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Biomedical subjects

P D Warriss

Publications and source records attributed to P D Warriss.

At least 19 recordsLinked to original sources

Measurements of footpad dermatitis in broiler chickens at processing plants.

A four-point photographic scale was developed to score the severity of lesions of footpad dermatitis (FPD) in broiler chickens. There was a linear relationship between the square root of the relative area of the lesions and their scores, and good agreement between different assessors using the scale. The scale was used to assess samples of 100 birds from each of 190 flocks slaughtered at two uk processing plants in 2002 and 2003; 12 of the flocks (6.3 per cent) had no lesions, but the others had lesions of different prevalences and severity. The maximum proportion of affected birds in a flock was 92 per cent. In the 178 affected flocks, 84.0 per cent of the birds had no lesions and 16.0 per cent had some evidence of FPD. The overall unweighted prevalence of birds with FPD in all 190 flocks sampled was 18.1 per cent; 10.2 per cent had only small lesions, on average equivalent in area to 2.1 per cent of the total area of the foot, 6.2 per cent had lesions on average equivalent to 6.6 per cent of the area of the foot, and 1.7 per cent had lesions on average equivalent to 21.5 per cent of the area of the foot. There were differences between the two plants in the overall prevalence and severity of FPD, but this may have been due to the fact that the plants were sampled at different times of the year.

Animal Husbandry↗

Comparison of the effects of fan-assisted and natural ventilation of vehicles on the welfare of pigs being transported to slaughter.

A total of 417 pigs with an estimated average liveweight of 91 kg were transported to slaughter in three journeys, carried out in late June, each consisting of a three-hour drive followed by a one-hour holding period at the slaughter plant before they were unloaded. The pigs were accommodated on the lower two decks of a three-deck articulated lorry, each deck having five equal-sized pens; half were kept in naturally ventilated pens and half in pens with fan-assisted ventilation. The pigs' body temperature was recorded as the temperature of the blood lost at exsanguination, and as the temperature of the inner surface of the ear measured by thermal imaging. The pigs carried on the upper deck were hotter than those carried on the lower deck, and the pigs carried at the front of the vehicle were hotter than those at the back. There were small differences between the temperatures of the pigs in the different pens, but overall the temperatures of the pigs kept in pens with fan-assisted ventilation were no lower than those of the pigs kept in pens with natural ventilation. The higher temperature of the pigs transported in the front of the vehicle was associated with significantly higher serum concentrations of cortisol and activities of creatine kinase, and a tendency to higher albumin concentrations and osmolality, suggesting that they may have been exposed to more physical and psychological stress, and were possibly slightly more dehydrated, than the pigs in the rearmost pens. The type of ventilation had no effect on the blood composition of the pigs.

Animal Welfare↗

Estimating the body temperature of groups of pigs by thermal imaging.

Measurements on 28 pens of pigs containing 384 animals to be slaughtered at a commercial abattoir showed that the mean ear temperatures of the pigs in each pen, measured with a thermal imaging camera, were significantly correlated (r=0.71, P<0.001) with the mean temperature of the blood the pigs lost at exsanguination. In measurements on 220 pigs in 16 of the 28 pens, the mean activity of serum creatine kinase was positively correlated with the mean ear temperature (r=0.55, P<0.05) and the mean concentration of serum cortisol was positively correlated with the mean blood temperature (r=0.50, P<0.05), suggesting that the hotter pigs were suffering from a higher level of stress.

Abattoirs↗

Preliminary study to examine the utility of using foot burn or hock burn to assess aspects of housing conditions for broiler chicken.

1. Eleven broiler chicken farms, representing 4 production system types, were visited during the last 5 d of the flock cycle: bird and flock details were recorded. Litter friability was assessed at 9 sites within the house, atmospheric ammonia was measured at three sites and bird cleanliness was assessed on a numerical rating scale. 2. For these flocks, hock burn, foot burn and breast burn were measured at the processing plant by standardised assessors. 3. Significant correlations were identified between the percentage of birds with foot burn and average litter score, average house ammonia concentrations and feather score. 4. No correlation was found between the percentage of birds with hock burn or breast burn and average litter scores, average ammonia concentrations or feather score. 5. No correlation was found between stocking density and foot burn, hock burn or breast burn.6. If confirmed, these findings may have implications for the draft EU Broiler Directive, for which it is proposed that permitted stocking density on farm may be determined by the incidence and severity of contact dermatitis measured on plant.

Animal Husbandry↗

Effects of stocking density, flock size and management on the welfare of laying hens in single-tier aviaries.

Management practices, stocking rate and flock size may affect laying hen welfare but there have been few replicated studies in commercial non-cage systems that investigate this. This study used a broad range of physical and physiological indicators to assess the welfare of hens in 36 commercial flocks. Six laying period treatments were examined with each treatment replicated 6 times. It was not possible to randomly allocate treatments to houses, so treatment and house were largely confounded. Three stocking rates were compared: 7 birds/m(2) (n = 2450), 9 birds/m(2) (n = 3150) and 12 birds/m(2) in either small (n = 2450) or large (n = 4200) flocks. In addition, at 12 birds/m(2), in both small and large flocks, birds were subjected to either standard (SM) or modified (MM) management. MM flocks had nipple drinkers and no nest-box lights. Bone strength, fracture incidence, heterophil:lymphocyte (H:L) ratio, live weight, organ weights, serum creatine, serum osmolality, muscle pH and faecal corticosterone were measured on samples of birds at the end of the rearing period and at the end of lay. During the laying period, mortality, production and integument condition were recorded at regular intervals. Birds housed at 9 birds/m(2) had higher mortality than birds housed at 12 birds/m(2) by the end of lay, but not higher than birds housed at 7 birds/m(2). Birds housed at 7 and 9 birds/m(2) had lower percent liver weight, and worse plumage condition than most of the 12 bird/m(2) treatments. Modified management tended to improve plumage condition. There were no clear effects of flock size on the welfare indicators recorded. At the end of the rearing period fracture incidence was almost negligible and H:L ratio was within a normal range. By the end of lay fracture incidence was 60% and H:L ratio was high, with no treatment effect for either measure. This, together with information on faecal corticosterone, feather loss and mortality, suggests that the welfare of birds in all treatments was relatively poor by the end of lay.

Animal Husbandry↗

Levels of foot pad dermatitis in broiler chickens reared in 5 different systems.

1. The prevalence and severity of foot pad dermatitis (FPD) was examined in 359 flocks of broiler chickens comprising about 3.93 million birds produced on 91 farms and reared under 5 types of system: standard intensive, free-range, organic, systems complying with the RSPCA Freedom Food scheme, and corn-fed. 2. The mean prevalence of FPD in standard systems was 14.8%. Flocks that had access to the outside (free-range and organic systems) showed higher prevalence of FPD than those kept entirely indoors (standard, corn-fed and Freedom Food systems). The lowest prevalence of FPD (9.6%) and severity of the lesions occurred in Freedom Food systems, and the highest prevalence (98.1%) and severity in organic systems. 3. The implication from the results is that there are large variations in the prevalence and severity of FPD in birds reared under different systems and this needs to be taken into account when assessing the overall welfare associated with each type of system.

Animal Feed↗

Multi-element survey of wild edible fungi and blackberries in the UK.

A survey of 12 metals including lead (Pb), copper (Cu), cadmium (Cd), mercury (Hg), arsenic (As) and platinum (Pt) was carried out using ICP-MS in 34 samples of wild fungi and 48 samples of wild blackberries collected from sites across the UK. On a fresh weight basis (mg/kg) levels of Pb were in the range 0.003-5.990, Cu 0.596-34.800, Cd<0.001-19.6, Hg<0.001-4.150, As 0.001-0.972 and Pt (microg/kg) 0.006-0.200, with higher concentrations found in fungi than in blackberries. The results of the survey showed that the concentrations of the metals were consistent with previous studies, where available. Concentrations in wild fungi of Pt, tin (Sn), and titanium (Ti) were significantly higher at urban sites than at rural sites. Urban blackberries had significantly higher levels of Pb, Ti, and Cd than rural ones, but lower levels of manganese (Mn). Pb, Ti and Sn concentrations were significantly higher in blackberries sampled near main roads rather than in rural areas.

Environmental Monitoring↗

The response of pigs to being loaded or unloaded onto commercial animal transporters using three systems.

Groups of pigs were subjected to three different systems of loading and unloading to and from commercial animal transporters. The systems under trial were: the use of a hydraulic tail-lift, a tail board ramp at an angle of 18 degrees and a modular system. The module was a container 2 m x 2.4 m x 1 m high into which the pigs were loaded. The module could then be lifted on and off the lorry with a fork lift truck. Non-invasive monitoring techniques were used to study the responses of the pigs. A subjective handling score, time taken to load and unload, skin temperature, heart rate and salivary cortisol were recorded. Loading and unloading were subjectively assessed as being easiest and quickest using the modular system, which also appeared to be less physically demanding for the animals, as evidenced by lower heart rate and a reduced maximum heart rate. However, with the modular system, elevated cortisol was found during the loading, unloading and resting periods. This could be interpreted as indicating that the pigs were unable to settle in the module and suffered some small degree of stress, which might become more of a problem during prolonged transport. Of the other two systems, there appeared to be little difference between the hydraulic tail-lift and the ramp.

Animal Husbandry↗

Relationship between maximum daily temperature and mortality of broiler chickens during transport and lairage.

1. Based on records of all (n = 59 171 843) broiler chickens slaughtered over three years at one processing plant, the overall mortality of birds in transit was 0.126%. 2. There was a pronounced seasonal effect with increased mortality in the summer months, particularly June, July and August. Mortality increased when the maximum daily temperature (measured in the shade) rose above about 17 degrees C at the start of the summer. 3. Between 17.0 and 19.9 degrees C, mortality was 30% higher than at lower temperatures. Between 20.0 and 22.9 degrees C it increased 2.6-fold, and at temperatures of above 23 degrees C 6.6-fold. There was no evidence of birds dying from hypothermia at very low ambient temperatures (down to -1 degrees C). 4. The implication from the results is that above a maximum daily temperature of 17 degrees C steps may need to be taken to ameliorate the damaging effects of transport on bird welfare.

Abattoirs↗

Defaecation and weight of the gastrointestinal tract contents after feed and water withdrawal in broilers.

1. Broilers were held under constant light for up to 24 h with access to feed and water, access to water only, or access to neither feed nor water. 2. Birds given continuous access to feed ate evenly over the 24-h period. Feed deprivation reduced drinking behaviour to about half of that when feed was available. Deprivation of feed, or of feed and water, had similar effects on defaecation and the reduction in the weight of the gut contents. It reduced the overall number of defaecations over the 24-h period to about 40% of that in birds given food and water, and the weight of the contents by about 75%. The maximum effect of deprivation on defaecation was seen after about 4 h, and on gut contents weight after about 12 h. 3. With longer fasting the contents of most parts of the gut, except the caeca, became wetter. 4. The findings may have implications for the practice of preslaughter food withdrawal to reduce the potential for soiling of the live birds and contamination of the carcase after slaughter. However, the likelihood is that relatively short overall feed deprivation times of not more than 8 to 12 h before killing may be desirable, but specifying firm recommendations on optimal feed withdrawal times requires further work.

Animals↗

Measurements of the degree of development of rigor mortis as an indicator of stress in slaughtered pigs.

The degree of development of rigor mortis in the carcases of slaughter pigs was assessed subjectively on a three-point scale 35 minutes after they were exsanguinated, and related to the levels of cortisol, lactate and creatine kinase in blood collected at exsanguination. Earlier rigor development was associated with higher concentrations of these stress indicators in the blood. This relationship suggests that the mean rigor score, and the frequency distribution of carcases that had or had not entered rigor, could be used as an index of the degree of stress to which the pigs had been subjected.

Abattoirs↗

Cleanliness of broilers when they arrive at poultry processing plants.

An eight-point photographic scale from 1 (very clean) to 8 (very dirty) was used to assess the cleanliness of the plumage of 69,783 live broiler chickens delivered in 54 loads to three processing plants which were each visited in spring, summer and winter. There were considerable variations between the plants and between the visits, but most birds were given scores of 6 or 7. The average plant scores were 6.07, 6.56 and 6.84, which were associated with frequencies of birds with scores of 7 or more of approximately 38, 56 and 73 per cent. There was some indication that longer feed-withdrawal times of up to 10 hours were associated with dirtier birds.

Animals↗

Assessment of possible methods for estimating the stocking density of sheep being carried on commercial vehicles.

Five methods for estimating the stocking density of sheep confined in a pen were assessed. The pen (2.35 m x 3.01 m) simulated the pens on a normal road transporter. The trial used 50 lambs (average weight 34 kg) of mixed sex and breed, held at five stocking densities--0.466 to 0.824 m2/100 kg or 214 to 121 kg/m2--covering the range used in commercial practice, and 14 assessors, all experienced in handling animals. The best method was that based on the girth measurement of a sample of animals to estimate liveweight and a count of the animals in the pen. The methods based on using a moveable gate to take up free floor space, assessing the difficulty of moving through the pen of animals, using photographic scales, and counting the numbers of sheep across transects were generally less successful.

Animal Welfare↗

Optimal lairage times and conditions for slaughter pigs: a review.

Keeping pigs in lairage provides a buffer to supply the slaughter line and allows the pigs to recover from the stress of transport. It has implications for the pigs' welfare by influencing their behaviour and ease of handling. In terms of pork quality, optimal lairage times for most pigs in the UK are probably one to three hours. Shorter lairage times are associated with more pale, soft, exudative (PSE) meat and longer times are associated with more dark, firm, dry (DFD) meat, more skin blemishes caused by fighting, and a lower carcase yield. However, when pigs have not been previously stressed by handling procedures, resting them in lairage may have no beneficial effects on the pigs' welfare or meat quality. At very high environmental temperatures there is evidence that a holding period of less than one hour may help to reduce the number of PSE carcases. At temperatures above 10 degrees C showering the pigs with water is beneficial. Fasting times need to be controlled to minimise the potential loss of carcase yield while reducing the volume of gut contents to reduce the risk of carcase contamination. Lairages can act as reservoirs of infection by pathogenic bacteria and there is evidence that longer holding times increase the risk of cross-contamination.

Abattoirs↗

Influence of the design of facilities at auction markets and animal handling procedures on bruising in cattle.

The movements of cattle at 12 livestock auction markets were observed to determine the possible causes of trauma leading to carcase bruising. Design faults included right-angled bends in races, dead ends, flooring with insufficient slope or grip, and steps. Sliding gates were often misused for goading cattle. Projecting fittings and square-edged corners were potentially injurious; conversely, rounded posts and curved races assisted the flow of cattle with minimal impacts. At all the markets, some cattle were hit directly and poked with wooden sticks, and the variations in their use could partially explain the differences between the markets in the prevalence of carcase bruising. Most harder hits were directed at less valuable parts of the body, such as the spine, hips and shoulders, and a survey of bruising at the abattoir showed that these were the areas with most bruising. In this survey of 48,926 carcases, the overall level of commercially significant bruising of 4.1 per cent was lower than the 6.5 per cent found in a previous survey. Carcases of cattle from markets had a greater incidence and severity of bruising (P<0.001) than those arriving directly from farms or dealers. Carcase bruising in young bulls was less (P<0.001) than in heifers and steers.

Abattoirs↗

Survey of the stocking densities at which sheep are transported commercially in the United Kingdom.

A total of 6578 sheep carried in 74 vehicles to one slaughter plant were monitored, and stocking densities, in terms of m2 floor area available per 100 kg liveweight, were estimated from the dimensions of the vehicle pens and estimates of liveweight based on chest girth measurements. The observed stocking densities ranged from 0.29 to 2.00 m2/100 kg liveweight, and the average density was 0.65 m2/100 kg. One per cent of the sheep were carried at estimated stocking densities of less than 0.3 m2/100 kg, 37 per cent at densities between 0.3 and 0.6 m2/100 kg and 57 per cent at densities between 0.6 and 0.9 m2/100 kg. Over 30 per cent of the animals in the survey were transported at densities higher than the working recommendations made by the Farm Animal Welfare Council.

Animal Welfare↗

Changes in the blood biochemical and haematological profile of neonatal calves with age.

Fourteen calves were used to investigate the changes from birth to 83 days of age in the concentrations of serum albumin, alkaline phosphatase, beta-hydroxybutyrate, plasma cortisol, serum creatine kinase, creatinine, iron, plasma fibrinogen, serum gamma-glutamyl transferase, plasma glucose, haptoglobin, serum non-esterified fatty acids, total protein, transferrin, triglycerides, urea and gamma globulin; the haematological variables measured were: basophils, eosinophils, haematocrit, haemoglobin, lymphocytes, mean cell haemoglobin, mean cell haemoglobin concentration, mean cell volume, monocytes, band neutrophils, neutrophils, platelets, red blood cells and white blood cells. The changes are presented as a series of graphs and the values are discussed in relation to the published reference ranges for adult cattle. Two populations of calves were identified which gave rise to a bimodal distribution for some of the variables. Differences in haematocrit, haemoglobin and red blood cell counts were apparent at birth, with raised values for these measurements being associated with an increased white blood cell and neutrophil count between three and 27 days of age.

Aging↗