Formalin and footrot in sheep

Changes in formalin concentration were measured over time in uncontaminated solutions and solutions heavily contaminated by mud, faeces, wool or straw. Shallow plastic trays containing 1.11 of a 9% aqueous solution of formalin were exposed for 6 days (trial 1) or 8 days (trial 2) to windy autumn weather. Evaporation of solution volumes was high (47-73%). Concentration generally increased over time: by 13-31% in trial 1 and by 61-162% in trial 2. These figures represent actual increases in percentage formalin of up to 3.0% in trial 1 and up to 7.6% in trial 2. Exposure to mud, sheep faeces or wool did not affect the increase in concentration but there was no increase in the presence of straw. As exposure to excessively concentrated formalin solutions produces hyperaemia, cracking of interdigital skin and lameness in sheep it is recommended that footbath solutions should be diluted to 2-S%, prepared on the day of use and discarded daily whether contaminated or not. Addition of formalin or water to existing solutions of unknown strength should be avoided.     

The F38-Like Group,a New Group of Caprine Mycoplasmas?

This paper concerns the taxonomic status of the F38-like group (MacOwan), a prime determinant of contagious caprine pleuropneumonia (CCPP). Extensive biochemical and serological investigations on strain F38 are reported. Some complex serological relationships with other mycoplasma species are revealed. The results, taken in conjunction with earlier published work on geno-typic characters, lead to the conclusion that final classification of these organisms should await further comparative studies of a number of field strains with a related group of strains classified as M. capri-colum.The characterization of F38 confirms its partial relationship to the “M. mycoides group” of ovine/caprine/bovine mycoplasmas, and has also revealed a very close phenotypic relationship to the bovine mycoplasma serogroup 7, a finding of potential diagnostic and epidemiological importance.Key words: mycoplasmas, classification, F38-like group     

Endocrine effects of heat stress in boars

The purpose of this study was to describe the temporal changes in peripheral plasma levels of testosterone and Cortisol in boars during and after heat stress. A total of 8 boars were utilized, 4 of them were exposed to 35°C, for 100 h in a climatic room, and 4 served as controls and were kept at 20 °C for 100 h in the climatic room.Blood samples were obtained via permanent vein catheters 3 times daily from 5 days before heat stress until 20 days after termination of heat stress. Testestorone levels were determined by radioimmunoassay and Cortisol by a competitive protein binding technique.For both hormones the pre-exposure levels were similar in both groups of boars. The control boars had significantly higher testosterone levels, while being in the climatic room, than during any other period. The experimental boars had slightly increased testosterone levels during the first day of heat stress and thereafter continuously decreased levels. In the control boars the testosterone levels returned to pre-exposure levels immediately after removal from the climatic room, whereas in the experimental boars the testosterone levels were dramatically increased during the first 5 days after exposure. The differences in Cortisol levels, between the 2 groups of boars were restricted to the period spent in the climatic room. During this period the experimental boars had significantly higher Cortisol levels.Key words: boars, heat stress, testosterone, cortisol     

Selenium and glutathione peroxidase levels in lambs receiving feed supplemented with sodium selenite or selenomethionine

Twenty-one 6 months old female lambs were divided into 7 groups and fed a basal diet containing 0.13 mg Se/kg. The basal diet was further supplemented with 0, 0.1, 0.5 or 1.0 mg Se/kg either as sodium selenite or as selenomethionine, and was fed for 10 weeks. Both feed additives produced an increase in the selenium concentration in the tissues analysed. Significant correlations were found between the concentrations of selenomethionine or sodium selenite added to the feed and the subsequent tissue levels. However, the selenium levels seemed to plateau at approximately 0.5 mg Se/kg of supplemented sodium selenite. The total glutathione peroxidase (GSH-Px) activity of the tissues increased when the selenium supplementation increased from 0 to 0.1 mg/kg for both selenium compounds. With further increase in selenium supplementation the GSH-Px activity in the tissues plateaued except in the blood where the activity continued to rise with increasing selenomethionine supplementation. The selenium dependent GSH-Px activity in the liver rose with increasing selenomethionine supplementation, but approached a plateau when 0.1 mg Se/kg as sodium selenite was added to the feed. The selenium concentration in whole blood responded more rapidly to the selenium supplementation than did GSH-Px activity. The experiment indicates that the optimal selenium concentration in the feed is considerably higher than 0.1 mg Se/kg, and that selenium levels of 1.0 mg/kg in the feed do not result in any risk for the animals or the consumers of the products.Key words: dietary selenium, lambs, selenium concentrations, glutathione peroxidase activities, tissues     

Sarcocystis spp. infections in naturally infected cats and dogs: levels of sporocyst production and the influence of host, environmental and seasonal factors on the prevalence of infection

Data obtained from faecal samples from 508 domestic cats and 481 dogs, previously found to have a high frequency of Sarcocystis spp. infections, were further examined to provide information on levels of sporocyst shedding and to ascertain the influence of host, environmental and seasonal factors on the prevalence of naturally acquired infections. Statistical analysis of prevalence data revealed that, of the factors examined, only host age in cats exerted any apparent influence. Infections were significantly more common in cats up to, rather than over, 6 months of age. Although they tended to be greater in dogs than cats, faecal sporocyst counts in both hosts were generally low, with the majority of infected samples containing 200 sporocysts per gram or less. In infected dogs the highest count recorded was 144,600/g with a mean of 2270/g, and in infected cats it was 11,100/g with a mean of 597/g.     

Oxfendazole resistance in Nematodirus spathiger

The occurrence of anthelmintic resistance in a field strain of Nematodirus spathiger is reported for the first time. In a controlled anthelmintic trial with naturally-acquired infections, oxfendazole at 5 mg/ kg and levamisole at 8 mg/kg were 0 and 86% effective respectively, against this strain.     

Membrana nictitans gland cyst in a dog

A cyst involving the gland of the 3rd eyelid was removed from an 8-year-old dog. Clinically the circumscribed mass resembled a pigmented neoplasm. Histologically the cyst was multiloculated, with homogeneous eosinophilic periodic acid-Schiff-positive content. Melanin pigment was present in epithelial cells and cystic lumens. Protective functions of the 3rd eyelid were retained following excisional biopsy.