棉茬地放牧对新疆山羊生产性能及组织结构的影响

【目的】以山羊为对象,研究棉茬地放牧对山羊生产性能及组织结构的影响。【方法】选取20只体况相近的山羊在棉茬地上自由放牧2个月,放牧期间无补饲。分别于放牧1个月和2个月后取样,测定采食量和消化率。【结果】随着放牧时间的延续,棉茬地上生物量降低,叶片、棉桃壳、细茎等可采食部分比例减少(P<0. 05)。采食部分的粗蛋白含量可达8%以上,但纤维素和木质素含量明显高于一般放牧草。山羊的日均采食量和排粪量在放牧第二个月略增加(P <0. 05),但有机质和粗蛋白消化率呈下降趋势(P <0. 01)。山羊在全放牧期间的总增重和日均增重水平分别为11. 27和0. 18 kg,在后期放牧阶段略下降。与放牧前相比,山羊血液中谷草转氨酶、谷氨酰基转移酶、尿素氮以及游离棉酚含量显著增加(P <0. 05),而铁元素含量显著下降(P <0. 05)。血液中免疫球蛋白G和免疫球蛋白M含量显著降低(P <0. 05)。显微结构显示,放牧结束时山羊肝细胞变性,充血;肾小球肿胀,肾小管上皮细胞坏死。超微结构则显示肝细胞肿胀变性,线粒体膜破裂;肾脏上皮细胞核固缩。【结论】棉茬地长期放牧会降低山羊的生产性能,对肝脏和肾脏组织结构有一定的损坏,在棉茬地放牧时适当补饲。

The Cotton Stalk and Its Utilization as Ruminant Feed Resource in Xinjiang

Two separate experiments were carried out: the first one involved a study of the chemical and some intrinsic feed characteristics of raw cotton stalk( CS) and the efficiency of chemical,biological treatments on the improvement of the feed value of CS. CS was treated with chemical treatment by mixing 3% Ca( OH)2( CS + Ca),3% urea( CS + U),3% urea +3% Ca( OH)2( CS + Ca + U). Moreover,CS was treated with biological treatment by inoculation of either Lentinus edodes( CS + Po) or Pleurotus ostreatus( CS + Pl) or crushing CS by adding minor ingredient processed into pellet feed,samples from all treatment were analyzed for the nutrients,In vitro dry matter digestibility( INDMD) and free gossypol detoxification rate. The second investigated was the use of crushed or granulation CS as a test feed followed by voluntary feed intake and preference test with sheep. CS + Ca + U treatment can reach up the CP and IVDMD to 9% and 36%,respectively. CS + Po decreased the fiber component and improved CP content and IVDMD. The free gossypol content declined and the free gossypol detoxification rate reached more than 50%. By feeding sheep under the same level of concentrate and corn silage,the voluntary feed intake and daily weight gain in granulation group is higher than in crushing group( P < 0. 05). Crushing CS by adding minor ingredient processed into a pellet feed was best in terms of improved nutritional quality,feed intake and preference,and it was safe and practical method that can be widely used in sheep production systems,to promote the CS feed utilization in similar areas.

Effect of Addition of Dried Beet-pulp on Silage Fermentation Quality of Fish Waste Inoculated with Lactic Acid Bacteria

[Objective] This study was to further enhance previous research in finding appropriate methods for preservation and utilization of fish waste.[Method]Fresh fish waste（head and viscera）from arabesque greenling（Pleurogrammus azonus）was mixed with dried beet-pulp and beet molasses at a ratio of 70：20：10 on fresh matter basis,respectively.These were inoculated with /without a commercial inoculant of Lactobacillus plantarum and ensiled at room temperature for 15,30,60 and 90 days.Fermentation quality and chemical composition of the silages were evaluated and a feeding trial conducted using hen layers with fish waste silage replacing 25% of a commercial formulated diet on dry matter basis.[Result] The concentration of lactic acid in the silages tended to increase with extension of the ensiling period and was significantly（P 〈 0.05）enhanced by the inoculant.The pH declined from 6.5 to around 4.4 during the first 15 days of the ensiling period and did not change much thereafter.The non-protein nitrogen（NPN）content increased two folds after 15 days in all silages relative to the material but the rate of volatile basic nitrogen（VBN）to total nitrogen（TN）was less than 10%.Feed intake and egg production was similar with replacement of 25% of the commercial formulated diet with fish waste silage.

Rumen Degradability and Post-ruminal Digestion of Nitrogen and Amino acids by Cows Grazing Temperate Pasture

This experiment was conducted to evaluate nutrient digestion in the rumen and flow to the duodenum of steers grazed on orchardgrass( Dactylis glomerata L.,OG) or meadowfescue( Festuca pratensis Huds.,MF.) pastures located on northern part of Japan without supplement. Fifty-two digestion trials were carried out grazing Holstein steers fitted with cannulas in the rumen,duodenum and distal ileum in the three years. The pastures were divided into several paddocks,and the steers grazed each paddock for a day and allowed double of dry requirements the grazing cattle. The pre-grazing herbage mass did not significantly differ between pastures but the crude protein( N × 6. 25) content of herbage ranged from 19. 3% to 27. 5% on OG pasture and from 20. 0% to 32. 8% on MF pasture. Total N and AA-N intake did not differ but the degradability of dietary nitrogen in the rumen( RDN) was higher in MF than in OG pasture. The ratio of RDN to OM truly digested in the rumen was negatively related to the apparent N absorption in the rumen,and it was suggested that the amount of apparent N absorption in the rumen would be positive when the ratio was above 25 g / kg. Non-ammonia nitrogen( NAN) and AA-N flows to the duodenum of steers were lower in MF than in OG pasture. Duodenal AA flows were more linked to duodenal NAN flows and accounted for approximately 60% of duodenal NAN flows. The proportion of methionine and lysine slightly increased in the duodenal flows compared with the consumed AA,but a comparison between the essential AA composition of milk and the lean tissue indicated that duodenal digesta was most limiting in methionine,lysine,arginine,and histidine,and that deficiencies of arginine and histidine for milk production were relatively small.