海南黑山羊生长期的能量与蛋白质需要量

试验选用12只海南黑山羊断奶羔羊（约4月龄）,采用饲养试验和消化代谢试验,研究生长期海南黑山羊的能量和蛋白质需要量及其代谢规律。试验羊分成4组,采用4×4拉丁方设计。按照Keral（1982）适宜于发展中国家的山羊饲养标准为参考设计了高能高氮、低能高氮、高能低氮、低能低氮4种能氮比的日粮。结果表明：舍饲海南黑山羊生长期干物质采食量与代谢体重和日增重的关系为DMI（g/d）=27.18W^0.75＋0.83△W＋210.76（r=0.8916）;总能、消化能、粗蛋白质和可消化蛋白质需要量的估测模型分别为GEI（MJ/d）=0.82W0.75＋0.028△W＋3.76（r=0.7804）,DEI（MJ/d）=0.59W^0.75＋0.021△W-0.24（r=0.6651）,CPI（g/d）=2.45W^0.75＋0.26△W＋22.14（r=0.5712）,DCP（g/d）=2.69W^0.75＋0.03△W-0.38（r=0.6605）;生长期海南黑山羊日粮总能代谢率平均为58.88%,粗蛋白的消化率平均为57.08%,净蛋白利用率平均为35.25%,每增重1g体沉积蛋白质需要量为0.37g。     

波尔山羊杂交改良海南黑山羊生长性能研究初报

测定并比较波尔山羊与海南黑山羊的杂种F1、F2代及海南黑山羊的0（初生）,2,4,6,8,10,12（周岁）月龄的体重、体高、体斜长、胸深、胸宽、胸围、腰角宽等体尺指标。结果表明：相应年龄的波黑F1、F2代羊的体重明显高于海南黑山羊,初生至周岁各生长测定阶段F1、F2代羊体重较海南黑山羊分别增加了6．25％。73．68％．15．34％～90．55％,杂交效果极其显著;海南黑山羊只有0～2月龄平均日增重指标处于较高水平,之后生长速度基本处于下降状态,而波黑F1、F2代的0．2月龄平均日增重指标处于更高水平。并具有2-4月龄和8-10月龄2个体重增长高峰期;0-4月龄和8-10月龄为波黑F1、F2的2个快速生长阶段,0．2月龄为海南黑山羊的快速生长阶段,此时期应加强饲养管理以充分发挥其生长性能,提高养羊业的经济效益;波黑F1、F2代胸宽和腰角宽明显大于海南黑山羊,有向其父本体型发展的趋势．具有典型的肉羊体型。研究结果能为海南黑山羊的合理开发利用及杂交育种提供理论基础和科学依据．     

大豆凝集素处理对肉仔鸡生长性能及小肠发育的影响

选用1日龄健康艾维茵肉仔鸡,从7日龄开始,分别进行饲喂基础日粮(对照组)和基础日粮添加大豆凝集素处理,以研究不同大豆凝集素添加水平对肉仔鸡生长性能、小肠发育的影响。结果表明:日粮中添加不同水平的大豆凝集素显著降低了肉仔鸡的平均日采食量(P0.05);0.05%和0.10%大豆凝集素添加组肉仔鸡的平均日增重、绝对增重和相对增重无显著影响(P0.05);肉仔鸡小肠长度和重量随着日粮中大豆凝集素添加水平的升高而呈线性增加,日粮中添加0.10%大豆凝集素显著增加了肉仔鸡的小肠长度及重量。研究结果提示,日粮中添加不同水平大豆凝集素,影响了肉仔鸡生长性能和小肠发育,对动物产生了抗营养作用。     

生长期海南黑山羊屠宰性能研究

选用12只海南黑山羊断奶羔羊(约4月龄),在舍饲条件下补充精料粗蛋白10.17 %,代谢能9.89 MJ/kg,饲养90 d后屠宰,测定海南黑山羊屠宰性能和肉品质。经测定,宰前活重、胴体重、净肉重、屠宰率和净肉率分别是21.5 kg、10.14 kg、7.13 kg、47.07 %、33.14 %。试验结果表明,生长期海南黑山羊具有较高的屠宰率和良好的产肉性能,肉质的各项指标均在正常范围内。     

世界天然橡胶主产国近期生产情况综述

用4种胶园土壤进行温室盆栽试验,研究4种土壤条件下不同施氮水平对橡胶苗根系生长的影响。结果表明：在不同母质土壤不同氮水平下,橡胶苗根系适应性存在着显著差异。在一定施氮量(≤30g/盆)条件下,侧根长度、表面积、直径、体积与干重随施氮量增加显著增加;高氮(60g/盆)条件下,侧根长度减少,根系变短变细,根重降低。这说明,在低氮条件下能刺激根系的生长发育,高氮条件抑制根系的大量发生。     

应用体外产气法研究3种农业废弃物对黑山羊的饲用价值

为了测定甘蔗尾叶、香蕉茎秆、菠萝叶3种热带农业废弃物对海南黑山羊的饲用价值,采用体外产气法测定3种热带农业废弃物的体外干物质消化率和产气量,并测定其营养成分和单宁含量.结果表明:甘蔗尾叶、香蕉茎秆、菠萝叶的体外于物质消化率(IVDMD)依次为49.68％、61.86％和79.56％,饲料相对值(RFV)依次为62.65％、77.23％和139.81％.总产气量(GP)、IVDMD与粗蛋白质(CP)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)均呈负相关,RFV与CP和总能量(GE)呈不显著正相关,而与ADF和NDF呈显著负相关(p＜0.05).综上所述,甘蔗尾叶、香蕉茎秆、菠萝叶对于海南黑山羊均具有一定的饲用价值,可作为黑山羊的粗饲料;在3种废弃物中,菠萝叶的饲用价值最高.     

氮肥对甜菜营养生长的影响

分析看出,施氮量与甜菜4个营养生长期的根、叶片、叶柄生长量均呈极显著正相关。苗期氮素主要用于促进叶片的生长,随生育进程根对氮素的依赖程度渐高;苗期、块根糖分增长期、糖分积累期不同氮素水平与T/R值呈显著正相关,与分配率呈显著负相关;叶丛快速生长期施氮量对T/P值、分配率无大影响;不同施氮量与叶面积、光合势呈显著正相关。     

稻种资源苗期氮素营养特性的基因型差异

 采用变异数和频数分析，对88份稻种资源进行了苗期氮素利用效率(NUE)、吸收效率(NAE)和氮素利用效率响应度(NUER)的基因型差异比较。结果表明： 1)不同稻种资源苗期的NUE、NAE和NUER存在显著的基因型差异，且受氮素水平的影响。低氮、中氮和高氮间的NUE存在极显著差异，并随氮素水平的升高而呈下降趋势。低、中氮间的NAE的差异不显著，但极显著地小于高氮；(低氮NUE-高氮NUE )/ 高氮NUE的NUER极显著高于(低氮NUE -中氮NUE)/ 中氮NUE、(中氮NUE -高氮NUE)/ 高氮NUE的NUER，且后两者间未达显著差异。 2)不同稻种资源苗期NUE、NAE和NUER的变异系数存在极大的差别(达20%以上)，大小顺序为NUER>NAE>NUE，即稻种资源苗期NUE、NAE和NUER的基因型差异大小是NUER>NAE>NUE。 3)不同稻种资源苗期NUE、NAE和NUER的基因型分布，基本上符合正态分布，拟合度最好的是NUE，其次为NAE，NUER最差。     

施氮量对不同氮效率冬小麦品种苗期生长的影响

为了研究施氮量对不同氮效率冬小麦品种苗期生长及其生理特性的影响,通过水培试验,选用小偃128(氮低效低响应型)、陕农78(氮低效高响应型)、西农2208(氮高效低响应型)和小偃503(氮高效高响应型)等4个不同氮效率的冬小麦品种,以氮水平和品种基因型分别为主、副处理,测定了苗期生长过程中叶片叶绿素含量(SPAD值)、光合特性和硝酸还原酶活性(NRA)等生理指标及地上、地下干物质量和含氮量。结果表明,苗期不同氮效率基因型小麦叶片SPAD值、NRA和光合速率及植株含氮量在一定施氮范围内随着施氮量的增加而增加,且施氮处理较不施氮处理均有显著增加,而同一施氮处理不同基因型品种间差异不大。     

日粮能量和蛋白水平对瘦肉型生长育肥猪生长性能的影响

选取60±1.5 kg、90.0±1.5 kg杜长大(D×L×Y)生长育肥猪48头(公母比例为1∶1),通过对平均采食量(ADFI)、平均日增重(ADG)和料重比(F/G)进行比较分析,考察蛋白和能量水平对其生长性能的影响。结果表明:日粮能量和蛋白水平对60～90 kg瘦肉型生长育肥猪ADG、ADFI和F/G均有显著影响(P<0.05);日粮能量和蛋白水平对90～120 kg生长育肥猪ADG的影响不显著(P>0.05),对ADFI、F/G影响显著(P<0.05)。60～90 kg、90～120kg阶段杜长大生长育肥猪适宜的能量和蛋白水平分别为13.90 MJ.kg-1、15.90%和14.62 MJ.kg-1、14.90%;多元回归分析得到90～120 kg瘦肉型生长育肥猪DEI、CPI与ADG的回归方程为:ΔW=-12.772DEI+23.467CPI+351.156(R2=0.881,P<0.05)。     

Seasonal changes in feed intake,diet digestibility and diet composition by lactating and non‐lactating goats browsing in a semi‐arid rangeland of Argentina

We determined the seasonal nutrient and secondary compound intake, in vivo diet digestibility (DD) and diet species composition of goats in different physiological states in a desert rangeland of Argentina. During the wet and the dry seasons, 24 mature female Creole goats (six non‐lactating, non‐pregnant and six lactating in each season) were used in a 2 × 2 factorial design. Diet botanical composition, DD and dry‐matter intake (DMI) were estimated by the combined use of visual observation, microhistological analyses of faecal samples and n‐alkane technique. Browse species dominated the goats’ diets (>80%) in both seasons and physiological states, with a twofold increase in the proportion of forbs during the wet season (p < 0.10). Lactating goats showed greater DMI than non‐lactating animals, and they also displayed greater intakes of some tanniferous (Mimosa ephedroides) and high‐protein (Atriplex lampa) shrubs (p < 0.10). Lactating and non‐lactating goats selected diets with adequate crude protein (CP) and fibre content but insufficient energy, although lactating goats tended to increase energy and tannin content in their diets (p < 0.20). Physiological state did not influence DD, but digestibility was greater (p < 0.10) in the wet season, attributed to the greater protein content and lower tannin content of the diet. These results have important implications for managerial interventions on traditional goat production systems in the study area aiming at enhancing goat nutrition and welfare, as well as the sustainability of rangeland resources in the region.     

海南西南部芒果营养特性的研究

调查结果表明,海南西南部3个芒果栽培品种(鸡蛋芒Dashehari、青皮Okrong、白象牙NangKlangwan)树体营养生长需氮量多,其次是钾和钙,果实生长需钾多,其次是氮;不同物候期芒果叶片养分含量存在着显著差异;不同芒果品种间养分含量存在着显著差异;鸡蛋芒果实养分积累模式为单S型,可分为3个阶段;海南西南部鸡蛋芒高产区与低产区叶片养分含量存在着显著差异,养分不足,特别是氮素不足限制了芒果产量的提高。      

Susceptibility of Sudanese Nubian goats, Nilotic dwarf goats and Garag ewes to experimental infection with a mechanically transmitted Trypanosoma vivax stock

The present study was conducted to study the susceptibility of two different types of Sudanese goats namely: Black Nubian, the Nilotic dwarf goats and ewes of Garag type to experimental infection with Trypanosoma vivax stock isolated from cattle outside tsetse area. The infection caused parasitaemia, anaemia and pyrexia in the infected goats. However, the Nilotic dwarf goats were more tolerant to the infection than the Nubian goats, showing significantly higher values of packed cell volume, haemoglobin concentration, total red and white blood cells counts and significantly low parasitaemia and low body temperature. Garag ewes which were found to be susceptible to T. vivax infection showed different signs of anaemia and pyrexia; it is recommended that comparative studies on sensitivity of this type and other different Sudanese types of sheep to Trypanosomosis should be conducted.     

Protein and energy utilization of boiled rice-legume diets and boiled cereals in growing rats

In growing rats, boiled milled rice-legume diets (2:1 N ratio) had lower energy digestigibility than boiled milled rice and equal if not better true digestibility, biological value, and net protein utilization (NPU). Rice-soybean diets showed better NPU than the other rice-legume diets. Boiled whole-grain corn and sorghum had lower digstible energy and NPU than boiled milled rice. NPU of the diets did not follow strictly the trend of the amino acid score of the diets; phenol (tannin) content reduced energy and protein digestibility of all diets, but sugars reduced energy and protein digestibilities of rice-legume diets only.     

The effects of concentrate energy source and protein content on milk production in cows given grass silage ad libitum

Sixteen Friesian cows were given four dietary treatments in a 4 × 4 Latin square experiment with a 2 × 2 factorial arrangement of treatments. The diets consisted of grass silage ad libitum plus 2 kg of hay per day and two types of concentrates of either barley or a mixture of barley, oats and fibrous by-products [200,200 and 600 g per kg dry matter (DM) respectively], with two protein contents. For the low-protein diets, barley- (B) and fibre-based (F) concentrates were given without protein supplements, while for high-protein diets 1 kg of both concentrates was replaced with fish-meal (FM). The concentrates were given at the rate of 9kgd^-1 for the cows (n= 12) and 8kg d^-1 for the heifers (n= 4). The cows given the F diets tended (P < 0·10) to have a greater silage dry matter intake and produced 1·5kg d^-1 more (P < 0·05) milk with a lower (P < 0·05) protein content than those given the B diets. Increasing dietary crude protein concentration with FM had no effect on feed intake but resulted in significant increases in milk yield (P < 0·01), milk protein content (P < 0·05) and yields of milk constituents. The response in milk yield to FM tended to be greater with barley than with fibrous supplement (+2·5 vs+ 1·5kgd^-1). Compared with B diets, the greatest relative increase occurred in lactose yield (0·07) when the corresponding F diets were fed, while FM produced the greatest response in protein yield (0·12). The calculation of the utilization of metabolizable energy (ME) for milk production showed that both the feeding of a concentrate consisting of different carbohydrate sources and inclusion of fish meal improved the utilization of ME, the effects being partially additive. It is concluded that the nutrient supply to the cow's tissues can be modified by the source of carbohydrate and protein supplementation as indicated by different responses in the yield of milk constituents. The production response to protein supplementation may depend on the source of carbohydrate in the concentrate.     

The effect of drying and processing red clover on the digestion of the energy and nitrogen moieties in the alimentary tract of sheep

The effect of artificial dehydration and processing of red clover on nutrient digestion and absorption has been studied with sheep. A total of three diets were fed, each at an intake of 900 g DM d^-1; comprising frozen (to represent fresh control), wafered and pelleted red clover.
Dehydration caused small depressions in energy and N digestibility. Grinding and pelleting had no further effect, although both treatments reduced the amount of energy digestion occurring in the rumen, frozen 63, dried 60, pelleted 48 MJ per 100 MJ digestible energy. Digestion of energy in the caecum and colon was increased on both dried diets, and in the small intestine on the pelleted diet.
Almost 40% of the extra duodenal energy on the pelleted diet was due to increased cellulose flow, with only 79% of digestible cellulose being digested in the rumen compared with 96% on the other two diets. There was an associated decrease in ruminal volatile fatty acid production of approx. 20%. Approximately half of the extra energy was due to an elevated flow of protein on the pelleted diet, but this increase was not reflected in amino acid absorption due to a reduced efficiency with the dried diets (frozen 72%, dried diets 54%).
The results demonstrate that dehydration and processing of red clover can markedly influence nutrient digestion and supply and thus offer attractive means of improving the nutritive value.     

The influence of milling on the nutritive value of flour from cereal grains. 6. Sorghum

Low-tannin sorghum was milled into flour with extraction rates between 100 and 64%. The nutritive value of the flours was studied by chemical analyses and in balance experiments with growing rats. The effects of amino acid supplementation was also examined. In general, the content of essential nutrients decreased when the extraction rate was lowered, but the content of fibre, tannins and phytate was also significantly reduced by milling. The digestibility of energy as well as protein was high, but the protein quality was poor, especially in flours of low extraction. Amino acid supplementation improved protein utilization and weight gain considerably. Femur zinc concentration was significantly depressed in the rats fed the amino acid supplemented diets, and sorghum seems to be a poor source of available zinc, in particular when it is highly refined. The poor zinc availability may be attributed to the high content of phytate.