Warm weather transport of broiler chickens in Manitoba. II. Truck management factors associated with death loss in transit to slaughter

This observational study was conducted to identify the cause of death and load level factors associated with mortality in 1 090 733 Manitoba broiler chickens transported to slaughter in spring and early summer. Death loss in transit was 0.346% and accounted for 19% of the total carcass condemnation. The death loss pattern was clearly bimodal, with a low death loss in 180 of 198 shipments. Cumulative death loss during the growing phase of production was consistently associated with increased transport mortalities in load level models and when comparing high death loss with low death loss truckloads. High ambient temperature at the time of slaughter and loading density of the truck were the major factors associated with exceptional death loss.     

Risk factors associated with early respiratory disease complex in broiler chickens.

Early respiratory disease complex (ERDC) is a term coined to describe an acute disease characterized by depression, respiratory distress, and increased mortality in 2-to-3-wk-old broiler chickens. Postmortem lesions include airsacculitis, fibrinous pericarditis, and perihepatitis. Colisepticemia is the primary cause of death. In order to investigate the association between ERDC and farm management factors, a retrospective case-control study was conducted by collecting data covering a 6-mo period (January-June 1997) from four broiler integrators on the Delmarva peninsula. Univariate and multivariate statistical analyses revealed that flock size was positively associated (P = 0.02) and layout time was negatively associated (P = 0.05) with ERDC.     

The occurrence of Campylobacter species in Hungarian broiler chickens from farm to slaughter

The reported number of human enteric diseases caused by thermotolerant campylobacters increased in the last few decades worldwide. The microorganism gets into the food chain mostly with poultry meat or meat products. We are not aware of the way the campylobacters infect the broiler flocks, and there is little information about the real prevalence, about the reaction of thermotolerant campylobacters to the environmental factors and about the possibilities of elimination of the bacteria from the food chain. As a part of the long study, samples were collected from a broiler flock from the first day of life to the slaughter of the animals, in summer and in winter. In the summer period, at the first two sampling days (days 0 and 12) all of the samples were negative. At day 26, one cloaca sample, one sample from the surface of the wall near the ventilation aperture and an insect-sample were positive. At day 42, we found Campylobacter spp. on every sampling point at the slaughterhouse. In the winter period, we could not find Campylobacter spp. either from 0 day old, or from 10- and 31-day-old chickens, but we found them at 42 days of age on the slaughter plant. At the slaughtering place, 93.3% of the live birds were infected with Campylobacter spp., and at the end of the processing line, the infection rate was 100%. We could isolate campylobacters from the hands of the workers and from the processing environment as well. Out of the positive samples, 95.5% was contaminated with Campylobacter jejuni.     

Longer journeys to processing plants are associated with higher mortality in broiler chickens.

1. The number of broilers recorded as dead on arrival (DOA) in 1113 journeys to a poultry processing plant was related to the length of the journeys. The average journey time was 3.3 h and the maximum recorded was 9 h. 2. Overall, 0.194% of 3.2 million birds were DOA. Mortality was higher for journeys which took longer. For journeys lasting less than 4 h the incidence of dead birds was 0.156%; for longer journeys the incidence was 0.283%. 3. There was some evidence that it was time of journey, rather than distance travelled, that was more important in determining mortality.     

Severe mortality in broiler chickens associated with Mycoplasma synoviae and Pasteurella gallinarum.

Severe economic loss due to high mortality and condemnation rates occurred on two commercial broiler facilities. Chickens had moderate-to-severe airsacculitis, pericarditis, perihepatitis, tracheitis, and synovitis. Pasteurella gallinarum was isolated from 16 of 18 pericardia, four of 14 livers, 11 of 16 air sacs, six of seven joints and one of 28 tracheas in pure culture. In addition, Mycoplasma synoviae was isolated from trachea and air sac. Lesions were suggestive of an Escherichia coli septicemia, but E. coli was isolated from only four of 28 tracheas and one of 14 livers in pure culture. A coronavirus was isolated from trachea and lung. Whether this coronavirus represented a vaccine or field strain of infectious bronchitis was not determined. These findings suggested that the severe lesions were due to a concomitant infection with an atypical strain of P. gallinarum.     

Risk factors associated with hydropericardium syndrome in broiler flocks.

A prospective study was undertaken to identify the epidemiological factors associated with the development and spread of the hydropericardium syndrome in broiler flocks. Data were collected between July 1989 and April 1990 from 131 flocks in 105 broiler production units pertaining to their demography, management practices, prophylactic procedures and concurrent diseases. The incidence rate of the syndrome in the whole population was 46.6 per cent. There were significant associations between the incidence in a flock and visits by a poultry vaccination crew (P = 0.014), the number of flocks raised (P = 0.004) and the source of light and heat (P = 0.007). Flocks that had one or more visits by a poultry crew were 15 times more likely to be affected by the syndrome than flocks that had no such visits. Premises where one flock was raised were nearly three times more likely to be affected than premises where two flocks were raised, and the use of electricity as a source of light and heat entailed a much lower risk of hydropericardium syndrome than kerosene oil.     

Flock infection and transport as sources of salmonellae in broiler chickens and carcasses.

Cultural monitoring was used to determine the incidence and sources of salmonellae in a 4160-bird broiler flock raised on litter in 32 pens. Twenty-five of the pens remained apparently free of salmonellae during the 49-day growing period. Salmonella johannesburg, first detected in the meat meal component of the starter ration, was recovered from the litter of seven pens and from the intestines of dead or culled chicks from two pens. Salmonella alachua was also recovered from two of these pens. Culture of swabs collected from the plastic crates used to transport this flock for processing showed that 97/112 (86.6%) were contaminated with salmonellae (15 serovars) before the birds were loaded. The crate washer at the plant did not remove salmonellae from these crates: 97/132 (73.5%) crates sampled after washing yielded salmonellae. Eleven serovar were recovered, including S. johannesburg and S. alachua introduced by the infected flock. Twelve of 31 chickens (38.7%) collected when the birds were unloaded at the processing plant were intestinal carriers of S. johannesburg and/or S. alachua and 29 (93.5%) were external carriers. Salmonella johannesburg, S. alachua and four other serovars were isolated from the feathers of these birds. Eleven of 25 (44%) carcasses tested from this flock yielded salmonellae. Salmonella johannesburg or S. alachua, first isolated from the infected flock, were recovered from five carcasses and S. haardt and S. Typhimurium, first isolated from the transport crates were recovered from six carcasses.     

Infectious stunting syndrome associated with disturbances of mineral metabolism and bone development in broiler chickens.

On a broiler farm with a rearing capacity of about 200,000 chickens, a disease characterised by growth retardation, variability in chick size, 'leg weakness', diarrhoea and increased mortality at 3 weeks of age occurred repeatedly, in several successive broiler flocks. Gross and histopathological findings were dominated by widening of the hypertrophic and ossification layers of the physes of long bones as well as by thickening, unevenness and defective calcification of the cartilage trabeculae. In the parathyroid gland, vacuolar degeneration of the cytoplasm of glandular epithelial cells, connective tissue proliferation and, here and there, cyst formation were seen. Additional findings included severe cerebellar oedema and neuronal degeneration. The pancreatic, myocardial and intestinal changes typical of infectious stunting syndrome (ISS) occurred only in a mild form. Four-week-old chickens exhibiting 'leg weakness' had significantly lower blood inorganic phosphate concentration and tibial ash content as compared to healthy chickens. The disease was successfully transmitted by oral administration of small intestinal homogenate from affected chickens. In a second experiment, however, the disease could not be transmitted with intestinal homogenate sterilized by irradiation. Large doses of vitamin D3 reduced the rate of growth retardation and defective calcification of bones. The digestive enzyme activities of the pancreas and small intestinal mucosa of 'infected' chickens were decreased as is typical of ISS.     

Viral and bacterial agents associated with experimental transmission of infectious proventriculitis of broiler chickens.

Proventriculitis of broilers can be reproduced by oral inoculation of day-old chicks with a proventricular homogenate from affected 3-wk-old broilers. The objective of the following studies was to isolate from this homogenate viral and bacterial isolates that could produce proventriculitis. A monoclonal antibody to infectious bursal disease virus (IBDV) was used to precipitate virus from the homogenate. A primary chicken digestive tract cell culture system was also used to isolate virus from a 0.2-microm filtrate of the homogenate, and a bacterium was also isolated from the homogenate. In trial 1, day-old birds were orally inoculated with either proventriculus homogenate or monoclonal antibody immunoprecipitated IBDV (MAB-IBDV). At 4, 7, 14, and 21 days postinfection (PI), 12 birds from each treatment group were subjected to necropsy. In trial 2, day-old birds were orally inoculated with either infectious proventriculus homogenate, suspect virus isolated in cell culture and propagated in embryo livers and spleens, or a bacterial isolate. Twelve birds from each treatment were subjected to necropsy at days 7, 14, 21, and 28 PI. In trial 3, treatments were maintained in negative pressure isolation chambers, and an additional treatment included virus plus bacterial isolate. Twenty-four birds from each treatment were subjected to necropsy at day 21 PI. In trial 1, infectious homogenate decreased body weight and relative gizzard weights at 4, 7, 14, and 21 days PI. Proventriculus relative weight was increased at days 7, 14, and 21 PI, and proventriculus lesion scores were increased at days 14 and 21 PI. Bursa/spleen weight ratios were decreased at day 14, and feed conversion was increased at days 4 and 21. The MAB-IBDV treatment decreased proventriculus and gizzard relative weights at day 4 PI, increased proventriculus lesion scores and bursa/spleen weight ratios at day 14, and decreased heterophil/lymphocyte ratios at day 21. In trial 2, all infected birds had significantly higher mean relative proventriculus weights at 21 days PI and had higher 4-wk mean proventriculus scores as compared with both control groups. In trial 3, birds treated with homogenate and birds treated with both suspect virus and the bacterial isolate had significantly higher proventriculus lesion scores; higher relative weights of proventriculus, gizzard, liver, and heart; lower body weights; and lower relative bursa weights compared with the saline control group. These studies suggest that infectious proventriculitis has a complex etiology involving both viral and bacterial infection.     

Studies on effect of lighting on "Sudden death syndrome" in broiler chickens.

Broiler chicken flocks were studied to determine the mortality from sudden death syndrome occurring in the flocks. The difference in the incidence of the syndrome in pullets and cockerels, and the age at which the most birds are affected were also studied. The weight of sudden death syndrome birds was compared with the flock average and the effect of continuous lighting as opposed to intermittent lighting was examined.The results suggest that; continuous lighting produces more sudden death syndrome deaths than intermittent lighting; that the incidence of sudden death syndrome is higher in cockerels than pullets; that the highest death rate occurred during the third and fourth weeks of life, and that sudden death syndrome birds on the average were heavier than the flock average.     

Farm management factors associated with bulk tank somatic cell count in Irish dairy herds

The relationship between bulk tank somatic cell count (SCC) and farm management and infrastructure was examined using data from 398 randomly selected, yet representative, Irish dairy farms where the basal diet is grazed grass. Median bulk tank SCC for the farms was 282,887 cells/ml ranging from 82,209 to 773,028 cells/ml. Two questionnaires were administered through face-to-face contact with each farmer. Herd-level factors associated with bulk tank SCC were determined using linear models with annual somatic cell score (i.e., arithmetic mean of the natural logarithm of bulk tank SCC) included as the dependent variable. All herd level factors were analysed individually in separate regression models, which included an adjustment for geographical location of the farm; a multiple regression model was subsequently developed. Management practices associated with low SCC included the use of dry cow therapy, participation in a milk recording scheme and the use of teat disinfection post-milking. There was an association between low SCC and an increased level of hygiene and frequency of cleaning of the holding yard, passageways and cubicles. Herd management factors associated with bulk tank SCC in Irish grazing herds are generally in agreement with most previous studies from confinement systems of milk production.     

Virulence factors of Escherichia coli associated with colisepticemia in chickens and turkeys.

Four hundred twenty turkey and 80 chicken Escherichia coli isolates from colisepticemic birds were examined for the following properties: heat-labile toxin (LT), heat-stable enterotoxin, verotoxin, colicinogenicity, hemolysin, and hydroxamate/aerobactin production. Twenty-four (5.7%) of the 420 turkey isolates and six (7.5%) of the 80 chicken isolates produced an LT that was cytotoxic for both Vero and Y-1 cells. In contrast, 48 (11.4%) of the turkey isolates and 18 (22.5%) of the chicken isolates produced a distinct LT that was cytotoxic only for Vero cells. In addition, 64 (80.0%) of the chicken isolates and 309 (74.0%) of the turkey isolates produced aerobactin. Colicinogenicity occurred in 51 (64.0%) of the chicken isolates, with 41 (51.0%) producing colicin V. By contrast, 254 (61.0%) of the turkey isolates produced a colicin, of which 176 (42.0%) produced colicin V. None of the chicken and turkey isolates produced hemolysin or heat-stable enterotoxin.     

Herd risk factors associated with sero-prevalence of Maedi-Visna in the Manitoba sheep population

Disease associated with Maedi-Visna infection results in substantial economic losses in affected sheep producing areas of the world. A survey was conducted to estimate herd and individual seroprevalence in the province of Manitoba and evaluate risk factors for seropositive herds. Of 2207 sheep sampled from 77 selected sheep flocks, the animal level seroprevalence was 2.47% and herd level seroprevalence was 25.10%. The herd-level factors of presence of clinical skin disease, herd size of > 70, history of musculoskeletal/lameness abnormalities, and the purchase of new stock (> 50) in the last 1 to 5 y, showed significant associations with seropositive herd status. The study documented a remarkable stability of low seroprevalence in the province over a 20-year period in the absence of a systematic disease control program.     

Reduced PKCalpha expression in pulmonary arterioles of broiler chickens is associated with early feed restriction

OBJECTIVE: The present study was conducted to investigate the effect of early feed restriction on protein kinase Calpha (PKCalpha) expression in pulmonary arterioles, which has been revealed to promote pulmonary vascular remodeling in pulmonary hypertensive broilers. METHODS: A total of 270day-old mixed sex commercial broilers were randomly distributed to a normal temperature control group (NT), a low temperature control group (LT) and a low temperature plus feed restriction group (LR). The PHS incidence, the right/total ventricular weight ratio (RV/TV), the vessel wall area/vessel total area ratio (WA/TA), the mean media thickness in pulmonary arterioles (mMTPA) and the expression of PKCalpha in the pulmonary arterioles were measured weekly. RESULTS: Low temperature treatment significantly increased the PHS mortality. The RV/TV, WA/TA and mMTPA values of group LT were significantly elevated compared with those of group NT on d 35 and 42. The LT chickens had increased PKCalpha expression compared with their NT counterparts on d 28 and afterwards. Feed restriction reduced the PHS mortality, RV/TV, WA/TA and mMTPA in cold-exposed broilers. The LR chickens had much lower PKCalpha expression in pulmonary arterioles than the LT chickens. CONCLUSION: Early time feed restriction inhibited pulmonary vascular remodeling in broilers, which might be partly attributed to reduced PKCalpha expression in pulmonary arterioles.     

Pathogenicity of Eimeria praecox alone or associated with Eimeria acervulina in experimentally infected broiler chickens

Eimeria praecox and Eimeria acervulina are two species of coccidia parasites infecting chickens, which develop in the duodenum. The purpose of this study was to evaluate the pathogenicity of E. praecox and to study interactions of this coccidium with E. acervulina. The results showed that the pathogenicity of E. praecox was related to the infective dose, and that its impact on individual weight and weight gain was significant from the lowest administered dose: 5000 oocysts per bird. No morbidity was observed, even with the highest infective dose, but faecal consistency alteration was higher with increasing infective doses. No consistent lesion was observed. When E. praecox was associated with E. acervulina with a low infective dose, performance deterioration seemed to be an additional effect of the two species. However, in the case of heavy infections, signs worsened along with duration of negative impact on growth, compared to a mono-infection.     

Prevalence and factors associated with it,of birds dead on arrival at the slaughterhouse and other rejection conditions in broiler chickens

1. Standardised data on husbandry were recorded for a flock of birds in one house on each of 150 broiler farms in the UK during the 4 d prior to slaughter.

2. For each flock, the incidence of birds found dead on arrival (DoAs) and the Meat Hygiene Service carcase rejection records were recorded at the slaughterhouse.

3. The mean percentage of birds in each flock found DoA was 0·12% (range 0–0·64%) and the mean percentage of Total Carcase Rejects (TCRs) for each flock was 1·23% (range 0·07–5·51%).

4. A general linear model was developed to examine factors associated with flock percentage DoAs. Assuming a linear relationship, all other factors remaining the same, a one percentage point (PP) increase in small/emaciated birds will result in a 0·155 PP increase in DoAs and a 1 PP increase in wheat in diet 4 will result in a 0·003 PP decrease. An increase by one in the total number of vaccines administered will cause a 0·029 PP decrease in DoAs, a 1 g increase in live weight at slaughter will be associated with a 0·000043 PP increase and a 1 PP increase in mortality on farm would be associated with a 0·000044 PP increase. A 1 PP increase in Ross birds decreases DoAs by 0·0004 PPS: there is also a seasonal effect.

5. The model developed for flock percentage TCRs found that a 1 PP increase in wheat in diet 3 will result in a 0·052 PP decrease in TCRs and a 1 PP increase in Ross birds will cause a 0·009 PP decrease. A 1 PP increase in birds culled on farm will be associated with a 0·03 PP increase in TCRs and the diagnosis of disease during the flock cycle increases TCRs by 0·397 PPs. A one day increase in age at slaughter will result in a 0·046 PP increase in TCRs.     

Effects of lairage time on body temperature and glycogen reserves of broiler chickens held in transport modules.

Commercial broiler chickens killed in two processing plants, one in the south of England, the other in Scotland, in two seasons (winter and summer) and on two occasions in each season, were used to investigate the effects of killing the birds immediately on arrival or holding them in lairage for one, two, three or four hours. The two most important consequences of holding the birds in lairage were that their body temperature increased and their liver glycogen was depleted. The body temperature increased with the time they were held in lairage, although most of the increase occurred in the first hour and the increase was greater in summer when ambient temperatures were higher. Liver glycogen depletion became apparent after about one to two hours in lairage. No evidence was obtained that the birds were significantly dehydrated or physically stressed by being kept longer in lairage.     

Farm factors associated with the use of antibiotics in pig production

The aim of this study was to investigate farm-level economic and technical factors that are associated with the use of antibiotics on pig farms. Identification of such factors, like farm size and net farm result, may help to increase epidemiological knowledge and to specify farm advice and policy making to reduce inappropriate use of antibiotics. The study used over 300 farm-year records collected during 2004 to 2007 from pig farms in the Netherlands. Data included economic and technical factors as well as antibiotic administration. Data were statistically analyzed for factors associated with antibiotic use, both for fattening pig and sow farms (piglets only), separately. The response variable was the average number of daily dosages per average pig year. Statistical analysis was performed on 16 and 19 potential explanatory factors for the fattening pig and sow farms, respectively. The results showed that, both on the fattening pig and sow farms, the average use of antibiotics increased from 2004 to 2006, but decreased during 2007, but the effect of year was not significant (P > 0.05). Use of antibiotics varied between individual farms. Large farm repeatability for the use of antibiotics in the different years was found. Factors associated (P < 0.05) with the use of antibiotics included: farm system, number of pigs, and population density in the region of the farm (for sow farms only). As these factors are easy to collect and to register, they can be used to specify farm advice and investigation, as well as for policy making. The majority of the technical and economic factors were not significantly (P > 0.05) related to the on-farm use of antibiotics. Therefore, it is recommended to focus future research on the potential role of socioeconomic factors associated with antibiotic use on pig farms.     

Prevalence of leg weakness in broiler chickens and its relationship with genotype.

A method for measuring the prevalence of leg weakness by assessing the walking ability of broilers was developed. Walking ability was divided into six categories, from completely normal to immobile. The method was found to give consistent results when performed by the same people. In a survey of commercial, intensively reared broilers, 90 per cent had a detectable gait abnormality and 26 per cent suffered an abnormality of sufficient severity for their welfare to be considered compromised. The prevalence of leg weakness in free range broilers, and three commercial breeds of broilers was determined. The results indicated that genetic factors were an important cause of leg weakness in broilers and also identified a possible relationship between liveweight and leg weakness.     

A cross-sectional study of risk factors associated with pulmonary lesions in pigs at slaughter

A cross-sectional study was conducted to identify herd-level factors that may influence the prevalence and severity of macroscopically visible pulmonary lesions in pigs at slaughter. Data were collected following abattoir inspection of 50 randomly-selected batches of 6335 pigs and by interviewing the producers. Macroscopic lung lesions were identified and scored semi-quantitatively in ?80 pigs/herd and the prevalence of pleuritis and pneumonia was 20.76% and 23.85%, respectively. Following multivariable analysis, the seroprevalence of Actinobacillus pleuropneumoniae (P < 0.001) and Mycoplasma hyopneumoniae (P = 0.018) and the number of pigs/nursery pen (P = 0.023) were positively associated, whereas average weaning age was negatively associated (P = 0.001) with the pleuritis score. Risk factors associated with a higher prevalence of pneumonia were the presence of pleuritis (P = 0.001) and the frequent purchasing of pigs (P = 0.020). The findings of this study indicate that the prevalence of pleuritis and pneumonia remains high in Belgium and management factors are central to disease control.