出雏时间与雏鸡性别比例关系的研究

以尼克红商品蛋鸡鸡胚和出壳雏鸡为材料，分析了不同出雏时间雏鸡性比例的变化，旨在探讨出雏时间与雏鸡性别的关系及鸡胚在孵化期不同性别生长发育的规律，为精细调控孵化条件和制定鸡苗销售计划提供依据。结果表明，不同时间出壳的雏鸡，性比例存在明显差异(P<0.05或P<0.01),并呈现出明显的规律性。在20d12h之前出壳的母雏比公雏多，20d时母雏比例最高(公母性比值为0.268±0.054)；其后公雏比例增加，到21d时公雏比例最高(公母性比值为2．184±0．090）；此后，母雏比例又逐渐增加。到21d16h时公母比例降低到1.453±0.099;但接近出雏结束时，公雏比例又有所回升，至出雏结束时，公母比例上升为1.75±0.057。     

六个蛋用型品种雏鸡出壳时间与性比率的观察

根据１９８７～１９９３年２月～７月对６个蛋用型品种鸡共２２批６７１３５只雏鸡出壳时间与性比率以及不同出雏月的性比率进行了观察研究。结果表明：（１）各品种鸡母雏出壳时间均早于公雏，平均早１．６～２．７小时；（２）各品种鸡都是在出雏前期母雏显著多于公雏。出雏后期则公雏显著多于母雏，而且临进出雏高峰期（２０～２０．５天）时公雏略多于母雏。但差异不显著（Ｐ＞０．０５）；（３）各品种的性比率为，京白、星杂５７９、海白、海褐公雏分别比母雏多０．８４％、１．３８％、１．６６％、１．０９％；而星杂２８８和雅康则母雏分别比公雏多１．２２％和０．４８％；（４）季节对性比率有一定的影响，一般早春母雏比例高于公雏，随着外界气温的升高母雏渐趋减少，公雏渐趋增多，即外界气温高的季节母雏比例有所下降。     

罗斯商品代鸡初生雏的公母比例

罗斯鸡是由英国引进的蛋用型种鸡之一。四系杂交的罗斯棕壳商品鸡,其初生雏可观察背部和头部的羽色以鉴别公母(母雏为金黄色或棕色,公雏为银色或白色)。我们于1986年2月5日至7月6日在松江县种禽场采用羽色鉴别方法共测定了21批雏鸡,查明在172550羽出壳苗鸡中,有公雏96606羽,占55.98％;母雏75944羽,占44.02％。通过肛门鉴别检验,白色羽公雏中有2～3％左右实际是母雏,其羽色呈微淡黄     

雏鸡出壳速度与性别关系的初步观察

雏鸡的出壳速度,即雏鸡啄破蛋壳开始至完全破壳出雏所需的时间。过去认为,雏鸡出壳的速度,只受种蛋品质、孵化条件等因素的影响,本次观察初步证明:雏鸡的出壳速度,与雏鸡的性别有着极大的关系,即公雏的出壳速度快,母雏的出壳速度慢。     

雏鸡公母鉴别歌

养鸡致富门路好，识别公母很重要．雏鸡出壳落下地，公母体态有差异．公雏头大脚又高，母雏脚矮且头小；公雏体躯多较长，母雏体躯则稍园；公雏走路直线行，母雏拉屎往后蹲；用指轻模鸡体尾，公略尖来母园肥；吹开尾毛看肛门，下有白点定是公；公雏翅羽略呈尖，母雏翅现稍微园；抓住鸡脚倒提起，头部下垂是母鸡；头向上钩弯曲颈，展翅拍打便是公；把鸡抓起放下地，若是公鸡跑得急．此说虽非句句灵，十之八九不差分，真知来源于实践，熟能生巧功自成．雏鸡公母鉴别歌@郭松阳$临湘市畜牧水产局!414300@刘菊清$临湘市园艺场鸡场@严细珍$临湘市…     

初生雏鸡的雌雄鉴别

雏鸡的雌雄鉴别在生产中具有广泛的意义,蛋用型雏鸡出壳后将公雏淘汰或单养作肉用,可节省育雏房舍、设备和饲料;肉用型雏鸡公母分养则母雏因没有公雏抢食而发育整齐,公雏又可喂给蛋白质含量较高的日粮促进快速育肥,缩短饲     

提高种公鸡利用率的措施

父母代鸡场是商品代鸡场的基础 ,种鸡品质的好坏对商品鸡至关重要。种公鸡的培育进雏前 2周 ,对育雏舍要严格按照消毒—冲洗—消毒的顺序进行消毒。对所有育雏用具熏蒸消毒 ,进雏前 3ｄ打开门窗通风、干燥 ,进雏前 1ｄ鸡舍升温至 36℃ ,相对湿度 60 %～ 80 %。进雏后 ,应在接雏室或操作间 (室温为 2 8～ 30℃ )清点数量 ,剔除弱雏、死雏 ,公母雏分开 ,进行喷雾消毒 ,放置 2ｈ装笼。引种时公母比例 ,一般为 1∶1 0 ,公雏单独装笼 ,密度比母雏减少 30 %～ 50 % ,笼养至 8周龄 ,每只鸡应占面积 370ｃｍ2 。7～ 1 0日龄 ,种公雏随母雏一起断啄。…     

种蛋长短径比例与所孵雏鸡性别关系的研究

一般认为，雏鸡的性别只有在出壳之后才能区分，在出壳之前，人们目前还无法准确地进行预测。但最近有人提出：种蛋长短径比例与雏鸡性别具有明显的相关性。他们认为长短径之比小于1.31时，鸡蛋呈倒三角形，孵出的鸡母雏占大多数；长短径之比大于1.36时，鸡蛋头尾难分，孵出的鸡大多为公雏。如果该理论成立，将会对养鸡业产生巨大的影响。为了探讨种蛋长短径比例与雏鸡性别的关系，我们特做了如下试验。材料与方法1种蛋的来源与分组：选取我校家禽室七五攻关培育的豫州蛋鸡913商品代种蛋511枚，逐一测定其长短径，并根据长短径比例将其分为…     

右岐杂鸡快、慢羽系着羽速度差异的研究

经三年多的选种和培育,我们已建立了石岐杂鸡的快羽系与慢羽系,并成功地进行繁衍和杂交,作为石岐杂鸡商品代自别雌雄的亲本.快、慢羽两系的主要差异在于其羽毛生长状态.按照遗传理论,负责雏鸡翼羽生长速度的基因在性染色体上,带有慢羽基因的公、母雏,出壳时主翼羽短于或等于覆主翼羽,有的主翼羽尚未长出;带有快羽基因的母鸡或带有纯合快羽基因的公雏,出壳时主翼羽长于覆主翼     

农户养鸡如何编制饲养计划

农户养鸡 ,对鸡群的周转计划、房舍设备计划以及饲料计划等要进行科学编制 ,做到心中有数。下面以 1 0 0 0只蛋鸡为例 ,编制一个饲养计划 ,供参考。1　鸡群的周转计划1 .1　育雏　需购进公母混群雏鸡 2 60 0只 ,育雏期为 6周。如购买的是鉴别母雏 ,则只需要 1 30 0只。假设育雏率为 90 % ,育雏末期成活数 =2 60 0只× 90 % =2 340只。公母比例为 1∶1。母雏数 =2 340只÷ 2 =1 1 70只 ,公雏可淘汰 ,也可集中育肥出售。1 .2　育成　从 6周末开始 ,由雏鸡转为育成鸡 ,育成期为 1 4周。育成率为 95 %。育成母鸡 =1 1 70只× 95 % =1 1 1 1只 ,…     

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.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

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.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

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