- Key points
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? the variation in the post-injection interval to oestrus was influenced by the stage of the oestrous cycle at which treatment was administered;
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? this variation was suffkient to reduce pregnancy rates to set-time inseminations;
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? an accurate aid for oestrus detection, such as tail painting, should be used routinely with PGF;
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? if PGF-treated cows were detected in oestrus before being inseminated, the pregnancy rates to first insemination were usually 10% higher than in untreated herd mates.
The study was designed to investigate the replication of a re-assortant H9N2 avian influenza virus (AIV) and induction of the interferon (IFNγ) response after aerosol or intranasal inoculation with the virus in guinea fowl. To determine virus shedding pattern, oropharyngeal and cloacal swabs and tissue specimens of trachea, lungs, spleen and caecal tonsils were collected post-inoculation (pi).
Infected guinea fowl showed mild clinical signs, while negative control guinea fowl remained healthy and active throughout the experiment irrespective of the inoculation route. However, the clinical signs were more prominent in guinea fowl infected through the aerosol route.
Virus was detected in all oropharyngeal and cloacal swabs up to 7 d pi in guinea fowl from both inoculation groups. However, virus was detected more frequently and in higher titres in oropharyngeal swabs and specimens of trachea and lungs from the group exposed to aerosols than in the group given intranasal drops.
In accordance with viral replication findings, expression of IFNγ was up-regulated on 1, 2 and 4 d pi to a significantly higher level in lung tissue specimens from the group exposed to virus aerosol than from controls treated with PBS intranasally. On the other hand, IFNγ was up-regulated above that of controls in lung tissue specimens from the group treated with intranasal drops of virus only on 4 d pi.
These findings indicate that virus administered in aerosols was more efficient in infecting the lower respiratory tract and in inducing activity of the IFNγ gene than virus administered as intranasal drops. The results of this study suggest that virus aerosols cause more intense respiratory infection and increase the shedding of the H9N2 AIV in guinea fowl, highlighting the potential role of guinea fowl as a mixing bowl for transmission and maintenance of H9N2 AIV between poultry premises.
It was concluded that:
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The variations in calcium concentration reflected both the known uptake of this ion by the albumen and medullary bone formation and destruction.
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The variations in magnesium concentration did not parallel the changes in calcium concentration.
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Magnesium was released into the blood during medullary bone formation.
A total of 32 Lactobacillus isolates, 8 each from the crop (LGFCP1–LGFCP8), proventriculus (LGFP9–LGFP16), ileum (LGFI17–LGFI24) and caeca (LGFCM25–LGFCM32) were isolated from 25 adult guinea fowl (Pearl variety), 22–28 weeks of age, and characterised morphologically, physiologically, biochemically and by molecular methods.
Isolates were screened for their probiotic quality using range of in vitro tests: aggregation test, cell surface hydrophobicity, resistance to bile salts and acidic conditions, enzymatic tests and coaggregation and antagonistic test.
Based on in vitro test results and a novel scoring method, the two best isolates were selected and partial 16S rRNA sequencing was done. BLAST (Basic Local Alignment Search Tool) analysis of sequence of isolate LGFCP4 showed 99% genetic identity with Lactobacillus plantarum and LGFP16 with Lactobacillus reuteri.
The study shows that these two microbial agents may be suitable as potential probiotic candidates in guinea fowl, as well as in a feed supplement for other poultry species.
Two experiments, which differed in breeder age, strain and season, were conducted to study the influence of low-intensity, short-duration thermal stimuli during the late phase of incubation on hatchability and performance. The first experiment conducted in April–June used eggs from Cobb × Ross broiler breeders at 35–41 weeks of age and the second experiment performed in February–April used eggs from Hubbard × Cobb broiler breeders at 49–53 weeks of age.
Eggs in the test group had the same physical environment as eggs in the control group except that incubation temperature was increased by 1?C for 2 h/d above the control group from 18 to 20 d of incubation (DI).
The results demonstrated that thermal stimulation of 1?C for 2 h/d above control incubation temperature during 18–21DI did not have any adverse effects on hatch and post-hatch performance of broilers.
In both experiments, treatment did not significantly alter the secondary sex ratio in hatched chickens, but hatch residue showed that the proportion of unhatched male embryos was significantly lower in the test groups than in the control groups.
In the first experiment, thermal stimulation improved feed conversion by 1.82% compared with the control.
2. The spermatozoa of the FS line had greater fertility than spermatozoa of the FC line, whether freshly diluted or cryopreserved. Cryopreservation resulted in a reduction in fertility, regardless of line. There were no significant line by genotype interactions.
3. There were fewer spermatozoa from the FG line than the FS line found in the perivitelline membrane (perivitelline spermatozoa). The increase in number of perivitelline spermatozoa with increasing sperm concentration was greater in the FS than FC line. However, the slope of the increase in sperm number in the perivitelline membrane with increasing concentrations of cryopreserved spermatozoa was zero.
4. A minimum of 103 perivitelline spermatozoa must be found on day 2 post‐insemination for duration of fertility to exceed three days. The ability to produce spermatozoa capable of reaching the forming perivitelline membrane appears to be a quantitative, rather than a qualitative, trait and may be subject to genetic manipulation. 相似文献
Semen was collected from Bobwhite quail males by simultaneously applying pressure to both the left and right sides of the vent without prior stimulation. Upon collection, the semen was diluted with 0.9 per cent saline solution to prevent dehydration. Semen volume measurements were made with a tuberculin syringe to which was attached a piece of graduated, fine‐bore plastic tubing. Females were artificially inseminated by placing the diluted semen in the posterior opening of the everted oviduct.
Mean duration of fertility of the eggs from six trials, two of which utilised only a single insemination, one of which was the final insemination of a series of weekly inseminations and three of which utilised two inseminations within a period of 24 hr, was 9.3 days. Percentage fertility of eggs improved considerably after the first trial probably due to improvement of technique and gain in experience. Average fertility of eggs for the six trials was 64–9 per cent.
The average time interval between insemination and the appearance of the first fertile egg was 3.4 days. Peak fertility was reached by the fourth day following insemination.
Fertility of eggs averaged 62.2 ±3.5 per cent and their hatchability averaged 77.2 ±1.4 per cent over a period of 31 weekly inseminations. These values were comparable to 60.2 per cent fertility and 78.9 per cent hatchability which were obtained from natural matings. 相似文献
Blood samples from 1-, 5- and 10-year-old broad-breasted white turkeys were used to determine haematological and serum values. There were 8 turkeys in each age group.
Mean haematocrit, haemoglobin and creatinine values were higher in the 1-year-old than in 10-year-old turkeys.
Mean alanine aminotransferase was greater in 1 year old than in 10 year olds and greater in 5 year olds than in 10 year olds. Aspartate aminotransferase values were significantly different between all age groups.
Mean alkaline phosphatase was less in 1-year-old than in 10-year-old turkeys. There were no significant differences between the three groups for cholesterol, glucose, total protein, albumin, globulin, calcium and bilirubin.
All male turkeys had higher haemoglobin and haematocrit values than age-matched females.
These data will help establish basic background references values in geriatric turkeys used in research.
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A signal from a detector indicating departure from normality
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The interpretation of the signal (diagnosis)
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A feed-back signal to the origin of the detection signal indicating corrective action.
This study examined the changes in eggshell strength and the genetic parameters related to this trait throughout a hen’s laying life using random regression.
The data were collected from a crossbred population between 2011 and 2014, where the eggshell strength was determined repeatedly for 2260 hens.
Using random regression models (RRMs), several Legendre polynomials were employed to estimate the fixed, direct genetic and permanent environment effects. The residual effects were treated as independently distributed with heterogeneous variance for each test week.
The direct genetic variance was included with second-order Legendre polynomials and the permanent environment with third-order Legendre polynomials.
The heritability of eggshell strength ranged from 0.26 to 0.43, the repeatability ranged between 0.47 and 0.69, and the estimated genetic correlations between test weeks was high at > 0.67.
The first eigenvalue of the genetic covariance matrix accounted for about 97% of the sum of all the eigenvalues.
The flexibility and statistical power of RRM suggest that this model could be an effective method to improve eggshell quality and to reduce losses due to cracked eggs in a breeding plan.
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the force required to shear egg shell material can be measured with high precision by pressing a narrow, flat‐ended plunger on to the shell;
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shearing force falls and the precision of its measurement rises as the radius of the plunger is reduced;
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shearing force is related linearly to shell thickness ;
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the regression line of shearing force on shell thickness does not pass through the origin but has a substantial positive intercept on the thickness axis, at about a third of the mean thickness ;
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there are differences between hens and between strains of hen in the magnitude of the intercept, but not in the slope of the regression;
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shearing force is affected also by the glossiness of the shell;
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shearing force was not significantly affected by stripped membrane thickness, number of mammillae per unit area of shell, shell organic content (standardised for shell thickness), shell curvature, shell colour, mottling score, translucent patch score, speckling score, age of the egg or age of the hen that laid it;
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measured with a plunger of radius 165 μm, the mean shearing strength of incremental shell was 57 kg wt/mm2 (3–7 ton/in2).
The findings suggest that the shearing strength of egg shells might be increased by direct selection and by selection for shell glossiness. 相似文献
This study had the aim of evaluating the effects of medium-chain fatty acids (MCFA) on performance, carcass characteristics, some blood parameters and antibody titre against sheep red blood cells (SRBC) in quail.
A total of 240 quail chicks were allotted to 4 treatments consisting of respectively 0, 1, 2 and 4 g/kg dietary MCFA.
There were no significant differences in body weight, feed intake and feed conversion ratio among treatments at different stages of the experiment.
MCFAs had no significant effect on breast, thigh, liver, spleen and bursa of Fabricius weight ratios. However, the relative weight of abdominal fat significantly decreased in quail receiving 0.2 and 0.4 MCFA as compared to other treatments.
Concentrations of low-density lipoprotein-cholesterol (LDL), triglycerides and total cholesterol were decreased and high-density lipoprotein (HDL)-cholesterol was increased in quail chicks receiving MCFA compared with control quail chicks. The concentrations of SRBC antibody were not statistically different among treatments.
It is concluded that MCFA significantly decreased LDL, triglycerides, cholesterol and abdominal fat and increased HDL in quail chicks.
A total of 360 fertile eggs from a broiler breeder strain (Ross 308) were used for in ovo feeding (IOF) of 0, 100 and 200 mg/kg Silybum marianum water extract at 17.5 d of incubation.
After hatching, 240 chicks were transferred to the experimental cages. The diets consisted of two types; one of them without extract and the other one containing 100 mg/kg of Silybum marianum extract. Then chicks were exposed to elevated temperatures 4°C above optimum from 7 to 28 d of age for 4 h per d and after 28 d they were kept at optimum temperature. The chicks were divided into 6 treatments with 4 replicates as a completely randomised 2 × 3 factorial design.
There was no effect of IOF of Silybum marianum extract on hatchability, body weight (BW) of hatched chicks or hatched chick BW/initial egg weight ratio. Chickens fed on the diet containing the extract had the highest feed intake, daily weight gains (DWGs), final BW and lowest feed conversion ratio.
At 28 d, the weights of heart, spleen and bursa of birds in the treatment groups given extract were higher, but abdominal fat weights were lower. At 42 d in those fed extract in the diet, the weights of spleen and bursa were higher and abdominal fat weights were lower than the other groups.
No differences were observed between groups in body temperature before application of the higher temperature but at 21 d and 28 d the body temperature of chicks given the Silybum marianum extract was lower than the other treatments during the elevated temperatures.
In birds fed on the extract in the diet, HDL and cholesterol concentrations were lowest at 28 d, whereas blood glucose levels were higher in the other treatments. At 42 d the cholesterol concentration was significantly lower in birds given extract in their diet.
These results indicated that dietary feeding of Silybum marianum extract resulted in an improvement in performance, immunity and carcass characteristics and decreased the adverse effects of the higher temperatures, specifically in reducing blood fat reduction, but IOF of the extract did not have an effect.
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the seasonal pattern of dry matter production from pasture, as determined primarily by species composition and the seasonal light and temperature regime;
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the varying requirements of the pasture plants at different times of the year, as determined by their morphological and physiological condition;
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the necessity to utilise a large proportion of the dry matter produced if animal production per hectare is to be maximised;
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late ‘winter calving in over 90% of the dairy herds; and
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the nutrient requirements of the herd at different stages of lactation.
A DiagNose II electronic nose (e-nose) system was tested to evaluate the performance of such systems in the detection of the Salmonella enterica pathogen in poultry manure.
To build a database, poultry manure samples were collected from 7 broiler houses, samples were homogenised, and subdivided into 4 portions. One portion was left as is; the other three portions were artificially infected with S. enterica.
An artificial neural network (ANN) model was developed and validated using the developed database.
In order to test the performance of DiagNose II and the ANN model, 16 manure samples were collected from 6 different broiler houses and tested using these two systems.
The results showed that DiagNose II was able to classify manure samples correctly as infected or non-infected based on the ANN model developed with a 94% level of accuracy.
This study aimed to evaluate the changes in physicochemical, textural and sensory characteristics of broiler (BR) and Taiwan native chicken (TNC) pectoralis muscle heated at temperatures of 50–95°C.
With increasing temperature, cooking loss, collagen solubility, shear force value and hardness, of samples increased in both chicken breeds. Rapid decreases in protein solubility were observed when the meat was heated to 50°C and gradually decreased thereafter.
Meat from BRs and native chickens performed differently upon heating in certain characteristics. TNC meat had longer cooking time and lower myofibrillar fragmentation index than BR meat did. TNC meat had higher collagen content, shear force values and springiness but lower collagen solubility than BR meat did.
BR meat had significantly higher onset and end transition temperatures than TNC meat did. In BR meat, a sensory analysis revealed that moisture release decreased and chicken flavour increased with increasing temperature.
Protein solubility, cooking loss and the texture of heated meat were highly correlated.
This study scientifically assessed the performances of the two breeds of chickens with different thermal treatments; producers could utilise the information to produce poultry products with more desirable qualities.
The objective of this study was to identify any issues arising during the laboratory testing of samples collected under the National Control Programme for Salmonella.
A questionnaire-based survey was conducted among Defra (Department for Environment, Food and Rural Affairs)-approved testing laboratories in order to identify any complicating factors that the laboratories may encounter during the processing of samples.
Samples were reported to arrive in good condition and within the specified time frame after collection. The only concern was that new clients may be unaware of the procedure or correct sampling consumables to use.
There was evidence of variability between laboratories regarding the sample testing procedure used, with deviation from the guidelines in some cases.
This finding suggests that further guidance for laboratories on methodology is likely to be beneficial as this could help improve the detection of low levels of Salmonella.
The study assesses the effectiveness of reversible head-only and back-of-the-head electrical stunning of chickens using 130–950 mA per bird at 50 Hz AC.
Three trials were conducted to compare both stunning systems: (a) behavioural assessment of return of consciousness, (b) insensibility to thermal pain, and (c) assessment of return of brain activity with visually evoked potentials (VEPs).
Assessment of behaviour suggested that the period of unconsciousness following head-only electrical stunning was shorter in hens compared to broilers.
Stunning across the back-of-the-head delayed the time to return of brainstem function compared to stunning with standard head-only electrodes. Additionally, back-of-the-head stunning produced a more prolonged period of electroanalgesia compared to head-only.
Based on examination of return of brain function with VEPs in hens, back-of-the-head stunning produced a shorter-lasting stun than standard head-only. However, even for standard head-only, the stun was notably shorter than previously reported. In some birds, brain function had returned within 9 s after the end of stunning.
The results suggest that some birds may recover consciousness prior to or during the neck cut. Based on these findings, back-of-the-head stunning and standard head-only stunning of hens should not be recommended without further development.
1. This study examined different glycerol concentrations (GC) and freezing rates to improve the quality of rooster spermatozoa frozen in straws, and to determine the effect of varying GC on post-thawed spermatozoa quality, as evaluated by fertility and hatchability.
2.The experiment included two tests. In test 1, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put in a rack (nine tiers with a 1 cm interval between every two tiers, 1 to 9 cm above liquid nitrogen (LN) source), and gradually frozen. The semen straws located in different tiers experienced different temperatures and freezing rates. The straws were then thawed and live sperm numbers determined. In test 2, rooster semen straws containing 2, 4, 6, 8 and 11% glycerol were put on optimal tiers (identified in test 1) for freezing, and stored at ?196°C. Hens were inseminated with the frozen semen (post-thawed and glycerol removed, about 4.0 × 108 sperm per hen), and eggs incubated.
3. The numbers of live sperm in the 11% glycerol group was higher than that in 2, 4 or 6% glycerol group (P < 0.05) for the semen straws on tiers 1 to 9, while that on tiers 1 to 5 was lower than that on tier 6 to 8 (P < 0.05). GC, freezing rate and the interaction between GC and freezing rate had a significant effect on live sperm numbers (P < 0.01). The highest fertility was in the 6% glycerol group and occurred on day 5 after insemination. The lowest fertility occurred in the 2% glycerol group on day 10 after insemination.
4. The optimal combination was 11% glycerol in straws located 6 cm above the LN surface (on tier 6). The 6% glycerol group achieved the highest fertility (77.6%), which surpassed that reported in recent years.