小澤 壯行

わが国の酪農は，飼養頭数規模の拡大にともない，乳牛初妊牛の導入によって後継牛を確保する経営体が増加している．しかし，北海道を主とする初妊牛価格は高騰していることから，安定した後継牛確保は喫緊の課題である．そこで本研究は，栃木県の家族労働力を主とする酪農経営に焦点を充て，後継牛確保の選択行動を決定付ける要因と公共育成牧場に対する利用者・非利用者の預託ニーズをCS分析によって明らかにし，公共育成牧場の発展可能性を検討した．分析の結果，①酪農経営の71.7％は後継牛を自家育成し，31.4％が公共育成牧場の預託制度を利用していること，②育成牛の預託は，牛舎収容力と労働力の側面で酪農経営を補完していること，③公共育成牧場は，受精卵移植や性選別技術を活用し，効率的な後継牛生産と収益性の高い乳牛初妊牛を産出していることが明らかになった．育成牛の預託は，飼養頭数規模の拡大に応じた後継牛確保の得策であることが示唆された．

酪農経営は，その経済性と持続性を追求しつつ，具体的な目標と計画をもって日々経営活動を行っている。安定した育成牛頭数の確保は初産牛を増やし，更新率や淘汰率を高めることにより，安定した生乳生産を実現させる。同時に，優良な後継牛の確保は，牛群全体の能力を向上・斉一化させることとなる。しかし，後継牛の育成は，生乳生産に結びつくまでの時間と労力，育成費用，及び育成牛の資産価値などが必ずしも明確でないことから疎かにされがちである。さらに，都府県の酪農経営は，飼養頭数規模を拡大する傾向にあることからも，効率的，かつ低価格の優良後継牛の自家確保が喫緊の課題となっている。そこで，本稿は，自家生産された育成牛の初産分娩までの生産費(以下，育成費用とする)を算出し，その経営経済性を検証する。併せて，優良後継牛の能力的評価額を明らかにし，初産牛能力水準の向上が，酪農経営に及ぼす経済効果を検討する。

酪農経営の収益性を規定する要因の1つに繁殖技術があげられるが，その経済的価値は酪農家に要され営農の場で利用された時に初めて生じる．本研究は性判別受精卵の利用を希望する酪農家層の経営特性および技術普及に必要な諸条件を明らかにすることを目的に，アンケートと聞き取り調査を実施した．これらの結果から性判別受精卵を「利用したい」，「既に利用している」と回答した酪農家は①多頭飼養，②後継者を確保，③性判別精液または受精卵移植の利用率が高い特性を有していた．したがって「性判別受精卵の利用に積極的な酪農家層」は「今後も酪農を永続させるため優良な後継牛の確保や牛群改良を志向し，先進技術の導入や利用に積極的な酪農家層」と推察される．また①繁殖技術の向上，②受精卵の価値に適した価格の設定，③酪農経営への収益性を明確化，④各種研究機関や育成牧場などによる利用推進の働きかけが利用普及に必要な諸要件として示唆された．

Simple liquid chromatographymass spectrometry (LC-MS) was applied to non-targeted metabolic analyses to discover new metabolic markers in animal plasma. Principle component analysis (PCA) and partial least squaresdiscriminate analysis (PLS-DA) were used to analyse LC-MS multivariate data. PCA clearly generated two separate clusters for artificially induced diabetic mice and healthy control mice. PLS-DA of time-course changes in plasma metabolites of chicks after feeding generated three clusters (pre- and immediately after feeding, 0.53 h after feeding and 4 h after feeding). Two separate clusters were also generated for plasma metabolites of pregnant Angus heifers with differing live-weight change profiles (gaining or losing). The accompanying PLS-DA loading plot detailed the metabolites that contribute the most to the cluster separation. In each case, the same highly hydrophilic metabolite was strongly correlated to the group separation. The metabolite was identified as betaine by LC-MS/MS. This result indicates that betaine and its metabolic precursor, choline, may be useful biomarkers to evaluate the nutritional and metabolic status of animals.

The establishment of a classification system for domestic animals on consumed feed stuff is thought to be important from both a hygiene and market point of view. We collected plasma samples of Romney lambs (Ovis aries) which were fed one of the following: a herb-clover mix (n=10) which included chicory, red clover, white clover and plantain; a plant-grass mix (n=10) which included plantain, ryegrass and white clover; or a grass mix (n=10) which included ryegrass and white clover. A total of 20 elements in plasma samples obtained from the lambs were analyzed using inductively coupled plasma mass spectrometry. The data were then analyzed by principal component analysis. The lambs were divided into three groups on a score plot depending on the different feed conditions. Furthermore, discriminant analyses of the elements were examined, using linear discriminant analysis with forward stepwise regression. This discriminant function correctly classified the samples from each group. The accuracy of classification of each group, as shown by 10-fold cross-validation, proved the effectiveness of the established discriminant function. It is concluded that using linear discriminant analysis might be a useful tool for the validation of elements from plasma in lambs grown in different conditions.

近年，山羊飼養の見直しと飼養熱の高まりがわが国において着実に定着しつつある．しかし，山羊産品の商品化には隘路が多く消費者の受容性が高い産品が早期に求められている．そこでメキシコで広範に嗜好されている山羊ミルクジャムであるCajeta（カヘタ）を開発試作し，これと市販の牛ミルクジャムを用いて10代から60代の男女計394名に対して官能試験，市販価格の推定および製品栄養成分分析を実施することにより，当該製品の受容性を明らかにするとともにその将来性について考察を加えた．この結果，山羊ミルクジャムは色調では牛ミルクジャムと比べて評価が高いものの，かおり，味および総合的評価などでは有意に評価が劣った．しかし被験者の7割以上が山羊ミルクジャムの総合評価に対して「普通」以上の評価を下していることからも，今後，山羊臭の改善などを行うことにより，商品化および市場参入が十分可能であることが示唆された．

A sensory survey was carried out using 4 different types of whole goat milk among middle-class females to investigate consumer acceptability of goat milk and whether there is an opportunity to expand the sale of goat milk products in Japan. Four different types of whole milk powder (domestic concentrate-fed, domestic pasture-fed, USA commercially canned, and New Zealand commercially canned) were used. Fresh cow milk was served as a control. Thirty-one housewives evaluated the 5 liquid milk samples for smell, taste and overall characteristics on a scale of 1 (low) to 3 (high). Chi-square analyses were carried out to detect significant differences between the milk types in each category. The goat milk from the USA was the most preferred goat milk with respect to smell and overall evaluation. Domestic pasture-fed milk received the lowest grade in the evaluation for its 'grassy and goaty' smell. This result shows us that pasture intake affects the taste and smell of powdered milk which gives the lowest evaluation by the participants. If Japanese goat milk producers want to be successful in the domestic goat milk market and compete against goat milk products from other countries, they should improve production methods and flavor of their products.

A consumer questionnaire conducted with the purpose of ascertaining the acceptability of goat milk and related products in Japan was carried out on 345 guarantees of Nippon Veterinary and Life Science University in December 2006. 275 effective responses (79%) representing middle class urban households were returned. The results revealed that (1) 30% of respondents have experienced drinking goat milk and only 10% are aware of the current retail situation of goat milk and related products; (2) over 70% of goat milk drinkers raised goats by hand at some point in their past and their first experience drinking goat milk was in infancy; (3) those with experience in drinking goat milk expressed a vague evaluation and minimal understanding of drinking goat milk; (4) respondents who were inexperienced goat milk drinkers expressed a strong desire to taste and a weak desire to purchase goat milk; (5) respondents expressed low recognition regarding retailed goat milk products, but those who had already purchased goat milk products expressed a high evaluation and strong desire to purchase these products again; and (6) recognition of goat milk characteristics is low, but those with high recognition also rate goat milk highly. Goats are perceived as being 'mild and familiar.' It is necessary for those who manage goat husbandry to present goat milk and related product tasting opportunities to consumers. The key point is to make the functional differences between cow and goat milk clear and present the advantages of goat milk at the fore of this promotion. Goat milk should not be promoted merely as a drink that is similar to cow milk, but must be positioned as a functional drink or health food in order to expand the Japanese goat milk market.

Plasma metabolite concentrations and activities of enzymes related to energy metabolism in plasma, peripheral leukocytes and liver of pregnant Romney ewes with restricted feeding were measured to assess those metabolites and enzymes as indicators for evaluating metabolic conditions in the ewes. The body weights and plasma lactate concentrations of the low-feeding ewes (about 1.0 times maintenance) were significantly lower than those of the high-feeding ewes (about 1.5 times maintenance). There were no significant differences ill plasma protein, glucose, triglyceride, cholesterol, pyruvate and immunoreactive insulin concentrations and plasma and leukocyte enzyme activities between both groups. Hepatic malate dehydrogenase activities were significantly higher and hexokinase activities were significantly lower in the low-feeding ewes than in the high-feeding ewes. Restricted feeding could maintain pregnancy and some plasma metabolites and peripheral leukocyte enzymes may be useful indicators for evaluating metabolic changes in ewes. (C) 2007 Elsevier Ltd. All rights reserved.

For sensory evaluation of fresh goat milk, a sample of 58 students from the Nippon Veterinary and Life Science University were randomly and evenly divided into two groups as "Group I" and "Group II". Only Group II received a 10-min lecture about the health benefits of goat milk. Bottles of commercial goat Milk were used for the tasting. Each participant was offered 100 ml of fresh goat milk and was given the option to leave residual milk if the flavour was not considered to be satisfactory. Milk was graded for taste, smell, richness and overall evaluation. Wilcoxon rank-sum test, Chi-squared analyses and one-way analysis of variance were carried out to search for significant differences between the two groups. Overall, goat milk was found to be moderately acceptable to both groups of trial participants. However, the amount of residual milk was lower in Group II compared to Group I (P<0.05). Thus goat milk was moderately acceptable to young Japanese adults. In addition, promoting the health benefits of goat milk to consumers via written and verbal information can significantly increase the amount of goat milk consumption.

Metabolite and immunoreactive insulin (IRI) concentrations, energy metabolism related enzymes activities and peripheral blood mononuclear cell (PBMC) populations were measured in blood of pregnant Angus heifers with differing liveweight change profiles (gaining or losing), in New Zealand to investigate the meanings of those parameters in the restricted feeding beef heifers. Beef heifers losing liveweight (-412 g/day) showed significantly lower concentrations of plasma IRI, and higher concentrations of plasma free fatty acid (FFA) than heifers gaining liveweight (483 g/day). The cytosolic and mitochondrial malate dehydrogenase (MDH) activities and MDH/lactate dehydrogenase (M/L) ratio in leukocytes of the liveweight losing heifers were significantly higher than those the liveweight gaining heifers. Percentages of cluster of differentiation (CD) 3 positive cells and natural killer (NK) cells in PBMC decreased significantly in the liveweight losing heifers compared to those in the liveweight gaining heifers. Plasma IRI and FFA concentrations, leukocyte cytosolic and mitochondrial MDH activities and CD3 positive and NK cell populations may be useful markers to evaluate metabolic conditions and immunity in the restricted feeding beef heifers.

Concentrations of metabolites and immunoreactive insulin (IRI) and activities of enzymes related to energy metabolism were measured in plasma of Korean and Japanese beef cattle, which were raised by the indoor feeding system programmed to feed larger amount of roughage in their growing periods and larger amount of concentrate diet in their finishing periods (Japanese feeding system), and grazing New Zealand beef cattle. By the Japanese beef grading system, Korean and Japanese beef cattle showed high beef quality score, average grade 3.3 and 3.6, respectively. The plasma free fatty acid and lactate concentrations and lactate dehydrogenase (LDH), malate dehydrogenase (MDH) and aspartate aminotransferase (AST) activities in Korean beef cattle were significantly higher than those in Japanese beef cattle. The plasma lactate concentration in Korean beef cattle was 8.40 mmol/l, which was similar to the values observed in lactic acidosis. The higher activities of plasma LDH, MDH and AST may indicate slight liver damage by slightly acidotic conditions in Korean beef cattle. New Zealand beef cattle fed on pasture which they harvest by grazing showed significantly lower plasma glucose, cholesterol, lactate and IRI concentrations and enzyme activities than those in Korean and Japanese beef cattle fed on larger amount of concentrate diets. Plasma metabolite concentrations and energy metabolism-related enzyme activities may be good indicators for evaluating metabolic conditions of beef cattle raised by different feeding systems.

Plasma metabolite and immunoreactive insulin concentrations and activities of enzymes related to energy metabolism in peripheral leukocytes were measured in growing Holstein calves. A ratio of girth of abdomen divided by girth of thorax (A/T ratio) of calves was significantly elevated after weaning, and the A/T ratio maybe a good indicator to evaluate rumen development. Plasma glucose and free fatty acid concentrations were changed in calves accompanying change in feeding. Activities of lactate dehydrogenase with pyruvate as substrate (LDH-P) and hexokinase (HK) in cytosolic fractions of peripheral leukocytes decreased significantly after weaning the calves reflecting the change of energy source from milk replacer with high percentages of fat and glucose and lactose as absorbable carbohydrate to pelleted feed containing starch as less absorbable carbohydrate and roughage. Some peripheral leukocyte enzymes such as LDH and HK may be good indicators to evaluate changes in energy metabolism of growing calves. (c) 2005 Elsevier Ltd. All rights reserved.

Three surveys and a sensory evaluation of goat meat were conducted in Japan to examine the current needs and future possibilities of goat meat consumption. The experimental results of the present study lead us to conclude the following: (i) improving the smell of goat meat and combining the sale of goat meat with recipes may increase goat meat demand among housewives (ii) it seems to be difficult to disseminate Okinawa goat cuisine to non-Okinawa residents because of the typical odor of goat meat, which is unlikely to be preferred by the public (iii) the "chewiness" of goat meat is rated highly by young participants according to a sensory evaluation, and loin meat is rated highly compared with hind leg meat and (iv) there is a rapidly increasing interest and a tremendous purchasing drive towards goat meat among university students. However, these facts call for further investigation of the goat meat demand in Japan. The following three further experiments are needed to solve this issue: (i) breeding to improve the taste of goat meat (ii) expanding the marketing of goat meat combined with the invention of Japanese-style goat recipes and tie-in sales supermarkets and (iii) implementing further sensory analyses to compare goat meat with other meat and carrying out market analysis in Japan.

The productivity and financial performance of dairy farms in New Zealand and Japan (Hokkaido) were analyzed. By recomposing the official statistics on the dairy industry relative to Japan, New Zealand has low milk yield productivity per cow, but higher per hectare performance because of their seasonal breeding and pasture grazing systems. In the revenue and expenses analysis, New Zealand had a high cash surplus ratio compared with Hokkaido. In the cost analysis, for expenses on a "per kg of raw milk" basis, New Zealand milk production costs are 29% of those in Hokkaido. More than 60% of the production costs were attributable to feed, interest charges and wages in New Zealand. In Hokkaido, the feed cost alone accounted for 73% of the total cost. There is also a remarkably high interest expenditure in New Zealand caused by non-subsidized fund procurement from finance organizations. In the financial analysis, New Zealand dairy farms have only approximately 50% of the total assets per cow compared with farms in Hokkaido. But total liabilities per cow in Hokkaido are twofold to threefold greater than in New Zealand. The difference between total assets and total liabilities shows that Hokkaido dairy farmers have an equity that is 50-200% greater than New Zealand dairy farmers. In the management analysis, New Zealand has a low turnover ratio of gross assets caused by the seasonal breeding system. In conclusion, New Zealand has higher per hectare production performance than Hokkaido, but has a low utilization of gross assets caused by a seasonal breeding system based on pasture grazing.