Evaluation of the Genetic Relationship between Longevity and Growth, Milk Yield and Fertility Traits in the Sahiwal Breed in Kenya

Direct selection for longevity results in improved health and fitness and even milk production of cows. However, longevity is lowly heritable and phenotypic information is obtained at the end of an animal’s life. Traits expressed early in life and which are favorably correlated to longevity can be useful in selecting for this trait. The aim of this study was to estimate genetic correlations between longevity and age at first calving, first lactation calving interval, number of services per conception, first lactation milk yield, and first parity lactation length. Heritability estimates for measures of longevity were also calculated. The measures of longevity were time between birth and last milking in days (Long1), time between first calving and last milking record in months (Long2), number of lactations initiated (Long3), and total number of days in lactation over all lactations (Long4), total milk yield over all lactations (kg) (Long5). A series of five-variate animal models were fitted to estimate the nature and magnitude of genetic and phenotypic correlations between each measure of longevity and the fertility and production traits. Genetic correlations between measures of longevity and age at first calving, calving interval and number of services per conception were negative ranging from -0.14 ± 0.05 to -0.96 ± 0.06, -0.06 ± 0.03 to -0.67 ± 0.08 and -0.02 ± 0.02 to -0.73 ± 0.34, respectively. Correlations between measures of longevity and first lactation milk yield ranged from 0.88 ± 0.01 to 0.97 ± 0.03. Those with first parity lactation length ranged from -0.10 to 0.72. Long1, Long4 and Long5, which measure time between birth and last milking day, total number of days in lactation over all lactations and total milk yield over all lactations (kg), respectively, had the highest heritability estimates. These three could therefore be used to directly select for longevity. Among the traits studied, first lactation milk yield and age at first calving had the highest genetic correlation with measures of longevity. Therefore, first lactation milk yield and age at first calving could, therefore, be used to indirectly select for longevity.

Study on the Rapid Method to Predict Longevity of Controlled Release Fertilizer Coated by Water Soluble Resin

The study discussed the rapid method to test and predict the longevity of controlled release fertilizers （CRFs） coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dissolving incubation and higher temperature leaching were used to study the patterns of the nutrient release of the CRFs. The correlation analysis between the days at 25℃ and the hours at 80℃ of Trincote 1 and Trincote 2 for the same cumulative release rates were conducted. Patterns of cumulative nutrient release curve followed one factor quadratic regression equation at each given temperatures, and each of relative coefficient was bigger than 0.995. As the temperature increased, nutrients release of the CRFs increased. The longevity of resin coated CRFs were predicted by use of both the cumulative nutrients release equation at 80℃ and the regression equation of release time needed for the same cumulative release rates between 25 and 80℃. There were only 0.3-6.9% relative errors between the tested longevity and predicted one. In conclusion, the longevity of resin coated CRFs could be predicted more quickly and precisely by use of the higher temperature short-term leaching method than that of the traditional differential release rate. The longevity of resin coated CRF could be rapidly and precisely predicted in a few hours by application of the higher temperature shortterm leaching method.

Association between growth rates, age at first calving and subsequent fertility, milk production and survival in Holstein-Friesian heifers

Age at first calving (AFC) affects the profitability of dairy enterprises. This study examined the relationships between AFC and subsequent fertility, milk production and survival up to third calving in UK Holstein-Friesian heifers;Study 1 comprised 134 consecutively born heifers from the same herd (AFC 764 ± 8 days) and Study 2 contained 445 heifers born on 17 farms (AFC 796 ± 6 days). Growth rates and fertility during rearing were monitored and animals were subsequently divided into four AFC groups for analysis: <23 months, 23 - 25 months, 26 - 30 months and >30 months. The actual AFC reflected both growth rate and heifer fertility, with later calving heifers already lighter by 6 months of age. The proportion conceiving to first service was highest (93% and 84% for Studies 1 and 2, respectively) for the youngest AFC group. Fertility in the first lactation was best in cows calving at 23 - 25 months and worst in the oldest AFC group. Milk production parameters in the first and second lactations were broadly similar between AFC groups but significantly more heifers with an AFC < 26 months calved for a third time. These younger calving animals therefore achieved more days in milk over 5 years, with >44% of their days alive spent in milk production compared with only 18% - 40% in cows calving at ≥26 months. Hence cows with an AFC < 26 months produced the most milk in their first 5 years of life. These results indicate that an AFC of 0.75 kg/d up to 15 months and good heifer fertility and resulted in the best subsequent performance.

Effects of delayed mating on the fecundity, fertility and longevity of females of diamondback moth, Plutella xylostella

The effects of delayed mating on the copulation duration, female fertility, fecundity, egg fertility, longevity and the number days alive after mating of females of diamondback moth （DBM）, Plutella xylostella, were studied. When male mating was delayed, the female fertility, fecundity, egg fertility, longevity and number days alive after mating of DBM decreased, and there was a negative correlation between the age of the moth with those variables except copulation duration. When female mating was delayed, the female fertility, fecundity, percent egg fertility and number days alive after mating of DBM also decreased, but the longevity increased, which also showed a negative relationship between the age of the moth with the variables except copulation duration and longevity. When both males and females delayed mating, the female fertility and fecundity decreased; egg fertility was affected marginally, and the longevity of females increased. The moth age was negatively correlated with those variables.

热固性树脂包膜控释肥料肥效期的快速预测方法

采用静水溶出率的方法,在25℃、40℃、60℃、70℃、80℃和100℃条件下,探讨了控释肥料中养分累积释放率与温度的变化规律,以期建立控释肥料肥效期或养分释放期的快速预测方法.结果表明,从低温到高温的各种温度处理下,Scotta公司的Osmocote热固性树脂包膜控释肥料养分累积释放曲线都呈二次曲线,相关指数R2均大于0.996.温度与包膜控释肥料肥效期间呈极显著的负相关,并符合一元二次方程,相关指数R2大于0.993.在高温下培养3或8 h建立的预测预报回归方程,可以快速而准确地预测预报包膜控释肥料在常温下（25℃）的肥效期,预测值与实测值只相差2.4 d;而习惯上的微分溶出率法却相差29～42 d.表明用高温下的肥效期预测预报回归法可以在数小时内准确、迅速地预测控释肥料的肥效期.同时该方法可作为控释肥料在线生产质量控制和市场上控释肥料质量检验的候选方法.

水溶性树脂包膜控释肥料肥效期快速检测方法研究

【目的】探索和建立80℃高温下的快速检测方法(高温短期淋洗法),预测水溶性树脂包膜控释肥料在25℃常温下的肥效期。【方法】采用常温静水溶出试验和高温淋洗的方法,并对常温25℃与高温80℃下供试肥料达到相同养分释放率所需时间进行相关分析。【结果】树脂包膜控释肥料累积释放曲线都呈二次曲线,相关系数r均大于0.995。随着温度的升高供试控释肥料养分释放加快。利用常温25℃与高温80℃高温短期淋洗达到相同养分释放率所需时间的回归方程,并结合80℃的释放曲线方程,可以快速而准确地预测这种包膜控释肥料在常温下养分释放率达到75%所需要的时间,即肥效期。两种树脂包膜控释肥料Trincote1和Trincote2肥效期的预测值与实测值相对误差只有0.3%～6.9%。【结论】采用高温短期淋洗法可以在数小时内比较准确、迅速地预测控释肥料的肥效期,与传统的静水溶出率法或土柱淋溶法相比,结果更准确,而且大大缩短了检测时间。该方法可作为树脂包膜控释肥料肥效期或养分释放期的快速检测方法。

混料设计法在控释肥配比中的应用研究

采用混料试验设计,探讨了包含多种供肥速度的速度复合型控释肥和单一供肥速度的单一速度型控释肥的养分释放速率。结果表明:(1)单一速度型控释肥(FP2,FP5和FP9)在养分快速释放期内,养分释放速率基本保持不变,其顺序为FP2>FP5>FP9;而对于速度复合型控释肥处理,其释放速率不是单一、固定不变的。(2)在培养-淋溶期间,对养分累积释放率≥30.0%的单一速度型控释肥料因子优化组合进行频数统计,发现控释肥FP2,FP5和FP9的混料比例分别为37.61%～45.02%,32.68%～40.83%和21.85%～23.94%。(3)模拟各肥料处理养分累积释放率的Richards函数方程的复相关系数均达到极显著水平,表明使用Richards方程能够准确地描述和预测养分的释放速率。

土壤施肥对烟粉虱生长发育、寄主选择及繁殖的影响

为探讨土壤施肥对烟粉虱种群的影响,在室内采用盆栽方法测定了11种氮、磷、钾施肥组合处理和对照处理的黄瓜苗上烟粉虱的发育历期、存活率、若虫大小、寄主选择、繁殖力及寿命等生命参数。结果表明,烟粉虱的发育历期受施肥影响显著;施肥对卵和低龄若虫存活率无显著影响,但对高龄若虫存活率及各龄若虫大小影响显著;成虫较喜欢在氮肥施用量适中且不施用钾肥和磷肥的黄瓜植株上取食和产卵,而不喜好氮肥施用量大且施用钾肥和磷肥的植株;烟粉虱的寿命及繁殖力在单独施用磷肥的黄瓜植株上低于对照处理的植株,在其他施肥处理上均高于对照。在氮肥施用量大且施用钾肥和磷肥的植株上,一个世代后烟粉虱种群增殖最大,达74.4倍;在单独施用磷肥时增殖最小,仅17.2倍。

双层和夹层包膜工艺对水基树脂包膜材料控释性能的影响

为了优化水基树脂的包膜控释性能,该文以脂溶性树脂为配合包膜材料,利用底喷风动流化床制造多层包膜控释尿素,并通过包膜控释尿素养分释放率的测定评价双层和夹层包膜工艺对水基树脂包膜材料控释性能的影响。研究结果表明:两种工艺相比,夹层包膜工艺能显著延长包膜控释尿素的肥效期,其肥效期是双层包膜工艺的5倍。在夹层包膜工艺中,内保护层厚度在5～15g/m2的范围内对包膜控释尿素的肥效期无明显影响,50g/m2水基树脂控释层和10g/m2脂溶性树脂外保护层夹层控释尿素的肥效期均约为260d。但是,夹层包膜控释尿素的养分释放模式与内保护层厚度有关,内保护层厚度达到10g/m2以上时,养分释放模式由抛物线型变成了S型。综上可知,脂溶性树脂内保护层较适宜的厚度为5～10g/m2,采用夹层包膜工艺能更好的发挥水基树脂的控释性能。

控释肥肥效期对裸地和栽培香蕉土壤N_2O减排效果的影响

【目的】研究不同肥效期的控释肥对裸地和栽培作物土壤N_2O减排效果的影响,为进一步研究大田条件下的减排效果提供参考。【方法】通过盆栽试验,采用静态箱法和气相色谱分析技术,对比研究了1、3、5个月3个肥效期的植物油包膜控释肥(CRF 1Mon、CRF 3Mon和CRF 5Mon)及其核心复合肥分别在裸地和栽培香蕉土壤中的N_2O日排放通量和累积排放量。【结果】控释肥肥效期显著影响N_2O排放峰数量、最大排放峰通量、累积排放量及增温潜势。裸地时,CRF 1Mon、CRF 3Mon和CRF 5Mon排放峰数量分别为5、3和3个,出峰时间均为监测的中后期,最大排放峰通量为CRF 1Mon>CRF 3Mon>CRF 5Mon,CRF 3Mon和CRF 5Mon的累积排放量显著低于CRF1Mon;栽培香蕉时,仅CRF 1Mon和CRF 3Mon在监测前期有明显的N_2O排放峰,分别为1和3个,累积排放量为CRF 1Mon>CRF 3Mon>CRF 5Mon。施用肥效期长的控释肥对栽培香蕉土壤的N_2O减排效果优于裸地,裸地时累积排放量降幅为24.06%~52.81%,栽培香蕉土壤的累积排放量降幅为54.22%~75.34%。【结论】施用肥效期长的控释肥以及栽培作物是减少土壤N_2O排放、降低温室效应的有效措施。

缓控释肥料缓释期的快速测定研究

采用25℃水浸提法和高温快速浸提法,研究了3种不同类型的缓控释肥料缓释期快速测定的最佳温度,测定三者在25℃下的缓释期,并对其在缓释期最佳测定温度和25℃下达到相同氮素累积释放率所需时间进行相关分析。结果表明:微溶性二价金属磷酸铵钾盐为包裹层的多层包裹粒状水溶性肥料(1#)肥料缓释期最佳预测温度为40℃,热塑性树脂包膜肥料(2#)和热固性树脂包膜肥料(3#)缓释期的最佳预测温度均为100℃。利用时间对应关系的预测方程得出1#、2#和3#缓控释肥料缓释期即氮素释放率达到80%所需的时间分别为38、205和158 d,与25℃下实际测定结果的误差分别为0(0%)、6(3.015%)和10 d(5.952 4%)。

两种缓控释尿素缓释特性比较分析

通过静水溶出率法比较了两种缓控释尿素的缓控特性。结果表明,两种不同缓控释尿素的初期养分释放率、养分释放期以及养分释放期内日平均释放速率均存在差异。A型缓控释尿素溶解速率慢,释放周期长,其养分释放期可达43 d,其释放速率在60 d之内均呈上升趋势;B型缓控释尿素溶解速率快,释放周期短,养分释放期为28 d,其在35 d前释放速率较快,35 d已累积释放84.63%,后期尿素释放较少,释放速率趋于平缓。

海洋无脊椎生物受精动力学模型:研究方法与应用

众所周知受精是物种繁衍的重要一步。不同于具有体内受精特性的物种，很多海洋无脊椎生物直接将精卵排放到自然水体中，不具有复杂的交配行为，不存在生物个体水平上的性选择（Sexual selection），其受精率主要依赖于水中精卵的相互作用。在理想状态下从生物物理学角度考虑，具有生殖细胞自由排放（Free—spawning）特性的水生生物，其生殖细胞在受精过程前散布于三维立体空间内，

烧烤食品对果蝇生物学特性的影响

以不同浓度的烧烤食品处理培养基饲养果蝇,观察统计与寿命相关的3个指标及子代成蛹数、成虫数、致畸率的作用。结果显示:低浓度的烧烤食品对果蝇寿命相关的3个指标作用不明显,高浓度的烧烤食品使果蝇寿命相关的3个指标显著下降,该作用还存在性别差异,表现出对雌性的影响大于雄性;烧烤食品能明显提高果蝇的繁殖力,但却增加了翅膀上的变异,出现了双焦状翅和单焦状翅。

The Influence of Altitude and Latitude on Breeding of Amomum tsaoko (Zingiberaceae)

Objective: To explore the effect of altitude and latitude on breeding of Amomum tsaoko Crevost et Lemaire, a flexistylous ginger, which fruit is used as common materia medica and a food condiment. Methods: The 7 populations were selected randomly from the three floristic zones of Yunnan. Adult plants and infructescences were chosen randomly to gain flower number and fructification percentage per inflorescence, and seed number per fruit. All date was analyzed by SPSS (13.0 version). Results: As A. tsaoko was distributed (or transplanted) from a habitat at lower latitude and/or altitude to a site of higher latitude and/or altitude, the flower number per inflorescence increased, on the contrary, the fructification percentage per inflorescence decreased. The competition for reproductive resource was beneficial to increase flower number and seed production. Conclusions: The habitats in south of the tropic of cancer were favorable to the reproduction of A. tsaoko, which reproductive costs were lower and harvest was higher. Increasing flower number per inflorescence may be a strategy to promote the plant to distribute into alpine habitats for both female and male reproductive success.

生育数量对中国农村父母寿命的影响研究

在老龄化加剧和三孩政策落地的共同背景下,生育与寿命权衡假说(即生育数量越多,寿命越短)对于中国样本是否成立呢?本文基于2014-2018年中国老年健康影响因素跟踪调查(CLHLS)数据,将已去世的农村老年人作为研究对象,研究生育数量对其寿命的影响,实证研究后发现:生育与寿命权衡假说可能仅存在于生育男孩数量对农村母亲寿命的影响中。相反,生育数量越多,尤其是女孩数量越多,父母寿命越长,这一积极作用在对父亲寿命的影响中更为显著。具体表现为:第一,孩子数量(尤其是女孩数量)对父母寿命存在显著正向影响,即每增加1个孩子,父母寿命增加0.42岁,每增加1个女孩,父母寿命增加0.56岁。第二,孩子数量、男孩数量和女孩数量均会对父亲寿命产生积极影响,并且女孩数量对父亲寿命的影响大于男孩数量;但生育数量对母亲寿命并无显著正向影响,甚至男孩数量会对母亲寿命产生负向影响。第三,生育男孩或女孩数量对城镇父母的寿命均无显著影响。第四,较晚的初育年龄与最后一胎生育年龄均对父母寿命存在显著正向影响(尤其是母亲的寿命)。因此,回答上述问题能够为积极生育政策的制定提供经验依据,有利于促进生育政策和健康老龄化政策的配套衔接,在提高生育水平的同时不降低老年人健康福利。

非离子氨对褶皱臂尾轮虫(Brachionus plicatilis)个体和种群生长发育及繁殖的影响

褶皱臂尾轮虫(Brachionus plicatilis)因繁殖速度快,易培养,可用来检测工业污染排放、农业和生活污水排放等引起的水体氨氮污染。通过对褶皱臂尾轮虫进行不同非离子氨浓度处理,研究氨氮污染对褶皱臂尾轮虫个体生长发育、繁殖以及种群生长的影响。同时,检测了不同时间处理后,超氧化物歧化酶(SOD)和谷胱甘肽S-转移酶(GST)在细胞内的活性。结果表明,低浓度非离子氨处理对褶皱臂尾轮虫的寿命影响不大,当海水中非离子氨浓度达到0.01‰时,褶皱臂尾轮虫的寿命和生育总量显著降低,生育总量的降低原因可能与褶皱臂尾轮虫在生育期未结束即发生死亡有关。同时,种群试验表明,高浓度处理组褶皱臂尾轮虫的环境最大容纳量降低,雄性褶皱臂尾轮虫产生的时间提前。通过检测褶皱臂尾轮虫受非离子氨胁迫后SOD和GST在细胞内的活性检测发现,高浓度非离子氨降低了褶皱臂尾轮虫体内2种抗氧化保护酶类的活性,依据衰老的自由基学说可知,随着有机体自由基的增加,有机体的衰老变化加速,推测为褶皱臂尾轮虫个体寿命缩短的原因之一。该试验不仅从个体水平,而且从宏观种群水平揭示了高浓度非离子氨对褶皱臂尾轮虫生长繁殖的影响,并从细胞内层面分析了产生该现象的可能原因,为非离子氨污染对海洋浮游生物的不良影响提供了有利证据。

黑河中游沙枣的传粉生物学研究

在甘肃省临泽县黑河中游的中国生态系统研究网络临泽内陆河流域研究站试验区对沙枣花粉育性、花粉-胚珠比(P/O)、花粉活力与寿命、花粉储存物类型等进行了观测。结果表明,沙枣花粉为全育的淀粉型花粉;晴天时,花药散粉后6h内,花粉活力维持在90%以上;雨天时,花药散粉后,花粉活力即低于3%;三瓣花、四瓣花单花产生的花粉量无显著性差异,P/O分别为15 250±1 497、14 143±1 438。

Effect of host-cocoon mass on adult size in the secondary hyperparasitoid wasp, Pteromalus semotus （Hymenoptera： Pteromalidae）

Parasitoids have long proven to be model organisms in studying resourcerelated constraints on immature development. Here we examine the relationship between host cocoon （= pupal） size in the gregarious endoparasitoid wasp, Cotesia glomerata, and development time and adult size in the solitary idiobiont hyperparasitoid, Pteromalus semotus. Little is known about the biology or ecology of this ecto-hyperparasitoid species, although it is one of the major secondary hyperparasitoids of C. glomerata. The size of the adult wasp covaried with the size of the host cocoon at parasitism. Moreover, female wasps were larger than male wasps for a given cocoon size. Adult wasps have remarkably long life-spans, 3 months on average. Longevity did not significantly differ with sex. We also examined how larvae of P. semotus exclude other potential competitors. P. semotus is protandrous, with females taking significantly longer to complete their development than males. In experiments where several eggs of P. semotus were placed on individual pupae of C. glomerata, newly hatched hyperparasitoid larvae moved rapidly over the surface of the host and destroyed the eggs of any conspecifics by biting them before they would initiate feeding on host tissues. Our results are discussed in relation to those with other studies with solitary ichneumonid idiobiont hyperparasitoids of C. glomerata.