Horse Preference,Forage Yield,and Species Persistence of 12 Perennial Cool-Season Grass Mixtures Under Horse Grazing

Cool-season grass mixtures are rarely evaluated for preference, yield, and persistence under horse grazing. The objectives of this research were to evaluate horse preference, forage yield, and persistence of cool-season grass mixtures under horse grazing. Eight commercially marketed and four experimental perennial cool-season grass mixtures were planted in 2009 in a randomized complete block with five replicates and grazed by four adult horses during 2010, 2011, and 2012. All mixtures contained four to six cool-season perennial grass species. Specie density measurements were taken in each spring and fall, and yield was mechanically measured before each grazing period. After grazing, preference was determined by visually assessing percentage of forage removal on a scale of 0 (no grazing) to 100 (100% of vegetation removed). Data were analyzed using a mixed-model analysis of variance and liner regression. Horses preferred mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy (P < .001). Horses had less preference for mixtures containing ≥30% orchardgrass (P < .001). Mixtures had similar (P = .11) forage yields that ranged from 6,100 to 7,082 kg ha⁻¹. After 2 years of grazing, orchardgrass and tall fescue increased; Kentucky bluegrass remained stable; and festulolium, meadow fescue, and perennial ryegrass had the greatest rate of decline in mixtures. Orchardgrass became the dominate species, regardless of initial percentage in the mixture. Mixtures containing tall fescue, perennial ryegrass, Kentucky bluegrass, and timothy should be planted in midwestern US horse pastures; however, mixtures will likely transition to tall fescue and Kentucky bluegrass–dominated pastures.     

Determination of Pasture Dry Matter Intake Rates in Different Seasons and Their Application in Grazing Management

Eight mature horses weighing 576 ± 32 kg (mean ± SD) were used to compare differences in pasture dry matter (DM) intake rate in October (period 1), February (period 2), and May (period 3). Horses were randomly assigned to a pair of adjacent 5 m × 5 m grazing cells containing nontoxic, endophyte-infected tall fescue. Horses had access to each cell for 4 hours. Pasture DM intake rate was estimated over the entire 8-hour period by measuring the pre- and postgrazing herbage mass within each cell and was expressed as kg DM/100 kg body weight (BW)/hr. Mean 8-hour DM intake rate in period 1 (0.17 ± 0.01 kg DM/100 kg BW/hr) was greater (P < .001) than for period 2 (0.09 ± 0.01 kg DM/100 kg BW/hr) and period 3 (0.11 ± 0.01 kg DM/100 kg BW/hr), but it was not different (P = .274) between periods 2 and 3. A second experiment using the same eight horses was conducted immediately after the first experiment, within each season, to determine whether the DM intake rates derived from the first experiment could be used along with estimates of maintenance digestible energy (DE) requirements and pasture DE concentrations to predict the amount of grazing time required for a horse to consume only its maintenance DE requirement and maintain zero BW change over a 6-week period. Grazing time necessary to maintain zero BW change was accurately predicted for period 1 only.     

铜尾矿对五种牧草生长情况的影响

通过盆栽实验,分析了铜尾矿对五种牧草生长发育和重金属抗性的影响。结果表明,百喜草、狗牙根、苇状羊茅能在铜尾矿上正常生长,实验草种的优劣势比较结果依次为:百喜草1.00>狗牙根0.98>苇状羊茅0.85>黑麦草0.73>苏丹草0.55。百喜草、狗牙根、苇状羊茅被认为是铜尾矿植被恢复与重建的优良先锋草种,并具有较强的重金属抗性。     

放牧绵羊牧食行为及采食量研究

在锡林郭勒草原对三种放牧绵羊(蒙古羊、引种羊、杂种羊)进行不同月份的牧食行为观察及采食量测定,结果表明:放牧绵羊9月份的采食时间比例均高于8月份;沙质草地放牧绵羊的采食和游走时间比例低于高平原草地;蒙古羊、引种羊和杂种羊沙质草地的平均采食量分别为1.15kg/d、1.60kg/d和1.35kg/d,高平原草地为1.56kg/d、1.82kg/d和1.71kg/d,分别相差0.41kg/d、0.22kg/d和0.36kg/d。     

牧草组织培养研究进展

总结了组织培养在牧草上的研究进展,分别从愈伤组织培养、花药离体培养、悬浮细胞培养、原生质体培养、茎尖培养以及胚胎培养等方面进行了讨论,概述了影响牧草组培的几种因素,分析和归纳了该领域研究出现的问题及发展趋势。     

不同种牧草的产量和品质

在中国科学院海北高寒草甸定位站以一年生黑麦草(Lolium perenne)、小黑麦(Triticale hexaploide)、燕麦(Avena sativa)和垂穗披碱草(Elymus nutans)为研究对象,对其产草量、牧草营养品质进行测定,以探讨不同牧草的产量和品质。结果表明:小黑麦干草产量为1345.50 g·m^-2,显著高于一年生黑麦草(974.93 g·m^-2)、垂穗披碱草(301.75 g·m^-2)和燕麦(329.60 g·m^-2)。小黑麦产量是垂穗披碱草和燕麦干草产量的4~4.5倍,是黑麦草干草产量的1.4倍。垂穗披碱草粗蛋白(CP)含量显著高于一年生黑麦草和小黑麦(P<0.05),一年生黑麦草粗蛋白(CP)含量最小。单位面积粗蛋白(CP)产量、粗脂肪(EE)产量、中性洗涤纤维(NDF)产量和酸性洗涤纤维(ADF)产量以一年生黑麦草最高,显著高于小黑麦、垂穗披碱草和燕麦(P<0.05)。     

A Review of Equine Grazing Research Methodologies

Recently, there has been a renewed interest and an increase in published research on equine grazing and pasture management. The objectives of this paper are to review equine grazing research methodologies with an aim to encourage standardized research procedures. This review highlights standard methods used in equine pasture-related research, including use of climate data and soil type; seed bed preparation and grazing management; determining forage nutritive value; defining forage maturity; tracking horse health parameters; evaluating different grazing systems; and future technologies. This review covers in-depth discussions on determining forage biomass yield, forage populations, ground cover, persistence, forage intake, and grazing behavior. Specifically, mechanical harvesting, hand clipping, rising plate meter, and falling plate meter are all methods used to determine forage biomass yield. Frequency grid, point sampling, visual assessment, Natural Resources Conservation Service pasture condition score, and the double Dominant, Abundant, Frequent, Occasional, Rare (DAFOR) scale can be used to track forage populations, ground cover, and persistence of pasture species. Three primary methods have been used when estimating horse forage intake including the difference between pre- and postgrazing herbage mass, the difference in pre- and postgrazing bodyweight, and use of digestibility and fecal output markers. Equine grazing behavior has been described by investigating preference, pre- and post-sward height, and bite and mastication rate. Awareness of key methodologies should encourage movement toward research protocol standardization that will allow for scientific comparisons and application of pasture-related research results across the horse industry.     

牧草的营养价值研究及其在反刍家畜中的应用

根据牧草的基本营养价值特性,综合了近年来人们对反刍家畜利用牧草及提高牧草营养价值的生物学研究成果。     

甘南玛曲不同年龄欧拉型藏羊放牧采食量季节动态研究

为确立高寒地区天然草地欧拉型藏羊放牧采食量的季节动态变化,本试验采用TiO₂外源指示剂法和瘤胃尼龙袋法分别测定欧拉型藏羊不同季节排粪量和牧草消化率从而计算放牧采食量。结果表明:玛曲高寒草地牧草干物质消化率(DMD)和粗蛋白(CP)含量夏季显著(P < 0.05)高于冬春季与秋季;欧拉型藏羊各年龄段排粪量3季差异显著(P < 0.05)且秋季 > 夏季 > 冬春季;随着年龄增长,欧拉型藏羊三季牧草采食量均有增大的趋势,同年龄段不同季节的藏羊采食量和代谢采食量(除4岁母羊)差异显著(P < 0.05)且秋季 > 夏季 > 冬春季;各年龄段藏羊累计牧草消耗量(AFC)差异显著(P < 0.05)分别为339.37,757.58,1185.93和1655.61 kg。由此可见,牧草干机物质消化率、排粪量和采食量夏秋季较高、冬春季较低,随着年龄增大排粪量和采食量有增高的趋势。因此,在高寒牧区应提倡草地季节性畜牧业,充分考虑牧草营养与动物营养需求之间的耦合性来提高经济和生态效益。     

内蒙古细毛羊日食量及对典型草原牧草的选食性测定

家畜对牧草的选食系数及基季节变化是草场评价和放牧决策的基础,家的采食量是评估草平衡的基本参数,在内蒙古典型草原区,对内蒙古细毛羊日食量与牧草无穷生测定表明,其日采食胆整个生长季平均为２．０６ｋｇ干物质,其季节动态为春季低,夏季高,秋季居中,在所研究草场上选食羊草、扁蓿豆、双齿葱、木地肤和糙隐子草等,而避弃大针茅、寸草 和星毛委陵菜等,为合理放牧提供了依据。     

Effect of Yeast Culture Supplementation on Digestibility of Varying Forage Quality in Mature Horses

Supplementation of yeast culture to equine diets has improved digestion of nutrients in some studies but not others. Improving the digestibility of lower-quality forages could be advantageous both for the producer and for the horse's health. The objective of this study was to evaluate the effect of yeast culture on digestibility of high- and low-quality forage in mature horses. Sixteen geldings (483.6 ± 25.5 kg and 6.8 ± 3.2 years), of Quarter Horse (n = 14) and Thoroughbred (n = 2) breeding, were used in a 4 × 4 Latin square design with 28-day treatment periods. Russell Bermuda grass hay of either high (13.1% crude protein (CP), 73.1% neutral detergent fiber (NDF), 35.3% acid detergent fiber (ADF), and 6.0% ash) or low (8.1% CP, 75.3% NDF, 37.6% ADF, and 4.3% ash) quality was offered at 1.35% of body weight (BW, dry matter [DM] basis). Diets consisted of high-quality forage with the addition of yeast culture (HY), high-quality forage without yeast culture (HC), low-quality forage with the addition of yeast culture (LY), and low-quality forage without yeast culture (LC). All horses were fed a commercial grain mix (12.6% CP, 25.4% NDF, 12.1% ADF, and 4.0% ash) offered at 0.45% of BW (DM basis) daily. Yeast culture was added to the grain mix during the morning feeding at a rate of 56 g per horse. Body weight was measured weekly and feed intake was adjusted accordingly. Fecal samples were obtained every 6 hours on the last 3 days of each treatment period. Horses receiving low-quality hay (LY and LC) had greater (P < .01) intake expressed as a percentage of BW compared with horses receiving high-quality hay (HY and HC). No influence of yeast culture supplementation was seen on intake of grain or forage (P < .23 and P < .62, respectively). Digestibility of DM, organic matter (OM), CP, and NDF were greater (P < .01, P < .01, P < .01, and P < .01, respectively) for the diets with high-quality forage compared with the diets with low-quality forage. Dry matter, CP, and NDF digestibilities were greater (P < .09, P < .03, and P < .05, respectively) for horses receiving LY compared with LC. Supplementation of yeast culture to mature horses improved digestibility of lower-quality Bermuda grass hay.     

放牧绵羊对恢复阶段退化草场营养物质含量的影响

选取内蒙古自治区克什克腾旗达来诺日镇典型草原区封育恢复中天然放牧草场,于2008年6～10月进行毛肉兼用细毛羊的暖季放牧试验.采用2×5完全随机试验设计,设定不同放牧方式(不放牧,连续放牧,四区、五区、六区轮牧)及2种放牧强度,研究围封过程中放牧绵羊对封育草场牧草营养物质含量的影响.结果表明,不放牧区牧草初水分、粗蛋白质、粗脂肪和粗灰分含量显著高于轮牧和连续放牧区,酸性洗涤纤维和中性洗涤纤维含量显著低于放牧区;随着放牧季节的延续,不放牧区牧草营养价值下降速度最慢,轮牧区次之,连续放牧处理下降最明显;四区、五区和六区轮牧处理间牧草营养物质含量变化差异不显著.放牧方式与放牧强度对草场营养物质含量动态变化表现出不同程度的瓦作效应.因此,在放牧强度适中时,划区轮牧能够体现其优越性,随着牧草生长季的延续,较好地保存牧草的营养价值.     

Effect of Sward Height on Pasture Nonstructural Carbohydrate Concentrations and Blood Glucose/Insulin Profiles in Grazing Horses

Six mature stock-type geldings with maintenance only requirements were used in a randomized cross-over design to determine the effect of sward height on pasture plant nonstructural carbohydrate (NSC) concentrations and blood glucose and insulin concentrations. Horses were randomly assigned to one of two tall fescue (Lolium arundinaceum Schreb cv Max-Q, Pennington Seed, Madison, GA) grazing cells (0.37 ha) having two different sward heights for a period of 7 days: (1) short (approximately 15 cm; n = 3) or tall (between 30 and 40 cm; n = 3). After the first 7-day period, treatment groups were reversed by moving horses to ungrazed cells having similar characteristics to those used in the first 7 days, so that all horses receive all treatments resulting in six observations per treatment. Both short and tall grazing cells were mowed to a height of approximately 15 cm 32 days before the experiment starts. The short grazing cells were removed to approximately 15 cm at 11 days before the start of the first 7-day period and again 1 day before the start of each 7-day period. All horses had access to pasture for 10 h/d beginning at 8 AM and ending at 6 PM. Although not at pasture, all horses were individually housed in 3.7 × 12.2 m partially covered pens containing automatic water troughs and a crushed stone surface. Herbage mass (kg DM/ha) was determined by use of a falling plate meter for each pasture to ensure that both groups of horses had adequate dry matter to provide grazing for at least 7 days. On day 7 of each period, jugular venous blood samples were collected from each horse before being turned out to pasture, and then at 2, 4, 6, and 8 hours after turn-out. Pasture samples were also collected from each grazing cell at the same time blood samples were taken. Serum and plasma from blood samples were harvested and analyzed for insulin and glucose concentrations, respectively. Pasture samples were analyzed for water soluble carbohydrate (WSC), ethanol soluble carbohydrate (ESC), and starch. The sum of WSC and starch were used as an estimate of NSC. Area under the curve (AUC) and peak concentration were calculated for both plasma glucose (PPG) and serum insulin (PSI) concentration and were analyzed using analysis of variance for randomized cross-over designs. Pasture WSC, ESC, starch, and NSC concentrations were analyzed using analysis of variance for randomized complete block design. A P value of < .05 was considered significant. Mean pasture plant NSC, WSC, and ESC concentrations were lower (P < .001) in short as compared with tall. Pasture plant starch concentration was not different between treatments. Mean pregrazing plasma glucose concentrations, PPG concentrations, and plasma glucose AUC were not affected by treatment. Mean pregrazing serum insulin concentrations were not affected by treatment. Mean PSI and insulin AUC were greater (P < .01) when horses grazed tall, as compared with short. In conclusion, decreasing the sward height by mowing pasture decreased NSC, WSC, and ESC concentrations and subsequently decreased the postprandial insulin response of horses grazing the pasture. These findings may be important in developing strategies aimed at preventing insulin resistance in grazing horses.     

Nitrate Poisoning in Horses Associated With Ingestion of Forage and Alfalfa

This report describes nitrate poisoning observed in thoroughbred mares. Nine horses died at a farm in Bursa, Turkey, between February and April of 2008. Five of them were pregnant. Clinical findings developed over a short period and included severe abdominal pain, limited response to analgesics and antispasmodics, diarrhea, shallow and rapid breathing, tachycardia, blue-brown discoloration of the mucosal membranes, tremors, ataxia, convulsions before death, and abortion in the pregnant mares. The main postmortem finding was chocolate brown–colored blood as well as congestion and inflammation of the intra-abdominal organs. Uterine rupture, colonic ruptures, and torsio uteri were seen in the pregnant mares. Stomach and intestinal ruptures were seen in four nonpregnant mares. High nitrate concentrations were determined in some grass and alfalfa samples used to feed the animals. Nitrate poisoning is considered to be very rare in horses, but, in this case, the clinical symptoms, postmortem findings, and nitrate levels in the collected samples supported nitrate and nitrite poisoning as the cause of deaths.     

牧草叶片的叶绿素含量与牧草耐盐性的关系

测定了九种牧草在人工控制不同含盐量的盆栽土壤中生长至拔节期的叶片叶绿素含量,总趋势是叶绿素含量随着土壤盐份增加而降低;在同一盐份条件下,较耐盐的种比不耐盐的种叶绿素含量高。     

浅谈宁夏半干旱地区牧草产业的可持续发展

在农业产业结构的调整进程中,草业得到了迅速发展,成为农村经济新的增长点。针对宁夏半干旱地区牧草产业发展中存在的问题,提出了可持续发展的对策。     

划区轮牧与草地可持续性利用的研究进展

划区轮牧是一种充分利用饲草生长旺季而进行的集约、区块式放牧管理系统。本文总结了近年来国内外轮牧制度的发展现状,概括了划区轮牧的优势包括:提高草地生态系统的功能性、草地生产力;降低草食动物肠胃线虫感染率;分析了其与传统连续放牧相比所具有的局限性。进一步从放牧类型的延展、放牧策略的改进、人为因素的投入、生态模型研究等多角度综合考究,提出综合协调生物因素与环境、平衡生态与经济以及优化牧企合作现状的轮牧策略,以期为轮牧对于生态恢复和草地可持续性利用的生产实践应用提供科学依据和优化管理的决策参考。     

青海海南不同季节牧场放牧绵羊采食量与消化率的研究

将模拟采集牧草标样法、全收粪法和两级离体消化相结合,测定放牧绵羊的牧草采食量和消化率。研究结果显示:冬春季、夏季和秋季绵羊的放牧采食量分别为462.16g/d±88.21g/d、1544.76g/d±263.02g/d、954.59g/d±179.51g/d,三季间差异极显著(P<0.01);牧草干物质消化率分别为49.91%±9.25%、53.07%±1.33%、52.57%±2.85%,三季间差异不显著(P>0.05)。     

放牧对温性荒漠草原植物群落特征与牧草营养品质的影响

为研究放牧对温性荒漠草原植物群落特征和牧草营养品质的影响,本文研究了放牧和围封对温性荒漠草原植物群落特征、牧草营养品质的影响及其相互关系。结果表明：放牧显著降低了植物群落的高度、盖度和生物量,显著增加了物种丰富度指数（P<0.01）;放牧显著增加牧草粗蛋白（Crude protein,CP）、粗脂肪（Crude fat,CF）、消化率（Dry matter digestibility,DMD）和代谢能（Metabolic energy,ME）,显著降低了牧草的中性洗涤纤维（Neutral detergent fibers,NDF）和酸性洗涤纤维（Acid detergent fibers,ADF）（P<0.01）;群落多样性指数与牧草CP,CF,DMD和ME呈显著正相关（P<0.01）,与牧草NDF和ADF呈显著负相关（P<0.01）;牧草CP,CF,DMD和ME与NDF和ADF呈显著负相关（P<0.01）。总之,放牧处理显著增加了物种丰富度指数和牧草营养品质。建议对围封温性荒漠草原进行适度放牧,以充分利用草地资源,保护草地物种多样性。