PCR Detection and Sequence Analysis of Torque Teno Sus Virus Strains from Guangdong Province

[Objective] Torque teno virus （TIT） is a novel virus with negative single-strand DNA discovered in recent years, which is ubiquitous and nonpatho- genie. Torque teno sus virus （TrsuV） is widely prevalent in swine populations, which is considered to be associated with some diseases such as post-weaning multi- systemic wasting syndrome （PMWS）. This study aimed to provided data for epidemiology of Tl＇suV in Guangdong Province. [Method] PCR primers were synthe- sized based on untranslated region （UTR） segment of TYsuV genome, to conduct PCR detection of 14 swine serum samples from two swine farms in Guangdong Province. A total of four PCR products of TrsuV1 and TrsuV2 from two swine farms were selected for cloning, sequencing and analysis. [ Result] Ten TrsuVl pos- itive samples （71% ） and eight TrsuV2 positive samples （57%） were obtained by PCR, including five double-positive samples （36%）. Sequence analysis of PCR products and reference strains showed that the UTR segments of samples GDTI-1 and GDT1-2 were both 305 bp, sharing 90.2% -95.1% similarity with Tl＇suVl reference strain, and the UTR segments of samples GDT2-1 and GDT2-2 were respectively 259 bp and 248 bp, sharing 67.3% - 100% similarity with TrsuV2 refer- ence strain. [ Conclusion] These results conformed that there are at least two types of Tl＇suV in Guangdong Province, with relatively high detection rates in some swine farms. Despite the putative harmlessness of Tl＇suV, the public health significance of TTsuV is noticeable due to its potential pathogenicity.

Feed profile analysis of oil palm‐integrated beef cattle farming systems by metabolic energy budgeting and implications for beef production and pastoral system design

Background:Oil palm is a tropical crop with worldwide plantings approaching 20 million ha and large areas in Indonesia,Malaysia and Thailand.The plantations are readily managed as silvopastoral systems incorporating cattle grazing(Oil Palm Silvopastoral System for Cattle,OPSC)but there is a need for analytical tools and data to understand system herbage supply and feed conversion efficiency(FCE).Methods:Metabolic energy budgeting was used to estimate herbage harvested by cattle in three OPSC subsystems,9 and 12 years after oil palm establishment,and FCE of the subsystems was determined.Understorey herbage was also analysed for nutritive value,botanical composition and herbage accumulation within one grazing‐regrowth cycle.Results:The herbage‐harvested estimate was 2.0−2.4 t dry matter(DM)ha^(-1) year^(-1) for 9 year old subsystems and 1.4-1.7 tDMha^(-1) year^(-1) for a 12 year old subsystem.Herbage metabolisable energy(ME)was 8.3−8.5 MJ kg^(-1) DM and crude protein(CP)was 15%-16%DM.FCE values for subsystems ranged from 32 to 94 kg DM kg^(-1) liveweight‐gain.Conclusions:Herbage DM yield is declining,while herbage ME is marginal but CP is adequate.FCE is suboptimal but can be optimised by defining the trajectory of declining herbage production with canopy closure as plantations age and matching stocking rate to herbage supply using a comparativestocking‐rate‐type statistic.