Biomedical subjects

L J Wilkins

Publications and source records attributed to L J Wilkins.

At least 19 recordsLinked to original sources

PubMed2006

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↗

PubMed2006

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↗

PubMed2006

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↗

PubMed2006

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↗

PubMed2005

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↗

PubMed2004

Investigation of palpation as a method for determining the prevalence of keel and furculum damage in laying hens.

Old breaks of the keel and furculum were identified by palpation in 500 end-of-lay hens from 10 flocks housed in free-range and barn systems, and the results were compared with the results obtained by a full dissection and inspection. The method was considered to be sufficiently precise to be used as a diagnostic tool although people using it would need to be trained. The results obtained by dissection indicated that 50 to 78 per cent of the birds in the flocks had breaks of the furculum and keel, but no other breaks of bones were detected.

Animal Husbandry↗

PubMed2004

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↗

PubMed2003

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↗

PubMed2003

Behaviour and welfare of individual laying hens in a non-cage system.

1. A leg band containing a transponder was fitted to 80 birds in a perchery containing 1,000 birds. 2. The transponder emitted a unique identification number when a bird walked on one of 8 flat antennae on the floor. The recording apparatus was used to measure the amount of time that each of the tagged birds spent on the slatted and littered areas in a 6-week period. 3. Some birds spent long periods of time on the slats, possibly as a means of avoiding repeated attacks. Duration on the slats was greatest in birds with the worst (as opposed to better) feather scores of the head, back and tail regions. 4. Birds that spent long periods on the slats were lighter than other birds at both 39 weeks of age and 72 weeks of age and had greater back, head and tail feather damage, consistent with these birds being victims of pecking. 5. Tagged birds received a social avoidance test outside the perchery at 39 weeks of age, which suggested that birds retreated to the slats in response to pecks rather than just to close proximity to other birds. 6. The failure to find that duration on the slats was related to anatomical indicators of stress (liver, spleen and bursa of Fabricius) suggests that retreating to the slats following pecking attenuates physiological stress responses. 7. We conclude that the provision of areas where birds in a large group can avoid pecking may improve the welfare of a minority of victimised birds.

Animal Welfare↗

PubMed2002

Effect of frequency of the stunning current waveform on carcase and meat quality of turkeys processed in a commercial plant in the UK.

1. This study compared the effects of electrical stunning delivered using high and low frequency waveforms on carcase and meat quality of turkeys processed under commercial conditions. 2. The use of a high frequency waveform (1400 Hz) resulted in a faster bleedout and an improvement in carcase quality associated with a substantial reduction in haemorrhagic downgrading conditions. 3. Frequency of the applied waveform influenced breast muscle pH and colour although the magnitude of the differences was considered to be of minimal significance in influencing consumer perception.

Abattoirs↗

PubMed2001

Effect of electrical stun/kill method, interval between killing and neck cutting and blood vessels cut on blood loss and meat quality in broilers.

1. Broiler chickens were killed using either an electrical waterbath (WB system) delivering 120 mA per bird (50 Hz, alternating current, AC) for 4 s or an alternative stun/kill method (ASK system); where head-only stunning for 1 s was immediately followed by head-to-body (vent) application for 1 s (150 mA, 50 Hz sine wave AC). Within each stun/kill system, the neck was cut ventrally or unilaterally 20, 60, or 180 s after killing. In addition, a control group of broilers was stunned with 100 mA per bird in a waterbath using 1500 Hz AC for 4 s and were bled by a ventral neck cut within 20 s. 2. Blood leaving the neck cut was collected for 90 s in a bin placed on an electronic balance and blood loss (g/kg body weight) calculated. 3. Individually identified, unplucked and uneviscerated carcases were held at ambient temperature until the end of the experimental day and then stored overnight in an air chiller (5 degrees C). The carcases were dissected and the incidence of broken furculum and coracoid bones, haemorrhaging in P. minor and P. major muscles, and discolouration of P. major muscles were determined. 4. When neck cutting was performed in broilers 20 s after the stun or kill, the ASK and WB systems, in comparison with high frequency stunning, produced on average about 10 g per kg less bleed out. Within the stun/kill systems, broilers killed by ASK had a greater bleed out than in the WB system. Neck cutting at 20 s or 60 s post-kill resulted in a greater bleed out than when performed after a delay of 180 s. Ventral or unilateral neck cutting resulted in a similar bleed out. 5. Stunning broilers with 1500 Hz AC resulted in lower incidences of broken bones, haemorrhaging in breast muscles and muscle discolouration post mortem than the stun/kill systems. These defects were significantly lower in the ASK than in the WB system. Delayed neck cutting increased the severity of discolouration occurring Post mortem in the breast muscles. 6. It is suggested that broilers killed by ASK can be neck cut with a delay of up to 180 s without compromising bleed out. The incidence of broken bones and haemorrhaging in breast muscles are significantly less with ASK than WB. 7. Owing to the commercial benefits and potential for improved welfare at slaughter, ASK would appear to be a better method than WB.

Abattoirs↗

PubMed2000

Variation in the colour of broiler breast fillets in the UK.

1. The normal range in colour of broiler breast muscle was assessed using an objective (instrumental) measure of colour in portioned breast fillets at a commercial processing plant. In addition, the relationship between colour and ultimate muscle pH (pH(ult)) was also examined. 2. Considerable variation in colour was evident although minimal inter-flock variation was found. The exceptions were 2 free range flocks which produced breast fillets significantly lighter and less red. 3. Extremes of colour are likely to be discriminated against at the point of purchase. 4. A clear relationship between pH(ult) and L* values was found which provides more evidence for the existence of a PSE like condition in broiler breast meat.

Animals↗

PubMed1999

Effect of very low pulsed direct currents at high frequency on the return of neck tension in broilers.

Broiler chickens were stunned electrically for one second or 10 seconds with a unipolar pulsed direct current (DC) at 550 Hz. The effectiveness of the stun was assessed from the birds' behaviour. All the birds were stunned effectively when more than 15 mA true root mean square DC was applied for either period. An increase in the duration of the applied current resulted in an increased duration of unconsciousness. However, the unipolar pulsed DC at 550 Hz did not induce cardiac arrest, and it must therefore be accompanied by a prompt and effective neck cut, severing both carotid arteries.

Abattoirs↗

PubMed1999

Effectiveness of different electrical stunning regimens for turkeys and consequences for carcase quality.

This study examined the effectiveness of electrical stunning of turkeys applied at 150 mA per bird utilising a range of waveform-frequency combinations. In addition, the effect of stunning treatment on subsequent carcase quality was examined. The effectiveness of stunning, as judged by time to recovery, was similar regardless of bird weight or applied stunning treatment. Increasing waveform frequency was associated with a decrease in the prevalence of ventricular fibrillation, although turkeys appeared more susceptible than broilers. Use of the higher frequency waveforms (500 and 1500 Hz) was associated with a marked improvement in carcase quality, particularly with regard to breast muscle haemorrhaging and their use may result in considerable commercial advantage.

Abattoirs↗

PubMed1999

Broiler stunning and meat quality.

The effects of electrical and concussion stunning on meat and carcass quality of broilers were compared. Broiler chickens (n = 165) were subjected to treatments: 1) electrical stunning with no fibrillation, 2) electrical stunning with fibrillation, 3) concussion stunning with restraint, or 4) concussion stunning with no restraint. Electrical stunning (100 V, 80 mA, 50 Hz sinusoidal waveform alternating current) was applied for 3 s. Concussion was applied using a nonpenetrative captive bolt gun with or without restraint. We assessed broken bones, hemorrhages, meat quality defects, blood loss, pH at 10 min and 24 h, and texture from breasts filleted 3 h and 24 h postmortem. Electrically stunned birds showed a significantly higher incidence of broken bones (P < 0.0001), coracoid and furculum bone hemorrhages (P < 0.0001), and nonbone hemorrhages (P < 0.0001) than birds stunned by concussion. However, the incidence of red wing tips (P < 0.005) and shoulder hemorrhages was significantly higher (P < 0.05) in concussion-stunned birds than electrically stunned birds. Electrically stunned and nonfibrillated birds had the fastest blood loss rate. The pH value at 10 min was the lowest in concussion-stunned and unrestrained birds. Breast muscles from concussion-stunned birds that were filleted at 3 h postmortem were more tender than those from birds stunned electrically (P < 0.05). We concluded that concussion stunning could be advantageous for early filleting.

Animals↗

PubMed1998

Effectiveness of electrical stunning applied using a variety of waveform-frequency combinations and consequences for carcase quality in broiler chickens.

1. The effectiveness of electrical stunning of poultry was assessed where the recommended current of 105 mA per bird was applied using a range of waveform-frequency combinations. In addition the effect of the treatments on subsequent carcase quality was investigated. 2. The use of frequencies greater than 50 Hz was associated with a failure to induce ventricular fibrillation. 3. All waveform-frequency combinations were equally effective in producing a stunned state; the time to recovery was not affected by stunning treatment but was significantly longer in heavier birds. 4. The use of high frequency (500 Hz and 1500 Hz) stunning currents resulted in a decrease in carcase downgrading and a marked reduction in the occurrence of breast muscle haemorrhages, which represent significant commercial benefits to be gained by their use.

Animal Welfare↗

PubMed1998

Carcase and meat quality in ducks killed with either gas mixtures or an electric current under commercial processing conditions.

1. The feasibility of killing 7-week old Peking ducks with gas mixtures and their effects on carcase and meat quality were evaluated and compared with killing in electrical waterbath under commercial conditions. 2. The prevalence of carcase appearance defects and broken bones in the carcases and haemorrhaging, pH, colour, cooking loss and texture of breast muscles were determined. 3. Ducks can be killed within 3 min by exposure to either 90% argon in air or a mixture of 30% carbon dioxide and 60% argon in air. 4. Gas or controlled-atmosphere killing of ducks, whilst they are still in their transport containers, would eliminate some of the welfare concerns associated with the conventional electrical waterbath stunning systems, without adversely affecting carcase and meat quality.

Abattoirs↗

PubMed1998

The problem of broken bones during the handling of laying hens--a review.

The major welfare concern during the handling of laying hens is that of broken bones. With particular reference to the United Kingdom, this paper reviews the work that has been done to quantify the problem, to examine the causes, and to investigate factors that affect it. The number of freshly broken bones found in live birds prior to slaughter and the number of old healed breaks found at slaughter are unacceptably high. End-of-lay hens from battery cages have especially fragile bones and these are easily broken during the rough handling that is received during depopulation. Birds from more extensive laying systems have stronger bones and suffer fewer breaks during depopulation but have a greater prevalence of old healed breaks. The old breaks occur as a result of collisions due to poor design within these housing systems. The number of fresh breaks can be reduced by increasing bone strength and handling birds with more care. The numbers of old breaks can be reduced by better design of housing systems and the physical environment within them.

Aging↗