陇东黄土高原苜蓿田昆虫群落的组成与结构分析

在陇东黄土高原苜蓿（Medicago sativa）田调查昆虫群落组成与结构,共采集昆虫21 021头,隶属12目69科115种。研究结果表明,鞘翅目、鳞翅目、膜翅目昆虫科、种数较多;同翅目、鞘翅目、半翅目和双翅目昆虫个体数量较多;优势种群是豌豆无网长管蚜(Acyrthosiphon pisum)、苜蓿盲蝽(Adel phocoris)、条纹根瘤象(Sitona lineatus)。害虫、天敌、中性昆虫和益虫所占比例依次是67.54%、19.79%、11.20%和1.47%。     

开放式兔舍水空调技术夏季降温效果

夏季高温严重制约中国兔业生产,蒸发降温方式在高温高湿的家兔主产区难以发挥有效作用。该研究以地下水为循环介质的非蒸发降温系统水空调用于外围护隔热性能不佳的开放式繁殖母兔舍,通过管道实现点对点局部降温,研究其降温效果。试验期内,试验舍兔笼内14:00平均气温较对照舍低2.5～3.3 ℃（P < 0.05）,相对湿度高8%。试验舍风速控制在0.7～1.4 m/s,温湿指数控制在25.5～29.0,较对照舍降低1.4～2.9（P < 0.01）,综合热环境状况较对照舍明显改善。舍内母兔在午后高温时段热性喘息有所缓解。结果表明,在开放式兔舍中夏季采用水空调系统进行局部降温,较为适合中国当前家兔养殖模式,有助于缓解夏季妊娠或哺乳母兔的热应激。     

浅谈户外养猪技术

由于动物福利、节约成本等原因,户外养猪得到了快速发展。在此就户外养猪的可行性、户外养猪基本条件与基本操作以及户外养猪效果进行了分析。     

Does body size of dairy cows,at constant ratio of maintenance to production requirements,affect productivity in a pasture‐based production system?

This study compared productivity of dairy cows with different body weight (BW), but a constant ratio of maintenance to production requirements in their first lactation, in a pasture-based production system with spring calving. Two herds, Herd L (13 and 14 large cows in 2003 and 2004 respectively; average BW after calving, 721 kg) and Herd S (16 small cows in both years; 606 kg) [Correction added after online publication 14 January 2011: 16 small cows in both years; 621 kg was changed to 16 small cows in both years; 606 kg], all in their second or following lactations, were each allocated 6 ha of pasture and rotationally grazed on 10 parallel paddocks with equal herbage offer and nutritional values. Winter hay, harvested from the same pastures, was offered ad libitum in the indoor periods in a tied stall barn. Each herd received, per lactation and year, approximately 2000 kg dry matter (DM) of concentrates and of fodder beets, equally distributed to every individual. Indoors, the L-cows ingested more DM than the S-cows (18.7 vs. 16.3 kg DM/cow per day; p < 0.01), but DM intake per 100 kg of metabolic BW was similar (13.0 vs. 13.1 kg DM/cow per day). Estimates based on the n-alkane technique gave similar results on pasture (17.9 vs. 15.5 kg DM/cow per day; p < 0.001). Roughage intakes per 100 kg of metabolic BW, at 13.5 kg DM/cow per day, were similar. Mean annual yield of energy-corrected milk (ECM)/ha was slightly higher for the S-herd than the L-herd (13,026 vs. 12,284 kg) but was associated with a higher stocking rate (on average +20%) for the S-herd. Feed conversion efficiency (1.2 vs. 1.3 kg ECM/kg DM intake) and overall milk production efficiency (45.3 vs. 47.3 kg ECM/kg metabolic BW) were similar in L- and S-cows. Thus, both dairy cow types were equally efficient in utilising pasture-based forage.     

青海天然草地牧草营养成分分析

通过对青海天然草地牧草4大类主要营养成分进行分析,结果表明:青海天然草地牧草具有粗蛋白质、粗脂肪、无氮浸出物含量高,粗纤维含量低,即"三高一低"的特点.与全国同类型草地牧草营养成分相比,粗蛋白质高2.61个百分点,粗脂肪高0.4个百分点,无氮浸出物高4.92个百分点,粗纤维低20.42个百分点.     

区域性水草畜系统平衡是生态畜牧业的核心

我国西部干旱荒漠草原区，水资源紧缺，普遍的超载过牧导致生态环境严重失衡，荒漠化严重，造成大规模的沙尘暴天气。解决这些问题的根本途径是：要在合理开发利用水资源的基础上，以水定草、以草定畜，合理确定灌溉人工饲草料基地发展规模和区域可持续载畜量，解决牲畜超载和冬春饲草不足的矛盾，实现区域性的水草畜系统平衡，使草原区的生态环境条件向良性化方向发展。     

小型往复式果园割草机设计

简述了小型往复果园割草机的市场前景;根据市场需求选择了与其相配套的主机,确定了基本结构和结构参数;在小型果园割草机上,最先采用了单点联接往复式切割器机构,从而简化了结构;同时,分析了切割器割刀运动及功率消耗.试验表明,该机设计合理、可靠,具有操作方便且仿形好的特点,符合农村经济水平和使用习惯.     

Milk fatty acid profile from cows fed with mixed rations and different access time to pastureland during early lactation

Milk fatty acid (FA) profiles were determined in Holstein cows (n = 27) fed total mixed rations (TMR) ad libitum (G0) or diet composed by TMR (50% dry matter [DM] offered) plus grazing of pasture with 6 hr of access time to paddock in one session (G1) or 9 hr in two sessions (G2) at 45 days in milk (DIM). Moreover, milk FA was determined at 65 DIM when G0 cows turned out to G1 diet without adaptation period (Post‐G0), G1 remained as controls. Milk FA was quantified using gas chromatography and mass spectrometry. Preformed FA at 45 DIM was greater (+27%) for G2 than G0 cows (p < .05). Stearic acid (C18:0) was 30% greater for G2 cows (p < .05). De novo FA was lowest for G2 cows (p < .05). Conjugated linoleic acid (CLA) did not differ (p < .12), while vaccenic acid (C18:1trans) was twofold greater for grazing treatments (p < .01). Linolenic acid [C18:3(n‐3)] was greatest for G2 and lowest for G0 cows (p < .01). Omega 6 FA was greater for G0 than grazing cows, mainly due to linoleic acid [18:2cis(n‐6); p < .05]. These results determined that n‐6/n‐3 ratio was almost threefold greater for G0 than grazing cows (p < .001). When diet of G0 cows changed to include pasture (Post‐G0), preformed FA increased (p < .05), explained mainly by the increase (p < .05) of stearic (C18:0) and C18:1trans, while de novo FA tended to decrease (p < .1). Moreover, the amount of CLA and C18:3(n‐3) tended to increase (p < .1) in Post‐G0 cows. Offering 50% of dietary DM from pasture modified milk FA profile in early lactation potentially beneficial for human health. When TMR‐fed cows were turned out to 50% pasture, milk FA profile reflected dietary change without need of an adaptation period.