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Biomedical subjects

C Riddell

Publications and source records attributed to C Riddell.

At least 37 records · Page 2Linked to original sources
PubMed1989

Photoperiodic effects on performance and leg abnormalities in broiler chickens.

Three experiments were conducted to examine the impact of changing photoperiod length on the performance of chicken broilers. Effect of long, constant (23-h) photoperiod length (23H) was compared with treatments where photoperiod increased from 6 to 23 h abruptly after 21 days (6H) or gradually during the experiment (INC). The 6H program was used in all three experiments, whereas the INC treatment was included only in Experiment 3. Differences between total body weight gains of birds in the 6H and 23H treatments were inconsistent and small in the three experiments. In Experiment 3, there were no differences between total body weight gains for INC, 6H, and 23H treatments. Feed-to-gain ratios for 6H broilers were significantly superior to those for birds on the 23H treatment for Days 0 to 21 (all experiments), Days 21 to 42 and Days 0 to 42 (Experiment 2), and inferior for Days 21 to 42 (Experiment 3). The INC treatment was significantly superior to the 23H program for all time periods and to 6H birds for Days 21 to 42 and Days 0 to 42. The 6H treatment significantly reduced the incidence of leg abnormalities in comparison with the 23H program in all experiments; the INC and 6H treatments were equal in incidence in Experiment 3. When data from the three experiments were combined, mortality due to sudden death syndrome and other causes for the 6H treatment was significantly lower than that of the 23H program; values for the 6H and INC treatments were not different in Experiment 3.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Dietary level of fat, calcium, and vitamins A and D3 as contributory factors to rickets in poults.

Two experiments were conducted on dietary predisposition to rickets in poults. The first experiment compared fat type (corn oil or tallow), level of added fat (3.5 or 7%), vitamin D3 (900 or 2,400 IU/kg feed), and total calcium (.6, 1.2, or 3%) inclusion in the diet. Poults fed diets supplemented with corn oil had higher percentage tibia ash than poults fed tallow-supplemented diets. Vitamin D3 included at 2,400 IU/kg feed increased body weights significantly by 2 and 4 weeks of age and lowered plasma alkaline phosphatase (AP) at 2 and 4 weeks compared with diets containing 900 IU/kg feed. Tibia ash was significantly greater with the higher vitamin D3 supplementation at 2 weeks. At 2 weeks of age both low (.6%) and high (3%) levels of dietary calcium increased plasma AP, decreased tibia ash, and decreased body weight compared with diets containing 1.2% calcium. By 4 weeks of age, diets containing 1.2 and 3% calcium had no significant effects on body weight and plasma AP; however, tibia ash was significantly greater with these levels than with the .6% calcium diets. The second experiment compared level of dietary tallow inclusion (2.5 or 7%) and supplementary vitamin A (4,000, 16,000, or 44,000 IU/kg feed). The high tallow diets decreased tibia ash at 3 weeks, and the maximum supplementation of vitamin A significantly depressed body weight. Clinical rickets were first noted at 18 days of age. By 26 days of age the higher level of dietary fat and the highest level of vitamin A caused a significant increase in severity of rickets. The results suggested that rickets can be induced by high dietary levels of tallow and vitamin A.

Alkaline Phosphatase↗
PubMed1981

Subclinical infectious bursal disease in commercial broiler flocks in Saskatchewan.

Five commercial broiler flocks, not vaccinated for infectious bursal disease virus, derived from infectious bursal disease virus-vaccinated breeder flocks were surveyed for evidence of bursal damage and infectious bursal disease virus infection. They were compared with two groups of birds raised in isolation. Serum samples from one day old chicks contained maternal anti-infectious bursal disease virus antibodies which declined to undetectable levels by four weeks of age. Serum antibody levels remained undetectable in both control groups and one commercial flock, whereas four of the five commercial flocks had actively produced anti-infectious bursal disease virus antibodies by slaughter age. The weight of bursae from infectious bursal disease virus-positive flocks declined as compared to controls after four weeks of age. The decline in weight correlated with the appearance of histopathological lesions. Infectious bursal disease virus antigen was demonstrated in selected infected bursae and infectious bursal disease bursae and infectious bursal disease virus was isolated from some of these damaged bursae. Clinical infectious bursal disease was not observed in any of the commercial flocks. The importance of subclinical bursal damage and immunosuppression is discussed.

Animals↗
PubMed1981

Two cases of mycobacteriosis in psittacine birds.

Two cases of mycobacteriosis in individual psittacine birds from two separate small aviaries are described. The lesions consisted of infiltration of organs with large macrophages, containing numerous acidfast organisms. There was no caseation or encapsulation of the lesions. No microbiological studies were conducted as mycobacteriosis was not suspected at the time of necropsy.

Animals↗
PubMed1980

A survey of skeletal disorders in five turkey flocks in Saskatchewan.

Losses due to skeletal disorders varied from 1.8 to 6.1 percent in five flocks, varying in size from 2040 to 7033 birds, of broad breasted white tom turkeys. Very little evidence of significant air-sacculitis due to Mycoplasma meleagridis was found in hatching poults or during the growing period. Major disorders causing the losses included rickets, rotated tibia, arthritis/osteomyelitis and long bone distortion. Rickets and arthritis/osteomyelitis due to infection with Staphylococcus aureus were significant problems only in one flock each, while rotated tibia caused significant losses in three flocks. Long bone distortion was the major cause of economic loss and occurred in all flocks. Possible causes of long bone distortion are briefly discussed.

Air Sacs↗
PubMed1978

Herpes virus of turkey vaccine: viraemias in field flocks and in experimental chickens.

In a field survey of viraemias due to vaccination of chickens with herpes virus of turkey, variation was encountered in titres and percentages of birds viraemic. The incidence of viraemias was much lower in sick than in healthy birds in flocks undergoing mortality from Marek's disease. In a concurrent experiment the same strain of chicken and the same commercial vaccine were used as in the field flocks affected with Marek's disease. A high incidence of viraemia and 84.6 per cent protection against Marek's disease were obtained with single vaccination at one day of age. Revaccination at 21 days of age produced no measurable benefits in the same experiment.

Age Factors↗
PubMed1977

Investigation of the vascular supply of the pectoral muscles of the domestic turkey and comparison of experimentally produced infarcts with naturally occurring deep pectoral myopathy.

Naturally occurring deep pectoral myopathy in 9 chickens and 6 turkeys was reviewed. The arterial blood supply to the pectoral and supracoracoid muscles was studied in normal mature turkey hens by preparation of arterial casts following perfusion with methyl methacrylate. Also, a latex-perfused turkey was dissected and the blood vessels supplying these muscles were identified. Six mature turkeys (under general anesthesia) were subjected to unilateral surgical obstruction of selected cranial and caudal pectoral arteries and veins and then were euthanatized and necropsied at various postsurgical times. tin 2 of the turkeys, infarction of pectoral and supracoracoid muscles was produced. Gross and microscopic examinations of these infarcts revealed that they were very similar to the lesions of deep pectoral myopathy.

Animals↗
PubMed1976

Pathological changes in chickens, ducks and turkeys fed high levels of rapeseed oil.

Rations containing 25% of either regular rapeseed oil (36% erucic acid), Oro rapeseed oil (1.9% erucic acid), soybean oil or a mixture of lard and corn oil were fed to chickens, ducks and turkeys. The regular rapeseed oil ration caused growth depression, increased feed conversion and anemia in all species. All the ducks and some of the chickens fed the regular rapeseed oil ration died. These dead birds were affected with hydropericardium and ascites. No deaths in the turkeys could be attributed to the regular rapeseed oil ration but some turkeys fed this ration had degenerative foci characterized by infiltrations of histiocytic and giant cells in the myocardium. Severe fatty change in the heart, skeletal muscles, spleen and kidney was found at an early age in all birds fed the regular rapeseed oil ration. Less severe fatty change but no other lesions were found in birds fed the Oro rapeseed oil and soybean oil rations.

Animal Feed↗
PubMedDate not supplied

Histopathologic and bacteriologic evaluations of cellulitis detected in legs and caudal abdominal regions of turkeys.

The objective of this study was to identify the causative agent of cellulitis in turkeys. Eighteen flocks from nine producers were sampled at the local processing plant, and 37 birds with cellulitis on legs or caudal thoracic area were obtained. None of the 37 birds with cellulitis had lesions in other organs. On gross examination, lesions were categorized into two groups: cellulitis with unopened skin lesions (type a) and cellulitis with opened skin lesions (type b). Histopathologically, cellulitis with unopened skin lesions had dermal necrosis with underlying fibrin and inflammatory exudate but cellulitis with open skin lesions had chronic granulomatous/granulation tissue-type reaction associated with foreign material. A complete bacteriologic study was conducted on 25 of 37 birds. Bacteria were isolated from 12 of the 25 birds with cellulitis lesions. No aerobic, microaerophilic, or anaerobic bacteria were isolated from the remaining 13 birds with cellulitis lesions. Escherichia coli was isolated in low numbers in mixed cultures with Proteus mirabilis, Lactobacillus spp., Klebsiella spp., and Staphylococcus spp. in 9 of 12 lesions. The remaining few cases yielded P. mirabilis in pure culture or in mixed culture with Pseudomonas aeruginosa. Types a and b cellulitis lesions in turkeys could be associated with primary contact dermatitis and skin abrasions, respectively. Their occurrence is likely associated with different management practices.

Abdomen↗
PubMedDate not supplied

Self-sealing sclerotomies for sutureless pars plana vitrectomy.

OBJECTIVE: To determine the efficacy of self-sealing pars plana sclerotomies for vitrectomy and to identify complications associated with this new technique. METHOD: There were 150 self-sealing sclerotomies performed in 50 patients undergoing pars plana vitrectomy between October 1996 and March 1998. RESULTS: Of the 150 sclerotomies, 115 (76.6%) did not require suturing while 35 (23.3%) were closed with one radial 7.0 vicryl suture. The scleral tunnel incisions ensured minimal loss of intraocular fluids during instrument exchange and scleral plugs were not required to avoid ocular hypotony during scleral indentation. Distortion of scleral flap incisions requiring a suture were commonly seen in procedures using multiple instrumentations and extensive explants. CONCLUSIONS: Sutureless sclerotomies are simple to perform, save operative time, and reduce the risk of peroperative hypotony following removal of instruments or the infusion cannula. The technique reduces postoperative inflammation, suture-related problems including astigmatism, and allows more rapid rehabilitation.

Adult↗