“桂蚕N2”日系亲本不同交配时长对产卵性能的影响

针对桑蚕新品种桂蚕N2日系亲本NJ7、NJZ在原原种、原种繁育时,常规交配4 h产卵性能不够好的特性,设计了交配时间延长到5 h、6 h、7 h的试验,以4 h作对照,比较四个不同处理间有效产卵蛾圈数、单蛾产卵数、不良卵率的差异,结果表明,不同交配时长对NJ7的产卵性能无影响,但NJZ不同交配时长产卵的有效卵圈数、单蛾产卵数有显著差异,不良卵率无显著差异,交配6~7 h,能增加有效产卵蛾圈、增加单蛾产卵数。     

改变蓖麻蚕蛾产卵习性的试验

怎样控制蓖麻蚕蛾的交配而使母体产卵集中并获得出蚁齐一?这是繁育蓖麻蚕原种的重要问题之一。有人(小泉清明等,1941)以蓖麻蚕蛾交配时间的久暂来研究母蛾产卵和受精的关系;交配9小时拆对,母体当晚所产的卵数占总产卵率40％,内中受精卵达98％,第二晚产卵率24％;交配15小时者,当晚的产卵率44％,(受精卵83％)。另有人(王高顺     

两广二号亲本的交配次数对产卵质量的影响研究

以广西两广二号四个亲本为材料,通过试验,探讨一次交配与二次交配对产卵的影响。结果表明,二次交配比一次交配的雌蛾产卵量都减少,不受精卵率增加。其中湘晖·7532的产卵量降低最少;芙蓉·932的产卵量明显降低;湘晖·7532和932·芙蓉的不受精卵率增加最多,7532·湘晖次之,芙蓉·932的不受精卵增加最少但良卵率最低;932·芙蓉的死卵率最低但空圈数最多。本文通过试验,探讨蚕种生产过程中,为降低劳动强度,减少劳动成本,提高蚕种质量以及尽可能避免原原种制种中出现二次交配情况应采取的措施和方法。     

澳洲坚果新害虫--脊胸露尾甲生物学习性观察

在云南省西双版纳种植区发现为害澳洲坚果的新害虫——脊胸露尾甲,为准确掌握其生物学习性,在室内以澳洲坚果果仁为食对其进行了饲养,并对各虫态的形态、成虫交配习性、产卵习性、卵的孵化率、各虫态的存活率进行了观察。结果表明：脊胸露尾甲的发育经历卵、幼虫、蛹、成虫四个虫态,其中幼虫分为3个龄期,随着龄期的增长,幼虫体长、体宽和头壳宽度逐渐增加。成虫羽化后不会立即交配,交配前期为（4.65±0.04）d,交配时长不等,初次交配时长为（13.78±0.29）min,雄成虫存在争夺交配权的行为。雌成虫产卵前期为（8.65±0.03）d,初次产卵量为(1.94±0.06)粒,在15:00-18:00时间段的产卵量/小时最高;雌成虫对产卵位置具有选择性,背光面的着卵率极显著高于向光面。卵的孵化率随着湿度的增加而不断提高。常规饲养条件下,卵、1龄幼虫、2龄幼虫、3龄幼虫、蛹的存活率分别为(86.50±0.69)%、(83.31±2.99)%、(94.85±0.71)%、(97.09±1.46)%、(98.77±1.23)%。本研究为脊胸露尾甲的生物学及防治提供参考依据。     

不同交配时间对“桂蚕N2”原原种产卵的影响

"桂蚕N2"原原种制种中分别交配4 h、5 h、6 h和7 h,调查中系原原种和日系原原种制种的有效卵圈率、产卵率和良卵率。结果表明:延长交配时间能增加有效卵圈数、产卵数、良卵数率,也能提高有效卵圈率和产卵率,但仅NJZ×NJ7交配4 h的产卵率与交配7 h的产卵率的差异达显著水平;4~7 h范围内不同交配时间的良卵率无显著差异。     

牛早期胚胎体外发育条件的研究

本试验研究了精卵共育时间和培养液等因素对牛早期胚胎体外发育的影响。精卵共育6～12h能显著提高受精卵的囊胚发育率,受精卵的囊胚发育率为23．2％～25．3％,共育时间为24h时,囊胚发育率降低,但精卵共育6h时卵裂率较低;TCM199、mBECMaa、mSOFaa均能支持体外受精卵的发育,其囊胚发育率分别为18％、30．7％和29．2％。试验结果表明：精卵于BM受精液中共育9h后,将其置于添加5％OCS的mBECMaa或mSOFaa中培养,能得到较高的体外生产胚胎的囊胚发育率。     

不同时间段柞蚕卵主要性状的差异

对辽蚕582、9906、抗大三个品种的不同产卵时段的柞蚕主要性状进行分析,得出第一昼夜卵具有更优良的经济性状,更有利于柞蚕良种繁育。秋季卵期调查中,三个柞蚕品种第一昼夜卵平均不受精卵数和平均卵重均优于第二昼夜卵。秋季放养调查中,三个品种第一昼夜卵平均发病率和产茧重量均优于第二昼夜卵。结果显示第一昼夜卵其主要性状均好于第二昼夜卵,因此选留第一昼夜卵放养,在柞蚕繁育过程中可达到抗病、抗逆及高产的要求。     

两广二号中系雄蛾冷藏24h对杂交原种良繁的影响

在杂交原种生产中常出现因品种间发蛾不一致而冷藏雄蛾的现象。为了解广西当家品种两广二号中系杂交原种生产中,对交品种雄蛾6℃冷藏24h对生产杂交原种质量的影响而设计试验。结果显示:932雄蛾6℃冷藏24h后与芙蓉雌蛾交配,芙蓉×932(冷)的有效卵圈率、产卵率、良卵率均显著低于芙蓉×932,并且芙蓉×932(冷)雌蛾单蛾产卵率和良卵率个体间开叉大。芙蓉雄蛾6℃冷藏24h后与932雌蛾交配,932×芙蓉(冷)的有效卵圈率、产卵率显著低于932×芙蓉;良卵率差异不显著。     

牛胚胎体外生产与早期胚胎发育的探讨

试验对牛胚胎体外生产技术中的体外受精液、精卵共育时间、血清和培乔液等影响早期胚胎体外发育的因素进行了研究。以BO（Brackett ＆ Oliphant）和BM（BO：成熟培养液=3：2）作为受精液，受精卵的囊胚发育率分别为26．0％和15．0％；精卵共育时间以9-12h为宜；受精卵在含血清FBS或OCS培养液中的专胚发育率分别为26．4％或29．9％，明显高于在无血清培养基中的囊胚发育率（10．3％）；TCMl99、mBECMaa、mSOFaa3种胚胎培养液均能支持受精卵的体外发育，在其中培养受精卵囊胚发育率分别为18．O％、30．7％和29．2％。试验结果表明：精卵于BM受精液中共育9～12h后，将假定受精卵置于添加5％OCS的mBECMaa或mSOFaa培养液中培养，能显著提高体外生产胚胎的囊胚发育率。     

耐低湿松毛虫赤眼蜂的筛选及在柞蚕卵内的发育过程

松毛虫赤眼蜂（Trichogramma）广泛应用于多种鳞翅目害虫的生物防治,但是西北干旱地区可利用蜂种较少,因此耐低湿松毛虫赤眼蜂的驯化非常必要,同时耐低湿松毛虫赤眼蜂在柞蚕卵内的发育过程研究对其规模化扩繁有重要意义。本研究通过低湿胁迫筛选出耐低湿松毛虫赤眼蜂种系,测定其对柞蚕卵的寄生率和出蜂率,并观察了50%湿度条件下的发育过程。结果表明,松毛虫赤眼蜂的寄生率和出蜂率随相对湿度下降呈降低趋势;且经低湿胁迫处理后,不会导致松毛虫赤眼蜂产生形态上的明显差异。在25±0.5℃条件下,耐低湿松毛虫赤眼蜂在柞蚕卵内的发育历期为10 d,其中卵期30 h,幼虫期24 h,预蛹期72 h,蛹期106 h,在产卵后240 h时,赤眼蜂羽化为成虫,羽化后即在柞蚕卵内完成交配,最后咬破柞蚕卵壳钻出,与70%湿度（对照）无差异。表明低湿胁迫可降低松毛虫赤眼蜂寄生率和出蜂率,但不会导致生长发育和形态上的明显差异。     

The egg production of Toxocara vitulorum in Asian buffalo (Bubalus bubalis)

The egg production of Toxocara vitulorum in Asian buffalo has been studied. Eggs were first present in the faeces of calves when they were 22.3 +/- 1.6 days old. In calves treated with pyrantel when 3 days old, the age at first patency was extended by 3.5 days indicating that there was no pre-natal transmission. Calves on only half the milk of the cow had a significantly longer prepatent period of 27.7 +/- 2.2 days. The peak egg output occurred in calves 35.7 +/- 2.6 days old and had a duration of 5.5 +/- 2.5 days with 98,000 +/- 63,700 eggs g-1 of faeces. The duration of the patent period was 35 +/- 12 days. The average lengths of populations of mature female parasites from different hosts at the time of peak egg output or older, ranged from 15.0 to 31.0 cm and was correlated with those of the males in the same populations (10.6-20.4 cm). The size of females was not affected by intraspecific competition. The proportion of males in the populations was 0.39 +/- 0.11. The egg output per female per day at the peak was 110,000 +/- 58,000 and was correlated with the size of the females at autopsy, but the egg output per female per day at the time of autopsy was lower and was not correlated, so it was concluded that the drop in egg counts was the result of reduced fecundity. The fertility of the eggs from faeces was greater than 92% throughout.(ABSTRACT TRUNCATED AT 250 WORDS)     

Some effects of changing protein levels during the pullet laying year

Three diets containing 12, 14 and 16 per cent crude protein were fed to laying pullets from 23 to 63 weeks of age. The laying year was divided into three periods of 10, 15 and 15 weeks to examine the effect of feeding these diets at different stages of lay. Eighteen treatments were used, representing all possible combinations of three diets in the first period, three diets in the second period and two diets (16 and 12 per cent) in the third period. Two groups of 75 pullets were allocated to each treatment.

In each period the diet had a significant effect on the rate of lay, egg output (g./day) showed a linear regression on protein intake. There was no indication that the amount of protein needed to maximise egg output was any less in one period than another, although the level of maximum output varied substantially as the year progressed.

Where the feeding of an inadequate level of protein in one period was followed by a higher level in the next, liveweight showed a marked recovery but there was little evidence of compensatory egg production. When the protein of the diet was reduced from 16 to 12 per cent, rate of lay fell sharply to a level below that of birds which had received the 12 per cent protein diet throughout.     

家蚕蛹期不同温度保护对产卵量及不受精卵的影响

以云蚕7、云蚕8为试验材料,调查分析蛹期不同温度保护对蚕种产质量的影响,蛹期遭遇28℃以上高温,会使不产卵母蛾、少产卵母蛾增多,不受精卵增加,良卵率降低,不受精卵率和生种百分率增高,影响蚕种产量和质量。     

家蚕不受精卵发生的几个生化因素

不同蚕品种的不受精卵率与熟蚕血液蛋白含量呈显著的负相关 ( -0 690 3 )。前蛹期 3 2℃高温处理对家蚕蛹血液蛋白含量和过氧化氢酶活性以及不受精卵的发生均有一定影响 ,表现为随高温时间的延长 ,不受精卵增加 ,蛹血液蛋白含量减少 ,过氧化氢酶活性减弱 ,不受精卵率与蛹血液蛋白含量和过氧化氢酶活性呈较明显的负相关关系     

Synchronisation of oestrus and fertility in buffaloes using a prostaglandin analogue

Cloprostenol, a prostaglandin analogue, was administered intramuscularly to a total of 35 cycling buffalo cows and heifers in two doses, each of 0.5 mg, given 11 days apart. Out of five cows and 12 heifers subjected to observations after the second injection of cloprostenol (day 0), all except one heifer responded. Signs of oestrus were most marked on days 3 or 4. Eighteen treated heifers were kept with buffalo bulls for four days after the second injection while a control group of nine heifers was kept with bulls for 21 days. The first-service conception rate, diagnosed by rectal palpation at 60 days, was 33 1/3 per cent in both groups. Twelve treated heifers were artificially inseminated at 72 and 96 hours after the second injection of cloprostenol, using fresh semen diluted in egg yolk--citrate extender. The first service conception rate at 60 days was 30 per cent.     

Experiments with the Cornell intermittent lighting system for laying hens

1. Two experiments were conducted to provide further evidence about rate of lay under the Cornell lighting system (2L:4D:8L:10D). Each used 1728 hens of each of 2 brown-egg stocks in 12 light-proof rooms. 2. In the first the Cornell system was compared at 2 light intensities (average values 2 and 10 lux) with a conventional step up lighting programme. In the second, Cornell lighting was introduced at 18, 21 or 24 weeks of age and compared with a step up programme. 3. Total egg output was essentially the same from the Cornell lighting system, using 10 h light/d, as from the step up programme using 16 h/d. When the Cornell system was applied abruptly at 18 weeks to pullets which had been reared on short days (8L:16D) sexual maturity was advanced, resulting in an increase in mean rate of lay to 72 weeks of age and a reduction in mean egg size. Application of the Cornell system from 21 or 24 weeks gave the same egg numbers and the same egg size as the step up programme. 4. Food intake was about 2% lower with the Cornell treatment in both experiments. Although this difference was not quite significant in either, it probably reflects a real effect of the reduced hours of light. It represents a greater potential cost saving than the reduced electricity consumption. 5. Birds in rooms with an average light intensity of 2 lux laid slightly fewer eggs but their eggs were 0.5 g heavier than those laid in rooms maintained at 10 lux. There were no interactions between light intensity and light pattern or between stocks and light pattern.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of the use of a morantel sustained release bolus in first and second year grazing cattle

In an experiment carried out in 1981 and 1982, the effect of the use of a morantel sustained release bolus (Paratect bolus) on the weight gain and a number of parasitological parameters of cattle was studied. In the first year 42 calves were divided into 3 equal groups, one group was kept outside and treated with a bolus (B), the second group was kept outside and was not treated (C), while the third group remained indoors (I). Groups B and C were grazed separately on contaminated pasture. During the first months Group B had a negligible egg output. The egg output in the controls was much higher and in mid-August they had to be treated for parasitic gastroenteritis. At the end of the grazing season the advantage in weight gain of Group B was 20 kg compared with the controls. During the housing period the growth in the 3 groups was not significantly different. At the start of the second grazing season half the animals of Groups B, C and I received a bolus (Groups BB, CB and IB). The other half remained untreated (BC, CC and IC). The animals treated with a bolus in 1982 gained significantly more weight (64 g/day) than untreated animals. Heifers turned out for the first time (IB and IC) showed much less weight gain than heifers in their second grazing season. The heifers which had previously grazed in 1981 had a very low egg output compared with Groups IB and IC, although the level of egg output of the latter was also not very high (max, almost 40 (eggs per gram (EPG)). In faecal cultures of heifers of Group BC, CB and CC, no Cooperia oncophora-larvae were seen from May onwards, indicating a strong immunity against this species. In Group BB very low numbers of C. oncophora-larvae were observed. In Groups IB and IC, C. oncophora was present during the whole season. At the end of the first season the level of herbage infestation on the control pastures was much higher. In 1982 only slight differences in level of infestation between the pastures were observed. At the start of the season in 1982 serum pepsinogen levels were much higher in the groups which grazed in 1981, compared with the indoor-fed groups. Groups BC and CC had significantly higher levels than Groups BB and CB and all 4 groups always had higher levels than Groups IB and IC.(ABSTRACT TRUNCATED AT 400 WORDS)     

不同日粮对快慢羽母番鸭的影响

不同日粮条件下快慢羽母番鸭的生长速度不同，羽慢羽母番鸭性成熟日龄分别为１６７日龄和１６４日龄；快、慢羽组１２产蛋周平均日产蛋率分别为３３．２３％和４６．９３％，二者差异显著（Ｐ＜（０．０５）。     

Optimum isoleucine requirement of laying hens and the effect of age

1. Medium weight laying hens were used for an assay to determine their isoleucine requirement between 26 and 36 weeks of age and again between 46 and 56 weeks of age. 2. Two isoleucine-limiting mixtures were formulated with similar amino acid profiles, one containing 198 g and the other 110 g crude protein per kg diet. These mixtures were blended to give a series of 11 diets with isoleucine contents ranging from 7.6 to 3.8 g/kg. The lowest protein diet was also fed with a supplement of L-isoleucine. Each of the 12 diets was given to 5 groups of 24 laying hens. 3. The daily isoleucine requirement of individual laying hens was estimated to be 9.48 mg/g egg output plus 44.47 mg/kg body weight per day for the 1st period and 12.11 mg/g egg output plus 6.86 mg/kg body weight per day for the 2nd period. Calculated optimum intakes of isoleucine for various ratios of cost of input to value of output are tabulated. For example, for a flock of medium weight hens producing an average of 50 g daily egg mass, the optimum isoleucine intake (mg/hen d) varied between 760 and 890 varying for ratios of costs to egg prices. 4. It is concluded that the isoleucine required per day does not decrease during the first laying year despite a decrease in rate of egg output.     

Growth of the conceptus in alpacas

OBJECTIVE: To determine growth of the alpaca conceptus during early gestation, using ultrasonography. ANIMALS: 40 pregnant alpacas (20 multiparous, 20 nulliparous). PROCEDURE: Transrectal ultrasonography with a 5-MHz probe was performed 3 times weekly from days 7 through 45 after copulation (day of copulation = day 0). Blood samples were collected for progesterone assay on days of ultrasonography. RESULTS: Forty embryonic vesicles and embryos were identified and measured. Embryonic vesicles were first detected on day 12 after copulation and appeared spherical. Cumulative percentage of embryonic vesicles detected was 50, 82.5, and 100% on days 12, 14, and 16, respectively. Embryos were first detected by day 22 and heartbeats by day 24. Similarly, cumulative percentage of embryos detected was 17.5, 82.5 and 100% for 22, 24, and 26 days after copulation, respectively. Embryonic vesicles occupied both uterine horns beginning on day 19. A positive correlation existed between length and width of embryonic vesicles. Size of embryonic vesicles and embryos and progesterone concentrations did not differ between multiparous and nulliparous females. Five sets of twins were detected from days 21 through 33 after copulation, but the conceptus identified in the right uterine horn became nondetectable between days 28 and 33. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography was useful in detecting the earliest appearance of alpaca embryonic vesicles and determining the changes in growth from days 12 through 45 after copulation. Embryos were first detected by day 22. Transrectal ultrasonography was not harmful to animals and did not provoke embryonic death in this study.