Serosurvey of five viruses in chickens on smallholdings in Bangladesh

A serologic survey was undertaken in chickens in smallholdings in Bangladesh for avian influenza A virus (AIV), egg drop syndrome '76 virus (EDS'76V), infectious bronchitis virus (IBV), Newcastle disease virus (NDV) and reovirus (RV) in three phases: January 2002-May 2003, September 2003-August 2004, and August 2005-March 2006. Four hundred thirty-six sera collected in the 2nd phase, 295 in the first phase, 755 in the 1st plus 2nd phases and 295 in the 1st phase were investigated for AIV, EDS'76V, IBV and RV, respectively, using enzyme linked immunosorbent assays. All 854 sera collected in the three phases were screened for NDV using hemagglutination inhibition test. In chickens 20% were seropositive to AIV, 3% to EDS'76V, 74% to IBV, 88% to NDV, and 47% to RV. The seroprevalence in flocks was 23% to AIV, 6% to EDS'76V, 79% to IBV, 89% to NDV and 56% to RV. Twenty-five percent chickens had > or = 10log(2)HI titers to NDV.     

Fish protein substrates can substitute effectively for poultry by-product meal when incorporated in high-quality senior dog diets

An experiment was conducted to analytically define several novel fish substrates and determine the effects of feeding diets containing these substrates on total tract nutrient digestibilities and on immune status of senior dogs. The control diet contained poultry by-product meal while test diets contained 20% milt meal (MM), pink salmon hydrolysate (PSH) and white fish meal (WFM) added at the expense of poultry by-product meal. Concentrations of lymphocytes positive for CD3, CD4, CD8 and CD21 cell-surface markers and immunoglobulin concentrations were measured. Gene expression of cytokines tumour necrosis factor (TNF)-, interleukin (IL)-6, interferon (IFN)-, IL-10 and transforming growth factor (TGF)-β was determined by quantitative real-time polymerase chain reaction. Major compositional differences were noted among fish substrates but apparent nutrient digestibility coefficients and immune indices were not affected by treatment. Fish protein substrates were found to be effective substitutes for poultry by-product meal, providing diets of high nutritive value for senior dogs.     

Efficacy of oxyclozanide against the rumen fluke Calicophoron daubneyi in experimentally infected goats

Paramphistome infections are very common in ruminants and may induce clinical signs, but little is known about effective treatments. In this study, the efficacy of oxyclozanide against Calicophoron daubneyi was studied in goats and its activity tested against immature stages (10 days post-infection) at a dose of 22.5mg/kg bodyweight (BW) and against adult stages using two doses (15 and 22.5mg/kg BW). There was a reduction (82%) in the number of immature worms (compared to controls) but the result was not statistically significant. When tested against adult stages, however, oxyclozanide reduced the worm burdens by 95.6% and 95.9% at doses of 15 and 22.5mg/kg BW, respectively, with no significant difference between the two doses. The experiment demonstrated that oxyclozanide is highly effective in reducing the number of adult paramphistomes in goats.     

A model to assess the use of caecal and faecal inocula to study fermentability of nutrients in rabbit

An in vitro gas production trial was conducted using 10 Hyla rabbits to evaluate the use of caecal and faecal inocula in fermentability studies. Caecal content (CI) and hard faeces (FI) were used as inocula. Six legume and six cereal concentrates were used as substrates. Gas production was recorded 19 times at 2–24 h intervals throughout fermentation (120 h). The fermentation characteristics (degraded organic matter, OMd; potential gas production, A; volatile fatty acid, VFA; ammonia, NH₃) were measured by testing the inoculum and substrate (legumes vs. cereals). The inocula were different (p < 0.01) in OMd (818.2 vs. 799.4 g/kg OM for CI and FI respectively), A (255.0 vs. 267.1 ml/g OM), total VFA (67.3 vs. 53.2 mmol/g OM) and NH₃ content (21.2 vs. 19.8 mmol/l). Moreover, the significant differences in the (acetate + propionate)/butyrate ratio (5.02 vs. 4.09 for CI and FI respectively, p < 0.01) and in the branched chain proportion (isobutyrate + isovaleriate)/total VFA (0.044 vs. 0.031, p < 0.01) indicate that the inocula differed in fermenting legumes or cereals, but the equations for estimating caecal fermentation characteristics from those of faeces showed R² values from 0.673 to 0.975 (p ≤ 0.01). Our results confirm that in vitro fermentation characteristics of faeces were highly related to those of caecal content.     

Early detection of bovine leukosis virus DNA in infected sheep using the polymerase chain reaction.

The early diagnosis of bovine leukosis virus (BLV) infection, the aetiological agent in enzootic bovine leukosis, is important for the implementation of control measures. BLV infection is currently assessed by the detection of circulating antibodies against the viral envelope protein, gp51. However, this approach has shortcomings in the time taken to detect anti-BLV antibodies (three to four weeks after infection), and in the failure to detect antibodies in some animals. Clearly a technique such as the polymerase chain reaction (PCR), which directly detects the presence of viral DNA, has advantages over methods designed to measure host antibodies. The use of PCR for the detection of proviral DNA in an affected DNA sample with as little as 10(-5) micrograms of host DNA using agarose gel electrophoresis followed by ethidium bromide staining is described here. It was possible to improve the sensitivity of this assay by using hybridisation analysis with a BLV gene probe. PCR used in combination with hybridisation analysis will provide a sensitive diagnostic assay to detect BLV when antibody tests give weakly positive or equivocal results.     

Site and extent of nutrient digestion by sheep fed alkaline hydrogen peroxide-treated wheat straw-alfalfa hay combinations at restricted intakes.

Five crossbred wethers (58 kg) fitted with cannulas in the rumen, duodenum, and ileum were used in a 5 x 5 Latin square design to study effects of feeding combinations of alkaline hydrogen peroxide-treated wheat straw (AHP-WS) and alfalfa hay at restricted intakes on site and extent of nutrient digestion. Additionally, flows and disappearance of N and amino acids (AA) in the small intestine were regressed on alfalfa nitrogen intake (ANI) to estimate alfalfa's contribution to postruminal N and AA supplies. Diets consisted of 80:20 forage:concentrate mixtures; diet designations were 80:0, 80% AHP-WS and no alfalfa; 60:20, 60% AHP-WS and 20% alfalfa; 40:40, 40% AHP-WS and 40% alfalfa; 20:60, 20% AHP-WS and 60% alfalfa; and 0:80, no AHP-WS and 80% alfalfa. A modest positive quadratic (P less than .05) response was noted for total tract digestibility (TTD) of OM; values were 76.5% for diets 80:0 and 0:80 vs 78% for diet 40:40. Ruminal digestibility (percentage of intake) of NDF and ADF increased in a quadratic manner from 43 and 30%, respectively, for diet 0:80 to 71 and 70%, respectively, for diet 80:0. Ruminal digestibility of fiber may have been enhanced due to linear (P less than .05) decreases in liquid and particulate dilution rates, resulting in increased ruminal residence time of fiber as alfalfa hay replaced AHP-WS. Liquid and particulate dilution rates decreased linearly from 6.4 and 5.2%/h, respectively, for diet 80:0 to 5.4 and 3.4%/h, respectively, for diet 0:80. Regression analysis of N data indicated that alfalfa N had a ruminal escape value of 26%.     

Evaluation of a guarded bronchoscopic method for microbial sampling of the lower airways in foals.

A novel method to reduce contamination of the bronchoscope during microbial sampling of the lower airways of foals was evaluated. Methylene blue (MB) was used as a nasopharyngeal dye marker to assess the relative contamination from the upper airways of bronchoalveolar lavage (BAL) specimens obtained by standard bronchoscopy (SB) and a "guarded" bronchoscopic method (GB). For GB, a clear sterile cellulose sheath was fitted over the bronchoscope in an effort to protect the endoscope tip and channel from contamination. Methylene blue was detected visually in seven of eight BAL samples from foals following SB, but in none of the samples recovered by GB (p less than 0.001). Significantly less MB was detected in BAL by spectrophotometry in the GB group as well (p less than 0.02). The GB was next employed to study the microbial flora in the lower airways of healthy weaned foals (n = 30). Bacteria were isolated from 29 of 30 (97%) BAL samples, and in moderate or large numbers from 26 of 30 (87%) of the foals. Potential pathogens, including Bordetella bronchiseptica, Streptococcus zooepidemicus, Staphylococcus aureus, Mycoplasma felis and Streptococcus pneumoniae, were cultured from the lower airways of foals. In conclusion, the bronchoscope and bronchoalveolar lavage specimens were readily contaminated by a dye marker placed in the nasopharynx of foals, and the degree of contamination was significantly reduced by sheathing the endoscope. This contamination during bronchoscopy may obscure the interpretation of isolates from BAL specimens from foals, which may possess a bacterial flora in the lower airways without cytological evidence of inflammation.     

Differences among breed crosses of cattle in the conversion of food energy to calf weight during the preweaning interval

The objective of this study was to determine whether F1 cows that differ in genetic potential for weight at maturity and milk yield vary in the conversion of food energy to calf weight gain. Food intakes and weight change data were recorded by pen for cows and calves from approximately 45 d postpartum. Cows assigned to the study were 7- to 9-yr-old F1s produced by top-crossing Angus, Hereford, Brown Swiss, Chianina, Gelbvieh; Maine Anjou, and Red Poll sires to either Angus or Hereford dams. Calves were sired by Simmentals. Experimental units were pens (10 to 12 cow/calf pairs); pen was replicated within breed of sire in each of 2 yr (n = 24). Calf weight gain and energy consumed by the dams differed among the F1s, as did the ratio of calf weight gain to energy consumed by the calf and cow. Angus or Hereford (35.8), Red Poll (35.7), or Maine Anjou (35.6) F1s produced more calf weight per unit of energy consumed (g/Mcal) by the cow and calf than Chianina (33.1) or Gelbvieh (33.7) F1 females; Brown Swiss cows were intermediate (34.3). Differences in food conversion efficiency exist among breed crosses. These differences seem to be associated with breed cross differences in genetic potential for milk yield and mature weight; an exception to this trend was the Maine Anjou.     

Technical note: a double L intestinal cannula for cattle

A double L-shaped intestinal cannula was developed in an attempt to overcome problems observed previously with simple T-type cannulas. The cannula was constructed from cyclopolyvinyl chloride water pipe fittings. Construction materials were fairly rigid, but by connecting the split cannula pieces with elastic castration bands the cannula had some flexibility. Placing a short cone over the exposed cannula barrel reduced mechanical damage to the intestine. The double L cannula required a much smaller incision in the intestine during surgical insertion than a T-type cannula; it also simplified replacement. Construction is described; use and performance of the cannula has been satisfactory.