A modified technique for flushing ova from the sheep uterus

Abstract

Extract

Sheep ova are normally obtained from the reproductive tract using the flushing techniques described by Hunter et al. (1955) Cumming, I. A. and McDonald, M. F. 1967. The production of ova by New Zealand Romney ewes following hormonal stimulation. N.Z. Jl agric. Res., 10: 226–236. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]. Oviduct flushes, in the writers' experience, give a higher recovery of ova than uterine flushes, but they result in more adhesions of the tract, which can cause infertility. Consequently, the development of satisfactory uterine flushing techniques appears necessary before ova can be recovered repeatedly from superior ewes. This paper describes such a technique.     

Seasonal effects of liming,irrigation, and acid precipitation on microbial biomass N in a spruce (Picea abies L.) forest soil

Summary Seasonal effects of liming, irrigation, and acid precipitation on microbial biomass N and some physicochemical properties of different topsoil horizons in a spruce forest (Picea abies L.) were measured throughout one growing season. The highest biomass N was recorded in autumn and spring in the upper soil horizons, while the lowest values were obtained in summer and in deeper horizons. The clearest differences between the different soil treatments were apparent in autumn and in the upper horizons. Liming increased the microbial biomass N from 1.7% of the total N content to 6.8% (Olf₁ layer) and from 1% to 2% of the total N content in the Of₂ layer. The main inorganic-N fraction in the deeper horizons was NO _inf3 ^sup- . An increase in cation exchange capacity was observed down to the Oh layer, while soil pH was only slightly higher in the Olf₁ and Of₂ layers after liming. The effects of irrigation were less marked. The microbial biomass N increased from 1.7% of total N to 4.8% in the Olf₁ layer and from 1% to 2% of total N in the Of₂ layer. In the Olf₁ layer an increase in C mineralization was observed. Acid precipitation decreased the microbial biomass N in the upper horizons from 4.8% of total N to 1.8% in the Olf₁ layer and from 2% to 0.5% in the Of₂ layer. No significant changes in soil pH were observed, but the decrease in cation exchange capacity may result in a decrease in the proton buffering capacity in the near future.     

Metabolism of 15N-14C-acetylurea in the sheep]

3 male sheep (phi 48.3 kg) were fed a semisynthetic diet containing acetyl urea as sole protein source and 15N-14C labelled acetyl urea (urea-C labelled) by intraruminal tube. A half life period of 4 hrs was established for the removal of labelled acetyl urea from the TCE-soluble portion of the ruminal fluid. The degree of 14C labelling in ruminal proteins was very low whereas the extent of 15N labelled protein synthesis was quite marked reaching a maximum between the 18th and 24th hour of experiment. The steepest rise of 15N incorporation into ruminal proteins was found to occur between 8 to 12 hrs after start of the experiment, i.e. at the time of peak level of 15N returned from 15N urea via the rumino-hepatic circulation. 23.3% of the amount of 14C activity administered (mean of all 3 experimental animals) was excreted through respiration. The curve patterns of both isotopes in the TCE soluble portion of the ruminal fluid were similar to that of the degasified TCE soluble portion of the blood blasma. At the peak time (8 hrs) a concentration of the nitrogen isotope of about 4 atom% excess of 15N was observed. The level of 14C labeling in blood plasma proteins was insignificant when compared with that of 15N labelling. The ratio at the peak time was 1:10; the same ratio was found for ruminal proteins. From this it can be concluded that the process of labelling of blood plasma proteins proceeds mainly through microbial protein synthesis. Sheep I and III excreted an average of 60.6% of 14C activity and 57.0% of the administered excess of 15N in the urine. 6 hrs after the beginning of the experiment 81% of the amount of urinary 14C activity was found to occur as acetyl urea; after 48 hrs this amount had decreased to 50%. All experimental sheep excreted a urinary sediment consisting mainly of acetyl urea. The level of faecal 14C excretion (1.4%-2.9% of the amount administered) was considerably lower than that of 15N excretion (9.1%--15.6% of the administered dose). The TCE soluble fraction of the faeces contained up to 2% of the 14C dose and 3% of the 15N dose. The true digestibility data of 15N from 15N acetyl urea varied between 96.4% and 98.2%. An average of 40.9% was obtained for the 15N balance over the 7-day trial period.     

The molecular basis of the sparse fur mouse mutation

The ornithine transcarbamylase-deficient sparse fur mouse is an excellent model to study the most common human urea cycle disorder. The mutation has been well characterized by both biochemical and enzymological methods, but its exact nature has not been revealed. A single base substitution in the complementary DNA for ornithine transcarbamylase from the sparse fur mouse has been identified by means of a combination of two recently described techniques for rapid mutational analysis. This strategy is simpler than conventional complementary DNA library construction, screening, and sequencing, which has often been used to find a new mutation. The ornithine transcarbamylase gene in the sparse fur mouse contains a C to A transversion that alters a histidine residue to an asparagine residue at amino acid 117.     

Primary orthostatic tremor in Great Danes

Two Great Danes were presented for an investigation of 6-month histories of incessant tremor of all 4 limbs and trunk occurring only when the dogs were standing at rest. Dog 1 was a 2-year-old intact female harlequin Great Dane living in the UK, and dog 2 was a 2-year-old castrated male fawn Great Dane living in the United States. The owners described both dogs as having constant quivering of the limbs while standing, suggestive of an involuntary dance, since the age of 18 months. The intensity of the tremors was reported in both dogs to have steadily increased since onset. In dog 1, tremors were noticed to be more pronounced in the fore limbs when she was eating and more pronounced in the hind limbs when she was trying to sit. The owner of dog 1 also reported that the dog could no longer assume a position of recumbency without manual assistance because of the severity of the tremors. Intermittently, tremors were reported to involve the facial musculature of dog 2. Vaccinations were current, and the owners of both dogs did not report any previous medical history, exposure to natural or manufactured toxins, or concurrent treatment. No familial relationship was identified between these 2 dogs.     

Variation in Occurrence of Dematiaceous Hyphomycetes on Forage Bermudagrass over Years, Sampling Times, and Locations

ABSTRACT Leaf samples of forage bermudagrass with symptoms of infection by species of Bipolaris, Curvularia, and Exserohilum (dematiaceous hyphomycetes) were collected from three swine waste application sites in Mississippi at eight sampling times during each of 3 years. Samples were assayed for pathogens by observing sporulation on plated leaf tissue. Among 3,600 leaves assayed, eight species of the three genera were observed. Features and criteria for the practical identification of species on plated leaf samples are described. Sporulation by dematiaceous hyphomycetes was observed on 97% of leaves; a single pathogen was observed on 20% and two to five pathogens were observed on 77% of leaves. Distributions of leaves among classes with one to five pathogens per leaf, for sites within years, always differed significantly (P = 0.01) from a Poisson distribution and usually included fewer leaves than expected with four or five pathogens. Significant (P = 0.05) variation in frequencies of occurrence of pathogens among 72 samples of 50 leaves each was attributed to pathogen species, sampling times, and species-time interactions. Exserohilum rostratum, Curvularia lunata, and Bipolaris cynodontis were the most frequent pathogens across years and sites; B. spicifera and C. geniculata were intermediate; and B. hawaiiensis, B. sorokiniana, and B. stenospila were least frequent. For the five most common pathogens, significant differences in frequency among locations were commonplace. Six pathogens exhibited significant (P = 0.05) positive and negative correlations with others in overall frequencies of occurrence across years, sampling times, and sites. However, chi(2) tests of dual occurrence indicated that interactions between specific pairs of pathogens in or on leaves are not likely to be major causes for overall frequency correlations. Results indicate that dematiaceous hyphomycetes typically infect forage bermudagrass on swine waste application sites in complexes rather than as individual species; that E. rostratum, C. lunata, and B. cynodontis are the predominant pathogens; and that frequencies of pathogens often differ significantly between locations.     

Resistance to benzimidazole and macrocyclic lactone anthelmintics in cattle nematodes in Argentina

In April 2003, persistent scouring and ill-thrift that was reported in calves form an intensive beef rearing operation in central Argentina despite treatments with benzimidazole and ivermectin. In order to conduct a controlled faecal egg count reduction test on this herd, 40 calves 5-8-months-old were selected on the basis that they had a nematode eggs per gram (epg) of faeces count greater than 150. Animals were divided into four groups (1-4) of 10 calves. Calves of groups 1-3 were treated, respectively, with subcutaneous injection of ivermectin (200 mcg/kg), ricobendazole (4 mg/kg) and levamisole (7.5 mg/kg), while calves of group 4 remained as untreated controls. The egg count reductions carried out 10 days later were lower than 15% in calves treated with ivermectin and ricobendazole, but 100% in animals receiving levamisole. Pooled post-treatment faecal cultures showed larval percentages of 92 and 95 for Haemonchus and 8 and 5 for Cooperia in the faeces of calves treated with ivermectin and ricobendazole, respectively. This is the first reported case of Haemonchus parasiting cattle showing simultaneous resistance to avermectins and benzimidazole type anthelmintics.