Judul: Kandidat vaksin iradiasi Streptococcus agalactiae untuk pencegahan mastitis subklinis pada ruminansia
Abstrak: Subclinical mastitis (SCM) is a disease that often infects dairy cow, which then decline milk production. Streptococcus agalactiae is well known as a dominant causative agent of SCM. An experiment to obtain gamma irradiated candidates vaccine of S. agalactiae for the prevention of subclinical mastitis in ruminants have been conducted. S. agalactiae bacteria selected for the irradiated vaccine material was isolated from dairy cows of subclinically mastitis from dairy farm in Bogor and Garut area. The S. agalactiae used in this experiment was group B (GBS) type, which is uncapsulated and has haemaglutynine (Hn+) property. Based on dose irradiation orientation, 17 Gy dose was found to weaken the GBS bacteria to have 50% lethal dose (LD50), which therefore, utilized to manufacture live vaccine. Irradiated GBS surface protein was characterized by SDS-PAGE and resulted to find more than 75 kDa of the protein’s molecular weight, where minimun of antigenically substance is 10 kDa. Infecting of the irradiated GBS using mice resulted in lack pathogenic properties of the bacteria, which is histophatology drawn that the mammary gland alveolly of mice grouped vaccinated with irradiated GBS and vaccinated then challenge, were remain producing milk, and significantly not different as compare to control animal. GBS vaccine irradiation did not cause inflammation of the mammary glands of mice tested, evidences showed that number of udder interstitial inflammatory cells around alveolly and gland epithelial cells in vaccinated mice groups were not significantly different as compare to the control group. Most interstitial inflammatory cells in challenged groups are found in mice that were challenged with virulent GBS and significantly different to be found more as compare to vaccine and control groups. Enzyme Linked Immunosorbent Assay (ELISA) to Ig-G serum showed levels of higher immune response in mice vaccinated group compare to control group. The overall experiment confirmed that attenuated GBS using gamma ray irradiation capable to induce immune response. This evidences were confirmed by an observation result in the application of GBS irradiated vaccine at Etawah dairy-goat, where immune responses are induced in those dairy-goats, and also were showed by the evidences found of higher concentration of Ig-G serum by ELISA in the vaccinated group than the control group. Milk production of vaccinated goat had no effect by vaccination. In summarize, irradiated SGB vaccine does not affect milk yield.
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Judul: Profil leukosit kambing peranakan etawah setelah vaksinasi iradiasi streptococcus agalactiae untuk pencegahan mastitis subklinis
Abstrak: Etawah cross breed goat was domesticated to fulfill human need on meat and milk. As a dairy milk producer etawah cross breed goat is susceptible to subclinical mastitis. Subclinical mastitis is often caused by Streptococcus agalactiae. Several methods had been developed to prevent subclinical mastitis, i.e., promoting sanitation and higiene, teat dipping, and vaccination. The objective of this reseach was to identify the efectiveness of irradiated vaccine S. agalactiae to prevent subclinical mastitis caused by S. agalactiae through observation of leucocytes profile. This research used pregnant healthy goats with four until five months gestation that were vaccinated three times with interval of 2 weeks. The vaccine volume used was 2 mL and contain 108 cfu/mL S. agalactiae administerated by subcutaneous route. The blood samples of 9 pregnant Etawah cross breed goats (5 vaccinated goats and 4 control goats) were taken out every one week post vaccinated. Samples were prepared to be blood smear preparation and stained with Giemsa and examined on leucocytes profile (relative value and total value). This study showed that limphocytes from treated etawah cross breed goats were higher than control. Relative and total value of lymphocytes in prevactination were significantly different (P<0.05) (73.67±2.05% and 5230±87 cell/μL) also postvactination 3rd (66.00±4.08% and 5676±1520 cell/μL). The study concluded that the secondary immune response from vaccination program already formed to prevent subclinical mastitis in etawah cross breed goat caused by S. agalactiae.
Keyword: Bogor Agricultural University (IPB), Streptococcus agalactiae., leucocytes profile, irradiation vaccine, etawah cross breed goat

Judul: Analisis Bifurkasi Hopf Dinamika Harga pada Model Ekonomi dengan Dua Waktu Tunda
Abstrak: Model dinamik dalam tulisan ini disusun dari model dinamika harga (Zhai et al. 2014) dengan mempertimbangkan dua waktu tunda yaitu pada variabel harga dan penawaran. Analisis pertama dilakukan dengan mempertimbangkan satu waktu tunda pada variabel harga. Dari hasil analisis diperoleh nilai interval waktu tunda sehingga model stabil pada titik tetapnya. Analisis selanjutnya dilakukan dengan mempertimbangkan waktu tunda pada variabel penawaran sebagai parameter dan memilih waktu tunda pertama dalam interval stabil. Dari hasil kedua analisis tersebut, ditemukan nilai waktu tundaan kritis yang menyebabkan sistem mengalami perubahan kestabilan, dari spiral stabil ke spiral takstabil. Pada nilai waktu tundaan kritis ini, ditunjukkan adanya bifurkasi Hopf dan kemunculan limit cycle.
Keyword: model dinamika harga, bifurkasi Hopf