补饲与不补饲条件下3种放牧率对高寒草地牧草与畜生产的影响

通过补饲和不补饲条件下放牧率对高寒草地牧草和家畜生产影响的研究，结果表明，３种放牧率对草地牧草产量影响不大，组间差异不显著。放牧率影响羯羊体重。在补饲条件下，羯羊日增长量随放牧率减小而增加；组间差异显著；不补饲使羯羊减重，羯羊日减重量随放牧率减小而降低。     

不同载畜量对羊草草地植被和家畜生产性能的影响

通过放牧强度对羊草草地植被和家畜生产影响的研究,放牧强度不同程度地改变了土壤养分状况,三种放牧强度下草地植物群落的高度、密度、盖度、频度、可食牧草产量无明显变化,组间差异不显著(>0.05)。放牧强度影响羯羊体重。羯羊日增长量随放牧强度减小而增加,羯羊生长量以中组为最佳,中组分别比低组、高组提高30.4%、17.6%,平均日生长量组间差异显著(<0.05);牧草干物质的采食量影响羯羊生长量,而日采食量中粗蛋白较干物质对羯羊生长的影响更为重要。草地放牧以中放牧强度(6只/hm2)为最佳。     

高寒草地放牧绵羊冬季补饲对不同放牧强度草地生产力的影响

为了研究放牧绵羊冬季补饲对高寒草地生产力的影响,试验通过不同放牧强度下补饲和不补饲处理,研究对草地物种数、植被盖度、地上生物量的影响。结果表明:在轻度放牧强度下补饲与不补饲对于植被盖度和地上生物量的变化有一定影响,但幅度较小;重度放牧强度下补饲与不补饲对于植被盖度和地上生物量的影响差别很大。说明补饲对减缓放牧绵羊对草地的破坏作用、减轻放牧压力、恢复植被等方面具有积极的意义。     

不同补饲水平对安格斯杂交肉牛生产性能的影响

选取28头12月龄安格斯杂交肉牛(安格斯牛×本地黄牛),随机分为4个处理(n=7):对照组、补饲1,2,3组,组间体重差异不显著(P>0.05)。于南方自然放牧条件下,补饲组分别补饲精料补充料每天0.5,1,1.5kg/头。180d的育肥结果表明:补饲1,2,3组与对照组比较,平均日增重分别提高34.38%,59.38%,96.88%,差异极显著(P<0.01);补饲3组的经济效益最好,补饲2组次之,并明显优于不补饲组。     

不同饲养方式对阿尔巴斯白绒山羊羯羊肌肉理化指标的影响

主要研究不同饲养方式对绒山羊羯羊肌肉理化指标的影响。从内蒙古白绒山羊种羊场的4月龄断奶羔羊群中选择30只去势公羔(羯羊)进行放牧补饲,每只补饲300 g玉米;从淘汰群中选择30只与放牧补饲组日龄相近的羯羊进行舍饲育肥,并按照试验设计饲喂全混合日粮。试验结束时,每组选择6只接近平均体质量的羯羊屠宰。结果表明:舍饲育肥和放牧补饲羯羊的肌肉肉色、p H、失水率、嫩度、剪切力、熟肉率和大理石花纹间差异不显著(P0.10),说明阿尔巴斯白绒山羊羯羊进行短期舍饲育肥与放牧补饲相比,对肌肉理化指标无显著的影响(P0.05)。     

补饲水平对甘肃高山细毛羊生产性能的影响

为了探讨补饲水平对高寒牧区甘肃高山细毛羊生产性能的影响,本研究选择12月龄甘肃高山细毛后备母羊48只,随机分为补饲Ⅰ组(颗粒饲料)、Ⅱ组[玉米(Zea mays)和苜蓿(Medicago sativa)干草]、Ⅲ组[玉米、苜蓿干草和燕麦(Avena sativa)干草]和对照组(不补饲),进行冬春季"放牧"+"补饲"试验,比较了后备母羊体重,剪毛量,毛纤维长度、细度、白度、强度和伸度等物理指标。结果表明,试验Ⅰ组、Ⅱ组和Ⅲ组试验羊平均日增重分别比对照组高148.29%、133.09%、96.76%;剪毛量各组之间差异不显著(P0.05);自然长度和伸直长度对照组均极显著低于Ⅰ、Ⅱ、Ⅲ组(P0.01),且自然长度Ⅰ组极显著高于Ⅱ组和Ⅲ组(P0.01),伸直长度Ⅲ组极显著低于Ⅰ组和Ⅱ组(P0.01),Ⅱ组显著高于Ⅰ组(P0.05);细度(直径)Ⅰ组最大,Ⅰ组极显著高于对照组(P0.01),且显著高于Ⅱ组(P0.05);白度Ⅰ组最高,Ⅰ组显著高于对照组(P0.05),其他各组之间均差异不显著(P0.05);强度和伸度补饲组均极显著高于对照组(P0.01),且强度Ⅰ组极显著高于Ⅱ组(P0.01),伸度Ⅰ组显著高于Ⅱ组(P0.05)。由此可见,补饲对体重、羊毛品质都有显著正向影响,高寒牧区冬春季节牧草营养缺乏,为了满足羊只营养需要,使甘肃高山细毛羊后备母羊能在1.5岁进行配种繁殖,在冷季放牧的基础上补饲1号料为最佳选择。     

妊娠期补饲精料对陕北白绒山羊日增重及肉绒品质的影响

为了解决陕北地区白绒山羊母羊产羔后营养不足导致体况恢复和生长缓慢问题，试验以600只陕北白绒山羊为研究对象，300只补饲精料记为补饲组，300只不补饲精料记为对照组，从补饲组和对照组各选取60只不同月龄的怀孕母羊及其所产羔羊(每组均为公母各半，且所有羔羊同一天出生)为监测对象，在母羊产羔日和羔羊出栏时测定母羊及羔羊体重，计算不同月龄母羊、羔羊日增重，同时测定出栏羔羊肌肉中粗蛋白、粗脂肪、粗灰分、干物质含量及肌肉剪切力、熟肉率、失水率和羊绒长度、细度、断裂强度指标，探究补饲精料和不补饲精料对陕北白绒山日增重及肉绒品质的影响。结果表明：补饲组和对照组12～18月龄母羊日增重显著高于18月龄以上母羊(P<0.05),随补祠时间延长，补饲组母羊体重均增加，但随月龄的增加，母羊日增重逐渐减少；对照组除12～18月龄母羊体重增加外，18月龄以上母羊体重均在降低，且随月龄的增加，母羊日减重逐渐增加。补饲组公母羔羊日增重较对照组公母羔羊分别显著提高12.32%和13.23%(P<0.05),补饲组和对照组公羔日增重较母羔显著提高8.31%和9.19%(P<0.05)。补饲组羔羊出栏时...     

高寒草地天然牧草Ca、P含量及其分布规律

高寒草地天然牧草是高原放牧家畜主要日粮来源,全年天然牧草营养的不均衡和家畜营养需要的恒定,严重制约了高寒草地畜牧业的发展。文章通过综述青海、西藏、甘肃和新疆有关高寒草地牧草营养价值的研究文献,整理综合高寒牧草Ca、P的营养成分数据,以不同牧草不同生长时期为划分单位,探究不同地域、不同生长期高寒天然牧草Ca、P含量极其分布规律,为高寒草地放牧家畜精准补饲饲养提供基础参数,通过适度补饲解决高寒草地营养供给不均衡问题。     

肉羊补饲紫花苜蓿试验研究

试验分为两期,第一期主要试验紫花苜蓿与其它牧草补饲肉羊的差别;第二期主要试验紫花苜蓿与一年生黑麦草不同的补饲搭配比例.通过两期试验可以说明育肥羊在放牧条件下补饲紫花苜蓿可以提高肉羊日增重水平,缩短育肥周期;可以提高肉羊粗饲料和精饲料的饲料报酬,减少饲料消耗.补饲紫花苜蓿较补饲其它牧草好,但差异不显著(P＞0.05).     

农养本地山羊补饲肥育试验

本文对农养本地山羊补饲肥育效果进行了探讨。试验结果表明 ,农养本地黑山羊、麻山羊在自然放牧未补饲的情况下增重性能、屠宰率、净肉率、经济效益等方面均没有明显差异 (P >0 0 5 ) ,放牧补饲的试验组 1、2、3、4组同放牧未补饲的对照 1、2组间均有显著差异 (P <0 0 5 ) ,对补饲日粮进行不同处理的试验 1组与 2组间、试验 3组与 4组间以及试验 1、2、3、4组间在增重性能、屠宰率、净肉率、经济效益等方面均差异不显著 (P >0 0 5 )。但试验结果表明 ,农养本地山羊补饲肥育能显著地提高日增重、胴体重、净肉重和经济效益 ,本地黑山羊和麻山羊无论补饲与否不存在品种间差异 (P >0 0 5 ) ,补饲日粮不同处理也没有引起肥育效果的显著变化 (P >0 0 5 )。     

Growth performance of yearling horses grazing bermudagrass pastures at different grazing pressures

Body weight gains and height at the withers were measured in yearling geldings grazing bermudagrass (Cynodon dactylon [L.] Pers.) pastures with neither energy nor protein feed supplementation at stocking rates of 6.7, 8.0, 9.5 and 12.4 yearlings per hectare. Weekly forage samples were taken to estimate the quantity and quality of available forage. These samples were clipped and separated into three equal lengths to characterize upper, middle and lower thirds of the canopy and to determine relationships between available forage and yearling growth rate. Average daily gain was influenced by stocking rate, but gain in height was not affected by stocking rate. Average daily gain ranged from -.31 to .37 kg/d and was negatively related to stocking rate. A quadratic relationship between available forage and ADG was detected. However, a linear relationship between ADG and available forage in top layers of the canopy indicated that animal performance might have been limited by availability of top layer forage in pastures subjected to light grazing pressure.     

Grazing behavior and performance of beef cattle as a function of sward structure and herbage quality under rotational and continuous stocking on species‐rich upland pasture

An experiment to reveal functional response and heifers' performance to sward characteristics and forage chemical composition was conducted for 5 years in rotational (RSS) and continuous (CSS) stocking systems on native species‐rich upland grassland. We measured sward characteristics, forage chemical composition, heifers' grazing behavior and live‐weight gains from July to September. Mean sward surface height was lower on CSS than on RSS; grass and forb density, and white clover stolon length, were similar. Herbage on CSS had higher crude protein content and lower crude fiber content than on RSS. No difference existed in time budgets of grazing, ruminating and resting between stocking systems and season, while grazing rates were higher on CSS. Stocking rate was 1671 and 1332 kg per ha on CSS and RSS, individual daily live‐weight gain 683 and 652 g on CSS and RSS. Gain per ha was 20 kg higher on CSS. Results suggested stocking systems on native species‐rich grassland had no effect on activity time budgets or animal performance. Both RSS and CSS allow similar outputs for stocking rates in terms of individual daily live‐weight gain. Key parameters determining heifers' behavior and performance were sward height, grass and forb density in the sward, and content of crude fiber and protein in forage.     

内蒙古典型草原草畜系统适宜放牧率的研究Ⅰ.以绵羊增重及经济效益为管理目标

(1)绵羊个体增重与放牧率呈线性负相关,个体最大增重临界放牧率,因季节不同而变化,随着个体增重与放牧率回归系数b绝对值的增大而降低,以始、终放牧期间所得临界放牧率最小,(2.04羊/hm²)。(2)公顷增重与放牧率的关系符合二次曲线,在达到公顷最大增重以前,随着放牧率的增大而增大,之后则随着放牧率的增大而下降,平均543羊/hm²。(3)公顷最大增重并不一定获取公顷最大利润,主要视买卖价格及其差值而定。(4)以冷蒿小禾草为主的退化草原,宜以个体最大增重的适宜放牧率作为管理标准,以使该类草原在利用中得以恢复。     

Effects of establishment method and fall stocking rate of wheat pasture on forage mass, forage chemical composition, and performance of growing steers

Stocking rate is a fundamental variable for managing pastures, and there is a distinct relationship between stocking rate and animal performance for each forage type. This research was conducted to determine the effects of fall stocking rate (SR) and method of establishment of wheat pasture planted into dedicated crop fields on animal performance during the fall and subsequent spring. There was a factorial arrangement of tillage methods used in the establishment of wheat pasture and fall stocking rates. Tillage treatments included 1) CT, seed sown into a prepared seedbed, 2) RT, a single pass with a light disk followed by broadcasting of seed, or 3) NT, direct seeding into the undisturbed stubble of the grazed-out wheat pasture from the previous year. The fixed SR during the fall were 1.9, 2.5, and 3.7 growing beef steers (Bos taurus L.)/ha. In the spring all pastures were grazed at the same fixed SR by steers for graze out. Data were analyzed using the mixed procedure of SAS as a randomized complete block design with field as the experimental unit and year as the block. Forage mass, forage nutritive composition, and animal performance during the fall or spring were not affected (P ≥ 0.14) by tillage method. During the fall grazing season, with increasing SR there were linear (P < 0.01) decreases in BW of steers upon removal from pasture, BW gain per steer, and ADG, whereas grazing-day per hectare and BW gain per hectare increased linearly (P < 0.01) with increasing SR. The carryover effects of fall SR into the spring grazing season decreased (P< 0.01) grazing-day per hectare and tended (P ≤ 0.09) to produce quadratic changes in BW upon removal from pasture and BW gain per hectare. Across the fall and spring grazing seasons, grazing-day per hectare increased linearly (P < 0.01) with greater SR, and BW gain per hectare increased quadratically (P = 0.02) with increased fall SR. A tillage treatment by fall SR interaction (P = 0.10) indicates that although there was no difference (P ≥ 0.12) due to tillage treatment in BW gain per hectare at 1.9 or 2.5 SR, NT fields produced (P ≤ 0.04) more BW gain per hectare than CT or RT at the 3.7 SR. Although increasing SR of growing steers leads to reduced animal performance in the fall and reduced carrying capacity in the spring, NT appears to be capable of withstanding greater fall SR with less impact on total production per hectare than CT or RT.     

Technical note: stocking equivalents and stocking rate-gain relationships for steers and cow-calf pairs grazing oversown bermuda grass.

Grazing experiments may use steers or cow-calf pairs for measuring animal performance on pasture treatments, but the validity of extrapolation between these classes of cattle has not been verified. A grazing study was conducted in the spring and summer of both 1988 and 1989 to determine stocking equivalents and stocking rate-weight gain relationships for steers and cow-calf pairs grazing Coastal bermuda grass (Cynodon dactylon [L.] pers.) oversown with rye (Secale cereale L.) and ryegrass (Lolium multiflorum Lam.). Average daily gain and stocking rate (SR; 3.2, 4.2, 6.2, and 7.4 animals per hectare for steers and 1.7, 2.5, 3.7, and 4.9 pairs per hectare for cow-calf pairs) were both adjusted so that comparisons could be made on an equal BW basis. Disk meter height readings were used as measurements of forage accessibility. Disk meter height responses to SR did not differ (P greater than .10) between steer and cow-calf paddocks. There was a linear (P less than .001) decrease in ADG as SR increased, but this decline was steeper (P less than .001) for steers than for cows or suckling calves. Steers tended to be more productive than calves at low SR but less productive at high SR. Disk meter heights for the range of SR used in the study did not differ (P greater than .10) for steers and cow-calf pairs at equivalent BW per hectare. Our study suggests that live BW is a reasonable basis for determining forage requirements of steers and cow-calf pairs under grazing conditions, but extrapolation of production between classes of livestock will not be reliable.     

草原放牧系统持续管理试验研究:试验设计及放牧率对草-畜系统影响分析

在内蒙古典型草原区中国科学院草原生态定位站研究不同放牧率、放牧方式和放牧季节对草原植物和家畜生产的影响。结果表明,地上现存量随着放牧率的增加而降低,但达到峰值的日期提前了。地上生物量与放牧率无明显趋向性变化。家畜增重随着放牧率的增大而下降,公顷总增重与放牧率成二次曲线关系。将放牧率对草原生产力的动态确定为可持续放牧率和改良放牧率。     

Diet composition and daily gain of growing cattle grazing dryland and irrigated cornstalks at several stocking rates

Diet composition and the relationships between daily gain of calves grazing cornstalks and certain characteristics of the available residue and diets selected by esophageally fistulated cattle were studied in two trials during November and December of 1984 (Trial 1) and of 1986 (Trial 2). Eight adult steers and four esophageally fistulated calves were used in Trials 1 and 2, respectively, to collect extrusa samples from dryland and irrigated fields grazed at several stocking rates. Steers grazing irrigated cornstalks selected a diet with more (P less than .05) starch and less (P less than .05) CP than those grazing dryland fields. As grazing continued, extrusa starch content decreased (P less than .05). In vitro DM disappearance (IVDMD) of both diet and the roughage fraction of the diet decreased (P less than .05) with days of grazing; this decrease was greater (P less than .05) at higher stocking rates. Calves grazing dryland fields gained faster (P less than .05) than calves grazing irrigated fields. With a low level of protein supplementation (213 g CP/d, Trial 1), daily gain was positively correlated with CP of both diet (extrusa) or available leaf plus husk but not with grain available per animal or with extrusa IVDMD, suggesting that protein was first limiting. With a higher level of protein supplementation (458 g CP/d, Trial 2), daily gain was correlated positively with residue available per animal and IVDMD of extrusa at the end of the grazing season. The energy value of feed consumed by cattle grazing cornstalks decreases with time, and complex interactions between protein needs and energy intake may occur.     

放牧绵羊行为生态学研究：Ⅲ不同放牧时期对放牧绵羊牧食行为的影响

在较低放牧率和限牧时间条件下，不同放牧时期对绵羊牧食行为的影响有：（１）当放牧时间缩短时，绵羊通过缩短反刍行为的时间而保持采食时间的相对稳定，并通过调整各采参数数以保持进食速率和日采食量的相对稳定，对饮水行为影响不大；（２）９月份反刍周期数和总反刍食团数量少，反刍时间最短；６月份每个食团咀嚼次数最少，咀嚼时间最短；（３）７月份排尿次数量多，每次排尿时间最长；９月份居中；６月份量少。排粪行淡差异不显     

放牧率对绵羊体重及繁殖性能的影响

通过不同放牧率对内蒙古本地绵羊(母羊)连续2年(2008～2009)的体重和繁殖性能的影响的研究表明:(1)在试验期内,随着时间的推移,不同放牧率下的绵羊体重总体上都呈上升趋势;间隔1个放牧率或以上的处理间,存在不同程度的显著性差异;(2)绵羊的个体增重与放牧率之间存在负相关关系;而公顷增重与放牧率的关系符合二次曲线关系,在达到公顷最大增重前,随着放牧率的增大而增大,之后随着放牧率的增大减小;(3)单位家畜增重和单位面积增重的交点的生态学意义在于放牧率为1羊/hm2,公顷增重和家畜个体增重相同;单位家畜个体增重对应的畜产品最优放牧率为0.50羊/hm2,单位面积家畜最大增重对应的畜产品最优放牧率为2.38羊/hm2;(4)过高的放牧率导致绵羊出现空怀现象及产羔率下降;羔羊的初生重和个体增重均随着放牧率的增大而减小,但其显著性差异仅表现在较高的放牧率与较低的放牧率之间,而在相邻放牧率间差异不显著。     

Response of lambs to continuous and rotational grazing at four grazing intensities on Midmar Italian ryegrass

Abstract

Irrigated Midmar Italian ryegrass (Lolium multiflorum Lam.) was grazed either continuously or rotationally at four grazing intensities by three successive sets of weaned lambs for the winter, spring and summer periods, respectively. The “put‐and‐take” system was applied. In the case of continuous grazing, amounts of available dry matter (DM) per hectare were varied, whereas with rotational grazing different grazing intensities were established by allocating different amounts of DM per unit livemass. Amounts of DM on offer were determined in both systems to provide a basis for comparison.

There were no differences in average daily gain (ADG) at equivalent levels of available DM between grazing procedures in winter. In both spring and summer, however, ADG at given levels of available DM was greater (P ≤0,01) with continuous than with rotational grazing. Stocking rate at equivalent levels of available DM was higher (P ≤0,01) for rotational as compared with continuous grazing in winter and summer, but in summer, grazing procedure had no effect on stocking rate. There was an interaction between stocking rate and grazing method in winter (P ≤0,01). At high stocking rates, ADG were higher (P ≤0,01) under rotational than under continuous grazing. In spring and summer the ADG for continuous grazing was higher (P ≤0,01) than that for rotational grazing at equivalent stocking rates. The estimated stocking rates for maximum gains/ha ranged in the different seasons from 45 to 123 lambs/ha.