Effect of the route of administration on the mucosal and systemic immune responses to Lawsonia intracellularis vaccine in pigs

In an on‐farm study, 40 weaned piglets aged 3 weeks were vaccinated with Lawsonia intracellularis vaccine orally, IM or IP while a fourth group remained unvaccinated. All vaccinated animals showed increased serum levels of L. intracellularis‐specific IgG antibodies, but significantly elevated concentrations of specific IgG, IgA and cytokines were generated in ileal mucosal secretions from the orally and IP vaccinated pigs when examined at 17 days after vaccination.     

Effect of Leptin on In Vivo Goat Embryo Production

The aim of this study was to evaluate the effect of leptin administration during superovulation on in vivo goat embryo production. Ten mature does were superovulated with 133 mg follicle‐stimulating hormone (FSH) i.m. in six descending doses at 12‐h intervals. The goats received 4.8 μg/kg human recombinant leptin s.c. (leptin group, n = 5) or phosphate‐buffered saline (PBS) (control group, n = 5) with the first and second FSH doses. The does were mated and subjected to embryo collection by transcervical technique 6 days later. The total number of cells per embryo and the number of cells with fragmented DNA were assessed in selected blastocysts by combining Hoechst 33342 and terminal dUTP nick‐end labelling (TUNEL) staining. Plasma concentrations of oestradiol (E₂) and progesterone (P₄) were determined by electrochemiluminescence from the day of FSH treatment, on the day of superovulatory oestrus and on the day before embryo collection. Compared with the control group, the does that received leptin had a higher number of transferable embryos (p < 0.005), fewer embryos classified as degenerated (p < 0.001) and fewer TUNEL‐positive cells/blastocyst (p < 0.001). The number of transferable embryos was positively correlated with E₂ concentrations on day of oestrus (r = 0.562; p < 0.01) and P₄ concentrations on the day of embryo collection (r = 0.912; p < 0.001). We concluded that in vivo leptin administration during FSH treatment improved embryo quality and affected ovarian steroidogenesis in superovulated goats.     

Percentage of Ubiquitinated Spermatozoa does not Correlate with Fertilizing Capacity of Thawed Bovine Semen

In the spermatozoa of some species, the ubiquitin–proteasome system detects altered proteins and tags them for elimination by the proteasome. In some species' ejaculates, a high proportion of ubiquitinated spermatozoa (i.e. those having ubiquitin bound to the altered or damaged membrane proteins) has been related to infertility. The aim of this study was to assess whether the percentage of ubiquitinated spermatozoa relates to fertility of dairy bulls and whether ubiquitination increases during protein remodelling that occurs during in vitro spermatic capacitation. Thirty‐two frozen semen straws from four high‐fertility (ReproMax^®) and four normal‐fertility (Normal) Holstein‐Friesian sires were evaluated. Ubiquitinated and capacitated spermatozoa were quantified by sperm ubiquitin tag immunoassay and chlortetracycline stain, respectively. Fertilizing capacity of sires was assessed by in vitro fertilization. No differences were found between Normal and ReproMax^® sires with regard to the observed percentage of ubiquitinated spermatozoa (42.97 ± 3.69% and 49.68 ± 9.27%, respectively; p > 0.05). Additionally, no differences were found in the percentage of ubiquitinated spermatozoa as a consequence of spermatic capacitation in either Normal (42.97 ± 3.69% before capacitation vs 44.67 ± 7.5% after; p > 0.05) or ReproMax^® sires (49.68 ± 9.27% before vs 45.05 ± 7.51% after; p > 0.05). The percentage of ubiquitinated spermatozoa in a thawed sperm samples did not correlate with its in vitro fertilizing capacity; thus, this assay does not prove useful to detect in vivo fertility differences between sires. Additionally, protein degradation occurring during remodelling of the spermatozoon plasma membrane during the capacitation process does not seem to involve the ubiquitin–proteasome system.     

Seeking Mathematical Strategies in Sperm Function Analysis: Between Scylla and Charybdis?

During the last decades, essential progresses in reproductive biotechnology were achieved, implying development of special spermatological techniques. The major problem was to set up simple, rapid, precise and adequate evaluation methods. The key aspect to be considered in all assays of sperm fertilizing function is capacitation. As not all spermatozoa respond to fertilizing conditions in a similar manner, it seems to be logical to assess samples via their response to these specific conditions. For the spermatological practice, the sensitivity of methodology for assessment and analysis of data with respect to differences in individual response, in heterogeneity of the population, and proper temporal characterization of the response is crucial for the improvement of evaluation procedures. Currently, most used statistical analytical tools in spermatology do not always fulfil these essential sensitivity requirements. We structured our paper concerning different fields of mathematical science (distribution analysis, fractal geometry, functional approximation and differentiation) related to the modern insights in sperm function analysis. The spectrum of methods we are going to review in this paper is restricted to basic ideas to illustrate how the accuracy and sensitivity of sperm evaluation assays may be improved by applying adequate elementary tools of the mathematical analysis.     

Dicoumarol toxicity in cattle associated with ingestion of silage containing sweet vernal grass (Anthoxanthum odoratum)

A diagnosis of dicoumarol toxicity in a herd of Friesian cattle was made following investigation of the deaths of three mature cows and eleven yearling heifers. Affected stock had been fed wrapped, bailed silage containing approximately 90% sweet vernal grass ( Anthoxanthum odoratum ). Sweet vernal grass contains coumarin, which can be converted to dicoumarol, a vitamin K antagonist, through the action of moulds. Most deaths were preceded by lethargy, severe anaemia and subcutaneous and internal haemorrhage. Dicoumarol toxicosis was suspected based on clinical signs, necropsy findings and prolonged prothrombin and activated partial thromboplastin times. Dicoumarol analysis of blood from affected animals and silage confirmed the diagnosis.     

Soil microbial, fungal, and nematode responses to soil fumigation and cover crops under potato production

Sodium N-methyldithiocarbamate (metam sodium) and 1,3 dichloropropene are widely used in potato production for the control of soil-borne pathogens, weeds, and plant parasitic nematodes that reduce crop yield and quality. Soil fumigation with metam sodium has been shown in microcosm studies to significantly reduce soil microbial populations and important soil processes such as C and N mineralization. However, few published data report the impact of metam sodium on microbial populations and activities in potato production systems under field conditions. Fall-planted white mustard (Brassica hirta) and sudangrass (Sorghum sudanense) cover crops may serve as an alternative to soil fumigation. The effect of metam sodium and cover crops was determined on soil microbial populations, soil-borne pathogens (Verticillium dahliae, Pythium spp., and Fusarium spp.), free-living and plant-parasitic nematodes, and C and N mineralization potentials under potato production on five soil types in the Columbia Basin of Eastern Washington. Microbial biomass C was 8–23% greater in cover crop treatments compared to those fumigated with metam sodium among the soil types tested. Replacing fumigation with cover crops did not significantly affect C or N mineralization potentials. Cumulative N mineralized over a 49-day laboratory incubation averaged 18 mg NO₃-N kg⁻¹ soil across all soil types and treatments. There was a general trend for N mineralized from fumigated treatments to be lower than cover-cropped treatments. Soil fungal populations and free-living nematode levels were significantly lowered in fumigated field trials compared to cover-cropped treatments. Fumigation among the five soil types significantly reduced Pythium spp. by 97%, Fusarium spp. by 84%, and V. dahliae by 56% compared to the mustard cover crop treatment. The percentage of bacteria and fungi surviving fumigation was greater for fine- than coarse-textured soils, suggesting physical protection of organisms within the soil matrix or a reduced penetration and distribution of the fumigants. This suggests the potential need for a higher rate of fumigant to be used in fine-textured soils to obtain comparable reductions in soil-borne pathogens.     

Earth tides can trigger shallow thrust fault earthquakes

We show a correlation between the occurrence of shallow thrust earthquakes and the occurrence of the strongest tides. The rate of earthquakes varies from the background rate by a factor of 3 with the tidal stress. The highest correlation is found when we assume a coefficient of friction of mu = 0.4 for the crust, although we see good correlation for mu between 0.2 and 0.6. Our results quantify the effect of applied stress on earthquake triggering, a key factor in understanding earthquake nucleation and cascades whereby one earthquake triggers others.     

Phosphorus and nitrogen dynamics during field incubations in forest and fallow subarctic soils

A knowledge of the nutrient dynamics that occur with land use changes, e.g., in clearing forests for farmland, is useful in choosing the most efficient soil and fertilizer management practices. To determine net in situ P and N mineralization and nitrification rates of forest floor materials and their nutrient value for agricultural crops, plastic bags containing different materials (moss, O horizon, and A horizon) collected from a subarctic black spruce (Picea mariana Mill.) forest were incubated for 2 years in their respective forest horizons and at 7.5 cm depth in a nearby fallow field. Net amounts of P and N mineralized were highest in moss and were similar in forest and field when the temperature and moisture content were similar, but smaller in forest when the water content was higher. Net nitrification was negligible in O and A horizon material but significant in moss during the 2nd year, occurring sooner and producing higher NO _inf3 ^sup- levels in the field (171 mg ha^-1) than in the forest (13 mg ha^-1). Moss P and N mineralization rates were correlated in the fallow field. Temperature, moisture content, and substrate quality were important factors controlling P and N dynamics of forest floor materials in a subarctic fallow field and native forest. In subarctic regions, incorporation and mineralization of forest floor materials could provide an early source of N and P (70 and 17 kg ha^-1, respectively) for succeeding agricultural crops.     

Decomposition of barley straw in a subarctic soil in the field

Summary The mass loss and N dynamics of barley stems and leaves, placed on the soil surface or buried, were examined over two summers. There was little difference in mass loss or N dynamics in straw placed 7.5 or 15 cm deep. However, the surface straw lost mass much more slowly and immobilized more N for a longer time than the buried straw. Filter paper had a slow rate of mass loss initially, but once started, lost mass much more rapidly than either the barley stems or leaves. Loss of mass was closely correlated with the cellulose loss in straw, whether buried or placed on the soil surface. The sustained rate of mass loss was 6.3 and 7.0% month^-1, respectively, for surface and incorporated leaves compared with 3.5 and 4.3% month^-1, for surface and incorporated stems. The greater loss sustained by the leaves was attributed to a lower lignin content rather than a higher N content, because the addition of N to the straw after 30 days in the field failed to increase CO₂ evolution. Maximum net N immobilization occurred within 30 days for all the barley straw, except for the stems placed on the ground surface, which did not reach maximum N immobilization until the second summer. Immobilization and mineralization of N were estimated for a 3000 kg ha^-1 grain crop. Surface straw immobilized 3.8 kg N ha^-1 in the 1st year and 9 kg N ha^-1 in the 2nd year, whereas incorporated straw immobilixed 3.5 kg N hs^-1 in the 1st year and mineralized 4.5 kg N ha^-1 in the 2nd year. Thus, in Alaska, residue management does not affect N fertilizer requirements in the 1st year, but an additional 13.5 kg N ha^-1 is required for surface residues in the 2nd year.     

Serving capacity of crossbred yearling beef bulls. II. Summer grazing activity and body temperature patterns during average and heavy mating loads at pasture

Ten low (LSC) and 10 high (HSC) serving capacity yearling bulls were exposed individually to 25 naturally cyclic (N) cows for 3 d (average mating load) and subsequently to 9 estrus-synchronized (S) cows for 1 d (heavy mating load) in a randomized complete block design consisting of 10, 4-d blocks. Bulls were fitted with vibracorders and temperature acquisition modules to record grazing activity and body temperature (BT), respectively. During the N cow treatment, LSC bulls had fewer (P less than .05) services per cow and a higher mount to service ratio than HSC bulls, and LSC bulls tended (P = .12) to graze less total time than HSC bulls (7.8 vs 9.0 h/d, respectively). However, both groups of bulls exhibited similar diurnal grazing patterns with two major daily grazing periods; the first (0400 to 1300) peaked early in the morning (0600) and the second (1700 to 2200) occurred in late afternoon and evening. During the S cow treatment, LSC and HSC bulls did not differ (P = .60) in grazing time or pattern, but similar mating activity was exhibited by both SC groups while exposed to S cows. Bulls grazed little during the hottest part of the day (1300 to 1700), and LSC and HSC bulls spent only 2.2 and 2.4 h, respectively, grazing during dark, cooler periods near midnight. Body temperature did not differ between SC groups and averaged 39.3 degrees C during N cow treatment and 39.4 degrees C during S cow treatment. Body temperature had a distinct, monophasic diurnal pattern in bulls exposed to an average mating load.(ABSTRACT TRUNCATED AT 250 WORDS)