Small‐scale heterogeneity in the soil environment influences the distribution of lawn grass and weeds

The association of the micro‐scale distribution of six plant species in a lawn, including the lawn grass, Zoysia japonica, with the soil's environmental factors was studied in an urban park in Kyoto, Japan. The cover of each plant species was scored in July and August. The relative elevation, depth of waterlogging after a shower, soil water content, and soil hardness were measured in 144 quadrats in a 12 m × 12 m plot. The subsurface soil was sampled at every fourth quadrat and was analyzed for the percentage of fine earth and the levels of total carbon, total nitrogen, and available phosphate. Three correlation criteria, namely the Pearson's, Mantel, and partial Mantel correlations, showed considerable disagreement in indicating whether or not there was a significant correlation between each plant species and environmental variable. Although the reason for the disagreement was not always clear, some unimodal or inverted unimodal responses of a plant species against an environmental factor, which was not detectable by the Pearson's correlation coefficient, were indicated to be significant by the Mantel or partial Mantel tests. There were four plant–environment pairs that had a significant correlation in all three criteria: Juncus tenuis in August had a positive correlation with the soil water content in July and August and a negative correlation with soil hardness and Z. japonica showed a negative correlation with the water content in August. The results suggest that the small patches of lawn with poor drainage are the sites of invasion by J. tenuis.     

Heart rate variability after horse trekking in leading and following horses

Horse trekking (HT) is having a stroll on a horse along a walking trail in a forest, field, and/or sandy beach. Generally in HT, horses exercise in tandem line outside the riding facilities. Because the leading horse will be confronted with stressors in the forefront, we hypothesized that the leading horse shows higher stress responses than the following one. In order to verify the hypothesis, we compared short‐term stress responses between each position in six horses. Exercise consisted of 15 min of ground riding and 45 min of HT with walking and trotting. Heart rate variability was analyzed for 5 min at 30, 60, and 90 min after the exercising period. There was no significant difference in heart rate during exercise between leading and following positions. The high frequency / low frequency power band of heart rate variability, an index of sympathetic nervous activity, after exercise, tended to be higher in the leading position than following one (P < 0.1). The result in this study can suggest that the leading horse was in a higher stressed state than the following horse after HT.     

Changes in the ovary and the peripheral concentrations of sex hormones after the aspiration of follicular fluid from the spontaneous follicular cysts of dairy cows

The aim of the present study was to clarify the ovarian and hormonal dynamics after the aspiration of follicular fluid in cows with follicular cysts. Follicular fluid was aspirated from the follicular cysts and follicles that were fated to become cystic follicles and other coexisting normal follicles, respectively, in lactating cows (n = 3). After the aspiration procedure, new follicles developed and reached a diameter of 25 mm without ovulation within 13–19 days. The plasma concentrations of inhibin decreased and follicle-stimulating hormone increased rapidly after the aspiration procedure, and subsequently increased and decreased, respectively, as a new follicle grew. No luteal structures developed after the aspiration procedure, and the animals’ plasma progesterone levels remained low. The present study indicates that the cystic follicles are never luteinized by the aspiration of follicular fluid, and consequently, new follicular cysts are observed to repeatedly develop.     

The effect of high ambient temperature on Ca,P and Mg balance and bone turnover in high‐yielding dairy cows

We investigated the effect of heat stress on Ca, P and Mg balance and bone turnover in lactating cows. In a 2 × 2 crossover design, four multiparous lactating Holstein cows were kept in a chamber and subjected to a constant moderate (18°C) ambient temperature (MT) or high (28°C) ambient temperature (HT). The cows were fed total mixed ration (Ca, 0.7%; P, 0.4%; Mg, 0.2%) ad libitum. The milk yield under HT (35.4 kg/day) tended to be lower (P < 0.10) than that under MT (43.2 kg/day). The concentrations of milk P (P < 0.05) and Mg (P < 0.01) were significantly lower under HT than MT. The Ca, P and Mg intake (P < 0.10); Ca (P < 0.10), P, and Mg (P < 0.05) secretion into milk; and Ca (P < 0.05), P (P < 0.01), and Mg (P < 0.05) absorption in the intestine were lower under HT than MT. The plasma osteocalcin, a marker of bone turnover, was significantly lower (P < 0.05) under HT than MT. Heat stress did not affect plasma C‐telopeptide of collagen type I, a bone resorption marker, and plasma parathyroid hormone concentration.     

Expression of pancreatic enzyme genes during the early larval stage of Japanese eel Anguilla japonica

ABSTRACT: To reveal the ontogeny of pancreatic exocrine function in the early larval stage of eel, cDNAs encoding major pancreatic enzymes, trypsinogen, amylase and lipase were identified from the Japanese eel Anguilla japonica and their expression pattern in larvae was analyzed. The cloned eel trypsinogen precursor consisted of 224 amino acids and showed 82.2% identity to trypsinogen-2 of winter flounder Pleuronectes americanus . The eel amylase precursor consisted of 512 amino acids and showed 77% identity to winter flounder amylase. Eel pancreatic lipase was composed of 470 amino acids and had 58.3% of identity to human pancreatic lipase. In the eel larvae, mRNA expression of trypsinogen and amylase was first detected at 6 days post-hatching (d.p.h.), and the expression level increased between 7 and 8 d.p.h. In contrast, mRNA expression of lipase was first detected at 8 d.p.h. Eel larvae start to feed actively at 8 d.p.h. Thus, it was indicated that eel pancreas starts to synthesize digestive enzymes at 6 d.p.h. and acquires full function by the onset of exogenous feeding at 8 d.p.h.     

Chub mackerel larvae fed fish larvae can swim faster than those fed rotifers and Artemia nauplii

ABSTRACT: Developmental changes of swimming speed were analysed in the chub mackerel Scomber japonicus raised on two distinct dietary regimens. One group was fed only zooplankton such as rotifers and Artemia nauplii (R group) and the other group was fed rotifers plus red sea bream Pagrus major larvae (Pm group). Fish from the Pm group grew faster than those from the R group, and both the cruise and burst swimming speeds were faster for the Pm group even when match-sized comparisons were made. Fish in the Pm group attained a standard length (SL) of 17.5 mm by day 14 and their cruise and burst swimming speeds were 5.39 SL/s and 18.45 SL/s, whereas the R group attained 17.35 mm SL by day 17 and their cruise and burst swimming speeds were 4.28 SL/s and 13.98 SL/s. The results suggest that the swimming speed of chub mackerel in the wild would develop differently depending on the food resources they happen to encounter.     

Relationship between milk production and plasma concentrations of oxidative stress markers during hot season in primiparous cows

Oxidative stress markers, ascorbic acid, and sulfhydryl (SH) residue concentration in primiparous cows' plasma and their relationship to milking performance during hot seasons were investigated. The rectal temperature of cows correlated negatively with SH residue (r = −0.38, n  = 38, P  < 0.05) and ascorbic acid (r = −0.34, P  < 0.05) concentrations in the cows' plasma. The group with a higher concentration of ascorbic acid over the mean value produced significantly more milk ( P  < 0.05) than did the group with a lower ascorbic acid concentration. Although the cows' milk production showed a positive correlation with ascorbic acid concentration in plasma (r = 0.47, P  < 0.05), the relation of SH residue concentration to milk yield was not constant. The plasma SH residue concentration during the hot season correlated positively with milk protein % (r = 0.38, P  < 0.05), lactose % (r = 0.35, P  < 0.05), and solid-non-fat (SNF) % (r = 0.47, P  < 0.05), respectively, but not with fat %. On the other hand, ascorbic acid concentration in plasma showed negative correlations with milk fat % (r = −0.34, P  < 0.05) and protein % (r = −0.49, P  < 0.05), but correlated positively with lactose % (r = 0.52, P  < 0.05). The produced amount (g/day) of milk protein (r = 0.42, P  < 0.05), lactose (r = 0.61, P  < 0.05), and SNF (r = 0.56, P  < 0.05) showed positive correlations with ascorbic acid concentration in plasma.     

Steer stress levels during long distance transport throughout the year in Japan

The objective of this study was to investigate transportation conditions and behavioral and physiological responses of beef steers to long distance commercial transport throughout the year Japan. Japanese Black × Holstein steers (7.9 ± 0.6 months of age; 320.0 ± 19.0 kg) were transported by truck in spring (n = 8), summer (n = 5), autumn (n = 8) and winter (n = 5). Transport distances (time) were 1020.6 km (25 h including lairage periods): 615.4 km (6.4 h) on expressways, 163.2 km (3.7 h) on arterial roads and 242.0 km (10.5 h) by ferry. The space allowance of the truck was about 1.6 m²/head in all seasons. Internal temperatures of the truck were 14.7 ± 4.7°C in spring, 27.9 ± 2.6°C in summer, 24.4 ± 2.8°C in autumn and 9.2 ± 4.3°C in winter. Although internal noise and airflow velocity of the truck were louder and greater while moving on expressways (101.1 ± 8.3 dB and 1.50 ± 1.50 m/s) than on arterial roads (92.0 ± 15.2 dB and 1.32 ± 1.41 m/s) (both P < 0.05), more steers lay down while moving on expressways (P < 0.001). Blood glucose, plasma cortisol, and serum triiodothyronine (T3) concentrations and ALT activity were higher in spring (all P < 0.05). This could be explained by that vibration acceleration (m/s²) of the truck in the longitudinal direction was greater in spring (?0.19 ± 0.43) than in the other seasons (?0.14 ± 0.09 in summer, ?0.15 ± 0.20 in autumn and ?0.15 ± 0.13 in winter) (all P < 0.05). Heart rate, serum concentrations of T₃, total cholesterol, total protein, and AST and ALT activities were higher just after transport than 1 week after transport (all P < 0.05). However, transport stress should be not severe, since no difference between before and after transport was shown on concentrations of plasma cortisol, blood lactate and serum NEFA, serum triglyceride and serum pH and liveweight.     

Age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle

It is well known that the immune system changes with age during development and maturation in Holstein cattle. But age-related changes in leukocytes and T cell subsets in peripheral blood of Japanese Black cattle still remain unclear. The aim of the present study was to investigate comparative changes of leukocytes (granulocytes, monocytes, B cells and T cells) and T cell subsets (CD4⁺, CD8⁺, γδ, CD8⁺γδ and WC1⁺γδ T cells) in Japanese Black cattle aged 0.5, 1, 2, 6, 18 and 36–41 (adult) months on flow cytometry using specific monoclonal antibodies for the cell surface markers. T cell proportion was approximately 40% in 2-month-old cattle and decreased to 20.6% in adults. In contrast, B cell proportion significantly increased from 7.4% to 28.2% with age. In T cell subsets the percentage of CD4⁺ T cells significantly increased from 40.5% to 60%, but that of WC1⁺γδ T cell subset significantly decreased with age. The percentages of CD8⁺ and CD8⁺γδ T cells did not change. The present study details the proportional changes in leukocyte and T cell subsets with age in the peripheral blood of Japanese Black cattle and these findings are similar to those described for Holstein cattle.