriness.

Temperature Effects on the Timing of Striped Bass Egg Production, Larval Viability, and Recruitment Potential in the Patuxent River (Chesapeake Bay)

The relationships between egg production (spawning behavior), larval growth and survival, and environmental conditions that larvae encounter were investigated in the Patuxent River tributary of Chesapeake Bay in 1991. Striped, bass (Morone saxatilis) eggs and larvae occurred predominantly above the salt front where conductivity was ≤800 μmhos cm−1. There were three prominent peaks in egg production, each coinciding with increasing temperatures. Estimated growth rates of 6-d, otolith-aged cohorts, which ranged from 0.15 mm d−1 to 0.22 mm d−1 (mean=0.17 mm d−1), were not demonstrated to differ significantly from each other. Observed zooplankton densities and temperature did not significantly affect growth rates. Stage-specific cumulative mortalities of combined cohorts were calculated for eggs (Zstage=0.20=18.1%), yolk-sac larvae (Zstage=5.80=99.7%), and first-feeding larvae (Zstage=2.95=94.8%). The very high mortality of yolk-sac larvae suggests that dynamic during this stage may have had a major impact on subsquent recruitment. Cohort-specific mortality rates of larvae were variable, ranging from Z=0.045 d−1 to 0.719 d−1, and were strongly temperature-dependent. Cohorts that experiented average temperature 20°C during the first 25 d after hatching had significantly higher mortality rates than those which experienced intermediate temperatures. Estimated hatch-date frequencies of larvae ≥8 mm SL indicated goo, very good, and very low potential recruitments for cohorst spawned during early-season (April 2–11), mid-season (April 12–24) and late-season (April 25–May 5), respectively. Because seasonal temperature trends and fluctuations are unpredictable, striped bass females cannot select a spawning time that guarantees their offspring will be exposed to optimum temperatures. Consequently, selection may have occured for spawning over a broad range of temperatures and dates, a behavior insuring that some larval cohorts will encounter favorable temperatures.

Different patterns of faecal egg output following infection of Scottish Blackface lambs with Ostertagia circumcincta

Faecal nematode egg counts were monitored in 184 Scottish Blackface lambs during natural exposure to a mixed, predominantly Ostertagia circumcincta infection and 12 lambs were selected which showed consistently zero (low count group; nine lambs) or consistently positive faecal egg counts (high count group; three lambs). These lambs were then treated with anthelmintic and challenged with 50 000 infective larvae of O. circumcincta and monitored thrice-weekly for 38 weeks; they were then re-challenged with another 50 000 infective larvae of O. circumcincta and monitored for a further 8 weeks. All sheep gave positive egg counts following deliberate infection. However, there was considerable variation among sheep in the size and timing of the peak in egg production. In particular, the pattern of mean values for faecal egg counts was different in the two groups. Egg counts were lower in the later periods of the extended infection in both groups of sheep. During the first half of the extended infection, egg counts were lower in sheep from the low count group, but during the second half of the infection the pattern was reversed and egg counts were lower in sheep from the high count group. There was a weak positive correlation between egg counts following anthelmintic treatment and 28 days exposure to natural infection and egg counts 28 days after a deliberate infection. Egg counts in the later stages of the deliberate infection were strongly but negatively correlated with egg counts following natural infection. The results of these studies show that differences in egg count following natural infection can be reproduced in experimental infections and that there is substantial variation in the pattern of egg production over time in different sheep. They also suggest that naturally resistant lambs are better able to delay worm development than naturally susceptible lambs.

Effects of choice feeding on the performance of village chicken after the peak of egg production

An experiment was carried out with village chicken at the laying stage raised on the semi-intensive system on three feeding treatments with each of 30 birds replicated three times. The three feeding treatments were: layer mash only, layer mash and corn as choices and choices of a high protein concentrate and corn. Feed and protein intake was significantly higher for birds on the layer mash and lower for birds on the choices of a high protein and corn diet. There was no differences in egg production for the birds fed the layer mash either alone or a choice with corn but lower for the birds on the choices of a high protein feed and corn. There was no differences in egg weight and gross efficiency for all treatments. The practice of choice feeding layer mash and corn could be adopted by farmers rearing village chicken under the semi-intensive system due to the lower cost.

Comparative Demography of Two Cucurbit-Attacking Fruit Flies, Bactrocera tau and B. cucurbitae (Diptera: Tephritidae)

Bactrocera tau (Walker) and Bactrocera cucurbitae (Coquillett) have similar geographic distributions, host ranges, and damage levels in China. The species were similar in duration of immature stages, preoviposition periods, and mean generation time, but differed in survivorship of their immature stages and adults, net reproductive rate, and schedule of egg production. Net reproductive rate was 58.8 and 72.9 for B. tau and B. cucurbitae , respectively. Egg production peaked at an earlier age for B. tau , and B. cucurbitae lacked a clear peak of egg production. B. tau stopped laying eggs at an earlier age than B. cucurbitae . The population growth rates of these two species are similar.

Selection for High and Low Threshold Body Weight at First Egg in Broiler Strain Females.: 4. Photoperiodic Drive in the Selection Lines and in Commercial Layers and Broiler Breeders

A two-way selection program, carried out for high and low threshold BW at onset of lay (ThrWtLay), decreased photoperiodic drive of the high line (HL) relative to the low line (LL). Photoperiodic drive in modern broiler breeder females was compared to layer females in experiments using the HL and LL lines, a commercial layer cross (LX), and a commercial broiler breeder female line cross (BX). Treatment groups were: NS, natural decreasing light to 20 wk, followed by natural light supplemented to 16 h daily with artificial light; NN, natural decreasing light to end of experiment; DD, dark room from hatch to end of experiment; ND, natural decreasing light to 20 wk, dark room thereafter. Under NS, mean age and BW at first egg was greater for the HL line than for the LL line. The difference increased by a further 8.9 d and 217.5 g under NN. Similarly, under NS, mean age and BW at first egg was greater for BX than for LX, and the difference increased by a further 22.6 d and 256.1 g under NN. These interactions indicate greater photoperiodic drive of LX and LL stocks relative to the HL and BX stocks. Prepeak and peak egg production (EP) was greatest for the LX, lower for the LL, and lower yet for HL and BX. Photoperiodic drive may be of major importance in determining prepeak and peak EP. Except for the DD treatment, age and BW of the LX cross at first egg were virtually identical across treatments, those of the LL line were similar, whereas those of the HL and BX stocks showed differences. Similarly, EP curves of the LX cross were virtually identical across treatments, those of the LL line were relatively uniform, but those of the HL and BX stocks again showed great differences. Standard deviation and coefficient of variation of peak EP were very low for the LX cross, still low, but significantly greater for the LL line, and significantly greater yet again for both HL and BX stocks. Thus, increased photoperiodic drive may also be associated with greater stability of reproductive performance. Selection for early onset of lay on release from feed restriction may provide a means of increasing photoperiodic drive and consequent reproductive performance of broiler breeders.

Effect of Delayed Light Stimulation on Egg Production by Broiler Breeder Pullets of Low Body Weight

This study attempted to determine if broiler breeder pullet flocks exhibiting mean body weights lower than the standard for lighting (2.04 kg or 4.5 lb) should be light stimulated at the recommended age (20 wk) or when the standard weight is attained. Measures of the initiation of production (age at first egg, 20% and 50% HDP) were delayed an average of six days in low weight pullets lit at the recommended age. Delaying lighting until the standard weight was attained delayed measures of the initiation of production on an additional three days, but did not delay peak egg production. Relative to low weight pullet lit at the recommended age, delayed lighting increased post-peak, total, and settable (egg weight >50g or >21.1 oz/dozen) egg production; however, mean egg weights did not differ. Delayed lighting also improved feed efficiency of low weight pullets to a level comparable to that of standard weight pullets lit at the recommended age.