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Biomedical subjects

T G Knowles

Publications and source records attributed to T G Knowles.

At least 37 records · Page 2Linked to original sources
PubMed1999

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.

Animal Welfare↗
PubMed1999

Effect on young calves of a one-hour feeding stop during a 19-hour road journey.

This study examined the effects of transporting calves less than four weeks of age on a journey at the limit of the maximum time laid down by recent EU legislation. In both summer and winter, 45 calves were transported by road for 19 hours. The journey included a one-hour break on the lorry in which the calves were given either a glucose/electrolyte solution, water, or nothing at all. Control groups of 15 calves remained on farm and were fed normally. The effects of the journey were greater during winter when liveweight loss was greater and more prolonged, and the calves suffered a depression in body temperature. Mid-journey feeding was of minimal benefit. Feeding electrolytes reduced the extent of dehydration as measured by changes in plasma total protein and albumin concentrations, but there was some indication that giving water alone was detrimental. Most of the variables which changed during the journey had recovered in line with the values in the control animals within 24 hours of the end of the journey, but the calves' liveweight and plasma creatine kinase activity took up to seven days to stabilise. The study highlighted the problem that young calves have in maintaining body temperature during transport, especially during colder weather.

Animal Feed↗
PubMed1999

A review of the road transport of cattle.

The transport of farm animals has been the subject of much research in recent years. This paper reviews the recent scientific literature pertinent to the road transport of cattle. The state of knowledge is summarised and recommendations for best practice based upon this are given. Areas which require further work are also identified.

Animal Welfare↗
PubMed1998

Ambient temperature below which pigs should not be continuously showered in lairage.

Showering pigs with cold water during preslaughter lairage is thought to be useful in reducing the body temperature of hot, easily stressed animals. However, showering when the ambient temperature is too low could chill them too severely. To assess the effects of showering and to determine a temperature below which pigs should not be showered, pigs from one source, passing through a commercial slaughterhouse lairage, were split into two groups of approximately 50 each, showered and unshowered, on 10 days with a range of ambient temperatures. The pigs' behaviour and any damage to their skin were recorded, various measures of body temperature were taken before and after showering, and blood taken at slaughter was analysed for plasma creatine kinase, cortisol and lactate. Showering prevented the usual reduction in activity observed in pigs in lairage at high ambient temperatures. On the basis of the reduction in their flank temperature during showering, it is recommended that pigs should not be showered continuously if the temperature inside or outside the lairage falls below 5 degrees C, and showering should cease if they are seen to be shivering.

Abattoirs↗
PubMed1998

A review of the road transport of slaughter sheep.

The transport of farm animals has been the subject of much research in recent years. This paper reviews the past and recent scientific literature pertinent to the road transport of slaughter sheep. The state of knowledge is summarised and recommendations for best practice based upon this are given. Areas which require further work are also identified.

Animal Welfare↗
PubMed1998

Effects of stocking density on lambs being transported by road.

Lambs were transported for 24 hours during summer and winter at a range of stocking densities. Shorn lambs of mean liveweight 39.5 kg were transported at densities of 0.448, 0.513, 0.602 and 0.769 m2/100 kg in July and fully-fleeced lambs of 37.3 kg mean liveweight were transported at densities of 0.613, 0.680, 0.775 and 0.909 m2/100 kg in February. Fewer lambs lay down and rested at high stocking densities and there was a marked increase in the plasma levels of creatine kinase at the highest stocking density in winter. All other measured effects of stocking density were small when compared with the overall effects of transport. There was a decrease in body temperature during transport, especially in the lambs that were recently shorn, even though they were transported during warm summer conditions. At the highest stocking density there was a smaller decrease in body temperature.

Animal Welfare↗
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↗
PubMed1997

Effects on calves less than one month old of feeding or not feeding them during road transport of up to 24 hours.

Two trials, each involving 56 calves less than one month old, demonstrated that the responses of calves to food and water deprivation during 24 hours of transport were similar to those observed in older cattle and lambs. There was increasing utilisation of body reserves and a measurable increase in dehydration, coupled with an increased loss of liveweight. Feeding 1 litre of glucose/electrolyte solution at eight-hour intervals did reduce the effects of food and water deprivation, but it is suggested that the minor benefits of mid-transport feeding during a 24-hour journey would not justify the disruption that would be caused by unloading and feeding. It would be better to complete the journey in as short a time as possible, providing the calves were carried under suitable conditions. Liveweight and the levels of plasma beta-hydroxybutyrate, non-esterified fatty acids, total protein and albumin had all returned to approximately pre-transport values after 24 hours of recovery. However, the calves had not started to gain in liveweight until some time after 24 but before 72 hours of recovery. The calves did not show the same marked responses in heart rate, plasma cortisol and plasma glucose that are observed in older cattle and in other species. They also appeared to be unable to regulate their body temperature closely, when they were transported during the winter. It is suggested that their lack of response to transport was not because they were unaffected but because they were physiologically unadapted to coping with transport.

Adaptation, Biological↗
PubMed1997

Potential effect of vibration during transport on glycogen reserves in broiler chickens.

Subjection of broiler chickens to random, narrow band vibration (2, 5, 10 Hz) for 1 h, simulating that experienced during normal road transport, did not significantly influence liver or muscle glycogen concentrations or muscle ultimate pH (pHu). Vibration for 3 h increased body temperature (P<0.05) and decreased (P<0.01) pHu in both 'white' pectoralis superficalis (PS) and 'red' biceps femoris (BF) muscles overall, but did not affect liver or muscle glycogen concentrations. However, higher vibration frequencies resulted in reduced (P<0.05) glycogen concentrations in liver and BF muscle. The conclusion was that vibration was unlikely to be the major cause of muscle glycogen depletion seen in transported broilers, but the reduction in pHu in the PS muscle after vibration may have been related to the similar effect seen in previous studies after normal transport.

Animal Husbandry↗
PubMed1996

Effects of feeding, watering and resting intervals on lambs transported by road and ferry to France.

Three lorry loads, each of approximately 530 lambs, were monitored during August 1994 while they were transported from the Midlands to France. Each lorry underwent a similar journey, designed to study the effects of a) 22 hours on a lorry broken by two hours of feed, water and rest after 15 hours, b) 34 hours on a lorry broken by eight hours of feed, water and rest after 24 hours and c) 24 hours on a lorry and lairage for the following 48 hours. Measurements were made on 180 lambs in each load, of liveweight, plasma betahydroxybutyrate (BHB), non-esterified fatty acids (NEFA), urea, total protein, albumin, osmolality, creatine kinase (CK), cortisol and glucose, before, during and after transport. Twenty-four hours of transport resulted in changes in some of the variables measured that were little different from those observed after 24 hours of feed and water deprivation; however, the high ambient temperatures during the transport resulted in a greater degree of dehydration. For journeys longer than 15 hours a two-hour rest in lairage with access to water and a palatable food source was beneficial in allowing some slight recovery. Although all the differences were in the direction that would be expected with recovery, they were often small and, within the sensitivity of the study, were only significant for NEFA and C.K. For journeys longer than 24 hours, an eight-hour rest in lairage with access to water and a palatable food source was beneficial and allowed material realimentation and rehydration before further transport for up to 10 hours. After 24 hours of transport, however, liveweight, plasma urea, total protein and albumin had only returned to basal levels after 24 hours in lairage and plasma BHB, CK and osmolality after 48 hours of lairage.

3-Hydroxybutyric Acid↗
PubMed1996

A survey to investigate potential dehydration in slaughtered broiler chickens.

A survey of 800 broilers arriving at two commercial slaughterhouses with a combined annual throughput of 40 million birds was carried out. Each plant was visited on four occasions throughout summer and winter and blood samples were collected from 100 broilers at exsanguination throughout the day of each visit. In all, the survey covered 16 lorry loads of broilers delivered to one plant and 20 loads delivered to the other. The blood collected was analysed for packed cell volume (PCV), plasma creatine kinase, total protein, sodium, glucose, osmolality and corticosterone. Based on the measures of PCV, plasma total protein, sodium and osmolality there was no evidence of dehydration amongst the lorry loads of birds delivered to the plants. There were differences between the two plants in the levels of all of the blood variables that were measured, except for those of plasma corticosterone.

Abattoirs↗
PubMed1995

Effects on sheep of transport by road for up to 24 hours.

Five groups of 20 slaughter sheep of approximately 37.9 kg liveweight were transported by road for either three, nine, 15, 18 or 24 hours and three groups were not transported, one of them being deprived of food and water for 24 hours. Before and after transport the liveweight and various blood variables were measured and heart rate and behavioural observations were recorded from subsets of the animals. With increased journey time there was a decrease in liveweight and an increase in the plasma levels of free fatty acids, beta-hydroxybutyrate and urea; however, the changes over 24 hours were similar to those in the group deprived of food and water. In the transported sheep, the heart rate and levels of plasma cortisol and glucose were increased by the stresses of loading and the initial stages of the journey, but after nine hours the sheep appeared, to some extent, to have adapted. They were able to lie down and did not appear to be physically stressed. Measurements of plasma osmolality, total plasma protein and albumin did not indicate that the sheep had become severely dehydrated after 24 hours of transport but upon their return, feeding and drinking activity was greater than that observed before the journey.

Adaptation, Physiological↗
PubMed1995

Effects on cattle of transport by road for up to 15 hours.

Twenty-four castrated male cattle aged between 12 and 18 months were transported by road for five, 10 or 15 hours, over distances of 286, 536 and 738 km. Half the animals were of Hereford x Friesian breeding and half of 'continental' type. The animals transported for five hours lost 4.6 per cent of their bodyweight, those transported for 10 hours lost 6.5 per cent and those transported for 15 hours lost 7.0 per cent; recovery to pre-transport values took five days. There was little evidence from changes in blood composition that a 15-hour journey was more stressful than a 10-hour journey. The cortisol concentrations were increased by the stresses of loading and the first part of the journey but then recovered as the journey continued. Creatine phosphokinase (CPK) activities increased progressively with the longer journeys and CPK, urea, albumin and osmolality levels recovered more slowly after the longer journeys. Increases in free fatty acids, beta-hydroxybutyrate and urea concentrations and the continued increase in urea levels after the end of the journeys suggested that the animals' normal pattern of feeding was disrupted. Increases in albumin, total plasma protein and osmolality indicated slight dehydration during transit which was quickly rectified by access to water. The two breed types responded similarly to transport, except that the increases in CPK were greater in the continental breeds, possibly as a result of their greater muscularity or greater sensitivity to stress. Based on the physiological measurements made and the subjective observations of behaviour a 15-hour transport period under good conditions is not unacceptable from the viewpoint of animal welfare.

Animal Husbandry↗
PubMed1994

Factors affecting the mortality of lambs in transit to or in lairage at a slaughterhouse, and reasons for carcase condemnations.

The computerised records of all the lambs slaughtered at one plant from August 1991 to July 1992 were used to determine the mortality rate throughout the year and to examine the variables that could have been associated with changes in the mortality rate. The plant processed 3.3 per cent of all the lambs that were slaughtered in the United Kingdom during the period. Lambs arriving for slaughter from a livestock auction were over four times more likely to die in lairage, or to have died during transport, than lambs which were sent directly from the farm. However, the overall mortality rate was only 0.0182 per cent and lower than that for other species for which figures were available. Changes in the mortality rate of the lambs from livestock auctions appeared to be associated with the price of slaughter lambs, and periods of increased mortality coincided with increased rates of carcase condemnations due to 'arthritis', 'abscess' and 'pleurisy'.

Abattoirs↗
PubMed1994

Long distance transport of export lambs.

Two commercial lorry consignments of 500 sheep were followed from the United Kingdom to their destinations in southern France, one journey of 800 miles taking 18 hours and the other of 950 miles taking 24 hours. Measurements were made of liveweight and skinfold thickness, and blood samples were taken from 100 sheep in each consignment, two days before departure and again immediately after the journeys. The results from each consignment were similar. High levels of plasma beta-hydroxybutyrate, free fatty acids and urea, both before and after the journeys, indicated that the animals were in a catabolic state. Before the journey this was probably as a result of their marketing through livestock auctions. After the journey the animals showed evidence of dehydration, indicated by increased levels of plasma total protein and albumin, and increases in plasma osmolality and skinfold thickness. The behaviour of the sheep after the journeys indicated that they were all alert and physically fit; they showed great interest in any food that was available and were only secondarily interested in drinking, and then resting.

Age Factors↗