Toshio Oshida

Antimicrobial susceptibilities of Mycoplasma isolated from bovine mastitis in Japan

Mycoplasma spp. are highly contagious pathogens and intramammary Mycoplasma infection is a serious issue for the dairy industry. As there is no effective vaccine for Mycoplasma infection, control depends on good husbandry and chemo-antibiotic therapy. In this study, antimicrobial susceptibility of Mycoplasma strains recently isolated from cases of bovine mastitis in Japan was evaluated by minimum inhibitory concentration (MIC). All Mycoplasma bovis strains were sensitive to pirlimycin, danofloxacin and enrofloxacin, but not kanamycin, oxytetracycline, tilmicosin or tylosin. M. californicum and M. bovigenitalium strains were sensitive to pirlimycin, danofloxacin, enrofloxacin, oxytetracycline, tilmicosin and tylosin, but not to kanamycin. This is the first report to describe the MIC of major antimicrobial agents for Mycoplasma species isolated from bovine mastitis in Japan.

Relationship between concentration of lingual antimicrobial peptide and somatic cell count in milk of dairy cows

Lingual antimicrobial peptide (LAP) belongs to the β-defensin family in cattle and is found in milk. LAP concentrations increase in milk from mastitic udders; however, the relationship between LAP concentrations and the somatic cell count (SCC) in milk remains to be elucidated in detail. Therefore, the present study was undertaken to investigate the relationship between LAP concentrations and the SCC in bovine milk to assess whether LAP may be used as an indicator of SCC. Milk was collected from 66 udders showing various SCCs. The SCC and LAP concentrations were measured in the milk. A significantly higher LAP concentration was observed in milk having 500-5000 × 10(3)cells/ml and >5000 × 10(3)cells/ml SCC groups than in lower SCC groups (<50 × 10(3)cells/ml and 50-500 × 10(3)cells/ml). A significantly positive correlation between LAP concentrations and SCCs in milk was observed (r=0.68). In milk samples with >26 nM of LAP, 92.0% of milk samples had high SCCs (>200 × 10(3)cells/ml). The concentration of LAP in milk infected with Staphylococcus aureus, Streptococcus bovis, Streptococcus dysgalactiae, and Escherichia coli was significantly higher than that in uninfected milk. These results suggest that the concentration of LAP can be a useful indicator of the SCC in dairy cows.

Comparison of seed germination of four Artemisia species (Asteraceae) in northeastern Inner Mongolia, China

Two psammophile-dominated Artemisia semi-shrubs (A. wudanica and A. halodendron) and two annual Artemisia forbs (A. sieversiana and A. scoparia) bear significant ecological functions in Horqin Sandy Land, but systematical information on their achenes’ germination is very limited. A set of studies were conducted to evaluate seed germination responses to storage periods and methods, different temperatures, lights conditions and sand burial depths, in order to determine inter-specific germination variation in the same genus and to explain how the species adapt to its microhabitat. Fresh achenes of A. wudanica, A. halodendron and A. sieversiana showed high germination capacities, but those of A. scoparia had obvious innate dormancy, which could be broken by chilling and dry storage, especially long-term dry storage. Achene germination of the two semi-shrubs preferred lower temperature fluctuation (10 to 22oC) and was not sensitive to light. But the two annuals preferred higher temperature fluctuation (34 to 22oC) and strong light for their achene germination. These four Artemisia species showed similar responses to sand burial, i.e. soil surface was most favorable for seedling emergence, and the deeper the sand burial, the fewer the seedling emergence. For the two semi-shrubs, their microhabitats are sand dunes with high temperature and intense light, which are not favorable for germination and seedling survival. Only rainfall contributes to temporary decrease of temperature and then triggers germination. We deduced that germination is not the main but a supplementary reproductive mode for the two semi-shrubs in sand dunes. For the two annuals, achene germination is the only reproductive mode, but different responses have been developed for microhabitat adaptation. For A. sieversiana, high germination capacities in wide temperature ranges and all light conditions could improve its competition and advancement in the wettest microhabitats. For A. scoparia, obvious innate dormancy of fresh achenes and germination inhabitation under unfavorable conditions are important adaptation to environmental disturbances.

Reliability in somatic cell count measurement of clinical mastitis milk using DeLaval cell counter

Somatic cell counts (SCC) measurements are typically performed using quantitative methods, such as the Breed method (Breed) and the Fossomatic method (FSCC). The DeLaval cell counter (DCC) developed recently is a quantitative somatic cell counter with a low initial cost and superior portability. However, since the DCC was specifically developed for measuring SCC of ≤ 4 × 10(6) cells/mL milk from bulk tanks or individual cows, its reliability for estimating SCC that exceed this concentration has not yet been clarified. This study therefore examined whether it is possible to accurately measure SCC by diluting milk samples with initial SCC of 4 × 10(6) cells/mL, as seen in clinical mastitis milk. We collected milk samples from 99 quarters of 99 Holstein cows with clinical mastitis. These milk samples were diluted 10-fold with saline and thoroughly mixed before performing SCC measurement with the DCC. The correlation coefficients of SCC measured by the FSCC, Breed and DCC methods indicated strong correlations between each pair of methods. The findings showed that DCC can be used to identify bovine clinical mastitis milk and is useful as a quantitative SCC measurement device on farm sites.

Patterns of Species Diversity across Scales and along the Slope on the Ecotone between the Active Sand Dune and the Inter-Dune Lowland in Horqin Sandy Land, China

To better understand the succession process of vegetation restoration from the active sand dune to the inter-dune lowland, species diversity which refers to species richness and abundance across scales and along the slope were studies in Horqin Sandy Land, China. A 0.25 ha square sampling plot, which sampled on the ecotone, was divided into five grain sizes and equal distance intervals along the slope from the top to the bottom. The results showed that both species abundance and richness increased as the grain sizes increased and along the slope, but the decreasing CV values indicated that species diversity gradually vary from heterogeneity to relatively homogeneity. In conclusion, species abundance and richness showed asynchronous changes and their relationship are more closely across scales than along the slope. Except that, more studies on the biotic and abiotic factors interaction concerning the vegetation patterns of sand dune ecosystems should be conducted. These could not only improve our understanding the mechanisms of vegetation invasion and succession, but also be beneficial for vegetation management and biodiversity conservation in semi-arid sand dune ecosystems.

Characteristics of soil seed bank of Caragana microphylla community under grazing and enclosure conditions in Horqin sandy land.

In this paper,the characteristics of soil seed bank of Caragana microphylla community under the grazing and enclosure conditions in Horqin Sandy Land,northeast Inner Mongolia,China were comparatively studied.The results are as follows:(1) The species of soil seed bank were dominated by the annual plants,and there was no significant difference in species richness between the grazed and fenced plots;(2) The seed density of soil seed bank in the grazing steppe was 3 475±519 seeds·m-2,it was 20 241±1 714 seeds·m-2 in the plots fenced for 6 years and 28 777±3 946 seeds·m-2 in the plots fenced for 12 years,and it was significantly higher in the fenced plots than that in the grazed plots;(3) The indexes of Shannon-Wiener and Simpson species diversity and Pielou evenness in the grazed plots were 1.36,0.68 and 0.56 respectively,and they were decreased with the increase of fenced time in the fenced plots;(4) Vertically,most seeds were found in topsoil of 0～2 cm in all plots,but the seed density of soil seed bank in all soil layers in fenced plots were significantly higher than that in the grazed plot;(5) The seeds were in an obvious aggregation distribution pattern in all plots,but the spatial heterogeneity of soil seed bank in the grazed plots was significant higher than that in the fenced plots.

The Effects of Iron Administrations on Vitamin B12 Contents in Blood, Body Weight and Other Characteristics of Blood in Piglets.

鉄剤の投与が仔豚の血中ビタミンB12 (以下, B12) 含量や貧血に関与する血液の諸性状 (Ht, Hb, Fe) および体重にどのような影響を与えるのかについて単味鉄剤とB12添加鉄剤を筋肉注射して, 鉄剤無投与豚と比較した。その結果, B12添加鉄剤は単味鉄剤の抗貧血効果を増強し, 増体効果があることが示唆された。

A comparative study on measured values of porcine blood biochemical constituents and hemolysis severity from serum and plasma.

豚血液の生化学成分の測定について血清を用いた場合と血漿を用いた場合の濃度差を比較し, あわせてそれぞれの溶血傾向について検討し, 以下の成績を得た。溶血程度を吸光度測定 (日豚会誌. 25. 1988) で比較し, 血清および血漿の溶血程度を区分した場合, 血清では-が53.3%, ±が33.3%, +が6.7%, ++が6.7%を占めたのに対し, 血漿では-が46.6%, ±が16.7%, +が20.0%, ++が16.7%を占めた。生化学成分の測定値について血清と血漿を比較した結果, 血清と血漿で差がないものとしてAlb, BUN, Na, K, Cl, ALP, CPK, GPT, LDH, Glu, T-chol および Tri-G があげられ, 差があるものとしてTP, T-bil, Cre, Ca, GGTおよびGOTがあげられた。血清と血漿の測定値で差があった項目について, 相関をみると, すべての項目について, 両者の間には有意な相関が成立した。さらに, 相関係数が0.7以上, 回帰係数が0.7～1.2の範囲のものとしては, TPおよびCaがあげられた。

Availability of dry chemistry method to clinical examinations of porcine blood.

豚の血液検査において, ドライケミストリー法による測定が可能かどうかについて, 従来法との比較によってその適用性を検討し, さらにドライケミストリー法での測定の精度を同時再現性によって検討した。その結果, 以下のような知見を見い出した。1) ドライケミストリー法と従来法との測定値の比較では, すべての項目で, 相関係数は危険率1%で有意であった。このうち, 相関係数が0.9以上と非常に高い相関を示したものは, K, GOT, Tp, ALP, CPK, BUNであり, 相関係数が0.8以上0.9未満と比較的高い相関性が得られたものは, Cre, Glu, T-chol, LDHであり, 相関係数が0.7以上0.8未満とやや高い相関性が得られたものはTri-G, Alb, GPT, Amy, GGTであった。なお, T-bil, Hb, Ca, Na, Clの相関性はやや低かった。2) 同時再現性試験での変動係数はNaが0.59%と最小で,GGTとT-bilが7.08%と最大で, 全項目平均すると2.71%であった。以上のように, 若干検討を要する項目もあるが, 今回のドライケミストリー法による血液成分の測定は豚の臨床検査には適しているものと考えられる。