藏北高寒草地牧草营养品质对放牧的响应机制

基于藏北高原的3个围栏与自由放牧试验样地,探讨了高寒草地牧草营养品质对放牧的响应机制.结果表明:在一个高寒草原化草甸冷季牧场,冷季放牧分别减少了24.29％和18.98％的杂草酸性洗涤纤维和中性洗涤纤维含量,并增加了41.05％的杂草粗灰分含量,从而增加了杂草营养品质;而没有改变群落和优势牧草营养品质.在一个高寒草原化...     

放牧对草地植物群落多样性和草地病害的影响

放牧是合理利用、培育改良草地的重要方式之一。通过不同放牧强度、放牧方式以及家畜采食等提高或降低草地植物病害的发病率和病情指数。草地植被群落多样性包括物种丰富度和寄主植物密度,通过影响寄主植物对周围环境资源的利用以及病原真菌的传播来提高或降低病害的发病率和严重度。同时,不同放牧强度、家畜采食习性、草地生产类型、放牧史以及放牧分布型也分别提高或降低草地植物群落多样性。本文综述放牧对草地植物群落多样性和草地病害的影响,指出在以后的研究工作中把放牧对草地植物群落多样性的影响与草地植物病害的影响结合起来,并在遗传多样性方面加以研究,最终切实可行地通过提升放牧管理达到减轻或防止草地病害发生的目的,实现统一放牧、病害管理以及草地资源可持续利用的目标。     

The effect of veld condition on the quality of diet selected by cattle grazing the Natal Sour Sandveld

The quality of diet selected by steers fistulated at the oesophagous was related to veld condition in a simulated rotational grazing system on the Natal Sour Sandveld. Six camps, ranging in veld condition score from 8,5 to 53%, were grazed simultaneously for a two‐week period in spring, summer, autumn and winter. Fistula samples were collected on the first, middle and last day of a period of occupation in a camp. Samples were analysed in terms of crude protein (CP), in vitro digestibility (IVD) and plant‐part (% leaf, % stem and % dead material) composition. Dietary quality in terms of CP, IVD and plant‐part composition was not related to veld condition but was dependent largely (P≤0,01) upon season and to a lesser extent upon period of occupation in a camp. It was concluded that in sourveld areas, where dietary quality may be limiting, the veld condition score may be a poor index of potential animal production.     

放牧强度对羊草草地植被特征的影响

通过小区控制放牧实验，研究了放牧强度对松嫩平原羊草草地植被特征的影响。结果表明：主要种群的高度、密度和生物量随季节的变化趋势不同，草地高度随放牧强度的增大而降低；一定程度的放牧可增加禾草在群落中的比例，提高牧草质量；随着放牧强度的增大，群落密度有增大的趋势，植物多样性指数先增高后降低，即中度放牧下多样性指数最大，有利于多样性的维持，多样性增加又增强草地对放牧的缓冲力。植物种数与多样性指数间没有明显的线性关系。     

Development of veld management research in the karoo region

The development of veld research in the semi‐arid Karoo areas since 1934 is outlined. It entailed key experiments on different types of veld, and the synthesis of grazing systems and their testing in experimental camps and co‐operatively on a practical farming scale. The experiments were primarily conducted with Merino sheep but Angora goats, Boer goats, cattle and Persian sheep were also employed. A large number of rotational grazing systems, special treatments and methods have been set out for the entire Karoo Region. The group camp approach serves as a basis for complete veld management planning in the Karoo Region.

Supporting research covered plant physiological, phenological and ecological studies; the determination of selective grazing habits of livestock; production of karoo bushes; and the development of research techniques especially in connection with quantitative and qualitative vegetation surveys.     

刈割对牧草生物量和品质影响的研究进展

刈割是一种常见的草地利用和管理方式,它可以通过两方面途径来影响牧草产量及品质。首先,刈割可以利用植物的补偿性生长,促进牧草生长并提高牧草产量。其次,刈割可以利用植物均衡性生长特性,改变牧草营养物质的沉积和分配方向,进而影响牧草品质。常见的刈割包括刈割频次、刈割时间和刈割方式。全面综述3种刈割对牧草产量及品质影响和相应作用机理,为适当利用刈割提高牧草产量及品质提供参考。     

The effects of grazing and supplemental protein concentrations during the grazing period on subsequent finishing performance and carcass quality in Japanese Black cattle steers

The effects of grazing and supplemental protein concentrations, provided during the grazing period, on subsequent finishing performance and carcass quality were investigated. This experiment was carried out using 15 Japanese Black cattle (Wagyu) steers. The steers were fed as follows: (i) grazing supplemented with moderate protein concentrate (GMP) (18% crude protein (CP); dry matter (DM) basis) before finishing, followed by feeding in a barn until slaughter; (ii) grazing supplemented with low protein concentrate (GLP) (14% CP; DM basis) before finishing, followed by feeding in the barn until slaughter; and (iii) no grazing before finishing (NG). From the end of the grazing season to the end of the growing period, the GMP and GLP steers were managed in the same way as the NG steers. All of the animals were fed the same diet in the finishing period (9 months to 28 months). None of the three treatments affected the average daily gains. For all treatments, chilled carcass weights were more than 450 kg and did not differ significantly among the groups. The longissimus muscle areas in the grazed steers were numerically larger than in those receiving the NG treatment. Fat thickness was significantly greater (P < 0.05) in the NG steers than in the grazed steers. The intramuscular fat and marbling scores were not affected in the grazed steers. In conclusion, the carcass quality of grazed steers was similar to that of the NG steers at a similar final age, and the quantity of meat in the NG steers would be less than that of the GMP and GLP steers. Therefore, spring‐born Wagyu steers should be grazed using the GLP supplement before fattening.     

垂穗披碱草/星星草混播草地优化牦牛放牧强度的研究

以植被和牦牛生产力变化为目标研究草地不退化的最大放牧强度,在垂穗披碱草/星星草高寒混播草地3年的牦牛放牧试验结果表明,1)优良牧草比例和牦牛个体增重的平均年度变化随放牧强度的增加而减小,牦牛个体增重和优良牧草比例的平均年度变化之间存在着正相关,因此确立了不同放牧强度下优良牧草比例的年度变化是评价高寒混播群落放牧价值的直接度量指标.2)虽然群落相似性系数和草地质量指数可以评价草场的相对变化,但相似性系数的变化与牦牛个体生产力没有显著关系,因而不能反映草场放牧价值的变化,而计算草地质量指数时,不同植物类群盖度的测定和适口性的判别受人为因素的干扰较大,因此它也不是一个很客观的指标.3)当放牧强度为9.97头/hm2时,优良牧草比例和牦牛个体增重的年度变化能维持基本不变,因此,可以认为该放牧强度是高寒人工草地生长季放牧不退化的最大放牧强度.     

Influence of stocking rate and grazing systems on available grazing in the northern cape 1

Abstract

The influence of rotational and continuous grazing systems, each applied with four stocking rates, on the above‐ground phytomass of veld was determined over four years.

Grazing systems showed a significant influence on available herbage during one year only. Increased stocking rates brought a progressive decline in above‐ground phytomass. During the fourth season (1980/81) the average grazing pressures at stocking rates of 10 ha, 7 ha, 5,5 ha and 4 ha/Large stock unit were 5 984 kg, 3 417 kg, 2 390 kg and 1 238 kg and 1 238 kg phytomass/Large stock unit, respectively. At the end of the fourth season (July, 1981) there was reserve grazing available on the various stocking rates for approximately 579 days, 337 days, 202 days and 76 days, respectively. The risk of high stocking rates in the marginal rainfall regions, is emphasised.     

高寒草甸优势物种饲用品质对短期放牧的响应

为了解放牧强度对高寒草甸牧草饲用品质的影响,以青藏高原东北边缘高寒草甸为对象,研究了轻度(0.75牦牛单位·hm-2)、中度(1.00牦牛单位·hm-2)和重度(1.25牦牛单位·hm-2)放牧下优势植物珠芽蓼(Polygonum viviparum)和线叶嵩草(Kobresia capillifolia)的全氮、酸性洗涤纤维、中性洗涤纤维含量以及牧草的可吸收营养物质总量和相对饲喂价值等的变化。在放牧末期,中度放牧下牧草的植株高度显著高于其他放牧强度(P0.05)。在整个放牧期,中度放牧下牧草的全氮含量高于其他放牧强度,其中珠芽蓼的全氮含量在放牧末期显著高于重度放牧(P0.05);各放牧强度间植物的酸性和中性洗涤纤维含量在放牧末期无显著差异;中度放牧下牧草的营养价值指数整体呈上升趋势或保持稳定。在青藏高原东北边缘,3年的短期中度放牧利用有利于高寒草甸主要优势物种珠芽蓼和线叶嵩草保持较高而稳定的饲用品质。     

The effects of continuous and rotational grazing of sourveld on the quality of herbage selected by Simmentaler heifers

A grazing trial was conducted at the Kokstad Agricultural Station to compare the dry matter digestibility (DMD) and crude protein content (CP) of diets selected by four fistulated cattle which were continuously and rotationally grazing sourveld. Two stocking rates of 1,0 and 2,3 animals/ha (0,5 and 1,2 LSU/ha) were applied under each grazing method. The mean DMD and CP values of diets selected in the continuous and rotational grazing treatments, respectively, were: DMD=64,3%, 62,3%; CP=6,63%, 6,88%. The effect of stocking rate on the quality of the diet selected varied between the two grazing methods. DMD and CP of diets selected under rotational grazing decreased with time during the week‐long period of stay in each paddock. On average, DMD and CP values on the first and sixth day respectively, were: DMD=66,6%, 60,5%; CP=8,37%, 6,01%. These differences were more pronounced at the higher than at the lower stocking rate. It was concluded that, although some of the treatment differences were small, grazing method differences in the DMD of diets might at least partially account for observed differences in livemass gains under the two grazing systems.     

利用方式、种植模式和施氮对多年生牧草产量及品质的影响

为探究不同利用方式下种植模式和施氮对牧草产量及品质的影响,本研究在甘肃环县对栽培草地设置放牧(G)和刈割(M)两种利用方式,每种方式下设无芒雀麦(Bromus inermis)单播(W)、红豆草(Onobrychis viciifolia)单播(H)与两者混播(WH)3种种植模式及0(N1)、80 kg·hm-2(N2)和160 kg·hm-2(N3)3个施氮水平.结果表明:1)放牧较刈割显著提高了总鲜、干草产量,显著降低了粗脂肪、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量,进而提高了相对饲用价值(RFV).2)WH和H处理较W显著增加了鲜、干草产量,且WH显著高于H;WH和H较W显著提高了粗蛋白和粗脂肪含量,显著降低了NDF含量,进而显著提高了RFV.3)总鲜、干草产量随施氮量的增加显著提高,N2和N3处理的粗蛋白、粗脂肪显著高于N1,而NDF和ADF显著低于N1,并显著提高了RFV.因此,无芒雀麦和红豆草混播草地在放牧下施氮160 kg·hm-2是一种适宜陇东地区放牧型栽培草地的管理措施.     

短期围封对辽西北退化草地群落牧草品质的影响

围封对退化草地牧草品质的影响是评价围封效果的重要方面.以辽西北退化草地为研究对象,研究3年间(2017-2019年)围封和自由放牧处理下群落特征和牧草品质各项指标的变化.结果表明:围封区群落高度、盖度、地上生物量、枯落物量以及牧草粗蛋白、非纤维性碳水化合物、产奶净能、奶吨指数显著高于放牧区(P<0.05),具有较高的营...     

Effect of water‐soluble carbohydrate content in orchardgrass pasture on grazing time and rumen fermentation in dairy cows

Two experiments were conducted to clarify the effect of water‐soluble carbohydrate (WSC) content in orchardgrass pasture on the diurnal distribution of grazing time. Six ruminally cannulated, non‐lactating dairy cows were grazed on either of two pastures with different orchardgrass cultivars containing low WSC (LWSC; cultivar: ‘Hokkai 28’) or high WSC (HWSC; cultivar: ‘Harunemidori’). The cows were grazed in morning and evening sessions in experiment 1, whereas the cows were grazed throughout the day in experiment 2. In experiment 1, grazing time of the cows on HWSC was longer than that of the cows on LWSC (P < 0.01). This difference was larger in the morning session than in the evening session (pasture × grazing session: P < 0.05). Effects on herbage intake were similar to those on grazing time. In experiment 2, daily total grazing time was longer for the cows on HWSC than for those on LWSC (P < 0.05). The cows on HWSC spent a longer time grazing than those on LWSC in the morning between 03.00 and 09.00 hours (P < 0.01). The results indicated that prolonged grazing time in the period between dawn and early morning could increase daily herbage intake in cows grazed on pastures of orchardgrass cultivars with high‐WSC content.     

休牧对西藏高寒草原和高寒草甸植被与土壤特征的影响

休牧是西藏主要放牧管理和草地保护的措施之一,目的是通过自然力的作用使退化草地的植被与土壤得到恢复,维持较高的多样性和生物量。本研究以西藏中部高寒草原和高寒草甸为研究对象,通过野外调查和室内试验分析,研究自由放牧和休牧对高寒草原和高寒草甸植物物种多样性、总生物量、地上地下生物量权衡以及土壤理化性质的影响,对比自由放牧和休牧对高寒草原和高寒草甸植被与土壤特征影响的差异。结果表明:在高寒草原与高寒草甸,休牧6~8年虽一定程度降低了植物群落的Simpson指数、Pielou指数、Shannon-Wiener指数,增加了植被总生物量,但变化均未达到显著水平(P>0.05)。休牧6~8年提高了地上和地下生物量权衡值,并促使植物更多地向地上部分生长,且在高寒草甸的作用效果更为明显。另外,休牧和自由放牧对高寒草甸以及高寒草原草地土壤机械组成、土壤微团聚体、土壤营养元素影响没有显著差异。综合分析发现,休牧对西藏高寒草地的植被恢复尚未产生明显的效果,表现为休牧对群落生物多样性、植被生物量和土壤理化性质影响均未达显著水平,因此,对西藏休牧的实施效果还有待于今后进一步的观测和研究。     

我国退牧还草工程重点县草原植被长势遥感监测

利用遥感和地理信息系统等先进技术手段,基于MODIS数据,对我国4大主要草地类型区的退牧还草工程县的草原植被长势进行了监测,主要结论如下:1)内蒙古东部退化草原区2005年草原植被长势虽然差于2004年的面积有上升趋势,但是总体长势良好,明显好于2004年;2)蒙甘宁西部荒漠草原区2005年草原植被长势较差,虽然生长季节草原植被长势差于2004年的面积呈上升趋势,但总体相对比较稳定;3)新疆北部退化草原区2005与2004年相比长势持平的草地面积所占比重大,比较稳定,呈现出长势好差交替的时序变化格局;4)青藏高原东部江河源草原区2005年草原长势好于2004年的草地面积占本区总草地面积的48.07%,长势差于2004年的草地面积占本区草地总面积的32.56%,与2004年持平的占19.37%,由此表明青藏高原东部区草原长势明显好于2004年同期,长势差和长势好于2004年的草原面积波动较为明显。     

Effect of feeding non-fibrous carbohydrate before grazing on intake and nitrogen utilization in dairy cows throughout the grazing season

Ten lactating cows were used to determine the effect of feeding non-fibrous carbohydrate (NFC) supplement before grazing on feed intake and nitrogen (N) utilization throughout a grazing season. The experiment was conducted from June to September. Cows grazed twice a day (2.5 h × 2) under a set stocking system and were fed NFC supplement (1 kg/4 kg of milk yield) 2 h before grazing (PRE) or immediately after grazing (POST). Cows were also fed a grass and corn silage mixture ad libitum. Herbage dry matter intake (DMI) was greater for PRE than for POST throughout the experiment and decreased from June to September. Conversely, silage DMI was less for PRE than for POST throughout the experiment and increased over the grazing season. Consequently, total DMI for PRE did not differ from that for POST. Milk urea-N concentration and urinary urea-N excretion in June did not differ between the treatments, whereas that after July was higher for PRE than for POST. Proportion of urinary N excretion to absorbed N intake in June was lower for PRE than for POST, but that after July was higher for PRE than for POST. Feeding NFC supplement before grazing would improve N utilization when cows eat large amounts of herbage high in N.     

Effects of supplemental protein sources during the grazing period on performance, ruminal characteristics and blood constituents in early weaned growing Wagyu steer calves

We investigated the effects of grazing and supplemental protein sources during the grazing period on growth performance, ruminal characteristics and blood constituents in 15 growing Wagyu steer calves weaned at 3 months of age. Each animal was allotted one of three treatments: (1) GSBM, soybean meal (SBM) supplemented as a protein source during a grazing period; (2) GCGM, corn gluten meal (CGM) supplemented as a protein source during a grazing period; or (3) NG, no grazing, in which steers were fed hay and GSBM concentrate only. The estimated rumen undegradable protein (RUP) concentration of CGM was higher than that of SBM. High RUP supplementation during the grazing period did not influence feed intake or growth performance. Compared with the NG treatment, the average daily gain in GSBM and GCGM calves was significantly depressed (P < 0.05). Bodyweight/withers height ratio in the NG calves tended to be greater than in the GSBM and GCGM calves. Final paunch girth/heart girth ratio in the GSBM and GCGM calves was significantly greater (P < 0.05) than in the NG calves. Supplementation with CGM did not influence ruminal ammonia nitrogen and blood constituents. These results indicate that CGM supplementation during the grazing period did not enhance the growth of Wagyu calves because the CGM diet probably did not elevate the metabolizable protein supply to the grazing calves above that of the SBM diet in our conditions.     

Effect of posttransportation grazing on the physiological condition and meat quality traits of Black Bengal goats

This study was designed to reveal the role of posttransportation grazing on the physiological condition and meat quality traits of Black Bengal goats. Twenty‐four castrated male Black Bengal goats were divided into a control (untransported) group and three treated groups: Walking and Transportation with Human Interference group (WTHI) (30 min walking before 6 hr transport and then 30 min walking with human interference), posttransportation grazing for 48 hr (PTG1), and posttransportation grazing for 72 hr (PTG2). The WTHI and PTG1 groups had a significant reduction in their blood concentrations of tri‐iodothyronine (T₃) and thyroxine (T₄), and a significantly higher neutrophil and lymphocyte (N:L) ratio compared with those of the control group. Blood concentrations of T₃ and T₄ and the N:L ratio of PTG2 returned to the control level after 72 hr of grazing. The final pH and water‐holding capacity values of meat were significantly higher in the WTHI group than in the control group, but those in the PTG2 group returned to the control level after 72 hr of grazing. These results demonstrate that posttransportation grazing for 72 hr is effective for recovering from damage induced by transportation stress.     

长期放牧下不同家畜对高寒灌丛饲草生物量和品质的影响

于2020年7-8月在东祁连山天祝高寒地区测定了放牧甘肃马鹿(Cervus elaphus kansuensis)、混牧牦牛(Bos grunniens)和藏羊(Ovis aries)34年的灌丛草地的饲草生物量和营养品质,以期为高寒灌丛草地放牧管理提供科学依据。结果表明：马鹿样地的饲用草本总生物量为1 423.78 kg/hm²,灌木总生物量为107 789.72 kg/hm2,灌木总生物量为107 789.72 kg/hm²,而混牧牦牛和藏羊样地的饲用草本总生物量为342.63 kg/hm2,而混牧牦牛和藏羊样地的饲用草本总生物量为342.63 kg/hm²,灌木的总生物量为176 279.54 kg/hm2,灌木的总生物量为176 279.54 kg/hm²;放牧马鹿样地中饲用草本的可溶性糖、酸性洗涤纤维和中性洗涤纤维分别为8.12%、36.70%和52.71%,均显著高于混牧牦牛和藏羊样地(P<0.05),分别高46.31%、6.53%和10.98%;杯腺柳(Salix cupularis)叶片的中性洗涤纤维含量、小叶金露梅(Potentilla fruticose)叶片的酸性洗涤纤维含量、小叶金露梅枝条和高山绣线菊(Spiraea alpine)叶片的相对饲喂价值分别为58.96%、51.31%、41.48%和76.94%,均显著高于混牧牦牛和藏羊样地(P<0.05),但高山绣线菊枝条的粗蛋白、高山绣线菊叶片的中性洗涤纤维、小叶金露梅枝条的酸性洗涤纤维和中性洗涤纤维以及杯腺柳叶片、小叶金露梅叶片和饲用草本的相对饲喂价值相反;放牧马鹿样地饲用草本的30小时中性洗涤纤维消化率、体外30、48 h干物质的消化率均显著低于牦牛和藏羊样地(P<0.05),分别低12.22%、12.42%和5.20%,其余指标均无显著性差异。综上所述,长期放牧马鹿有利于提高草地生产性能。