羊皮涂饰技术

针对羊皮的各种性能,对不同种类羊皮的涂饰技术和涂饰要点进行了较为详细的论述。主要为:羊皮手套革,羊皮服装革,绒面效应涂饰,软鞋面革,打光或仿打光革,鼓软鞋面革,擦色革和龟裂革等品种。     

Ruminal metabolism of leafy spurge in sheep and goats: A potential explanation for differential foraging on spurge by sheep,goats, and cattle

Leafy spurge (Euphorbia esula) is an introduced forb that is invading western rangelands. Goats (Capra hircus) readily graze the plant, but cattle (Bos tarus) generally and sheep (Ovis aries) locally appear to develop conditioned flavor aversions to leafy spurge. They either avoid the plant entirely or graze it reluctantly. We hypothesized that: (1) a diterpene diester that can occur in leafy spurge was an aversive agent, and (2) diet selection differences among ruminant species may be partly a function of differential ruminai metabolism of aversive phytochemicals, and further that cattle and sheep may be reluctant to graze leafy spurge because their ruminai microbes do not metabolize certain leafy spurge chemicals as do ruminai microbes in goats. Sheep did not develop an aversion to a novel food when its consumption was followed by an intravenous injection of ingenol 3,20-dibenzoate (P=0.34). Sheep did develop an aversion to a novel food when its intake was followed by a dose of leafy spurge fermented with sheep ruminai digesta, but not when followed by a dose of leafy spurge fermented with goat ruminai digesta (P= 0.03). This suggests that goat ruminai microbes may modify leafy spurge such that it does not elicit an aversion in sheep.This research was supported in part by a grant from the Cooperative States Research Service (91-38300-6158). All experimental procedures with ruminants followed a protocol approved by the U.S. Sheep Experiment Station's Animal Care and Use Committee. Mention of trade names or companies does not constitute an implied warranty by USDA or the authors.     

Fatty acids,vitamins and cholesterol content,and sensory properties of cheese made with milk from sheep fed rapeseed oilcake

The aim of the present study was to evaluate the influence of rapeseed oilcake used for feeding sheep on the content of fatty acids (FA), tocopherols, retinoids, and cholesterol of milk and cheese, and on the sensory properties of cheese. Indoor animal feeding (in winter) is the highest cost of production for cheesemakers, and the inclusion of locally produced rapeseed oilcake in the concentrate feed formulation can reduce the cost of cheese production, as long as the quality of the cheese is not altered. The experiment was carried out in March (mid lactation) with 72 Latxa sheep from an experimental farm located in the Basque Country (northern Spain). Two homogeneous groups of animals (n = 36) were set to receive each a different diet based on commercial or rapeseed concentrate, respectively, and forage (Festuca hay). Animal production parameters were individually recorded for each feeding group, whereas bulk milk from each group was used for cheesemaking trials. The rapeseed concentrate had higher amounts of unsaturated FA (mainly C18:1 cis isomers, C18:2 cis-9,cis-12 and C18:3 cis-9,cis-12,cis-15) and tocopherols than the commercial concentrate. The inclusion of rapeseed oilcake in the diet of dairy sheep did not compromise animal production parameters or milk gross composition. Bulk milk and cheese from sheep fed rapeseed concentrate showed higher content of unsaturated FA and tocopherols than those from sheep fed commercial concentrate. No differences were observed in the content of retinoid in milk and cheese between feeding groups, whereas the cholesterol content was slightly lower in cheese made with milk from sheep fed rapeseed concentrate. Thus, milk and cheese from sheep fed rapeseed concentrate had a healthier lipid profile. In addition, the inclusion of rapeseed oilcake in the diet of sheep did not change the typical sensory attributes of Protected Denomination of Origin Idiazabal cheese. Therefore, rapeseed concentrate could be a good local resource for feeding sheep to improve the nutritional quality of dairy products and to provide higher returns to farms.     

饲养方式对新疆多浪羊肉品质的影响

分别以戈壁滩放养及工厂集约化饲养的6 月龄多浪羊背最长肌为对象,分析测定不同饲养条件下羊肉的屠 宰性能、pH值、持水力、嫩度、色泽、抗氧化能力、脂肪酸含量、肌原纤维超微结构等指标。结果表明：工厂集 约化饲养组多浪羊肉的嫩度、成熟7 d的亮度值和脂肪酸总量优于戈壁滩放养组（P＜0.05）,而戈壁滩放养组多浪 羊肉的持水力、抗氧化能力、宰后1 d的红度值及多不饱和脂肪酸含量优于工厂集约化饲养组（P＜0.05）;工厂集 约化饲养组多浪羊肉肌原纤维密度较大、直径小,肌原纤维之间排列紧密;而戈壁滩放养组的多浪羊肉肌原纤维密 度小、直径大,肌原纤维之间空隙较大。两种饲养方式各有优势,在生产中可考虑结合已有的饲养条件加以完善, 以生产出更优质的羊肉。     

响应面分析法优化羊血中SOD的热变性提纯工艺条件

利用响应面分析法(Response Surface Methodology)对羊血中SOD的热变性提纯工艺进行优化。在单因素实验基础上选取实验因素与水平,根据中心组合(Box-Benhnken)实验设计原理采用3因素水平的响应面分析法,依据回归分析确定各工艺条件的影响因子,以SOD的比活力为响应值作响应面和等高线。在分析各个因素的显著性和交互作用后,得出最佳工艺条件为:热变性温度55℃;热变性时间15min;0.01mol/lCuCl2的添加量2%。在最佳工艺条件下,SOD活性为1072.43U/mg蛋白。     

Phenotypic factors affecting coagulation properties of milk from Sarda ewes

In this study, milk-coagulation properties (MCP) were characterized in the Sarda sheep breed. Milk composition and MCP [rennet-coagulation time (RCT), curd-firming time [time to reach a curd firmness of 20 mm (k₂₀)], and curd firmness (a₃₀), (a₄₅), and (a₆₀)] were obtained extending the lactodynamographic analysis from 30 to 60 min from a population of 1,121 ewes from 23 different farms. Managerial characteristics of farms and parity, individual daily milk yields and stage of lactation of ewes were recorded. Data were analyzed using a mixed-model procedure with fixed effects of days in milk, parity, daily milk yield, and flock size and the random effect of the flock/test day nested within flock size. Sampled farms were classified as small (<300 ewes) and medium (300 to 600 ewes), and these were kept by family operations, or as large (>600 ewes), often operated through hired workers. Daily milk yield was, on average, 1.58 ± 0.79 L/d and variability for this trait was very high. The average content of fat, protein, and casein was respectively 6.41, 5.39, and 4.20%. The class of flock size had a significant effect only on curd firmness, whereas days in milk affected RCT and k₂₀. The flock test day, parity, and daily milk yield were important sources of variation for all MCP. The mean value of RCT (8.6 min) and the low occurrence of noncoagulating samples (0.44%) confirmed the excellent coagulation ability of sheep milk compared with cattle milk. A more rapid coagulation was observed in mid-lactating, primiparous, and high-yielding ewes. The k₂₀ was usually reached in less than 2 min after gelation, with the most favorable values at mid lactation. The mean value of curd firmness 30 min after rennet addition (a₃₀) was, on average, 50 mm and decreased to 46 and 42 mm respectively after 45 (a₄₅) and 60 min (a₆₀). The decreasing value of curd-firmness traits was likely to be caused by curd syneresis and whey expulsion. The correlation between RCT and a₃₀ was much lower than in dairy cows and about null for a₄₅ and a₆₀. This means that curd firmness in dairy ewes is almost independent of gelation time and this can provide specific information for this species. In conclusion, this study showed that milk from Sarda sheep is characterized by an earlier gelation, a faster increase in curd firmness with time, and greater curd firmness after 30 min compared with dairy cows. Furthermore, correlations between MCP in sheep are much lower than in bovines and some of the assumptions and interpretations related to cows cannot be applied to sheep.     

两种饲养方式下苏尼特羊肉的氧化稳定性

以舍饲、放牧两种饲养方式下的12?月龄苏尼特羊股二头肌为实验材料,分别测定脂质氧化产物含量、硫代巴比妥酸值、抗氧化能力、抗氧化酶活力以及抗氧化酶相关调控基因表达量等指标并进行比较分析,旨在探索两种饲养方式下苏尼特羊肉的氧化稳定性。结果表明：放牧饲养苏尼特羊肉TBA值高度显著低于舍饲饲养（P＜0.001）;羊肉中主要的脂质氧化产物为己醛、庚醛、壬醛、1-辛烯-3-醇以及2,3-辛二酮,其含量均在放牧饲养羊肉中显著较低（P＜0.05）,表明舍饲饲养羊肉的脂质氧化程度相比放牧饲养羊肉更严重。放牧饲养羊肉的总抗氧化能力（P＜0.01）、铜离子还原能力（P＜0.05）和超氧化物歧化酶（superoxide dismutase,SOD）（P＜0.001）、过氧化氢酶（catalase,CAT）（P＜0.05）、谷胱甘肽过氧化物酶（glutathione peroxidases,GPx）（P＜0.05）活力均显著高于舍饲饲养,说明放牧饲养羊肉中的抗氧化酶活力较高,能有效抑制脂质氧化。通过抗氧化酶相关调控基因表达量的分析得出,舍饲饲养羊肉中脂肪氧合酶基因表达量高度显著高于放牧饲养（P＜0.001）,而SOD（P＜0.001）、CAT（P＜0.05）和GPx（P＜0.05）基因表达量均显著低于放牧饲养,从分子水平验证了放牧饲养羊肉的抗氧化能力较舍饲饲养好。     

Nitrogenous constituents in the urine of cattle,sheep and goats

Ten samples of urine from dairy cows, five from sheep and four from goats were analysed to assess the distribution of urinary nitrogen (N) among various chemical constituents in order to gain a better understanding of the reactions undergone by urinary N in soil. Total N in the cow urine ranged from 6.8 to 21.6 g N litre^?1, of which an average of 69% was present as urea, 7.3% as allantoin, 5.8% as hippuric acid, 3.7% as creatinine, 2.5% as creatine, 1.3% as uric acid, 0.5% as xanthine plus hypoxanthine, 1.3% as free amino acid N and 2.8% as ammonia. In the sheep urine, total N ranged from 3.0 to 13.7 g litre^?1 of which an average of 83 % was present as urea; creatine accounted for 5.3% of the N; hippuric acid and allantoin both accounted for 4.3%, while each of the other constituents amounted to less than 1% of the total N. The goat urine was similar to the sheep urine but with a lower ratio of creatine to creatinine and a somewhat higher proportion (2.0 %) of the total N as amino acid.     

北方质次土种绵羊皮制作光面毛革生产工艺的研究

采取酶助浸水、分步脱脂、酸性酶软化、铬—铝结合鞣制、KS—1树脂复鞣剂和改性戊二醛复深填充、分次加脂的工艺路线，以蒙古路土种绵羊皮为原料生产光面毛革，对浸水酶、软化酶、复鞣材料用量及软化、浸酸时间等重要工艺参数进行了优化，得出了利用质次土种绵羊皮加工光面毛革的工艺，所得坯革感观和机械性能良好。     

滩羊肉宰后成熟期间ATPase活力变化对微观结构及保水性的影响

为研究宰后成熟期间ATPase活力变化对滩羊肉微观结构以及保水性的影响,以6 月龄滩羊背最长肌（Longissimus dorsi）为研究对象,分析其4 ℃成熟0、1、2、4、8 d时Na＋-K＋-ATPase、Ca2＋-ATPase、Caspase-3活力以及肌肉微观结构、pH值与滴水损失率的变化情况。结果表明：随成熟时间延长,Na＋-K＋-ATPase与Ca2＋-ATPase活力先升高后降低,成熟1 d时达到最大值;Caspase-3活力先升高后降低,成熟2 d时达到最大值;滴水损失率先升高后降低,pH值先降低后有所回升;总蛋白、低盐溶性蛋白及高盐溶性蛋白质量浓度均逐渐减少,水溶性蛋白质量浓度成熟2 d后显著降低（P＜0.05）;成熟至8 d时,肌原纤维断裂,肌纤维之间、肌束之间、肌纤维及肌膜之间形成间隙,Z线断裂,H带消失;相关性分析结果表明Na＋-K＋-ATPase活力与各指标均呈极显著相关性（P＜0.01）,Ca2＋-ATPase活力与pH值、Na＋-K＋-ATPase及Caspase-3活力均呈极显著相关性（P＜0.01）。结论：滩羊肉宰后成熟过程中Na＋-K＋-ATPase与Ca2＋-ATPase活力变化可能促使下游Caspase-3激活,Caspase-3水解结构蛋白可能导致肌肉组织在不同部位形成间隙,在重力作用下肌肉中的水分流入间隙中,引起滩羊肉滴水损失升高,保水性变差。