家畜孟德尔性状全同胞家系选择育种进度的研究

本文提出了固定家畜多个不相连锁显性性状的全同胞家系选择体制，并探讨了其育种进度，研究证明，全同胞家系选择效果全同胞家系大小Ｎ的制约。Ｎ越大，选择越准，育种进度越大，。Ｎ＝１ＪＦ ，该系统体制就退化成所谓的“理想型横交固定”，此时选择效果最差“多元测交”体制的育种进度高于全同胞家系选择，但后世代间隔短，简便易行，育种成本低。选择位点越多，群体育种水平越高，不同选择体制的育种进度差异越大。     

混合家系遗传力的显著性检验

<正> 性状的遗传力是一个很重要的遗传参数,它反映了性状遗传变异的规律,通常用于估计育种值、制定综合选择指数和预测家畜的选择反应等,因此它是家畜育种工作中的一个重要依据。 吴常信(1981)首次定义了“全同胞—半同胞”混合家系,所谓一个混合家系,是指由一头公畜与数头母畜交配后所生后代组成的家系,即同一母畜内的后代是全同胞,不同母畜间的后代是半同胞。在猪、     

近交危害及其防止措施

所谓近交是指亲缘交配，它是指五代以内双方具有共同祖先的公母畜交配。在家畜中近交程度最大的是父女、母子和全同胞交配。其次是半同胞、祖孙、叔侄、姑侄、堂兄妹、表兄妹间的交配。近交是育种工作的重要工具，在培养或改良新品种中发挥着重要作用。但对于个体养殖户和...     

近交系猪群的现代化饲养管理

1近交系的命名 近交系是由全同胞兄妹或亲子连续20世代交配而育成的，其近交系数应达到或大于98．6％，且所有个体可以追溯到一对共同祖先。亲子配或全同胞配是近交的2种极端形式，也称“急骤近交”。     

复合育种值在畜牧生产中的应用研究

复合育种值是根据家畜个体本身、祖先、同胞及后裔的性能资料，采用估计育种值的方法计算所得。利用宁夏地区某牛场14头荷斯坦奶牛及其各种亲属（母亲、同胞、女儿）的产奶量对其产奶量复合育种值进行了计算，并根据复合育种值的高低对所选14头奶牛进行了排序，其中9号、13号、8号及12号奶牛具有较高的复合育种值，分别为6611．78、6519．58、6511．78和6506．08kg。据调查，此种排列与实际生产中表现相一致。因此，复合育种值为奶牛选种选配提供了重要依据，在家畜育种生产中具有重要的实践意义。     

蜜蜂闭锁种群育种

闭锁种群育种，简称闭锁育种，通称闭锁繁育，普遍运用于家畜育种中，例如20世纪40年代提出的家畜“群体继代选育法”就需运用闭锁繁育。该选育法的要点是：①选集基础群。根据育种目标的要求，选择和搜集育种素材，用其组成基础群，使制约待建品系的每一特征和特性的基因，都汇集在基础群这一基因库内：     

松辽黑猪的培育

本文介绍了在已组建的基础群的基础上,育种前期以质量性状选择为主,采用三品种杂交,重视亲本品种和优秀个体的选择,采用避免全同胞和半同胞的随机交配法,控制近交系数,采用重叠式不完全小群闭锁选育法等选育方法培育松辽黑猪。     

Hasemann-Elston回归分析法

Hasemann- Elston 回归分析法是由Hasemann和 Elston于 1 972年针对在人类群体中存在全同胞小家系的情况下进行基因定位而提出的 ,以下将该方法作一介绍。1　基本假定　　 Hasemann- Elston回归分析法适用于在全同胞家系中进行基因定位之用 ,随着家畜基因定位研究工作的开展 ,该方法也同样适用于具有全同胞家系的畜种 ,如猪及体型较小的反刍动物。应用该方法的基本假定为 :在一个全同胞家系中假定只有二个全同胞 ,其双亲的某一遗传标记都为杂合子 ,并至少有三个等位基因 ,如父亲有等位基因“A1”和“A2”,母亲为“A1”和“A3”,这样根据…     

技术创新，优质禽业发展的不竭动力——第六届中国优质禽育种与生产研究会学术讨论会暨代表大会：优质鸡肌内脂肪含量遗传选择

提高肌肉品质是优质肉鸡育种的主要目标之一。肌内脂肪（IMF）是肌肉品质的主要指示指标，它通过氧化时对肌纤维束的溶解作用而提高肌肉嫩度和多汁性。而且IMF富含磷脂，磷脂通过美拉德（Mailard）反应产生香味。将IMF作为主选性状进行选育，可以提高肌肉品质。本实验采用矮脚肉鸡F系（合成品系j脂肪沉积能力强，正向选择）和北京油鸡（地方鸡种，体脂少，双向选择）为育种素材，将90日龄胸肌IMF含量作为主选性状，从2000年开始，已完成了6个世代的选育，其中选择系保持500－800只产蛋母鸡群量，对照系保持70只公鸡，200只母鸡的随机交配群体。选择方法采用同胞测定，家系选择。     

家畜育种值估计方法及其发展

家畜育种的目的和任务就是选择优秀的公畜和母畜留作种用,通过它们之间的合理交配产生优良的后代,如此经过世代选择,从而提高家畜的生产水平。从遗传学角度来讲,只有通过基因型选择才能得到最大的选择效果,即按家畜的育种值进行选择。但是,育种值不能直接进行度量,只有通过表型予以估计。因此,家畜育种值的估计就成为家畜育种中主要的和经常性的工作。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in