《饲料质量分析与品质检测》课程实验考核模式改革与实践

针对《饲料质量分析与品质检测》课程实验长期以来考核方式存在的弊端,尝试通过教学改革建立一套能够有效反映学生学习成绩的科学合理、公平公正的实验课考核模式。实践表明,学生从思想上转变了对实验课的认识．极大地提高了学生的积极性、主动性及分析问题和解决问题的能力。     

植物甾醇对泌乳前期奶牛生产性能及血浆生化指标的影响

本试验旨在研究添加不同剂量植物甾醇对泌乳前期荷斯坦奶牛生产性能及血浆生化指标的影响。选用泌乳期相近的健康荷斯坦奶牛24头,随机分成4组,每组6头,Ⅰ组为空白对照组,饲喂基础日粮,Ⅱ、Ⅲ、Ⅳ组分别在基础日粮中添加200、400和800 mg/d植物甾醇,研究不同添加量的植物甾醇对奶牛生产性能及血液生化指标的影响。结果表明：①各试验组血浆生化指标Ⅱ组变化最为明显。较Ⅰ组而言,Ⅱ组血浆雌激素、孕酮、催乳素、卵泡刺激素、黄体生成素、干扰素、白细胞介素2、高密度脂蛋白胆固醇均显著提高（P＜0.05）,丙二醛含量显著下降（P＜0.05）。②较Ⅰ组而言,Ⅲ组血浆白细胞介素2、高密度脂蛋白胆固醇均显著提高（P＜0.05）。③与Ⅰ组相比,Ⅳ组血浆甘油三酯含量明显下降（P＜0.05）,总超氧化物歧化酶显著提高（P＜0.05）。添加植物甾醇可提高奶牛的泌乳量,改善奶牛内源激素不平衡的状况,并促进奶牛发情,改善奶牛脂类代谢情况,改善奶牛体质,其中200 mg/d植物甾醇添加量为最适添加量。     

Experimental studies on the impact of an increased dose of anionic salts on the metabolism of dairy cows

Summary

This study was initiated to investigate the influence of a daily dose of anionic salts (AS) above the valid upper limit at present on metabolism of dairy cows. Eleven non‐pregnant and non‐lactating Holstein‐Friesian crossbred cows with a permanent rumen cannula were used in a study with a controlled feeding design. The initial daily dose was 2500 meq/day, which resulted in a Dietary Cation Anion Difference (DCAD) of ‐211 meq/kg dry matter. Every seven days, the daily dose was raised by 500 meq. If a cow stopped eating, the application of AS was stopped and these cows were monitored over the next seven days. On day 30 another batch of hay, having the same DCAD but higher concentrations of minerals and energy, was fed. Blood and urine samples were taken to monitor acid‐base balance and calcium concentrations. Acid‐base balance was strongly influenced by AS. Blood pH dropped steadily and reached values around 7.23. Urine pH dropped quickly below 6 and remained at that level regardless of the increased dosage of AS. Net acid base excretion (NABE) fell continuously with the increase of the dosage of AS and reached values below ‐200 mmol/l. Calcium concentrations in the serum were nearly stable, but those in urine increased sharply and remained on an elevated level with increasing doses of AS. A few days before the individual cow's refusal of feed intake, calcium excretion in urine decreased. The majority of cows stopped eating while consuming a diet containing 3500 to 4000 meq AS except two animals who consumed up to 6000 meq/day AS but they received the better hay in the second half of the treatment period. In this time pH in blood increased slowly. NABE remained stable on a low level at ‐100 mmol/l. The results showed that with an increasing amount of AS fed the risk of clinical acidosis increased. The decreasing urine concentrations of calcium indicate a breakdown of the compensation capability of the single cow. Besides the dose of AS fed, the quality of the feed stuff might be another factor concerning the tolerance of cows against AS.     

One or Two Feeders for Groups of 16 Growing–Finishing Pigs: Effects on Health and Production

Over a 3-year period, seven batches of growing-finishing pigs in groups of 16 pigs (total 672 pigs) were fed using one or two singlespace feeders. The pigs with access to two feeders had a significantly lower number of skin lesions (P<0.0001) and higher daily weight gain than did the pigs with access to one feeder (863 vs. 837 g day- 1 , P<0.05). The within-pen variation in daily weight gain was higher in the pens with one feeder than in the pens with two feeders (SD 139 vs. 106g day- 1 , P<0.0001). The pigs with access to two feeders consumed more feed during the period when they were allowed to eat ad libitum , in comparison to the pigs with access to one feeder (2.07 vs. 1.97 kg day- 1 , P<0.05). The feed conversion ratio of the pigs did not differ between the two treatments. No differences in carcass meat percentage, health or number of remarks at slaughter were detected. A comparison was made between using computerized IVOG® feeders, with individual recording of feed intake, and conventional feeders. The feed conversion ratio was poorer for the pigs fed with the IVOG-feeders than for those fed with conventional feeders. The automatic recordings from the IVOG-system showed that there had been a higher daily feed intake during the ad libitum period. During the restricted period the pigs had a lower daily weight gain than with the conventional feeders.     

Effects of dietary fructo-oligosaccharide on villous height and disaccharidase activity of the small intestine,pH, VFA and ammonia concentrations in the large intestine of weaned pigs

Abstract

An experiment was conducted to investigate changes in the lumen and wall of the intestinal tract of weaned pigs caused by fructo-oligosaccharides (FOS) and consequences for growth. Twelve male pigs weaned at 24 days were individually housed and fed either control, 0.25% FOS, or 3% FOS diets for 21 days after weaning. The pH of chyme in the caecum and proximal colon were lower (p<0.001) in 3% FOS compared to other treatments. Mean molar proportions (%) of total SCFA values along the large intestine were significantly affected by FOS diet. Acetic acid was significantly higher in control compared with other treatments. Butyric acid and isobutyric acid were significantly increased in 0.25 and 3% FOS compared to the control. Feed intake, empty body weight gain, disaccharidase activities and villous height in the small intestine were not significantly affected by FOS. It was concluded that dietary FOS stimulates fermentation in the large intestine, but does not significantly affect enzyme activity, ammonia content, villous height and growth.     

Status of selenium and vitamin E on Norwegian organic sheep and dairy cattle farms

Herbage selenium (Se) concentration is generally low in Norway. It is unknown whether feeding practices on Norwegian organic farms fulfil the dietary needs of Se and vitamin E for sheep and dairy cattle. Therefore we analysed Se in soil and herbage, and Se and vitamin E in animal blood in the indoor feeding season at 14 organic dairy and 14 organic sheep farms. The herbage Se concentration was low. Approximately 50 and 35% of all samples in the first and second cut, respectively, had Se concentrations below the detection limit of 0.01 mg/kg dry matter (DM). The median (10th, 90th percentile) Se concentrations were <0.01 (<0.01, 0.03) and 0.02 (<0.01, 0.06) mg/kg DM in the first and second cuts, respectively. Whole blood Se concentrations were 0.10 (0.04, 0.15) μg/g in dairy cattle and 0.14 (0.03, 0.26) μg/g in sheep. Vitamin E concentrations were 4.2 (2.7, 8.4) mg/l in dairy cattle and 1.3 (0.9, 2.4) mg/l in sheep. None of the soil or plant variables explained the variation in herbage Se concentration, although Se in soil and plant tended to be correlated. Herbage Se concentration was inadequate to meet the dietary Se requirements. Vitamin E requirement was only met in dairy herds. We recommend Se and vitamin E supplementation to ruminants on organic farms.     

饲用油脂的营养价值及其在养殖业中的应用进展

油脂作为饲料中的能量来源已广泛应用于动物饲料中。在动物日粮中添加油脂不仅可以满足动物高生产性能的需要,还可以提高饲料利用率。文章主要概述了饲用油脂的来源、营养价值及其在养殖业中的应用现状。     

Dual potential of microalgae as a sustainable biofuel feedstock and animal feed

The rise in global population has led to explorations of alternative sources of energy and food. Because corn and soybean are staple food crops for humans, their common use as the main source of dietary energy and protein for food-producing animals directly competes with their allocation for human consumption. Alternatively, de-fatted marine microalgal biomass generated from the potential biofuel production may be a viable replacement of corn and soybean meal due to their high levels of protein, relatively well-balanced amino acid profiles, and rich contents of minerals and vitamins, along with unique bioactive compounds. Although the full-fatted (intact) microalgae represent the main source of omega-3 (n-3) polyunsaturated fatty acids including docohexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the de-fatted microalgal biomass may still contain good amounts of these components for enriching DHA/EPA in eggs, meats, and milk. This review is written to highlight the necessity and potential of using the de-fatted microalgal biomass as a new generation of animal feed in helping address the global energy, food, and environmental issues. Nutritional feasibility and limitation of the biomass as the new feed ingredient for simple-stomached species are elaborated. Potential applications of the biomass for generating value-added animal products are also explored.     

饲料添加剂学课程教学效果的改进措施

探讨了饲料添加剂学课程教学中存在的问题,并提出了教学改革的措施。     

常绿岩垂草饲料营养价值研究

[目的]分析常绿岩垂草和过江藤的饲料营养价值。[方法]剪取过江藤和常绿岩垂草的地上茎叶,测定其营养指标,并与常用饲草进行比较,分析其作为饲草的开发价值。[结果]与过江藤相比,常绿岩垂草具有明显的速生与丰产能力。常绿岩垂草的粗脂肪、粗纤维、粗灰分、赖氨酸、维生素C、Ca、Fe含量明显高于过江藤,粗蛋白和全P含量明显低于过江藤。与常用饲草黑麦草、紫花苜蓿、谷草、玉米秸杆相比,常绿岩垂草具有较高的粗脂肪、粗灰分含量和较低的粗纤维、粗蛋白质含量。[结论]常绿岩垂草具有较高的饲料开发价值。