Shin-ichiro Ogura

Effect of Suckling Systems on Serum Oxytocin and Cortisol Concentrations and Behavior to a Novel Object in Beef Calves

We investigated differences between effects of natural- and bucket-suckling methods on basal serum oxytocin (OT) and cortisol concentrations, and the effect of OT concentration on affiliative and investigative behavior of calves to a novel object. Ten Japanese Black calves, balanced with birth order, were allocated evenly to natural-suckling (NS) and bucket suckling (BS) groups. Blood samples were collected at the ages of 1 and 2 months (1 week after weaning) calves, and serum OT and cortisol concentrations were measured using enzyme-linked immunosorbent assay and enzymeimmunoassay tests, respectively. Each calf at the age of 2 months (2 weeks after weaning) was released into an open-field with a calf decoy, and its investigative and affiliative behaviors were recorded for 20 minutes. In 1-month-old calves, the basal serum OT concentration (25.5±4.9 [mean±standard deviation, pg/mL]) of NS was significantly higher than that of BS (16.9±6.7) (p<0.05), whereas the basal cortisol concentration (5.8±2.5 [mean±standard deviation, ng/mL]) of NS was significantly lower than that in BS (10.0±2.8) (p<0.05). Additionally, a negative correlation was noted between serum OT and cortisol concentrations in 1-month-old calves (p = 0.06). Further, the higher serum OT concentration the calves had at 1 month old, the more investigative the calves were at 2 months old but not affiliative in the open-field with a calf decoy. Thus, we concluded that the natural suckling method from a dam elevates the basal serum OT concentration in calves, and high serum OT concentrations induce investigative behavior and attenuate cortisol concentrations.

Distribution of radioactive cesium in soil and its uptake by herbaceous plants in temperate pastures with different management after the Fukushima Dai-Ichi Nuclear Power Station accident

Abstract The accident at Fukushima Dai-Ichi Nuclear Power Station (NPS) extensively contaminated the agricultural land in the Tohoku region of Japan with radioactive cesium [sum of cesium-134 (134Cs) and cesium-137 (137Cs)]. We evaluated the status of radioactive cesium (Cs) contamination in soil and plants at the Field Science Center of Tohoku University, northern Miyagi prefecture, 150 km north of the NPS. In seven pastures with different management, we examined: (1) the distribution of radioactive Cs in soil, (2) the concentration of radioactive Cs in various herbaceous plant species and (3) the change in radioactive Cs content of plants as they matured. We collected samples of litter, root mat layer (root mat soil and plant roots), and subsurface soil (0–5 cm beneath the root mat) at two to three locations in each pasture in December 2011 and May 2012. The aboveground parts of herbaceous plants (four grasses, two legumes, and one forb species) were collected from May 9 to June 20, 2012, at 14-d intervals, from one to five fixed sampling locations in each pasture. The distribution of radioactive Cs in soil differed among pastures to some degree: a large proportion of radioactive Cs was distributed in the root mat layer. Pasture management greatly influenced the radioactive Cs content of herbaceous plants (p < 0.001); plant species had less influence. Radioactive Cs content was highest (> 3 kBq kg−1 dry weight) on May 9 and significantly decreased with maturity (p < 0.001) for most of the pastures, whereas it remained low (0.04–0.18 kBq kg−1 dry weight) throughout the measurement period in the pasture where composted cattle manure was applied. The soil-to-plant transfer factor was negatively correlated to pH(H2O) (R2 = 0.783, p < 0.001) and exchangeable K content (R2 = 0.971, p < 0.001) of root mat soils, which suggests that surface application of composted cattle manure reduces plant uptake of radioactive Cs by increasing the exchangeable K content of the soil. The radioactive Cs content of plants decreased with plant maturity; its degree of decrease (May 9 to June 6) was smaller in legumes (80.6%) than grasses (55.5%) and the forb (58.6%). Radioactive Cs content decreased with plant maturity; also, the proportion remaining in the aboveground plant was higher in legumes (80.6%) than grasses (55.5%) and the forb (58.6%).