黄羽肉鸡慢羽羽型遗传及分布规律研究

对“８８２”黄羽肉鸡慢羽系后代以及利用留种的四类羽型进行两两交驻 种后代的羽型进行了观察统计。结果发现：慢羽系的一代四类羽型鸡的分布以倒长型为主体羽型（６５．９４％）,然后是未出型（２６．３８％）而等长型（５．９５％）和微长型（１．７３％）在四类羽型鸡所占的比例很小。不同性别之间四种羽型的分布趋势没有发生改变,但分布比例存在较大差异,羽毛生长较差的未出型在公鸡中所占的比例比在母鸡中所占的比例大,而     

固始鸡快慢羽纯系的选育及自别雌雄效果研究

对固始鸡自然群研究得知，快羽占8．60％，慢羽占91．40％，说明固始鸡的原始种群主要以慢羽为主。其羽型分布结果为：快羽中R1型占68％，R2型占32％；慢羽中，倒长型占58．8％，等长型占16.5％，未长型占24．7％，未出现微长型。依据鸡的快慢羽显隐性关系以及伴性遗传的原理，通过个体选择、测交和纯繁扩群等方法建立了固始鸡快、慢羽纯系。将建立起来的固始鸡快、慢羽纯系进行纯繁，其后代快羽及慢羽比例分别达到了99.5%和99．7％以上。经两系自别配套知，其后代雏鸡羽速自别雌雄的准确率达到了99%以上。     

番鸭羽型分布及快慢羽性状遗传的研究

对2634只RF系白番鸭的羽型分布进行了测定,并对羽型划分标准及番鸭快慢羽性状的遗传进行了研究。结果表明,2634只雏番鸭中,快羽型个体（主翼羽长于覆主翼羽2mm以上）占90．47％;慢羽型个体（主翼羽长于及主翼羽2mm和2mm以内）占9．53％;慢羽基因和快羽基因的频率为分别0．0649和0.9351。通过3种组配观测羽型的遗传方式。快羽♂×快羽♀后代雏鸭105只均为快羽型;慢羽♂×慢羽♀后代119只雏鸭快慢羽分别为32只和87只,慢羽对快羽呈显性。快羽♂×慢羽♀后代181只雏鸭中,快羽公母鸭分别为11只和78只,慢羽公母鸭分别为78只和14只。可见番鸭的快慢羽是受性杂色体基因控制的伴性性状。     

瑶山鸡慢羽系羽型与出壳体重相关性研究

为了探讨瑶山鸡慢羽系羽型与出壳体重之间是否存在相关性,试验在瑶山鸡自然群体中观测主翼羽稍长于覆主翼羽型(稍长型)、等长型、主翼羽明显短于覆主翼羽型(倒长型)和主翼羽未长出型数量,并与瑶山鸡出壳体重进行相关性分析。结果表明:4个慢羽型中等长型雏鸡所占比例最高(36.08%),之后依次为倒长型(34.49%)、主翼羽未长出型(6.33%)。除主翼羽未长出型的出壳体重比其他三种类型偏低以外,羽型对出壳体重的影响不显著(P0.05)。说明瑶山鸡慢羽系羽型与出壳体重不存在相关关系。     

不同慢羽型鸡翼生长规律和体重发育规律的研究

为研究慢羽性状在不同鸡品种间是否有差异,选择出壳雏鸡200只,采用羽速鉴定的方法将其分为快羽型组、等长型慢羽组、倒长型慢羽组和微长型慢羽组4个组,每周测量主翼羽、覆主翼羽、尾羽、体重并进行统计分析。结果显示:21～28日龄,等长型慢羽鸡的主翼羽长度显著长于微长型(P0.05);14日龄等长型慢羽鸡在覆主翼羽长度上显著长于快羽型、倒长型、微长型(P0.05),49日龄微长型慢羽鸡覆主翼羽长度显著长于倒长型(P0.05);28～42日龄,快羽型、倒长型慢羽鸡的尾羽长度显著长于微长型(P0.05)。结果表明:贵州黄鸡不同慢羽型的主翼羽生长速度比覆主翼羽和尾羽快,鸡翼和体重在开始生长发育后都呈直线增长趋势。     

泸州黄羽乌鸡羽速与体重关系的研究

在泸州黄羽乌鸡中,选出长型,微长型,等长型,短型,未出型5种羽型的鸡,每15天称重一次,结果,各羽型鸡120龄体重没有显著差异。     

常羽乌骨鸡羽色,肤色性状遗传的研究

用３年时间，通过纯繁选育和杂交测定，研究了常羽（黑羽）乌骨鸡羽色，羽型和朊色性状结果表明：黑色羽能稳定真实遗传，并为显性，羽型分布慢羽占８７．３％，快羽占１２．７％。     

清远麻鸡快慢羽系羽速与生产性能的研究

试验选取清远麻鸡快慢羽群体共200只,通过对初生羽毛长度、体重、鸡冠高度和羽毛成熟性等指标的测定,并对初生羽毛长度和羽毛成熟性进行相关性分析,探讨清远麻鸡快慢羽系各阶段生产性能的差异,解析初生羽毛长度与早熟性状之间的关系。结果表明:(1)1日龄快羽R2型的主翼羽长度和平均羽毛长度均极显著长于慢羽倒长型(L2)(P<0.01),但其主翼羽和覆主翼羽长度差值极显著短于慢羽倒长型(L2)(P<0.01);(2)42日龄时,慢羽倒长型(L2)公鸡体重极显著大于快羽R2型(P<0.01);110日龄时,快羽R2型母鸡的冠高显著高于慢羽母鸡(P<0.05),同时,快羽R2型母鸡羽毛成熟性也极显著优于慢羽倒长型(L2)母鸡(P<0.01);(3)快羽R2型鸡羽毛成熟性与初生翼羽长度呈中度正相关(r=0.264~0.322),分别达到显著水平(P<0.05)或极显著(P<0.01)。研究结果提示,清远麻鸡快慢羽系中最常见的快羽R2型和慢羽倒长型(L2)的各阶段的生产性能具有一定的差异,快羽R2型的初生羽毛长度可对羽毛成熟性实施间接选育。     

羽速基因在万载康乐黄鸡自别雌雄中的应用

以万载康乐黄鸡为研究对象,经3年选育,建立了万载康乐黄鸡快羽品系和慢羽品系。通过调查发现,万载康乐黄鸡群体中以快羽鸡为主,占89.4%,慢羽中倒长型(称为S1型)占84.6%,然后为等长型或微长型(统称为S2型)。以快羽公鸡和慢羽母鸡进行交配,对自别雌雄准确度进行测定,后代平均自别雌雄鉴别率达97%以上。快羽群中鉴别率偏低,为95.79%,慢羽中鉴别率为100%。以S1型为母本与快羽公鸡交配,其后代中会出现少量的S2型,这说明S2型的后代中也会出现少量的S1型。结果表明:羽速基因具有剂量效应或存在修饰基因或受环境影响,其主翼羽与覆主翼羽相对长度为连续分布,易导致表现型与基因型不符,再加上可能的性别转化及大群检测误差等均是导致其鉴别率达不到100%的原因。     

寿光鸡快慢羽自别雌雄配套系的建立与应用

试验通过寿光鸡和快羽系琅琊鸡进行测交,观察后代中羽速和羽色的表型和分离比例。选择具有纯合基因的快、慢羽兼具黑色素扩散基因的寿光鸡作为亲本,建立快慢羽纯系系谱F1代。选留F1代快羽公鸡与慢羽母鸡建立自别雌雄配套系。结果表明,黑羽对麻羽的遗传方式是完全显性遗传;快慢羽纯系后代快、慢羽比例分别达到99.72%和99.76%以上;羽速自别雌雄准确率公雏99.85%以上,母雏99.77%以上。     

辽宁绒山羊毛囊群结构的研究

辽宁绒山羊的产绒性能与其皮肤毛囊结构是密切相关的。通过组织切片技术观察辽宁绒山羊皮肤毛囊结构,并对获得的数据进行最小二乘均数分析,研究了辽宁绒山羊羔羊不同月龄,不同季节毛囊密度和S/P值的变化及出生类型,母羊年龄对毛囊性状影响。结果表明,辽宁绒山羊的毛囊群主要是由3个初级毛囊和若干个次级毛囊组成的三毛群,三毛群占毛囊群总数的75%左右。次级毛囊呈楔形群排列在中心初级毛囊和外周初级毛囊中间,随着羔羊月龄的增长,毛囊密度逐渐下降,S/P值逐渐上升,S/P在6月龄达到最大值。成年羊初级毛囊密度季节间变化不大,次级毛囊密度和S/P值表现出明显的季节变化,4月份次级毛囊密度和S/P值最小,9月份次级毛囊密度和S/P值最大。     

Reproductive performance in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

Angus (A), Santa Gertrudis (S), and Gelbvieh (G) sires were mated to A and S dams to produce five mating types (A X A, S X S, S X A, A X S and G X A) in each of four calf crops. The study involved 501 matings. Overall means for the traits measured (calves born/cows exposed, Julian birthdate, calving ease, percentage of live calves at 24 h, birth weight, survival to weaning and gestation length) were 74.2%, 48.8 d, 96.4%, 33.2 kg, 95.4% and 283.8 d, respectively. Angus dams had a 14 percentage point (P less than .05) advantage over S dams for percentage of calves born/cows exposed. The effect of heterosis in crosses of A and S for percentage of calves born/cows exposed was negative (-11.1%) and approached significance. The percentage of calves born/cows exposed were 84.4, 70.4, 76.1 and 62.3 for the A X A, S X S, S X A and A X S mating types, respectively. Matings involving A sires and dams produced calves significantly earlier in the calving season than did matings involving S sires and dams. Matings involving S sires and dams produced calves with significantly longer gestation periods than matings of A sires and dams. Calving ease score and survival to weaning were not affected by breed of sire, breed of dam, age of dam, sex of calf, or the interaction of breed of sire X breed of dam. Percentage of live calves at 24 h indicated that straightbred S calves were significantly less viable at birth than the other four mating types.(ABSTRACT TRUNCATED AT 250 WORDS)     

Responses to 19 generations of litter size selection in the Nebraska Index line. I. Reproductive responses estimated in pure line and crossbred litters

Our objective was to estimate responses in reproductive traits in the Nebraska Index line (I) after 19 generations of selection for increased litter size. Responses were estimated in dams producing pure line, F1, and three-way cross litters. A total of 850 litters were produced over six year-seasons, including 224 pure line litters, 393 F1 litters produced from I and C females mated with Danbred NA Landrace (L) or Duroc-Hampshire (T) boars, and 233 litters by F1 L x I and L x C females mated with T boars. Contrasts of means were used to estimate the genetic difference between I and C and interactions of line differences with mating type. Farrowing rates of lines I (u = 91.0%) and C (u = 92.8%) did not differ. Averaged across all genetic groups, mean number born alive per litter was 10.1 pigs, and number and weight of pigs weaned per litter, both adjusted for number nursed and weaning age of 12 d, were 9.7 pigs and 34.4 kg, respectively. Averaged across mating types, direct genetic effects of I were greater than C (P < 0.05) for total born (3.53 pigs), number born alive (2.53 pigs), number of mummified pigs (0.22 pig), and litter birth weight (2.14 kg). The direct genetic effect of line I was less than C (P < 0.05) for litter weaning weight (-1.88 kg). Interactions of line effects with crossing system were significant (P < 0.05) for total number born, number of stillborn pigs, number weaned, and litter weaning weight. In pure line litters, I exceeded C by 4.18 total pigs and 1.76 stillborn pigs per litter, whereas the estimate of I-C in F1 litters was 2.74 total pigs and 0.78 stillborn pig per litter. The contrast between I and C for number weaned and litter weaning weight in pure litters was 0.32 pig and -0.28 kg, respectively, compared with 0.25 pig and -2.14 kg in F1 litters. Crossbreeding is an effective way to use the enhanced reproductive efficiency of the Index line.     

A study of the microbial flora of the anterior vagina of normal sows during different stages of the reproductive cycle

SUMMARY Sterile guarded swabs were used to sample the anterior vaginal and cervical area of 23 normal healthy sows during various stages of the reproductive cycle. The samples were collected one week before farrowing, within 24 hours of farrowing, weekly up to weaning, at mating and at 2 and 3 weeks after mating, and then plated and incubated aerobically and anaerobically. At least one positive sample was obtained from each sow and at each stage of the reproductive cycle. Most positive samples (78.3%) were obtained on the day of farrowing and the least 3 weeks after mating (19.0%). The second highest number of positive samples (45.5%) was found immediately after mating. Although there was no significant difference among sows of different parities, there was a trend for older sows to have more positive samples after farrowing (84.6%). There was a greater decrease in positive samples after farrowing and after mating among younger sows compared with older sows. A wide range of bacteria including aerobic and anaerobic species, were recovered from 142 Isolates. The more representative bacteria were Streptococcus spp (23.2%); Escherichia coll (22.5%); Staphylococcus spp (19.0%) and Corynebacterium spp (13.4%). Of the cultures, 54.7% were pure and 45.3% were mixed. Both the percentage of bacterial isolates as well as the type of culture (pure or mixed) were similar to those frequently reported in clinical cases of vulval discharge syndrome. The results indicate that sows usually develop infections of the reproductive tract at farrowing and mating but these infections do not normally persist.     

Fiber type composition of rostral and caudal portions of the digastric muscle in the dog

The distribution of muscle fiber types in rostral and caudal portions of the musculus digastricus (digastric muscle) was studied in 6 dogs. Staining procedures which stain specifically for type IIM fibers, a fiber type found in other muscles supplied by the trigeminal nerve, were used. Rostral and caudal portions of the muscle were compared because the rostral portion is innervated by the trigeminal nerve, and the caudal portion is innervated by the facial nerve. The musculus triceps brachii (triceps muscle), which contains fiber types I and IIA, and the musculus masseter (masseter muscle), which contains type IIM, were used as controls. Mean fiber diameters were calculated for each of the muscles. Both portions of the digastric muscle exhibited the same histochemical behavior, possessing types I and IIA myofibers. Neither portion contained type IIM fibers. Type I fibers in the masseter muscle were histochemically different from type I fibers in the other muscles studied. Type II fibers predominated in all 3 muscles, but there were significantly (P less than 0.001) more type I fibers in the triceps muscle than in either portion of the digastric muscle or in the masseter muscle. Type II fibers were significantly larger than type I fibers in the caudal digastric (P less than 0.01) and masseter (P less than 0.05) muscles. There was no difference in the size of type I or type II fibers between any of the muscles studied (P greater than 0.20).     

Responses to 19 generations of litter size selection in the NE Index line. II. Growth and carcass responses estimated in pure line and crossbred litters

Our objective was to estimate responses in growth and carcass traits in the NE Index line (I) that was selected for 19 generations for increased litter size. Differences between Line I and the randomly selected control line (C) were estimated in pure line litters and in F1 and three-way cross litters produced by mating I and C females with males of unrelated lines. Contrasts of means were used to estimate the genetic difference between I and C and interactions of line differences with mating type. In Exp 1, 694 gilts that were retained for breeding, including 538 I and C and 156 F1 gilts from I and C dams mated with Danbred NA Landrace (L) sires, were evaluated. Direct genetic effects of I and C did not differ for backfat (BF) at 88.2 kg or days to 88.2 kg; however, I pigs had 1.58 cm2 smaller LM area than did C pigs (P < 0.05). Averaged over crosses, F1 gilts had 0.34 cm less BF, 4.29 cm2 greater LM area, and 31 d less to 88.2 kg than did pure line gilts (P < 0.05). In Exp 2, barrows and gilts were individually penned for feed intake recording from 27 to 113 kg and slaughtered. A total of 43 I and C pigs, 77 F1 pigs produced from pure line females mated with either L or Danbred NA 3/4 Duroc, 1/4 Hampshire boars (T), and 76 three-way cross pigs produced from F1 females mated with T boars were used. Direct genetic effects of I and C did not differ for ADFI, ADG, G:F, days to 113 kg, BF, LM area, ultimate pH of the LM, LM Minolta L* score, or percentage of carcass lean. Interactions of line effects with crossing system were significant only for days to 113 kg. Pure line I pigs took 4.58+/-4.00 d more to reach 113 kg than did C pigs, whereas I cross F1 pigs reached 113 kg in 6.70+/-3.95 d less than C cross F1 pigs. Three-way cross and F1 pigs did not differ significantly for most traits, but the average crossbred pig consumed more feed (0.23+/-0.04 kg/d), gained more BW per unit of feed consumed (0.052+/-0.005 kg/kg), grew faster (0.20+/-0.016 kg/d), had less BF (-0.89+/-0.089 cm), greater LM area (5.74+/-0.926 cm2), more lean (6.21+/-0.90%), and higher L* score (5.27+/-1.377) than the average pure line pig did (P < 0.05). Nineteen generations of selection for increased litter size produced few correlated responses in growth and carcass traits, indicating these traits are largely genetically independent of litter size, ovulation rate, and embryonic survival.     

Selection for weaning weight in Targhee sheep in two environments. I. Direct response

In 1961, selection for 120-d weight was initiated in two flocks from a common base population of grade Targhee sheep. At Davis, sheep were maintained on a good plane of nutrition, on irrigated pasture or in drylot. At Hopland, sheep grazed annual grassland range, with supplementary feeding only at mating and lambing. Selected (DW) and control (DC) lines were maintained at Davis from 1961 through 1977. A selected (HW) line, replicate control (HC1 and HC2) lines and a line (DH) mated to the Davis DW rams were maintained at Hopland from 1961 through 1980, with the exception that HC2 was terminated in 1977. Multiplicative factors were used to adjust weights for effects of age of dam, sex and type of birth and rearing. Response to selection was estimated as the difference between selected and control line linear regression coefficients of adjusted line means on year. The Hopland replicate controls did not differ significantly from each other (HC1 - HC2 = .004 +/- .056 kg/yr), and the control line data were pooled (HC). The overall control line mean 120-d weights on a female, single, mature-dam basis were 33.2 and 30.4 kg at Davis and Hopland, respectively. Direct response was greater at Davis than at Hopland: DW - DC = .524 +/- .073 kg/yr (P less than .001); HW - HC = .151 +/- .034 kg/yr (P less than .001). Corresponding realized heritabilities were .17 and .06. Direct response for the DH line was DH - HC = .226 +/- .036 (P less than .001); realized heritability was .08. Response in the DH line was greater (P less than .05) than that in the HW line: HW - DH = -.075 +/- .037 kg/yr. This indicates that: (1) genetic improvement made on a higher plane of nutrition was expressed, but to a lesser degree, under range conditions and (2) selection under better feed conditions resulted in at least as much improvement in growth rate in a range environment as did selection under range conditions.     

雁鹅羽毛毛囊形态结构与分布特点研究

雁鹅羽毛毛囊形态结构和分布特点与其羽绒性能密切相关。本试验采用组织切片技术和光学显微方法观察成年雁鹅羽毛毛囊形态结构和分布特点,用最小二乘均数法对胸、腹和背部羽区的毛囊密度、毛囊直径和S/P值的变化进行分析,以及性别因素对毛囊性状的影响进行研究。结果显示,雁鹅羽毛初级毛囊和次级毛囊均属有髓毛囊,二者独立发生发育并独立分布。鹅的次级毛囊显微形态结构与初级毛囊基本相似,但次级毛囊的羽嵴于羽髓周围呈放射状均匀分布,没有凸出的脊柱状较大嵴突存在。成年雌性雁鹅在其胸、腹、背部羽区的初级和次级毛囊密度均显著高于雄性雁鹅(P＜0.05),雁鹅胸、腹部羽区的次级毛囊密度和S/P值均显著高于背部的毛囊密度和S/P值(P＜0.05)。次级毛囊直径因性别差异变化较大,雄鹅胸、背部羽区的次级毛囊直径显著大于雌鹅(P＜0.05);且雄雌鹅腹部次级毛囊直径均显著小于其背部的次级毛囊直径(P＜0.05)。     

Growth characteristics in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

A total of 343 calves (males and females) were evaluated for preweaning average daily gain, weaning weight (WW), feedlot average daily gain to slaughter (ADGF), slaughter weight (SW), pelvic height (PH), pelvic width, pelvic area, weaning conformation score (WS) and ratio of weaning weight to the dam's weight at weaning (R). Mating types included straight-bred Angus (A) and Santa Gertrudis (S), the reciprocal crosses of these two breeds and Gelbvieh (G) X Angus. Straightbred S and A X S crosses had the heaviest WW, followed by S X A and G X A crosses; straightbred A had significantly smaller WW than all other mating types. The crossbreds and the straightbred S had higher WS than straightbred A. The ratio of WW to cow weight was largest for S X A. The straightbred S and A X S crosses had significantly lower R values than the other mating types. Weaning weight per cow exposed, computed as the product of weaning rate and weight, indicated that straightbred A had an advantage over the other mating types (156.5 kg), whereas S and S X A were intermediate (147.9 and 147.6 kg, respectively) and A X S was lowest (128.9 kg). Feedlot gain was highest for A X S, though not significantly greater than for straightbred S or G X A. Straightbred A gained significantly less than other mating types except S X A. Straightbred A were found to be significantly smaller at slaughter than the other mating types. The S X A and G X A were intermediate; the straightbred S and A X S were significantly larger for SW.(ABSTRACT TRUNCATED AT 250 WORDS)     

Staphylococcus aureus associated with mammary glands of cows: genotyping to distinguish different strains among herds

The hypothesis that strains of Staphylococcus aureus are more likely to be unique to a herd than common to several herds was tested. Herds (n=28) from nine geographic areas of Korea, with elevated milk somatic cell counts (>500000 cells/ml) were enrolled in this study. Mammary quarter milk samples were aseptically collected from all lactating cows (n=616) with at least three functional quarters. Milk was cultured and S. aureus isolates were typed using pulse field gel electrophoresis of DNA SmaI digests. A total of 181 cows were identified as having S. aureus intramammary infections. A total of 52 different types of S. aureus were identified and 34 (65.4%) were associated with a single herd. A total of 18 types of S. aureus were found in multiple herds; 14 types were found in two herds, and four types were found in three herds. Herds with 1, 2, 3, and more than 3 types, were: four (14.3%); eight (28.6%); nine (32.1%); and seven (25.0%). The data indicate that the majority of strains were found in one herd only, and more than 90% were found in two or less herds, suggesting that strains of S. aureus are more likely to be restricted to a single herd, than found in multiple herds.