Biomedical subjects

T G Knowles

Publications and source records attributed to T G Knowles.

At least 19 recordsLinked to original sources

PubMed2006

Herd health planning: farmers' perceptions in relation to lameness and mastitis.

Between December 2002 and December 2003, the herd health planning activities on 61 dairy farms in the uk were compared with several measures of lameness and mastitis. Lameness had been reported as a problem in 53 of the herds directly by the farm and in the other eight by the nominating local veterinary practice; 54 of the farms also reported having a mastitis problem. Fifty-three (87 per cent) of the farms had some form of written herd health plan, of which 21 (40 per cent) had been in place for 12 months or less. All the farms were recording mastitis in some way, although 38 (62 per cent) of the farmers did not review these records and only four retained the results of a comprehensive record review. Farms defined as having a high incidence of mastitis were more likely to be reviewing their health records, but farms defined as having a high prevalence of lameness in a sentinel group of early lactation heifers were less likely to be reviewing their health records.

Animal Welfare↗

PubMed2006

Methods used in veterinary practice to maintain the temperature of intravenous fluids.

To determine the methods used in veterinary practice to maintain the temperature of intravenous fluids, and the users' impression of their efficacy, data were collected from a survey of 150 veterinary practices. Of the 99 per cent of the practices that warmed intravenous fluids, the use of a heat retention bag cover was most popular and was considered most effective. In a laboratory experiment, four methods of maintaining the temperature of intravenous fluids were compared. The results showed that there was a significant loss of heat through the giving set. A heat retention cover was an effective device for maintaining the temperature of the prewarmed fluid in its bag. The use of ;hot hands' (a sealed surgical glove containing warmed water) was most effective in reducing heat loss from the delivered fluid, and was aided by prewarming the giving set.

Animals↗

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

Postal survey of the population of South American camelids in the United Kingdom in 2000/01.

The members of the two leading British camelid breeders associations were surveyed by means of a postal questionnaire between December 2000 and January 2001; 696 questionnaires were posted and 218 usable responses were returned. A total of 3520 camelids were recorded, of which 2719 (77.2 per cent) were alpacas (Lama pacos) and 726 (20.6 per cent) were llamas (Lama glama). Ninety-four per cent of the camelid herds were of one species, and 70 per cent of the animals were kept for more than one purpose. Camelids imported from South America were present on 45 per cent of the units surveyed. Husbandry procedures and preventive health measures were uniform; 92.2 per cent of the animals were kept on pasture all year round, 99 per cent were supplemented with hay and 97.7 per cent with concentrate feed; 88.1 per cent were vaccinated against clostridial disease with a multivalent vaccine licensed for sheep, and 96.3 per cent were treated periodically with anthelmintic drugs. During 2000, ill health, other than dermatological conditions, was reported by 24.3 of respondents, and 32 different conditions were described. Skin disease was reported by 51 per cent of breeders. Zinc deficiency was diagnosed presumptively as the cause of skin disease by 31.9 per cent of the respondents, and ectoparasitism by 26.4 per cent. Of those who treated a skin condition, 71.9 per cent reported an improvement, but less than half of them considered the improvement to have been permanent.

Animal Feed↗

PubMed2006

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↗

PubMed2005

Comparative study of the efficacy of eprinomectin versus ivermectin, and field efficacy of eprinomectin only, for the treatment of chorioptic mange in alpacas.

The efficacy of eprinomectin versus ivermectin (Study 1: a single-centre, randomised, treatment-controlled, blinded field trial), and the field efficacy of eprinomectin (Study 2: a single-centre, open, un-controlled field trial) for the treatment of chorioptic infestation in naturally infested alpacas were assessed in two studies. Thirty alpacas, all positive for Chorioptes sp. mite, were randomly allocated to two treatment groups in Study 1. Group A received a single topical administration of a 0.5% formulation of eprinomectin at the dose rate of 500mug/kg. Group B received three subcutaneous administrations at 14 days interval of a 1% formulation of ivermectin at the dose rate of 400mug/kg. Response to treatment was assessed by periodic mite count, and skin lesions scored. In Study 2, one group of 19 alpacas received four administrations at weekly interval of topical eprinomectin at the dose rate of 500mug/kg, and response to treatment was monitored by mite counts. No localised or systemic side effects were observed in either trial. There was a statistically significant decrease in mite counts on day 7 (P<0.001) within treatment Groups A and B of Study 1, but mite counts increased again on day 14 and remained high for the duration of the trial in both treatment groups. On day 14 of Study 2, there was a statistically significant reduction in mite counts (P<0.008) and the mite counts remained very low throughout the remainder of the study. The eprinomectin protocol employed in Study 2, consisting of four weekly topical administrations at the dose rate of 500mug/kg of body weight, proved highly effective at reducing the Chorioptes mite burden in alpacas.

Administration, Cutaneous↗

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↗

PubMed2003

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↗

PubMed2003

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↗

PubMed2003

Serum IgE and IgG responses to food antigens in normal and atopic dogs, and dogs with gastrointestinal disease.

In human food allergy, with or without concurrent atopy, there may be significant increases in serum allergen-specific IgE. Serological methods have been tried but are not currently recommended for diagnosis of suspected food allergy in dogs. The aim of this study was to investigate humoral immune responses to food antigens in dogs. Serum IgG and IgE antibodies specific for food antigens were measured by enzyme linked immunosorbent assay (ELISA) using polyclonal anti-dog IgG and IgE reagents. Antigens tested were beef, chicken, pork, lamb, chicken, turkey, white fish, whole egg, wheat, soybean, barley, rice, maize corn, potato, yeast and cow's milk. Three groups were examined: normal dogs, dogs with atopic dermatitis (AD); and dogs with one of four types of gastrointestinal (GI) disease: small intestinal bacterial overgrowth (SIBO), inflammatory bowel disease (IBD), food-responsive disease, and infectious diarrhoea. Statistically significant differences in food-specific antibodies were not detected between the GI subgroups. There were statistically significant differences in the IgE concentration between the normal dogs, and dogs with atopic or GI disease, for all of the antigens tested. There were statistically significant differences in the average IgG concentrations between the normal dogs, and dogs with atopic or GI disease, for all of the antigens tested, except egg and yeast. The relationship of antigen responses for pooled data was analysed using principle component analysis and cluster plots. Some clustering of variables was apparent for both IgE and IgG. For example, all dogs (normal and diseased) made a similar IgG antibody response to chicken and turkey. Compared with other groups, atopic dogs had more food allergen-specific IgE and this would be consistent with a Th(2) humoral response to food antigens. Dogs with GI disease had more food allergen-specific IgG compared with the other groups. This may reflect increased antigen exposure due to increased mucosal permeability which is a recognised feature of canine intestinal disease.

Animals↗

PubMed2003

Effects of journey and lairage time on steers transported to slaughter in Chile.

Steers representative of the most common type, weight and conformation slaughtered in Chile were transported for either three or 16 hours and held in lairage for three, six, 12 or 24 hours. Measurements of liveweight, carcase weight, and the postmortem pH and colour of muscle were made to assess the economic and welfare effects of the different transport and lairage times. Compared with the short journey, the longer journey was associated with a mean (se) reduction in liveweight of 8.5 (2.8) kg, and there was a further decrease of 0.42 (0.18) kg for every hour that the animals were kept in lairage after 16 hours of transport, an increase in final muscle pH, a decrease in muscle luminosity and an increase in the proportion of carcases downgraded because they were classified as 'dark cutting The carcase weights also tended to be lower after the longer journey and after longer periods in lairage.

Abattoirs↗

PubMed2003

Mercury in UK imported fish and shellfish and UK-farmed fish and their products.

Total mercury concentrations were measured in fish and shellfish and their products imported into the UK and also in UK-produced farmed salmon and trout. Three hundred and thirty-six samples were collected using a two-stage sampling plan. The sample plan was weighted to reflect consumption, but with some bias towards fish that might accumulate higher levels of mercury, such as large predatory fish at the top of the food chain. The highest levels of total mercury were found in billfish (swordfish and marlin) and shark. Mercury concentrations in the five samples of fresh/frozen shark ranged from 1.006 to 2.200 mg kg(-1), all above the European Commission limit for the species, and concentrations in 20 samples of fresh/frozen billfish ranged from 0.153 to 2.706 mg kg(-1) with 13 samples above the 1.0 mg kg(-1) limit for the species. One sample of Antarctic ice fish was collected and had a mercury concentration of 0.664 mg kg(-1). The limit for this species was 0.5 mg kg(-1). One sample of fresh/frozen tuna out of the 20 collected had a mercury concentration above the limit of 1.0 mg kg(-1) (1.5 mg kg(-1)), but all other fresh tuna samples were well within the regulatory limit (average 0.4 mg kg(-1)). Mercury concentrations in canned tuna were lower with concentrations on average half that measured in fresh/frozen tuna. Mercury concentrations in UK-farmed salmon and trout were relatively low. The maximum concentration found in 46 samples of fresh/frozen or smoked trout and salmon was 0.103 mg kg(-1).

Animals↗

PubMed2002

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↗

PubMed2000

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↗

PubMed1999

Relationship between food deprivation before transport and aggression in pigs held in lairage before slaughter.

Pigs from three farms were deprived of food for up to one hour, 12 hours or 18 hours before being sent for slaughter. In lairage, the animals' behaviour was monitored, and at slaughter a blood sample was collected and analysed for cortisol, lactate and creatine phosphokinase, potential indicators of stress and physical activity. The carcases were assessed for skin damage as an index of fighting, and rigor in the hind leg as an indicator of stress and/or fatigue. Measurements were also made of cold carcase weight, backfat thickness and liver glycogen concentration. General activity was very high on entry to the lairage pen. Drinking and mounting occurred almost immediately. Fighting developed after an exploratory period, and could last up to 60 minutes. There were large differences in the behaviour of pigs from the three farms. Pigs from farm A fought frequently but showed little mounting activity, whereas pigs from farm C were involved in mounting but little fighting. The period of food deprivation had no effect on average skin damage or rigor score, but the frequency of carcases with the highest scores was different The pigs deprived of food for up to an hour had the lowest incidence of severe skin damage and high rigor scores. Boars had a higher incidence of severe skin damage but a lower incidence of carcases with a high rigor score than gilts. Liver glycogen was almost completely depleted in the pigs deprived of food for 12 and 18 hours and was lower in the pigs deprived for up to an hour than in animals fed immediately before slaughter. The period of food deprivation had no effect on the levels of cortisol, creatine phosphokinase or lactate in the blood.

Abattoirs↗

PubMed1999

Effects on cattle of transportation by road for up to 31 hours.

The physiological and behavioural effects on cattle of transporting them for periods of 14, 21, 26 and 31 hours, including a stop for a rest and drink on the lorry after 14 hours, were studied in 120 transported animals and 48 control animals. The physiological measurements indicated that a journey lasting 31 hours was not excessively physically demanding, but many of the animals chose to lie down after approximately 24 hours. The animals that lay down had higher plasma cortisol levels than those that remained standing. Many animals chose not to drink during the rest stop. Physiological measurements made after the journeys indicated that 24 hours in lairage, with hay and water freely available, allowed the animals to recover substantially, although not completely, irrespective of the journey time.

3-Hydroxybutyric Acid↗

PubMed1999

Behavioural and physiological responses of pigs to being transported for up to 24 hours followed by six hours recovery in lairage.

Ninety-six pure-bred Large White pigs weighing 80 to 100 kg were either not transported or transported for eight, 16 or 24 hours, and then either slaughtered immediately on arrival at the abattoir or kept in lairage for six hours before being slaughtered. The pigs travelling for eight, 16 or 24 hours lost 2.2, 2.0 and 4.3 per cent of liveweight, respectively, and the pigs travelling for 24 hours lost 2.6 per cent of hot carcase weight Both liveweight and hot carcase weight recovered during the lairage period although there was a net liveweight loss in comparison with the control animals. Only transport for 24 hours led to losses in carcase weight The concentration of non-esterified fatty acids increased with the time spent travelling. The concentrations of cortisol, creatine phosphokinase and lactate were all low in comparison with the levels found in commercially slaughtered animals. Plasma albumin and protein concentrations indicated that the animals were becoming dehydrated during the longer journeys. The animals lay down for most of the journey and appeared to be asleep. During the period in lairage, the animals transported for eight hours had two distinct periods of feeding and drinking but spent most of the time lying down, but those transported for 16 and 24 hours showed far more eating and drinking activity. All the groups appeared tired, but the urge to eat of the groups transported for 16 hours, and especially 24 hours appeared to be more important. There were behavioural and the physiological differences between the transported groups and the controls. Six hours in lairage with access to food and water allowed most of the physiological parameters to return to pretransport levels.

Animals↗