Smoke Water and Heat Shock Influence Germination of Shortgrass Prairie Species

Smoke or heat from fire can act as a cue that affects seed germination. We examined germination responses of 10 plant species (six forbs, two shrubs, two grasses) native to the southern High Plains in the United States, to smoke, heat, and their interaction in a laboratory experiment. Smoke treatments were applied by soaking seeds in 1∶5, 1∶10, or 1∶100 (v/v) Regen 2000® smoke solution for 20 h. Heat treatments were applied by placing seeds in an oven at 50°C or 80°C for 5 min. Nine species responded to smoke, heat, or both. Results showed that smoke can enhance, inhibit, or not affect seed germination. Germination capacities of Gutierrezia sarothrae (Pursh) Britton & Rusby and Astragalus crassicarpus Nutt. were promoted by 1∶5 and 1∶100 dilutions of smoke water, respectively; Coreopsis tinctoria Nutt., G. sarothrae, Salvia reflexa Hornem., Digitaria ciliaris (Retz.) Koeler, and Panicum virgatum L. were inhibited by high and/or moderate concentrations of smoke water either in germination percentage or in mean germination time. Germination percentage of Solanum elaeagnifolium Cav. increased following an 80°C heat treatment. Interaction effects between smoke and heat on germination also were detected. Smoke and heat treatments might be useful as management tools for promoting or suppressing specific target species of shortgrass prairie communities in future habitat management.     

Influence of porcine intestinal pH and gastric digestion on antigenicity of F4 fimbriae for oral immunisation

Newly weaned piglets can be orally immunised against F4+ enterotoxigenic Escherichia coli (ETEC) infection with F4 fimbriae. However, to efficiently develop a vaccine against ETEC induced postweaning diarrhoea, knowledge of the stability of the F4 fimbriae to different pH and gastric digestion is needed. The gastrointestinal pH in suckling and recently weaned piglets was measured and the stability of F4 fimbriae to different pH and to pepsin was assessed in vitro. In the stomach the lowest pH was found in the fundus gland region. Gastric pH values below 2.5 were not found in suckling piglets or at the day of weaning, in contrast to piglets 1 and 2 weeks postweaning. Along the first half of the small intestine and in the caecum, a negative correlation was found between pH and age. The F4 fimbriae were stable to pH 1.5 and 2 for 2 h, whereas longer incubation periods resulted in conversion of the multimeric forms into monomers. The F4 fimbriae were partially degraded by incubation for 15-30 min in simulated gastric fluid at pH 1.5 and 2, and completely digested from 3 h onwards. At pH 3, the fimbriae maintained their antigenicity for at least 4h. The results demonstrate that gastric digestion will only have a limited impact on oral immunisation since liquid passes through the stomach relatively quickly (50% within 2 h). However, we previously demonstrated that the transit times are prolonged shortly after weaning. Shortly after weaning it could be necessary to protect the F4 fimbriae against gastric digestion to obtain efficient oral immunisation of the piglets.     

Immunoblotting, ELISA and culture evidence for Chlamydiaceae in sows on 258 Belgian farms

The prevalence of Chlamydiaceae infections on 258 closed pig breeding farms in Belgium was examined. For this purpose, 258 farms were randomly selected in the provinces West-Vlaanderen (44%), Oost-Vlaanderen (20%), Antwerpen (10%) and Vlaams-Brabant (6%). Of all farms examined, 96.5% were positive for Chlamydia-specific antibodies in ELISA and most were moderately to strongly positive. ELISA results revealed only 9 (3.5%) sero-negative farms. None of the ELISA negative sera reacted in immunoblotting. Only 212 of 249 ELISA positive sera reacted positive in immunoblotting. Additionally, 23 autopsy samples were examined by isolation in Vero cells. The major outer membrane sequence of the one isolate obtained showed 98.6% amino acid homology to the one of Chlamydophila psittaci strain CP3, formerly isolated from a pigeon. Present observations indicate that chlamydial infections are nearly endemic in the Belgian pig population and that Belgian pigs can become infected with C. psittaci. Nevertheless, the role and significance of Chlamydiaceae as pathogens in pigs remain unsolved and require further investigation.     

Climatic and edaphic conditions at eragrostis lehmanniana nees sites in Arizona,USA and the cape province,RSA and potential seeding sites in Southern Africa

Climatic and edaphic conditions at Eragrostis lehmanniana Nees sites in southeastern Arizona, USA were compared with those in the Cape Province, RSA to determine a range of conditions under which the species might be expected to establish and persist in southern Africa. Mean annual precipitation amounts and temperature extremes were highly variable where Lehmann lovegrass predominates, but in most summers precipitation accumulations ranged from 150–220 mm and temperature extremes ranged from 20–35°C in 30–40 days. Soils at Lehmann lovegrass sites in the Cape Province were more coarse textured and nutrient concentrations were usually less than at sites in southeastern Arizona; but trends in particle‐size distributions and measured chemical concentrations were generally equivalent. Climatic and edaphic conditions in central Botswana and northeastern Namibia generally range between those in southeastern Arizona and the Cape Province, RSA and we expect that seeded Lehmann lovegrass stands in these areas would enhance semi‐desert grassland productivity.     

Pulmonary pharmacokinetics of tulathromycin in swine. Part I: Lung homogenate in healthy pigs and pigs challenged intratracheally with lipopolysaccharide of Escherichia coli

The objective of the study was to assess the pharmacokinetics of tulathromycin in lung tissue homogenate (LT) and plasma from healthy and lipopolysaccharide (LPS)‐challenged pigs. Clinically healthy pigs were allocated to two dosing groups of 36 animals each (group 1 and 2). All animals were treated with tulathromycin (2.5 mg/kg). Animals in group 2 were also challenged intratracheally with LPS from Escherichia coli (LPS‐Ec) 3 h prior to tulathromycin administration. Blood and LT samples were collected from all animals during 17‐day post‐tulathromycin administration. For LT, one sample from the middle (ML) and caudal lobes (CL) was taken. The concentration of tulathromycin was significantly lower in the ML after the intratracheal administration of LPS‐E. coli (P < 0.02). In healthy pigs and LPS‐challenged animals, the distribution of the drug into the lungs was rapid and persisted at high levels for 17‐day postadministration. The distribution of the drug within the lung seems to be homogenous, at least between the middle and caudal lobes within dosing groups. The concentration versus time profile of the drug and pharmacokinetic parameters in two different lung areas (middle and caudal lobe) were consistent within the groups. The clinical significance of these findings is unknown.     

The pharmacokinetics of maropitant citrate dosed orally to dogs at 2 mg/kg and 8 mg/kg once daily for 14 days consecutive days

The pharmacokinetics of maropitant were evaluated in beagle dogs dosed orally with Cerenia^® tablets (Pfizer Animal Health) once daily for 14 consecutive days at either 2 mg/kg or 8 mg/kg bodyweight. Noncompartmental pharmacokinetic analysis was performed on the plasma concentration data to measure the AUC_0–24 (after first and last doses), C_t (trough concentration—measured 24 h after each dose), C_max (after first and last doses), t_max (after first and last doses), λ_z (terminal disposition rate constant; after last dose), t_1/2 (after last dose), and CL/F (oral clearance; after last dose). Maropitant accumulation in plasma was substantially greater after fourteen daily 8 mg/kg doses than after fourteen daily 2 mg/kg doses as reflected in the AUC_0–24 accumulation ratio of 4.81 at 8 mg/kg and 2.46 at 2 mg/kg. This is most likely due to previously identified nonlinear pharmacokinetics of maropitant in which high doses (8 mg/kg) saturate the metabolic clearance mechanisms and delay drug elimination. To determine the time to reach steady‐state maropitant plasma levels, a nonlinear model was fit to the least squares (LS) means maropitant C_t values for each treatment group. Based on this model, 90% of steady‐state was determined to occur at approximately four doses for daily 2 mg/kg oral dosing and eight doses for daily 8 mg/kg oral dosing.     

Conception rates to fixed-time artificial insemination of two oestrus synchronisation programmes in dairy heifers

AIM: To evaluate the conception rate to fixed-time artificial insemination (FTAI) of two oestrus synchronisation programmes in dairy heifers on eight farms over 2 years.

METHODS: The study was conducted in 2008 and 2010 on eight farms near Palmerston North, New Zealand. Nulliparous Friesian and Friesian×Jersey heifers (13–15 months of age) were randomly allocated to one of two oestrus synchronisation programmes. Group 1 (GPG+P4; n=330), received gonadotrophin-releasing hormone (GnRH) I/M on Day 0, a progesterone (P4)-releasing intravaginal device from Days 0–7, prostaglandin F_2α (PGF) I/M on Day 7 and a second dose of GnRH at the time of FTAI on Day 9. The second group (P4+PGF; n=343) received a P4-releasing intravaginal device from Days 0–7, PGF on Day 6 and FTAI on Day 9. Pregnancy was diagnosed from Days 42–52 by transrectal ultrasonography.

RESULTS: The overall conception rate was 52.4% and 54.8% for the GPG+P4 and P4+PGF groups, respectively. The odds of conception for the two treatments were not different (OR=0.90; 95% CI=0.67–1.23), nor was there any difference between groups in different years (p=0.58). Farm affected conception rate (p=0.002), but there was no interaction with treatment (p=0.92) .

CONCLUSIONS: This study has shown that an alternative synchronisation programme can produce similar results in terms of conception rate to the GPG+P4 treatment, currently commonly used in heifers. More research is required to establish whether other modifications to the GPG+P4 programme can produce similar results at lower costs, and to identify and quantify farm factors which affect the economic benefit of heifer synchronisation.

CLINICAL RELEVANCE: This study indicated that synchronising heifers with P4 and PGF resulted in conception rates equivalent to those resulting from a GPG+P4 treatment, but with reduced drug costs. However, because heifers in the GPG+P4 group received the second GnRH injection at the time of AI, they needed only three yardings as opposed to the four required for the heifers treated with P4 and PGF. Thus, the choice of programme for an individual farm will depend on that farm's circumstances, in particular the cost of yarding the heifers.     

Understanding foot-and-mouth disease virus transmission biology: identification of the indicators of infectiousness

The control of foot-and-mouth disease virus (FMDV) outbreaks in non-endemic countries relies on the rapid detection and removal of infected animals. In this paper we use the observed relationship between the onset of clinical signs and direct contact transmission of FMDV to identify predictors for the onset of clinical signs and identify possible approaches to preclinical screening in the field. Threshold levels for various virological and immunological variables were determined using Receiver Operating Characteristic (ROC) curve analysis and then tested using generalized linear mixed models to determine their ability to predict the onset of clinical signs. In addition, concordance statistics between qualitative real time PCR test results and virus isolation results were evaluated. For the majority of animals (71%), the onset of clinical signs occurred 3–4 days post infection. The onset of clinical signs was associated with high levels of virus in the blood, oropharyngeal fluid and nasal fluid. Virus is first detectable in the oropharyngeal fluid, but detection of virus in the blood and nasal fluid may also be good candidates for preclinical indicators. Detection of virus in the air was also significantly associated with transmission. This study is the first to identify statistically significant indicators of infectiousness for FMDV at defined time periods during disease progression in a natural host species. Identifying factors associated with infectiousness will advance our understanding of transmission mechanisms and refine intra-herd and inter-herd disease transmission models.     

Effect of Supplementation of Taurine or Trehalose in Extender on Immunolocalization of Tyrosine Phosphoproteins in Buffalo and Cattle (Karan Fries) Cryopreserved Spermatozoa

The present study assessed the effects of incorporation of Taurine or Trehalose in extender on immunolocalization of tyrosine phosphoproteins, Cryocapacitation and other sperm quality parameters (motility, viability and membrane integrity) in post‐thawed sperm from Buffalo (Murrah) and Cattle (Karan Fries). Six ejaculates from six individual bulls from both species were chosen at random and split into four aliquots: one aliquot without dilution (fresh sample), another diluted in egg yolk tris‐citrate (EYTC) extender and the rest of aliquots with EYTC dilution supplemented with taurine (50 mm ) or trehalose (100 mm ), respectively, and cryopreserved. Following cryopreservation, semen were thawed and assessed for standard semen quality parameters. Extent of capacitation in cryopreserved spermatozoa was measured by inducing in vitro acrosome reaction followed by dual staining. Immunolocalization of tyrosine phosphoproteins was carried out by immunocytochemistry using primary antibody clone pT‐154 (anti‐phosphotyrosine antibody) and FITC‐conjugated secondary antibody. Immunofluorescent signals were analysed for level of protein tyrosine phosphorylation in spermatozoa. Post‐thaw semen evaluation showed supplementation of taurine or trehalose to EYTC extender significantly (p < 0.05) increased motility, viability and membrane integrity of spermatozoa in both species. Percentage of cryocapacitated spermatozoa was significantly (p < 0.05) higher in cattle as compared to buffalo and degree of cryocapacitaion of spermatozoa decreased significantly (p < 0.05) upon supplementation of additives in both the species. It was also found that tyrosine phosphoproteins were localized differentially in fresh and cryopreserved spermatozoa. Supplementation of taurine or trehalose to freezing extender changed the localization of tyrosine phosphoproteins in cryopreserved spermatozoa similar to fresh in both the species. The results obtained clearly indicated that supplementation of taurine or trehalose to EYTC prior to cryopreservation improves Buffalo and Cattle sperm quality in terms of cryocapacitation and immunolocalization of tyrosine phosphoproteins during freezing–thawing process.