Effect of relationships among clinical mastitis incidence,reproductive performance,and culling rate on the lifetime of dairy cows at Hiroshima University Farm

Farm managers' decision to cull dairy cows is based on the cows' milk production, history of disorder(s), and reproductive performance, each of which affects dairy cows' lifetime (herd life and productive lifespan). We investigated the relationships among the incidence of clinical mastitis (CM), the reproductive performance, and the culling rate. We also assessed the effects of these relationships on the lifetimes of dairy cows, using the records made before and after the introduction of an automatic milking system (AMS) at Hiroshima University Farm. Milk yield, CM incidence density, and culling rate of dairy cows increased after the AMS introduction. The CM incidence was associated with an elongation of the calving interval in cows with the same parity. CM in the 1st parity might have caused the reductions of the cows' lifetime and their parity at culling. A higher age at first calving (AFC) was associated with an increase in culling rate but did not lead to a significant decrease in lifetime. Investigations of the factors mediating CM in the 1st parity or AFC with CM incidence or culling rate in the later stages might contribute to the control of lifetime of dairy cows.     

Lesion-based analysis of leaf blast suppression in mixture of rice cultivar and a resistant near-isogenic line

Leaf blast suppression in multilines was evaluated based on the number of susceptible lesions observed in a pure stand of susceptible rice cultivar Sasanishiki, and in 1 : 1 and 1 : 3 mixtures of Sasanishiki and a resistant near-isogenic line, Sasanishiki BL4 or BL7, from 1998 to 2001. The number of lesions first observed in fields in the 1 : 1 and 1 : 3 mixtures were close to theoretical numbers calculated using the number of lesions observed in the pure stands and the ratios of the susceptible Sasanishiki in the mixtures. The ratio of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand was 0.29 and 0.09, respectively. The relationship between these ratios and the ratios of susceptible Sasanishiki in mixtures was defined in an equation to estimate the degree of leaf blast suppression. Validation studies for the ratios of the number of lesions in the 1 : 1 and 1 : 3 mixtures to the number in the pure stand were conducted in two different locations and showed that the ratios are almost acceptable. The calculated autoinfection to alloinfection ratio was 1.3 and 1.4 in the 1 : 1 and 1 : 3 mixtures, respectively, suggesting that the calculated ratio will affect the degree of leaf blast suppression. Thus, predictors were obtained to estimate leaf blast suppression for effective blast control in multilines.     

Tree size dependence of litter production, and above-ground net production in a young Hinoki (Chamaecyparis obtusa) stand

The study was carried out in a 9-year-old hinoki cypress (Chamaecyparis obtusa (Sieb. et Zucc.) Endl.), stand over a span of three years from July 1992 to June 1995, primarily to predict litter production from exteral tree dimensions by combining open-top clothtrap and clipping methods. Litter production was virtually concentrated in October and November. Stem cross-sectional area at the crown base was proved to be the reliable predictor of litter production, and that single regression model was evolved irrespective of year. The regression model had proportional constants of 2.696 × 10⁻² and 3.540 × 10⁻² kg cm⁻² year⁻¹ for leaf litter and total litter production, respectively. Utilizing the model, leaf litter production of the stand was assessed to be 5.04, 5.12, and 4.99, and total litter production to be 6.48, 6.58, and 6.40 Mg ha⁻¹ year⁻¹ for the first, second and third year, respectively. Biomass increment was 6.67, 7.80, and 7.70, tree mortality was 0.15, 0.13, and 0.41, and insect grazing was 0.09, 0.05, and 0.002 Mg ha⁻¹ year⁻¹ for the first, second and third year, respectively. Above-groud net production was therefore 13.39, 14.55, and 14.51, Mg ha⁻¹ year⁻¹, and biomass accumulation ratio (biomass/net production) was 1.86, 2.21, and 2.76 year for the first, second and third year, respectively. Considering data from earlier studies and the results of this study, biomass accumulation ratio,BAR (year), of hinoki stands was best related to above-ground biomass,y (Mg ha⁻¹), using the power function:BAR=0.112y ^0.936. Excluding seedling stands, leaf efficiency (above-ground net production per unit leaf mass) of hinoki stands was 0.91±0.02 (SE) Mg Mg⁻¹ year⁻¹, irrespective of stand biomass or age.     

2,4-Nonadienal and benzaldehyde bioantimutagens in Fushimi sweet pepper (Fushimi-togarashi)

Fushimi sweet pepper, "Fushimi-togarashi", is one of the "Kyo-yasai", traditional vegetables, in Kyoto, Japan. The chloroform fraction of Fushimi sweet pepper showed bioantimutagenicity on UV induced mutation in Escherichia coli B/r WP2. The bioantimutagen was purified with silica gel chromatography and identified as 2, 4-nonadienal (ID(50) = 20 microg/plate) on the basis of GC retention time and EI-MS spectrum of authentic 2,4-nonadienal. The sweet pepper also contained a known bioantimutagen, benzaldehyde (ID(50) = 2 mg/plate). Additive bioantimutagenicity was also observed by 2, 4-nonadienal with benzaldehyde. 2,4-Nonadienal did not show bioantimutagenicity in an UV excision repair deficient strain, E. coli B/r WP2s uvrA(-)(). Furthermore no delay of the first cell division after UV irradiation was observed in E. coli B/r WP2. These results indicate that the bioantimutagenic activity of 2, 4-nonadienal on UV mutagenesis might depend on the excision repair system in E. coli B/r WP2.     

Monosaccharide composition of sweetpotato fiber and cell wall polysaccharides from sweetpotato, cassava, and potato analyzed by the high-performance anion exchange chromatography with pulsed amperometric detection method

The cell wall materials (CWMs) from sweetpotato (Ipomoea batatas cv. Kokei 14), cassava (Manihot esculenta), and potato (Solanum tuberosum cv. Danshaku) and commercial sweetpotato fiber as well as their polysaccharide fractions were analyzed for sugar composition by the high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) method. The separation of arabinose and rhamnose, and xylose and mannose, by this method has been improved using a CarboPac PA 10 column. Pretreatment of the CWMs and cellulose fractions with 12 M H(2)SO(4) was required for complete hydrolysis to occur. Commercial sweetpotato fiber was found to be mainly composed of glucose (88.4%), but small amounts of other sugars were also detected. Among the root crops, sweetpotato CWM had the highest amount of pectin and galacturonic acid. Fucose was detected only in cassava CWM and its hemicellulose fraction, while galactose was present in the highest amount in potato CWM. Among the polysaccharide fractions, it was only in the hemicellulose fraction where significant differences in the sugar composition, especially in the galactose content, were observed among the root crops.     

Rice false smut pathogen, Ustilaginoidea virens, invades through small gap at the apex of a rice spikelet before heading

Ustilaginoidea virens, the false smut pathogen of rice, produces false smut balls on spikelets after heading. To clarify how the fungus invades spikelets during the booting stage, we developed a fungal strain that expresses a green fluorescent protein gene and injected conidia from this strain into rice sheaths. Observations at 48?h post-inoculation showed many conidia were present on spikelet surfaces, and the conidia had germinated and the hyphae have gradually grown by 120?h post-inoculation. By 144?h, hyphae had invaded spikelets through their apices, via the small gap between the lemma and palea and had already reached all floral organs.     

Effects of intravenous ghrelin injection on plasma growth hormone,insulin and glucose concentrations in calves at weaning

Ghrelin action, which stimulates growth hormone (GH) secretion, may alter during the weaning period in calves. Our objective was to compare the effects of intravenous ghrelin injection on plasma GH, insulin and glucose concentrations in calves around the weaning period. Four Holstein bull calves were fed whole milk and allowed free access to solid feeds, and weaned at 7 weeks of age. Measurements were performed at weeks 1, 2, 4, 6, 7, 9, 11 and 13, when calves were intravenously injected with ghrelin (1.0 μg/kg body weight (BW)) through a catheter, and jugular blood samples were obtained temporally relative to the injection time. Estimated digestible energy intake per metabolic BW transiently decreased at week 7 because of low solid intake immediately after weaning, and thereafter gradually increased. Plasma insulin and glucose concentrations were not affected by ghrelin injection at all ages. In contrast, plasma GH concentrations increased with ghrelin injection at all ages. The incremental area of GH at week 7 was greatest and significantly higher compared with weeks 2, 4, 6 and 9. This result suggests that nutrient insufficiency immediately after weaning enhances GH responsiveness to ghrelin.     

Evaluating the rumen‐protected lysine stability in forage‐based total mixed rations in vitro and determining the lysine Brix value

Three rumen‐protected lysine (RPL) products (AjiPro^®‐L, LysiPEARL^TM, and Feedtech Bypass Lysine^TM: A, B, and C, respectively) were tested for stability in two forage‐based total mixed rations (TMR1, 41.3% dry matter (DM), and TMR2, 49.5% DM) (experiment 1) and for Brix value (experiment 2). In experiment 1, each RPL product (2 g each) and TMR diet (200 g) were mixed and stored in plastic bags at 20°C for 0, 1, 3, 6, 12, 24, and 48 hr. In experiment 2, each RPL product (2 g) was dispensed into ion‐exchanged water (20 ml) and kept at 20°C for 0, 0.5, 1, 3, 6, 12, 24, and 48 hr. At each time point, free lysine (Lys) content and Brix values of extracts were measured, and Lys release (LR, %) was calculated. All RPL products LR% varied with varying diets DM and increased with increasing of time exposed to diets; it was highest in C, followed by B, and then A. Water LR% positively correlated with that from diets and with Brix values of Lys dissociated in water. Our results indicated that Lys dissociation from RPL products is affected by diet DM content. Brix value may be used as a potential marker for RPL protection efficacy.     

Release of Bound Lipids in Cereal Starches Upon Hydrolysis by Glucoamylase

The raw starch granules from corn, rice, and wheat were hydrolyzed by practically pure glucoamylase (Rhizopus niveus). The bound lipids remaining in the residual starches were investigated, of which the major components of the lipids, free fatty acids (FFA) in corn starch, FFA and phospholipids (PL) in rice starch, and PL in wheat starch were determined. In each case, the bound FFA and PL were decreased to some extent during the initial stage of hydrolysis. During the later stages, the FFA continued to gradually decrease, while the level of PL stabilized. It was interesting that some of the bound lipids were released from the granules upon glucoamylase hydrolysis, differing from the model amylose-lipid complexes. Furthermore, the structures of the residual starches were investigated. The blue value and λ_max of the starches were increased by partial hydrolysis of the starch granules using practically pure glucoamylase. Two gel-permeation chromatography analyses revealed that the relative amount of amylose fraction was increased by glucoamylase hydrolysis, and also that the increments were reduced by the defatting of bound lipids. The results suggest that the increase in amylose fraction is attributable to the existence of bound lipids in the granules.     

Marker-assisted selection of low erucic acid quantity in short duration Brassica rapa

Low erucic acid (LEA) rapeseed, which has accumulated mutant fatty acid elongase genes at the BnFAE1.1 and BnFAE1.2 loci of the A- and C-genome, respectively, is an important oilseed crop. Short growing turnip rape (B. rapa) is also important as a catch crop in the continuous cropping of rice in Asia but there is no LEA B. rapa cultivar for cultivation in South Asia. In order to develop LEA turnip rape cultivars, high erucic acid turnip rape cultivars were interspecifically crossed as recurrent parents to a canola quality rapeseed. In the meantime, we monitored incorporation of the mutant bnfae1.1 (e1) gene into A-genome of turnip rape, using a dCAPS primer pair, which can amplify PCR fragment only for the mutant e1 gene from A-genome. The early backcross progenies showed poor seed set, but which was improved in advanced progenies. Finally, homozygous e1e1 genotypes were established in the selfed progenies of BC₂–BC₃, and their LEA content was confirmed by gas-chromatography analysis. Our results and promising lines will contribute to LEA-trait selection in turnip rape and rapeseed breeding.