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Biomedical subjects

P M Hocking

Publications and source records attributed to P M Hocking.

At least 55 records · Page 3Linked to original sources
PubMed1999

Evaluation of intraarticular opioid analgesia for the relief of articular pain in the domestic fowl.

An experimental paradigm, based on the microcrystalline sodium urate-induced arthritis pain model, was used to investigate the potential peripheral analgesic properties of a variety of opioid agonists. The response criteria were changes in behavioral profiles and pain-related behaviors over 60 min commencing 1 h after intraarticular injection. The testing system was used to determine the potential optimum dose of intraarticular application of morphine sulphate (1-3 mg), fentanyl citrate (0.5-3 mg), and buprenorphine hydrochloride (0.05-1 mg). None of the opioid analgesics used had any effect on pain behavior, and it was concluded that opioids with a high affinity for the mu receptor when injected intraarticularly were unlikely to be of use in the treatment or diagnosis of inflammatory arthritic pain in the strain of domestic fowl chosen.

Analgesia↗
PubMed1999

The relationships between vaginal collagen, plasma oestradiol and uterine prolapse in turkeys.

Uterine and vaginal collagen content and plasma oestradiol concentration were measured in traditional, male-line and prolapsed male-line turkeys to investigate the higher incidence of uterine prolapse in the male-line strain. The effect of exogenous oestradiol on vaginal collagen and plasma oestradiol was also tested in the traditional and male-line strains. Vaginal collagen was significantly lower in the male-line compared to the traditional-line, while it was lowest in prolapsed male-line turkeys. Plasma oestradiol concentration was higher in the traditional-line than the male-line. No difference in plasma oestradiol concentration was found between prolapsed and non-prolapsed male-line turkeys. Administration of oestradiol for 7 days significantly raised plasma oestradiol concentration but had no effect on vaginal collagen. Decreased vaginal collagen content was associated with uterine prolapse and may predispose the male-line strain to uterine prolapse. There was no evidence from these results to support an involvement of oestradiol in uterine prolapse in male-line turkeys.

Animals↗
PubMed1999

Welfare of food restricted male and female turkeys.

1. The welfare of male and female male-line turkeys fed ad libitum or food-restricted was determined at 4, 8, 12, 16, 20, 24, 28, 36(38) and 46(48) weeks of age using behavioural and physiological indices of well-being. Traditional turkeys fed ad libitum were kept as a control treatment. Restricted male and female male-line turkeys were fed to 0-5 during rearing and subsequently to 0-8 of sex-specific ad libitum-fed body weight. In another treatment, male-line males were fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 2. Traditional turkeys and restricted male-line turkeys were more active than ad libitum-fed birds of both sexes. Restricted turkeys showed a high incidence of wall pecking. In the breeding period, about 0.4 of the observations of male-line males were of strutting behaviour whereas traditional male turkeys showed no strutting behaviour at the end of the breeding period. 3. The heterophil lymphocyte ratio (HLR) and the proportion of basophils were not increased in food-restricted turkeys. The HLR was relatively low in traditional birds, compared with male-line turkeys during the rearing period. 4. Plasma corticosterone concentrations were increased by food restriction during the rearing period. Corticosterone concentrations were relatively high in traditional turkeys at 4 and 8 weeks of age only. 5. Plasma lactate dehydrogenase (LIDH) activity was higher from 12 to 24 weeks of age in ad libitum-fed male-line turkeys and was consistent with mortality from cardiovascular disease in this group of turkeys. The pattern of activity of aspartate transaminase was similar, and alkaline phosphatase was inversely related to that of LDH. 6. It was concluded that turkeys may be better able to adjust physiologically to the demands of food restriction than broiler breeders and that there were few deleterious consequences of restricting male turkeys after 18 weeks of age. Male-line turkeys were less active than traditional turkeys.

Animal Feed↗
PubMed1999

Assessment of pain during locomotion and the welfare of adult male turkeys with destructive cartilege loss of the hip joint.

1. An assessment was made of the potential pain and stress from musculo-skeletal disease at 54 weeks of age in large male-line turkeys fed ad libitum or on restricted amounts of food. Males from traditional turkey lines were used as a negative control. 2. Traditional turkeys were fed ad libitum and male-line turkeys were fed ad libitum or restricted to 0.5 during rearing and subsequently to 0.8 of sex-specific ad libitum-fed body weight or fed ad libitum to 18 weeks and 0.8 of ad libitum thereafter. 3. Pain was assessed at 54 weeks of age by the change in number of steps taken by turkeys with or without musculo-skeletal disease after a course of betamethasone, a steroid anti-inflammatory agent with analgesic properties. 4. The numbers of steps over 24 h were recorded using a pedometer and were similar in all 4 treatments before and after treatment with the analgesic. It was concluded that there was no evidence for pain associated with musculo-skeletal disease among the turkeys in this experiment. 5. Musculo-skeletal disease was not associated with raised heterophil-lymphocyte ratio, a recognised index of stress.

Analgesia↗
PubMed1999

Visualization and modelling of the thermal inactivation of bacteria in a model food.

A large number of incidents of food poisoning have been linked to undercooked meat products. The use of mathematical modelling to describe heat transfer within foods, combined with data describing bacterial thermal inactivation, may prove useful in developing safer food products while minimizing thermal overprocessing. To examine this approach, cylindrical agar blocks containing immobilized bacteria (Salmonella typhimurium and Brochothrix thermosphacta) were used as a model system in this study. The agar cylinders were subjected to external conduction heating by immersion in a water bath. They were then incubated, sliced open, and examined by image analysis techniques for regions of no bacterial growth. A finite-difference scheme was used to model thermal conduction and the consequent bacterial inactivation. Bacterial inactivation rates were modelled with values for the time required to reduce bacterial number by 90% (D) and the temperature increase required to reduce D by 90% taken from the literature. Model simulation results agreed well with experimental results for both bacteria, demonstrating the utility of the technique.

Agar↗
PubMed1998

Interaction of age, strain, sex and food restriction on plasma creatine kinase activity in turkeys.

1. Plasma creatine kinase activity was determined at 4, 8, 12, 16, 20, 24, 28, 38 and 48 weeks of age in male and female traditional turkeys fed ad libitum, in male and female turkeys of a sire-line fed ad libitum or restricted to 0.5 during rearing and subsequently to 0.8 of sex-specific ad libitum-fed body weight, and in sire-line males fed ad libitum to 18 weeks and 0.8 of ad libitum body weight thereafter. 2. Plasma creatine kinase activity was low in traditional turkeys and increased rapidly after 12 weeks of age in males and females of the sire-line of turkeys. 3. Food restriction decreased the activity of plasma creatine kinase. 4. There was no difference in plasma creatine kinase activity between the sexes during rearing. After the onset of lay, the activity in plasma from females decreased at 38 weeks of age and rose dramatically in restricted females at 48 weeks when the birds had ceased laying. 5. The changes in plasma creatine kinase activity in females were associated with concomitant changes in ovarian activity as reflected in altered plasma triglyceride concentrations.

Aging↗
PubMed1998

Comparative development of the ovary and production, fertility and hatchability of eggs from traditional turkeys and a contemporary male-line fed ad libitum or restricted.

1. Ovarian function was assessed at first egg and at 44 and 54 weeks of age in traditional turkeys and in a male-line fed ad libitum or restricted to 0.5 of ad libitum during rearing. Egg production was recorded daily and fertility and hatchability were determined at 2 ages. 2. Age at sexual maturity did not differ between the 3 treatments. 3. The number of follicles at first egg in the male line averaged 16.3 compared with 8.9 in traditional turkeys. Food restriction in the male line decreased the number of yellow follicles to 14.6 at first egg and restricted birds were largely in a non-reproductive state from 44 to 54 weeks of age. 4. The total number of recorded ovipositions to 54 weeks of age in male line fed ad libitum or restricted and traditional turkeys respectively were 40.1, 25.2 and 70.7; comparable productions of normal shelled eggs were 28, 20 and 66.3. 5. There were no differences between treatments in fertility after a single insemination at 2 different ages. Hatch of fertiles after the first inseminations were 71.4, 45.5 and 90.3 respectively for male line fed ad libitum or restricted and traditional turkeys.

Aging↗
PubMed1998

A preliminary estimate of the heritability of plasma troponin T in broiler chickens.

1. Male and female broiler chickens of a pure line were selected over one generation for low or high plasma, cardiac-derived troponin T concentrations at 12 h of age. 2. Heritability of plasma troponin T was moderately high (h2 = 0.38 +/- 0.06), and there was no difference in mean body weights of parents (G0) of the 2 lines at 4 and 19 weeks of age. 3. This preliminary study suggests that broiler breeder companies will be able to select for resistance against heart damage and ascites.

Animals↗
PubMed1997

The structure of avian cartilage: a combined X-ray and biochemical analysis.

The antitrochanter is a cartilaginous extension of the avian hip joint that is susceptible to degenerative changes. This study consisted of X-ray diffraction and complementary biochemical examination of collagen in the turkey antitrochanter from the articulating surface through to the bone. X-ray diffraction was performed by means of synchrotron radiation with a 200 microns collimated beam to examine the antitrochanter from three 24-week-old, large, male turkeys. The arced distribution of intensity from equatorial reflections was used to determine the parameter g(psi), the probability distribution of fibril angular orientation. Analysis of five distinct regions showed a variety of fibril orientation profiles. The surface of the cartilage exhibited a near isotropic profile. The superficial fibrous region contained well-aligned fibrils parallel to the surface. The middle hyaline region was less well organized, but fibrils were orientated in a direction similar to that of fibrils in the superficial fibrous region. The deep hyaline region exhibited a bimodal distribution of fibril orientation. The ossified front (decalcified) showed an alignment similar to that seen in the middle hyaline region. Biochemically, two main regions were found. The first, 1.2 mm from the surface, consisted of type I collagen and the deeper region (1.26-3.0 mm) consisted of type II collagen. The change from type I to type II was abrupt (less than 80 microns).

Animals↗
PubMed1997

Effects of male body weight, strain and dietary protein content on fertility and musculo-skeletal disease in naturally mated broiler breeder males.

1. The effects of male body weight at mating and different rates of gain on overall fertility were studied in two strains of broiler breeder males fed on a diet containing 160 or 120 g crude protein/kg. Sexual activity, musculo-skeletal disease and culling were also assessed. 2. There were no differences in early fertility between males weighing 3.0 or 3.5 kg at the start of the mating period, or between males gaining 1.0 or 1.5 kg body weight from mating to 60 weeks of age. 3. There were no differences in fertility between males fed on the two diets differing in crude protein content. 4. One strain of male had lower fertility than the other and this was associated with a greater weight of breast muscle, lower frequency of observed copulations and a higher number of incompleted matings. 5. Sexual activity declined and the number of spermatozoa trapped on the perivitelline membrane increased with age. 6. There were no differences among the treatments in the prevalence of musculo-skeletal lesions (destructive cartilage loss). As a proportion destructive cartilage loss occurred in 0.67 of the males at 66 weeks of age. Degeneration of the antitrochanter was present in 3 of 50 females examined and a cartilage flap in the medial condyle of the tibiotarsus occurred in 15 of these birds. 7. Beak lesions were the most important cause of male culling which averaged 0.24 as a proportion of the males at the start of the experiment.

Aging↗
PubMed1997

Effects of dietary crude protein content and food intake on the production of semen in two lines of broiler breeder males.

1. The effects of dietary crude protein (CP) concentration and feeding rate on semen production and quality from 21 to 66 weeks of age were assessed in a factorial experiment with 48 caged broiler breeder males from 2 strains. 2. The probability of obtaining semen and semen volume were lower in one of the two strains but the concentration and yield of spermatozoa were similar. 3. There was no evidence that males which were fed on an increasing quantity of food produced more semen or a greater concentration of spermatozoa than males on a fixed allocation of 120 g/d food. 4. The concentration of spermatozoa was lower in males fed on a diet containing 160 compared with 120 g CP/kg. On termination of the experiment, average testes size was small and testicular function was absent in a large proportion of the males on the high protein diet.

Animal Husbandry↗
PubMed1997

Comparison of food intake, rate of consumption, pecking activity and behaviour in layer and broiler breeder males.

1. The food intake, rate of food consumption (g/min) and behavioural time budgets of individually caged broiler and layer (white egg) males were compared in the early morning (1.5 to 3.5 h after onset of photoperiod) and afternoon (5.5 to 7.5 h after photostimulation) on 4 different days at 11 to 12 weeks of age. Correlations among rate of consumption, the proportions of time on different activities and previously estimated scores for fearfulness were calculated. 2. Food intake and rate of consumption were two-fold greater in broilers than in layers. The proportion of time spent feeding in the morning was lower in layers compared with broilers and was similar in the afternoon. Rate of consumption was higher in the morning than in the afternoon in both lines. 3. Overall, a similar proportion of time was spent feeding, standing and sitting in both lines. The birds were more likely to be sleeping (eyes closed) in the afternoon than in the morning. 4. The proportions of time spent on preening, pecking and stereotypic pacing were greater in layers than in broiler breeders. The proportion of time spent drinking tended to be higher in broiler breeders than layers. 5. Two measures of fearfulness, aversion to a looming human and a novel rod were respectively positively and negatively correlated to time drinking and stereotypic pacing. 6. The time spent in stereotypic pacing was negatively related to rate of consumption and time spent preening. 7. The results suggest that low food intake is associated with increased arousal, fear and frequent feeding and drinking. There was no evidence that beak related activity was related to fearfulness.

Aggression↗