The effect of different grazing heights on carcass and meat quality characteristics of Nellore cattle fattened in pastures of Convert grass

Carcass characteristic and meat quality from bulls and Nellore steers (n?=?64 total) subjected to different grazing heights (15, 25, 35, and 45 cm) were evaluated isolatedly, under continuous grazing and variable load, in pastures of Convert grass. The experimental period was from May 2015 to June 2017, in an area of 16 ha, divided into 16 paddocks of 1 ha. The experimental design was randomized blocks with four replications. Each paddock was grazed by three animals and regulators, used to adjust grazing heights. The final slaughter weight, hot carcass, and crude protein in the meat of steers were higher when the pastures were managed at 42 cm. When the pasture was managed between 25 and 35 cm in height, greater fat thickness, marbling, muscle:bone and muscle+fat:bone ratio and lower color* of the meat and percentage of bone were found. For the steers, the height of 40 cm provided higher fat thickness and marbling in the meat. The loss during thawing in meat was greater at 28 cm in height. The heights of grazing alter the carcass characteristics and meat of bulls and steers.

     

Liveweight performance of crossbred and zebu cattle grazing on native or rhodes grass pastures

Summary Two experiments are described involving 33 crossbred (mainly Simmental and Jersey × Zebu) and 33 Zebu (Horro and Boran) bulls and steers. In experiment I, growth rates of crossbred and Zebu cattle rotationally grazed on either native pasture or Rhodes grass(Chloris gayana) were compared during a 140 day grazing period at a stocking rate of 2.4 animals/ha. In experiment II, growth rate of cattle rotationally grazed for 140 days on native pasture was compared with that of a similar group grazed on Rhodes grass either rotationally or continuously at a stocking rate of seven animals/ha.On native pasture the average daily gain by Zebu animals was similar to that of the crossbreds whilst on Rhodes grass liveweight gain of Zebu animals was lower than that of the crossbreds. Daily gains of cattle were significantly (P<0.01) greater on continuous compared with rotationally grazed Rhodes grass.

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Rendimiento En Peso De Bovinos Cruzados Y Cebu En Pradera Nativa Y Pasto Rhodes

Resumen Se describen dos experimentos; el primero con 33 animales cruzados (Simmental y Jersey × Cebú) y el segundo con 33 Cebú (Horro y Boran) toros y novillos. En el experimento I, se compararon las ratas de crecimiento del ganado cruzado y del Cebú en pastoreo rotacional en pradera nativa o pasto Rhodes (Chloris gayana), durante 140 días, con una carga animal de 2.4 animales por hectárea. En el experimento II, se comparó la rata de crecimiento de un grupo de ganado en pastoreo rotacional en pradera nativa durante 140 días, con aquella de un grupo similar en pasto Rhodes con pastoreo rotacional o continuo, con una carga animal de siete por hectárea. En pradera nativa, el promedio de ganacia diaria de los animales Cebú fue similar a aquel del grupo de animales cruzados, mientras que en pasto Rhodes la ganancia de peso de los animales Cebú fue más baja que aquella de los animales cruzados. Las ganancias diarias de peso de los animales fueron significativamente (P<0.01) mayores en pastoreo contínuo, comparado con el pastoreo rotacional en pasto Rhodes.

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Performances Ponderales De Zebus Et De Metis Zebus Entretenus Sur Des Paturages Naturels Et Das Paturages D'Herbe De Rhodes

Résumé Deux expériences utilisant 33 métis (principalement Simmental et Jersey x Zébu) et 33 zébus (Horro et Boran), taureaux et bouvillons sont décrites.Dans la première, les gains de poids des métis et des zébus entretenus à raison de 2,4 animal à l'hectate par rotation, soit sur des pâturages naturels ou sur de l'herbe de Rhodes ont été comparés durant 140 jours.Dans la seconde expérience, le taux d'accroissement pondéral du bétail entretenu, par rotations des pâturages, pendant 140 jours sur des pâturages naturels a été comparé avec celui d'un groupe identique d'animaux entretenus sur de l'herbe de Rhodes soit par rotation, soit de façon permanente à raison de 7 têtes à l'hectare sur les pâturages naturels; le gain journalier de poids par zébu a été semblable à celui des métis tandis que le gain de poids des zébus entretenus sur de l'herbe de Rhodes a été inférieur à celui des métis. Les gains journaliers de poids ont été significativement (P<0,01) plus élevés chez les animaux en pacage permanent comparés avec ceux obtenus par la rotation des pâturages d'herbe de Rhodes.

     

不同建植期混播草地群落特征的年际动态

针对新疆昭苏山前平地草甸草原严重退化的问题,采用耕翻混播种植6种豆科和禾本科牧草的方式,研究不同种植年限混播草地的物种消长、群落特征和产量变化。结果表明,混播草地植物组成、群落结构与对照(天然草地)相比均发生了明显变化,栽培牧草种占据绝对优势,牧草地上生物量均显著高于对照（P<0.05）;除2008年外,最高生物量均在7月中旬,比天然草地提前15 d以上,最高地上生物量平均为2 500 g·m-2,是天然草地的2.54倍。随着种植年限的延长,草地原有牧草先后出现,致使群落物种丰富度、多样性、均匀度总体呈增加趋势;栽培牧草重要值总体呈下降趋势,其中禾本科牧草呈增加而豆科牧草呈下降趋势,草地生产力虽呈下降趋势但仍保持较高生产力。     

柴达木盆地水源涵养功能时空特征分析

水源涵养是柴达木盆地生态服务的主导功能之一,对维护青藏高原的生态安全发挥着重要作用.本研究利用柴达木盆地土地利用、气象、土壤、地形等数据,采用InVEST模型对盆地生态系统水源涵养功能的时空特征进行分析,并计算水源涵养功能的冷热点分布格局.结果表明:1)草地是柴达木盆地的主要的植被类型,占盆地总面积的30.00％,主要...     

兰州地区再生水灌溉对冷季型草坪草土壤养分的影响

本试验以兰州地区常见冷季型草坪草黑麦草(Lolium perenne)品种首相(Premier)、潘多拉(Panterra),草地早熟禾(Poa pratensis)品种百斯特(Barrister)、百胜(Barvictor),高羊茅(Festuca arundinacea)品种凌志(Barlexas)、易凯(Easy Care),以及白三叶(Trifolium repens)品种努克(Nanouk)和紫花苜蓿(Medicago sativa)品种阿尔冈金(Algonguin)为研究对象,利用兰州大学榆中校区污水处理中心的再生水对其灌溉,以自来水灌溉为对照。通过温室盆栽试验,研究了再生水灌溉处理下冷季型草坪草的土壤特性变化。试验发现,再生水灌溉处理的土壤有机质含量极显著高于对照(P0.01),土壤速效钾、碱解氮和土壤全氮含量均显著高于对照(P0.05)。除首相、潘多拉外,其他6种供试植物的土壤全磷含量均显著高于对照(P0.05)。除紫花苜蓿外,其他7种绿地植物的土壤全钾、全钠含量均高于对照,差异显著(P0.05)。综上研究表明,再生水中富含的营养元素不仅能显著提高土壤的有机质含量而且还能有效改善土壤速效养分供应状况。因此,在兰州地区合理利用再生水对绿地进行灌溉具有可行性。     

围封对伊犁河谷春秋草地土壤种子库的影响

以伊犁河谷昭苏马场春秋草地不同围封年限草地(围封6年、围封5年、围封1年和未围封)为对象,采用空间序列代替时间序列的方法,对围封条件下退化草地自然恢复过程中持久土壤种子库的变化进行了研究。结果表明:随着围封年限的增加,土壤种子库的密度和物种数逐渐增加,显著增加了禾本科草类和豆科草类土壤种子密度,杂类草所占比例逐渐下降。禾本科草类和莎草类种子只存在0~5cm土壤表层。土壤种子库与地上植被的物种相似性,随草地的恢复呈增大—减小—增大的变化趋势。     

放牧利用下气候因子和奶牛排泄物施肥对混播草地牧草生长的影响

研究了奶牛排泄物施肥对草地牧草生长速率、年产量的影响,分析了研究区主要气候因子(月均温,降水和日照时数)对牧草生长的效应。3个气候因子对牧草生长均具显著正效应(P<0.05和P<0.01),其影响顺序为降水>温度>日照时数;草地牧草的生长可很好地用PGR=a+b×P模型估测,PGR为牧草月生长速率,P为月降水量,a和b为常数。草地排泄物施肥能增加牧草生长速率,显著增加牧草年产量(P<0.05),使翌年牧草高峰期提前。通过对研究区降水资料和放牧家畜采食牧草需求资料分析,进行合理饲料预算,可做到以草定畜。     

基于CSCS方法的甘南自然植被NDVI时空分布特征研究

基于综合顺序分类系统(CSCS)模型,利用地理信息系统技术手段,模拟出甘南潜在自然植被类型图,并且结合国际地圈生物圈计划(IGBP)土地覆盖数据集,制作出甘南残存潜在自然植被分布图和残存潜在自然植被典型区分布图。在此基础上,利用2001-2010年MODIS数据分别研究了残存潜在自然植被分布区及其典型区的NDVI年度和月度变化特征。研究结果表明,1) 甘南残存潜在自然植被分布区面积达33 940 km²,占甘南总土地面积的92.53%;2) 残存潜在自然植被典型区主要分布在玛曲县、碌曲县及迭部县部分地区和夏河县北部,在舟曲、卓尼和临潭县分布较少;3) 甘南地区NDVI在2001-2010年期间都呈现出上升趋势,7种植被类型的月最大值出现在7-9月。     

Growing cattle on winter wheat pasture: management and herd health considerations.

Some management and supplementation strategies that have potential to improve efficiency of production of wheat pasture stocker and feeder cattle; decrease production risk and income variability, and thereby increase growth of the industry; and strengthen the economies of rural communities in the southern Great Plains are presented in this article.     

Offstream water and trace mineral salt as management strategies for improved cattle distribution

The objective of this study was to test the combined effect of offstream water and trace mineral salt on cattle distribution in a riparian meadow and its adjacent uplands. From July 15 to August 26, 1996 and 1997, three treatments were each randomly assigned to one pasture in each of three blocks. Sixty cow/calf pairs were then randomly allotted to the grazed pastures. The treatments included 1) stream access and access to offstream water and trace-mineral salt (off-stream), 2) stream access and no access to offstream water or trace-mineral salt (no-offstream), and 3) ungrazed control. The response of cattle was measured through visual observations of cattle distribution, grazing activity and travel distance, cow/calf performance, and fecal deposit distribution. Distribution patterns of the cattle, measured as the distance of cattle from the stream, was characterized by a time of day x treatment x time in grazing period x year interaction (P < 0.05). No-offstream cattle began the day further from the stream than offstream cattle but consistently moved closer to the stream after the morning grazing period (0600 to 0900). Differences in distribution patterns between the two treatments were more pronounced early in the grazing period than late in the grazing period. Grazing activity, fecal deposit distribution, and travel distance of cattle were not affected by the presence of offstream water and trace-mineral salt. Cows and calves with offstream water and trace-mineral salt gained 11.5 kg and 0.14 kg/d more, respectively, than no-offstream cows and calves averaged across years (P < 0.05). Overall, cattle distribution patterns and cow/calf performance were influenced by the presence of offstream water and trace-mineral salt. Changes in distribution were most pronounced early in the grazing season.     

A comparison of grass and grass/legume pastures under irrigation in the Outeniqua area of the southern Cape

Two grass and five grass/legume pastures were evaluated over a period of two seasons at two seasonally set grazing pressures and under two grazing management systems, involving five and seven paddocks per flock and a seven‐day period of stay. Grazing capacity was most limiting during winter. Pastures with fescue as grass component had, overall, the highest grazing capacity, while white clover‐based pastures had the highest animal production. The legume content of the grass/legume pastures was markedly higher on the seven than on the five‐paddock system. Dry matter and animal production of white clover‐based pastures was favoured by a seven‐paddock system as opposed to a five‐paddock system, while mixtures containing lucerne and pure grass pastures were either not influenced by grazing management or promoted by a five‐camp system.     

生草覆盖对苹果展叶过程中光合特性的影响

为揭示生草覆盖与清耕苹果园展叶过程中光合特性的差异, 本研究采用气体交换和叶绿素荧光动力学技术分析5年龄苹果园生草覆盖和清耕条件下苹果展叶过程中光合和荧光参数的变化规律。结果表明, 展叶初期, 生草覆盖和清耕处理叶片叶绿素含量、净光合速率(Pn)、性能指数(PICS)和820 nm光吸收的振幅(ΔI)显著低于完全展开叶片(EL), Pn分别为EL的26.9%和18.4%, PICS分别为EL的67.7%和53.4%, ΔI分别为EL的35.6%和30.5%;生草覆盖处理叶片叶绿素含量、Pn、PICS和ΔI显著高于清耕处理。生草覆盖和清耕处理叶片PSⅡ功能在展叶初期已有很大程度的发育, PSⅠ功能的发育程度相对较低;生草覆盖促进了展叶初期叶片PSⅡ和PSⅠ功能的发育, 因此具有较高的光合效率。     

Kikuyu poisoning of cattle in New South Wales and its relationship to pasture fungi on kikuyu grass (Pennisetum clandestinum)

In the late summer and autumn of 1980 kikuyu poisoning of cattle was diagnosed on 9 farms in New South Wales resulting in 213 deaths among 1370 cattle at risk. Clinical, autopsy and histopathological findings are described and are consistent with those previously recorded. Kikuyu grass samples from 5 paddocks in which deaths were occurring were examined for the presence of fungi. Myrothecium spp were not present. Fusarium semitectum, F. moniliforme var subglutinans, Penicillium spp and a Phoma sp were the most common fungi isolated but with the exception of F. semitectum were not consistently present. F. semitectum was present in adjacent kikuyu grass paddocks in which deaths were not occurring. Two of the farms had army caterpillar (Mythimna convecta) infestations. Army caterpillar faeces present in these paddocks did not contain Myrothecium spp; the fungi present reflected the population present on the kikuyu grass. These findings do not suggest a mycotic cause for kikuyu poisoning.     

混播种类和群体结构对豆禾牧草混播系统氮素利用效率的影响

为从物种多样性和空间结构方面阐明豆禾牧草混播系统高效生产机制,将混播种类(单播、2种牧草混播、4种牧草混播和6种牧草混播)、混播群体空间结构(行距+同行/异行/异行阻隔)作为影响因素,从豆科牧草固氮能力、转氮效率、氮素营养竞争、种间相容性和生产性能分析和比较豆禾牧草在不同混播方式中氮素固定、转移和利用效率对混播系统生态功能的贡献程度。结果表明:1)混播处理的牧草产量、N产量均显著高于单播(P<0.05),生产性能显著提高;但生产性能未随混播种类的增加而提高,异行混播+30 cm行距的混播群体结构具有较高的生产性能。2)固氮量随混播种类的增加而呈下降趋势,转氮量和转氮率随混播种类的增加而呈先下降后上升的趋势,而固氮率和贡献率变化不明显;异行混播+30 cm行距的混播群体结构具有较高的转氮量、转氮率和贡献率。3)营养竞争比率随混播种类的增加变化不明显,豆科牧草相对产量和相对产量总和随混播种类的增加而呈增加趋势;异行混播+30 cm行距的混播群体结构具有较高的豆科牧草相对产量和相对产量总和,但营养竞争比率较低。4)牧草产量与转氮量呈极显著正相关(P<0.01),而相对产量总和与氮素营养竞争比率呈极显著负相关(P<0.01)。因此,混播种类对于豆禾牧草混播系统生产性能的提升作用有限,高养分利用效率的物种组合可能更为关键;通过混播群体空间结构的优化可以使豆禾混播牧草根系氮素固定、转移、利用途径和效率得到提高,为混播系统生产性能的提升提供了重要途径。     

放牧牛羊对云贵地区禾草/白三叶草地群落稳定性的影响

禾草/白三叶(Trifolium repens)草地是中国南方喀斯特地区主要刈牧地之一,探究不同家畜放牧下禾草/白三叶草地植被构成和群落稳定性,可一定程度揭示其植被演替特征。本研究定量分析了多年放牧牛(grazing cattle pasture,GC)、放牧羊(grazing sheep pasture,GS)的禾草/白三叶草地群落特征、物种多样性、生物量构成及群落稳定性。结果显示:1)草地死物质量及植物物种数为GC>GS,植物物种Simpson指数为GS>GC;2)草地禾草[多年生黑麦草(Lolium perenne)、鸭茅(Dactylis glomerata)及原生禾草]、原生双子叶(马鞭草科、车前科、酢浆草科和十字花科)及适口性中等植物地上生物量组分为GC>GS,播种白三叶地上生物量组分为GS>GC;且GC草地地上生物量以禾草为主(77.20%),GS草地地上生物量以禾草(51.79%)和豆科(28.02%)为主;3)草地土壤K含量为GC>GS;4)GC草地植物种Raunkiaer频度直方图呈反J型,群落演替度(37.08)比GS草地(45.45)的低。研究认为,GC草地群落处于相对稳定状态,而GS草地群落处于更高演替阶段,牛放牧更利于禾草/白三叶草地群落稳定性和物种多样性的维持。因此,放牧时可实行牛、羊混牧制,或牛、羊轮牧制,以提高禾草/白三叶草地的稳定性和生产力。     

Effect of strategic anthelmintic treatment and pasture management on productivity and control of nematode parasites in weaner-yearling beef cattle

Three groups of 17 beef calves were used to evaluate effects of strategic anthelmintic treatment on safe (group 1) and contaminated (group 2) pasture in comparison with minimal treatment at weaning and contaminated pasture (group 3). The investigation extended from weaning in November 1982 to the following August. Results of faecal egg counts, herbage larval counts, plasma pepsinogen and tracer calf worm counts in autumn and spring indicated minimal levels of infection on safe pastures provided in November and April (group 1). A decided weight gain advantage for group 1 was achieved from November to April, but the rate of gain was not consistent after April and transfer to the second safe pasture. Final average weights in late August were: group 1, 368 kg; group 2, 336 kg; group 3, 262 kg. All were significantly different (P less than 0.05). Worm counts from representative yearlings in September revealed low to moderate levels of Ostertagia ostertagi in group 1. In contrast group 2 cattle had large, almost exclusively O ostertagi infections; group 3 cattle had exceedingly high levels of Trichostrongylus axei infection and moderate to high levels of O ostertagi. Marginal evidence of type 2 ostertagiasis was observed in individual animals of group 2 and group 3.     

寒地型草坪草养护管理要点

草坪的养护园林建设上可以说是一项复杂的系统工程。养护管理的好,可有效延长草坪的利用年限,年度内可延长绿化观赏期,只种不管或轻管,草坪将失去其生态效益及观赏功能。     

Parasites of domestic and wild animals in South Africa. XXXVII. Ixodid ticks on cattle on Kikuyu grass pastures and in Valley Bushveld in the eastern Cape Province

Individual calves, exposed to infestation for 14 d on dry-land Kikuyu grass pastures on the coast near Alexandria, were slaughtered at approximately monthly intervals over a period of 2 years and examined for ticks. Although seven species were recovered total tick burdens were for the most part low. Changing the acaricide with which other cattle on the farm, but not the survey calves, were treated from an organophosphate-based compound to a synthetic pyrethroid resulted in a marked sustained reduction in the number of ticks on the calves. Successive pairs of yearling cattle exposed to infestation on a farm in Valley Bushveld were slaughtered at monthly intervals over a period of 2 years and examined for ixodid ticks. Eleven species were recovered, of which Amblyomma hebraeum, Haemaphysalis silacea, Rhipicephalus appendiculatus and Rhipicephalus glabroscutatum were the most abundant and prevalent. Adult A. hebraeum were generally most numerous from early to late summer, adult R. appendiculatus from mid to late summer, and adult R. glabroscutatum from spring to mid-summer.