Search

The effects of long-term feeding of wood kraft pulp (KP) silage containing sweet-potato shochu distillery by-product (SDP) on feed intake, feed digestibility, rumen fermentation, and growth performance of Japanese Black steers were investigated during the early fattening period. Ten Japanese Black steers (9.8 ± 0.6 months of age) were used in this study. Five steers (KP group) were fed KP silage as a replacement for 10% timothy hay (dry matter bases), in contrast to the other five (control group). KP silage consisted of 92.9% KP and 7.1% SDP (dry matter bases). The experiment was conducted for 18 weeks. No significant differences were observed in terms of feed intake, feed digestibility, or daily body weight gain between the groups. In addition, diurnal changes in the rumen pH and ruminal lipopolysaccharide activity did not differ between the groups. However, the plasma concentration of aspartate transaminase in the KP group was slightly lower (P = 0.078) than that in the control group. Thus, our study suggested that feeding KP silage does not reduce feed intake or affect the rumen fermentation or growth performance of Japanese Black fattening steer.

This study was to examine the effects of dietary vitamin K (VK) 3 supplementation on immune-related substances in milk, oxidative stress indices in plasma and VK1, and menaquinone 4 (MK-4) in plasma and milk in periparturient dairy cows. Forty healthy perinatal Holstein-Friesian dairy cows were used in this study. Twenty-one animals were randomly selected and categorized into the VK3 supplemented (50 mg/day/head as VK3) group; the remaining 19 were categorized into the control group. On day 3 after calving, blood and milk were sampled, and their chemical components were determined. The VK3 supplemented group had significantly higher menaquinone 4 levels in plasma and milk on day 3 postpartum than the control group. In addition, there was a significant increase in the immunoglobulin G (IgG) level in milk. VK3 may be absorbed from the gastrointestinal tract and converted to MK-4, the biologically active form of VK, in the mammary gland and other tissues. It was thought that the increase in MK-4 level in plasma and milk induced an increase in the concentration of IgG in milk. VK3 supplementation to periparturient dairy cows may contribute to the production of colostrum with high concentrations of IgG and MK-4.

The purpose of this study was to investigate the carbon dioxide (CO

In this study, we evaluated the partial replacement of roughage with wood kraft pulp (KP) on rumen fermentation and productivity of dairy cows. Eighteen cows were divided into control and KP groups. The KP group started adaptation to KP 3 weeks before calving; after calving, they were fed a total mixed ration for 12 weeks, wherein 18% Timothy hay was replaced with KP. The dry matter intake, body weight, and milk yield and composition were similar in the control and KP groups. The average daily rumen pH was higher with KP feeding, and the average daily ruminal temperature remained lower at 16 days after calving (P 0.05). The concentration of volatile fatty acids remained unaltered, the molar proportion of acetic acid decreased, and the molar proportion of propionic acid increased, indicating a low acetic acid:propionic acid ratio (P 0.05). Lipopolysaccharide activity in the rumen fluid was higher in the KP group (P 0.05); however, the rumen microbiota were unaffected. The digestibility of dry matter and neutral detergent fiber increased 12 weeks after calving, whereas excretion of urinary nitrogen decreased (P 0.05). Partial replacement of roughage with KP did not suppress rumen fermentation and maintained postpartum productivity.

The effect of dietary vitamin K

We investigated the physiological changes during the fattening period and production characteristics in Japanese Black steers bred and raised using the typical feeding system in Japan. Here, 21 Japanese Black steers aged 12 months were used, with experimental period divided into early (12–14 months of age), middle (15–22 months), and late fattening phases (23–30 months). The liver transcriptome, blood metabolites, hormones, and rumen fermentation characteristics were analyzed. Blood triglyceride and non-esterified fatty acid concentrations increased, whereas blood ketone levels decreased, with fattening phases. Blood insulin increased with fattening phases and was positively correlated with carcass weight and marbling in late fattening phases. Rumen fermentation characteristics showed high propionate levels and low butyrate levels in late fattening phases, likely due to increased energy intake. Genes related to glucose metabolism, such as SESN3, INSR, LEPR, and FOXO3, were down-regulated in late fattening phases. Genes related to lipid metabolism, such as FABP4, were up-regulated, whereas FADS1 and FADS2 were down-regulated. These findings suggest that the physiological changes resulted from changes in the energy content and composition of diets. Liver metabolism changed with changes in fat metabolism. Insulin was strongly associated with physiological changes and productivity in Japanese Black cattle.

This study aimed to examine the effects of feeding kraft pulp (KP) on the growth performance, feed digestibility, and rumen fermentation of Japanese Black fattening steers. Ten Japanese Black fattening steers (aged 26 months) were randomly divided into control and KP groups. The control group (n = 5) was fed concentrate feed without KP, and the KP group (n = 5) was fed concentrate feed containing 10% KP. Both the groups were provided rice straw as roughage. The experiment was conducted over a period of 12 weeks. There was no significant difference in dry matter intake, daily body weight gain, and nutrient digestibility between both groups. No difference was observed in the ruminal concentrations of volatile fatty acids among the groups. At weeks 8 and 12 after the onset of the experiment, the acetate‐to‐propionate ratio in the ruminal fluid of the KP group was significantly higher than that of the control group. The average daily pH of ruminal fluid and activity of ruminal lipopolysaccharide did not differ between the groups. Our results suggested that the growth performance and feed digestibility in the Japanese Black fattening steers were not influenced by replacing concentrate feed with KP.

We investigated the effects of wood kraft pulp (KP) feeding on feed digestibility and rumen fermentation of Japanese Black (JB) steer in the middle fattening stage. The feeding experiment was carried out a replicated 3 × 3 Latin square design using six JB steers (16.2 ± 0.8 months of age). Steers were fed rice straw and three concentrated feeds: commercial formula feed (control), formula feed containing 7.5% KP on a dry matter (DM) basis (7.5% KP), and formula feed containing 15% KP on a DM basis (15% KP). Feed digestibility and rumen fermentation parameters were recorded for 3 days during the measurement period, after an adaptation phase of 11 days. There was no significant difference in DM intake per day among diets. A slightly higher digestibility of neutral detergent fiber was observed in steers fed 15% KP, compared with those fed other diets (P = 0.059). The butyric acid ratio in rumen fluid was higher in steers fed KP diets than in steers fed control (P = 0.083). The average ruminal pH was unaffected by KP diets. This study suggests that replacing 15% of concentrated feed with KP has little effect on feed digestibility and rumen fermentation in JB fattening steer.

The aim of this study was to develop prediction equations for methane (CH4 ) emissions from lactating cows using the CH4 /carbon dioxide (CO2 ) ratio in the breath measured in the automatic milking system (AMS) and to evaluate the predicted values and factors affecting the CH4 /CO2 ratio. The model development was conducted using a dataset determined in respiration chambers or head boxes (n = 121). Then, gas measurements in the AMS as well as in the head box were carried out with six lactating cows fed one of three different levels of neutral detergent fiber (NDF) content, following a 3 × 3 Latin square experimental design. The obtained equation that is suitable for practical use on farms to predict CH4 was CH4 (L/day) = -507 + 0.536 live weight (kg) + 8.76 energy-corrected milk (kg/day) + 5,029 CH4 /CO2 (adjusted R2 = 0.83; root mean square error = 40.8 L/day). Results showed that the predicted values correlated positively with the observed values, the determined CH4 /CO2 ratio increased with increasing dietary NDF content, and the detected eructation rate was in the normal range. On the other hand, the CH4 /CO2 ratio was affected by the time interval between measurement and last eating before the measurement.

We conducted a meta-data analysis to develop prediction equations to estimate enteric methane (CH4 ) emission from beef cattle in Southeast Asia. The dataset was obtained from 25 studies, which included 332 individual observations on nutrient intakes, digestibilities, and CH4 emissions. Cattle were provided tropical forage or rice straw, with or without concentrates in individual pens equipped with indirect open-circuit head hood apparatus. The simplest and best equation to predict daily CH4 emission was CH4 (g/day) = 22.71 (±1.008) × dry matter intake (DMI, kg/day) + 8.91 (±10.896) [R2 = 0.77; root mean square error (RMSE) = 19.363 g/day]. The best equation to predict CH4 energy as a proportion of gross energy intake (CH4 -E/GEI, J/100 J) was obtained using DMI per body weight (DMIBW, kg/100 kg), content (g/100 g DM) of ether extract (EE) and crude protein (CP), and DM digestibility (DMD, g/100 g); CH4 -E/GEI = -0.782 (±0.2526) DMIBW - 0.436 (±0.0548) EE - 0.073 (±0.0218) CP + 0.049 (±0.0097) DMD + 8.654 (±0.6517) (R2 = 0.39; RMSE = 1.3479 J/100 J GEI). It was indicated that CH4 emissions from beef cattle in Southeast Asia are predictable using present developed models including simple indices.

A Gram-stain-variable, strictly anaerobic, rod-shaped, catalase-negative and endospore-forming bacterial strain, designated MJC39T, was isolated from grass silage preserved in Hokkaido, Japan. Growth occurred at 20–42 °C, pH 5.0–7.0 and NaCl concentrations up to 2 % (w/v). The isolated strain MJC39T produced butyric acid in peptone yeast extract medium with glucose. The DNA G+C content of strain MJC39T was 34.4±0.2 mol%. The major cellular fatty acids (>10 %) were C14 : 0, C16 : 0 and summed feature 3 (including C16 : 1ω7c/C16 : 1ω6c). No respiratory quinones were detected. The polar lipids of strain MJC39T were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol, one unidentified lipid, one unidentified aminolipid, two unidentified glycolipids, one unidentified phospholipid, one unidentified aminoglycolipid and one unidentified phosphoaminoglycolipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain MJC39T was a member of the genus Clostridium and is closely related to Clostridium tyrobutyricum JCM 11008T (95.8 % similarity) and Clostridium algifaecis MB9-7T (95.5 % similarity). Based on the genotypic, phenotypic and chemotaxonomic characteristics, strain MJC39T represents a novel species of the genus Clostridium , for which the name Clostridium pabulibutyricum sp. nov. is proposed. The type strain is MJC39T (=JCM 31506T=DSM 103944T).

The objectives of this study were to estimate genetic parameters and to perform a genome‐wide association study (GWAS) for predicted methane‐related traits in Japanese Black steers. The methane production and yield traits were predicted using on‐farm measurable traits, such as dry matter intake and average daily gain. A total of 4,578 Japanese Black steers, which were progenies of 362 sires genotyped with imputed 551,995 single nucleotide polymorphisms (SNPs), had phenotypes of predicted methane‐related traits during the total fattening period (52 weeks). For the estimation of genetic parameters, the estimated heritabilities were moderate (ranged from 0.57 to 0.60). In addition, the estimated genetic correlations of methane production traits with most of carcass traits and feed‐efficiency traits were unfavorable, but those of methane yield traits were favorable or low. For the GWAS, no genome‐wide significant SNP was detected, but a total of four quantitative trait locus (QTL) regions that explained more than 5.0% of genetic variance were localized on the genome, and some candidate genes associated with growth and feed‐efficiency traits were located on the regions. Our results suggest that the predicted methane‐related traits are heritable and some QTL regions for the traits are localized on the genome in Japanese Black steers.

The objective of this study was to develop a prediction equation for methane-related traits in beef cattle and evaluate this equation using datasets with different cattle breeds and roughage rates. Enteric methane emission (CH4 , l/day) was measured using open-circuit respiration chambers. Dry matter intake (DMI, kg/day), body weight (BW, kg), daily gain (DG, kg), total digestible nutrients (TDN, %DMI), and roughage rate (Rrate, %) were used as independent variables, and methane-related traits-CH4 , CH4 per DMI (CH4 /DMI, l/kg), and methane conversion factor (MCF, %)-were used as dependent variables. The best-fit equations to predict methane-related traits using a total of 76 records were CH4 = -676.7 + 0.04194 × BW + 29.88 × DMI + 7.883 × TDN + 4.367 × Rrate, CH4 /DMI = -52.24 - 1.193 × 10-3 × BW - 5.905 × DG + 1.077 × TDN + 0.5008 × Rrate, and MCF = -11.43 - 5.308 × 10-4 × BW - 1.223 × DG + 0.2336 × TDN + 0.1157 × Rrate. The predictive ability of the developed equations differed between roughage rates but not between breeds. For CH4 , the predictive ability of the developed equations was better compared with previously reported equations in the low roughage rate dataset, but not in the high roughage rate dataset. Our results suggest that the developed equations of methane-related traits can be applied in beef cattle fed with low roughage diets.

This study was aimed at two objectives: 1) explore the possibility of near infrared (NIR) spectroscopy to determine the content of common dietary fatty acids (FAs) and fat content in cow's liquid milk for better individual cow's feed management; 2) using aquaphotomics obtain better understanding of interaction between water molecular structure and FAs and gain more insight into their functionality. For these purposes, 252 milk samples were collected from 9 cows during 14 weeks and FAs content measured using gas chromatography as a reference method. Applying aquaphotomics NIR spectral analysis, quantification was attempted using 1300–1850 nm region where both water and FAs absorbance bands are located. The results showed possibility of quantification for 8 common dietary FAs which was more accurate when spectral region was narrowed to 1600–1800 nm. In the external validation, good predictions (R2> 0.75, RPD>1.5), were obtained for caproic and caprylic and acceptable for capric, lauric, myristic, myristoleic, palmitoleic and oleic acid (0.55 1.5). Interpretation of influential variables in regression models revealed contribution of water absorbance bands related to protonated and hydration water, which originate from the water-FAs interaction and are important for their self-organization into assemblies with different morphologies.

The effect of wood kraft pulp (KP) feed on dietary digestibility, ruminal fluid pH, rumen fermentation characteristics, and milk production performance in lactating dairy cows was examined. Four lactating dairy cows were used for the feeding experiment by the cross‐over design. The control group and KP group were set up as treatments. The control group was fed total mixed ration (TMR) (40% roughage and 60% concentrate) and the KP group was fed TMR containing 12% KP that replaced half of the rolled corn in the control diet. The dry matter intake, digestibility of the feed components, and milk yield were not significantly different between control group and KP group. The number of times that the ruminal fluid pH was below 6.1 tended to decrease in the KP group compared to the control group (p

We improved the dry ash procedure for detecting titanium dioxide (TiO2 ) in cattle feces containing chromium oxide [corrected] (Cr(2)O(3) ). First, the effect of amount of sodium sulfate (Na2 SO4 ) on the recovery of TiO2 from cattle feces that contained Cr2 O3 was evaluated. Average recovery of TiO2 at the 2.5 g Na2 SO4 level was significantly higher (P < 0.0001) than that at 0.75 g Na2 SO4 . Second, the effect of Cr2 O3 concentration on the recovery of TiO2 of cattle feces by using two levels of Na2 SO4 addition was examined. The recovery of TiO2 decreased with the increase in the amount of Cr2 O3 at the 0.75 g Na2 SO4 level but was consistently high at 2.5 g Na2 SO4 . Third, the recovery of Cr2 O3 from cattle feces was checked. The recoveries of TiO2 and Cr2 O3 were high enough at the 2.5 g Na2 SO4 level. Fourth, the improved dry ash procedure (5 mL of concentrated H2 SO4 and 2.5 g of Na2 SO4 were used for sample digestion) was compared to the wet ash procedure. Average recovery of TiO2 by the improved dry ash procedure was significantly higher (P = 0.0077) than that by the wet ash procedure. Thus, the improved dry ash procedure can be used for TiO2 analysis in cattle feces containing Cr2 O3 .

To decrease the age at first calving in Holsteins, the effects of average daily body weight gain (ADG) and crude protein (CP) level until first insemination on growth performance and milk production were examined. The MM group had a target ADG of 0.75 kg and received a diet with a CP level of 14%. The HM and HH groups had a target ADG of 1 kg; both these groups received a diet with CP levels 14% and 16%, respectively. The ADG in the HM and HH groups was 1.1 kg, whereas in the MM group it was 0.97 kg (P < 0.01). The HM and HH groups showed no differences in withers height at body weight 350 kg. The ages at first calving in MM, HM and HH groups were 23.1, 21.0 and 21.8 months, respectively. The HM and HH groups had lower milk yield at day 305 than the MM group (P < 0.01). These results suggest that growth performance until first insemination should be maintained at an ADG of 0.97 kg or less with a CP level of approximately 14%, to shorten time until first insemination and prevent the decrease of milk yield.

We investigated the effect of cellooligosaccharide (CE) or a combination of dextran and Lactobacillus casei ssp. casei strain JCM1134T (synbiotic; SB) feeding on growth performance, fecal condition and hormone concentrations in Holstein calves. Fifty-two female Holstein calves were randomly assigned to three treatment groups: CE feeding group (n = 16), SB feeding group (n = 18), and control group (n = 18). Body weight at 90 days of age, as well as daily body weight gain (DG) and feed efficiency after weaning to 90 days of age were greater (P

Methane (CH(4)) is the second most important greenhouse gas (GHG) and that emitted from enteric fermentation in livestock is the single largest source of emissions in Japan. Many factors influence ruminant CH(4) production, including level of intake, type and quality of feeds and environmental temperature. The objectives of this review are to identify the factors affecting CH(4) production in ruminants, to examine technologies for the mitigation of CH(4) emissions from ruminants, and to identify areas requiring further research. The following equation for CH(4) prediction was formulated using only dry matter intake (DMI) and has been adopted in Japan to estimate emissions from ruminant livestock for the National GHG Inventory Report: Y = -17.766 + 42.793X - 0.849X(2), where Y is CH(4) production (L/day) and X is DMI (kg/day). Technologies for the mitigation of CH(4) emissions from ruminants include increasing productivity by improving nutritional management, the manipulation of ruminal fermentation by changing feed composition, the addition of CH(4) inhibitors, and defaunation. Considering the importance of ruminant livestock, it is essential to establish economically feasible ways of reducing ruminant CH(4) production while improving productivity; it is therefore critical to conduct a full system analysis to select the best combination of approaches or new technologies to be applied under long-term field conditions.

In order to investigate the energy expended in chewing during eating and rumination in sheep fed timothy or sudangrass hay at the same intake level, the energy expenditure of the head was measured using the arterial-venous difference technique and that of the whole body was measured using an open-circuit, indirect respiration calorimeter. There was no difference in the per-chew energy expenditure between timothy hay and sudangrass hay during eating and rumination, but for both types of hay there was a difference in energy expenditure between eating (0.25 J per chew per kilogram body weight) and rumination (0.18 J per chew per kilogram body weight). There was no effect of time period after feeding on the energy expended in one chew during eating and rumination. On average, for a given type of hay, the energy expended in chewing during eating + rumination accounted for 4.9% of the daily energy expenditure of the whole body.

Metabolism trials were conducted on six wethers and four Brahman steers given Ruzi grass hay with different levels of soybean meal in order to compare the effects of protein levels on energy and nitrogen balances, and fiber digestion between the two animal species. Crude protein (CP) contents in four dietary treatments were 3.4%, 6.9%, 10.4%, and 13.9% with the different levels of soybean meal supplement. Digestibilities of crude fiber, neutral detergent fiber and acid detergent fiber were greatly improved in sheep by the supplement of soybean meal until the CP content in the whole ration reached 10%. The difference was more than 10 units in each fiber fraction. While in cattle, fiber fraction digestibilities in the animals given Ruzi grass hay without soybean meal supplement were relatively high. The values were then improved by the smallest amount of supplement (6.9% CP). Beyond this level, there was no effect of the supplement. Although digestibility of CP was lower in sheep when no protein supplement was given, it was higher in sheep when high protein diets were given (10.4 and 13.9% CP). The total digestible nutrient and digestible energy contents well represented overall features of the differences in nutrient digestibilities between sheep and cattle. With lower levels of soybean meal supplement, these values were lower in sheep than in cattle. While, with higher levels of the supplement, there was no difference in the values between the animals. Sheep are often studied as a model animal for cattle in order to examine nutritive value of feed resources. It was suggested in the design of feeding trials using sheep, that CP content of whole ration, in which a target feed resource is included, should be more than 10%.

This study compared the effects of two levels of crude protein (CP) supplementation during a close-up dry period on the productive performance, nitrogen balance, and blood profiles of Holstein cows. Eighteen cows (8 primigravid and 10 multiparous), 21 days prior to calving, were divided into four groups and fed a diet containing a low (11.5 to 12.7% CP) or high (14.1 to 15.3% CP) level of protein. Following parturition, all cows were offered the same diet. Nitrogen balance was measured 12 d to 10 d prior to the expected calving date. Whole feces and urine were collected. The higher close-up CP did not improve milk production during the early lactation period (14 w) in multiparous cows but tended to increase production by 2 kg of milk per day in primigravid cows. There were no differences in the weight of calves, the weight of the placenta, or the incidence of calving difficulty. Nitrogen intake, urine nitrogen and nitrogen retention were increased by the higher CP diet in primigravid and multiparous cows. All groups of cows showed a positive nitrogen balance. In particular, higher nitrogen retention was observed in primigravid cows fed the higher CP diet. With the exception of plasma urea nitrogen (PUN), non of the blood profiles were influenced by the CP level. The higher close-up CP increased the PUN during the period studied in primigravid and multiparous cows. These results indicate that a CP level of 14% during a close-up dry period is optimal for primigravid cows, and 12% CP level is sufficient for multiparous cows.

Four female Holstein cattle (Holstein, average body weight (BW) 359 kg), four castrated male native cattle (Native, 257 kg) and four castrated male swamp buffaloes (Buffalo, 543 kg) were subjected to urea space measurements to determine body composition of the different animals and to investigate the effect of 48 h of water deprivation on the change of body composition in Northeast Thailand. The percentage of empty body protein (EBPRO) compared to empty body weight (EBW) was similar among Holstein, Native and Buffalo. The percentage of empty body water (EBH 2 O) was the highest in Native, while the percentage of empty body fat (EBFAT) was the highest in Buffalo. After the dehydration, mean BW decreased in Holstein, Native and Buffalo, and not only water but also protein and fat were mobilized. The percentage of EBPRO was similar among Holstein, Native and Buffalo; however, the percentage of EBFAT was the highest in Buffalo and the percentage of EBH 2 O was the highest in Native. After dehydration, the percentage of EBFAT decreased and the percentage of EBH 2 O increased in all animals.

本研究の目的は，乳牛と肉牛の窒素摂取量（乾物摂取量やタンパク含量）と窒素排泄量の関係を調べ，また両方に適用できる窒素排泄量を予測する一般式の作成を試みることであった．用いたデータは，日本では泌乳中のホルスタイン種95頭，ホルスタイン種去勢牛45頭と黒毛和種去勢牛23頭の窒素出納試験成績，外国では33の文献より得た泌乳中のホルスタイン種と去勢肥育牛の値を用いた．本研究の結果，泌乳牛は肥育牛に比べ尿による窒素排泄割合が低かった．すべてのデータに対して線形式と指数式をあてはめた結果，窒素摂取量と糞と尿による窒素排泄量の間に正の関連性がみられた．しかし，尿による窒素排泄量は泌乳牛と去勢肥育牛で大きく異なっていたが，尿中と乳中の窒素の合計と摂取窒素の関係をみると決定係数が大幅に向上した．また，糞による窒素排泄量は窒素摂取量より乾物摂取量との方がいずれの式に関しても決定係数が高かった．

The mRNA expression of sodium-glucose transporter 1 (SGLT1) and fatty acid translocase (CD36) in the gastrointestinal tract of Holstein cattle and Saanen goats before and after weaning was investigated. Before weaning, the expression of both SGLT1 and CD36 was highest in the jejunum, relative to the other parts of the gastrointestinal tract in both species. The expression of SGLT1 and CD36 in the duodenum was second highest in the goats. After weaning, SGLT1 and CD36 expression in the small intestine significantly decreased in both species. The expression of both types of transporters was also detected in the forestomach. From these results, it was concluded that the jejunum is probably the major absorption site for glucose and long-chain fatty acids before weaning, and that the expression of both types of transporters decreases after weaning in cattle and goats.

乳牛における産次・乳期による乳生産量の違いに対するインスリンの調節作用について検討するため，泌乳初期（5週）の初産牛（5頭）および経産牛（9頭），泌乳後期（30～33週）の経産牛（4頭）を供試し，グルコース（0.1g/kgBW），インスリン（0.2IU/kgBW）を頸静脈より投与し，投与前後の血漿インスリン，グルコース濃度を測定した．その結果，泌乳初期の乳量は，初産で経産より有意に少なく（P＜0.01），経産牛の乳量は，泌乳後期で初期より有意に少なかった（P＜0.01）．グルコース刺激インスリン分泌反応は，初産泌乳初期で，経産泌乳初期より有意に大きく（P＜0.01），インスリン基礎濃度も，初産泌乳初期および経産泌乳後期で，経産泌乳初期より有意に高かった（P＜0.05）．また，インスリン刺激グルコース減少反応は，経産泌乳後期で初産および経産泌乳初期より有意に大きかった（P＜0.05）．以上の結果から，産次・乳期による乳生産量の違いに，インスリンによる調節が働いている可能性が示唆された．

ルーメンバイパスメチオニン製剤の飼料添加が乳牛の産乳，繁殖および窒素排泄に及ぼす影響について，2年間で延べ81頭のホルスタイン種乳牛（2産以上，平均産次3.6産）を供試して分娩前4週から分娩後14週までとする飼養試験により検討した．対照区の飼料はチモシー乾草，ヘイキューブおよび配合飼料の混合飼料（TMR ; 設計値 粗タンパク質（CP）16.0％，非分解性タンパク質率35.1％，可消化養分総量（TDN）74.9％）を用い，メチオニン添加区（以下メチオニン区と略）は対照区飼料にDLメチオニン67％製剤を1日20g添加した．1年次（実験1）は飼料中CP含量が14.9％と設計値よりも低く，このため両区ともCP摂取量が少なくなったが，乳量および乳タンパク質量はメチオニン区が多く（P＜0.01），添加効果が示された．2年次（実験2）の飼料中CP含量は16.0％と設計値どおりであり，飼養成績においては乳タンパク質率がメチオニン区でやや高かったほかに有意な差はなかった．摂取量から乳中移行量を差し引いて求めた糞尿中窒素排泄量は飼料中CP含量が低かった1年次の方が2年次に比べて72g少なかった．血漿中メチオニン濃度は，メチオニン添加により有意に上昇したが，その他の血液成分に差はなく，繁殖に及ぼす効果も明らかではなかった．以上のことから，ルーメンバイパスメチオニン製剤の適切な活用により，乳生産の効率化と低タンパク質飼料の利用による窒素排泄量低減の可能性が示された．

The effect of multiplicative scatter correction (MSC) on wavelength selection for near infrared (NIR) calibration to determine fat content in raw milk was investigated. Short-wave NIR spectra (700–1100 nm) of raw milk samples were measured. The calibration equations for fat content were performed by multiple linear regression (MLR) using original, second derivative and MSC-treated spectra. It was found that first wavelength selection from the fat absorption band for a calibration equation was generally effective in all cases of original, second derivative and MSC-treated spectra. However, correlation plots did not always work well because of the multiplicative scatter effect presented in the samples. Whereas, correlation plots were still useful in the case of MSC-treated spectra and normalised second derivative spectra, even when the original spectra exhibited a multiplicative scatter effect.