杜洛克约克夏长白种猪的氟烷基因与经济性能之间的相关性研究

本研究采用PCR-RFLP技术检测了长白、约克夏和杜洛克猪群的RYR基因的多态性,分别分析了RYR基因与猪的产仔数(TNB)、初生重(LBW)、仔猪28日龄重(LWT28)、背膘厚(TheBackfatThickness)、死胎数(ND)之间的相关关系。对群体遗传结构分析表明,在约克夏、杜洛克猪群中,有氟烷基因存在;长白猪群中,未发现有该基因存在。通过对RYR基因分型研究,在约克夏和杜洛克猪群中,未发现有隐性纯合基因型(nn)个体,仅存在纯合基因型(NN)个体和杂合型(Nn)个体。不同氟烷基因型(NN,Nn)之间在产仔数方面存在差异性显著(P<0.05)。约克夏猪群中,比较了头胎的平均产仔数,结果发现,Nn个体的产仔数(TNB)比NN个体平均多1.7045头/胎;杜洛克猪群中,Nn个体的产仔数(TNB)比NN个体平均多2.5758头/胎;经产胎次中,平均产仔数分别多0.3898和0.9956头/胎。杂合型(Nn)个体显著高于纯合基因型(NN)个体(P<0.05)。在两层和三层膘厚检测中发现,在杜洛克猪群和约克夏猪群中,纯合基因型个体均低于杂合基因型个体,因此在背膘厚方面两种基因型(NN,Nn)个体存在差异性显著(P<0.05)。在仔猪28日龄重方面,杂合型(Nn)个体则低于纯合基因型(NN)个体,差异性显著(P<0.05);仔猪初生重方面,纯合基因型个体的仔猪初生重与杂合型个体差异不显著(P>0.05);死胎数方面,?     

七个贵州地方猪种RYR1基因突变的分布

兰尼定受体1(Ryanodine Receptor1,RYR1)基因中的单个氨基酸(R615C)是导致猪应激综合征、影响肉质的重要原因。采用RFLP方法,以大白猪、二个杂交猪群(杜洛克×长白猪×大白猪和长白猪×大白猪)为对照,研究了糯谷猪、萝卜猪、柯乐猪、宗地花猪、香猪、关岭猪和黔南黑猪7个贵州地方猪种RYR1基因突变的分布类型。结果表明,从柯乐猪中检测到一例杂合基因型RYR1Nn,杂合基因型的发生频率为2.08%,其余6个贵州地方猪种糯谷猪、萝卜猪、宗地花猪、香猪、关岭猪和黔南黑猪均为正常的基因型RYR1NN,对照组中,外三元、外二元杂交猪和大白猪中均检测到RYR1Nn基因型,杂合基因型的发生频率分别为11.11%、12.12%和5.77%,说明贵州地方猪种中RYR1基因的突变频率低于商品猪,但也存在一定的比例,应加强对地方猪种的利用和保护。     

猪遗传性对其鲜腰排的可口性、颜色和外观特征的影响

本研究是为了确定不同遗传背景猪的猪肉品质特征。试验用猪来源于 :杜洛克 ,皮特兰 (氟烷阴性 ,NN) ,皮特兰(氟烷阳性 ,nn) ,巴克夏猪 ,汉普夏猪 (rn+) ,汉普夏猪 (RN- )和一个合成系。以 10人为一组 ,通过训练 ,评估没烤过的瘦肉和肥肉的外观以及烤猪排的风味和肌理。同时测定 HunterL*、a*和 b*值 ,色泽角度 ,烹调损失和 Warner- Bratzler剪切力。猪的遗传背景不同 ,其猪肉在视觉上颜色有差异。杜洛克、巴克夏、皮特兰 - nn和合成系猪的排骨粉红色最浅。巴克夏猪的排骨瘦肉中大理石纹最多 ,而皮特兰 - nn猪的排骨瘦肉中大理石纹最少 ;皮特兰 (nn)和汉普夏 (rn+)猪的排骨 a*值最高 ,而杜洛克、皮特兰 (NN)和汉普夏 (RN - )猪的排骨 a*值最低 ;就排骨的烹调损失而言 ,杜洛克猪低于汉普夏 (rn+)、皮特兰 (NN)和合成系猪。皮特兰 (nn)和汉普夏 (rn+)猪的排骨剪切力最大。汉普夏 (RN- )猪的排骨肉汁最多 ,其次是汉普夏 (rn+)、皮特兰 (NN)、巴克夏和杜洛克猪。剪切力分别与异味强度、金属味和咀嚼性成正相关 (r分别为 0 .72、0 .94和 0 .6 9) ,与甜度成负相关 (r=- 0 .73)。综上所述 ,遗传背景对所测的许多肉品质特性有重要影响     

部分引进猪种α1-岩藻糖转移酶基因多态性研究

本研究采用PCR RFLP技术对4个引进猪种杜洛克、约克夏、长白猪和皮特兰共计122头猪的FUT1基因进行了多态性分析。结果表明：4个猪种在该FUT1基因座位存在多态性，但抗性基因型AA仅在杜洛克和皮特兰猪中分布。卡方检验结果表明，长白猪与皮特兰间FUT1基因基因型分布差异极显著，长白猪与杜洛克猪之间差异显著，约克夏与皮特兰间差异也显著。     

规模化养猪的关键——合理搭配品种

合理搭配品种对养猪意义极大。目前外国优良四大名猪吉林省都有,这就是丹麦长白猪、英国大约克夏猪(也可以称大白猪或苏白猪)、美国杜洛克红毛猪、美国汉普夏白带猪,其中长白猪用得最早最普遍,汉普夏猪用得最少,近年来约克夏猪也开始受欢迎。有的地方由于长期连续使用长白猪进行级进杂交,商品猪开始变得又长又窄逐渐退化,而约克夏猪粗而短,前期生长较快,用它和长白杂种杂交后代变得粗而宽很受养猪户的欢迎。杜洛克猪由于毛色红、杂交后代不是白色,开始不受欢迎,但杜洛克公猪和长白杂种杂交后其后代绝大多数为白色,因此作为第二父本还是比较理想的。但无论长白还是约克夏、杜洛克,由于生长快、瘦肉率高,要求条件也较高。一旦饲料、气候、管     

大约克、杜洛克及长白猪胴体性能及肉品质比较

选择出生日期相近、生长发育良好、体重100 kg左右的大约克、杜洛克及长白猪各10头屠宰,测定其胴体性能、肉质性状及背最长肌氨基酸、脂肪酸含量。结果表明,长白猪胴体直长比杜洛克高3.31%(P0.05),平均背膘厚大约克比长白低27.48%(P0.01),胴体瘦肉率以杜洛克猪最高(61.17%),分别比大约克和长白猪高3.49%(P0.05)、4.44%(P0.05)。杜洛克a值最高(15.30),分别比大约克和长白猪高12.58%(P0.01)、11.76%(P0.01);a24值杜洛克比长白高7.27%(P0.05);背最长肌剪切力以杜洛克最小(3.15 kg),分别比大约克及长白猪低25.36%(P0.05)、24.28%(P0.05);肌纤维直径以长白猪最细(70.30μm),比杜洛克低12.52%(P0.05);肌内脂肪含量以杜洛克猪最高(2.13%),分别比大约克和长白猪高65.12%(P0.01)、19.66%(P0.05),长白猪比大约克猪高37.98%(P0.05)。背最长肌17种氨基酸和4种脂肪酸含量品种间差异不显著。     

提高仔猪成活率的技术要点

1能繁母猪的品种 我国优良的地方猪品种具有性早熟、产仔多、耐粗饲等特点,但是瘦肉率低,有待于进一步选育与提高。引进的国外猪品种,瘦肉率较高,生长快,饲料转化率高。长白猪平均产仔数11.1头,约克夏猪平均产仔数10.75头。杜洛克猪平均产仔数9.78头,汉普夏猪平均产仔数8.66头,皮特兰猪平均产仔数9.7头。由于品种造成的产仔数低的因素改变起来相当困难,在生产中应多选择一些繁殖能力强的品种猪作种用,以提高产仔数。     

杜洛克、汉普夏、波中回交母猪杂种后代的生产性能比较

据D.L.Kuhlers,S.B.Jungst和J.A.Little(1985)报导,为了测定不同品种的母猪对仔猪断奶前后各种生产性能的影响,试验采用杜长(3/4杜洛克×1/4长白)、汉长(3/4汉普夏×1/4长白)、波长(3/4波中×1/4长白)回交母猪100头,在每头母猪的发情期中与2头约克夏公猪随机交配(共用约克夏公猪9头),计299窝,产仔猪3721头。妊娠期间全部饲养在未     

瘦肉型商品猪杂交组合筛选

试验采用公猪有杜洛克(杜)、汉普夏(汉)、约克夏(约),杂种母猪有约克夏×长白(约长)、约克夏×苏白(约苏)、梅山×长白(梅长),杂交方式为杜×约长、杜×约苏、汉×约长、汉×约苏、约×梅长5种.每一组合配种30窝.从每个组合的后代中挑选12～14头仔猪作肥育试验,180日龄时各挑选4头猪作屠宰测定.试验结果经方差分析,产仔数、180日龄活重,各组合间差异不显著(P>0.05);各组合料肉比为2.95～3.29,90kg屠宰各组合瘦肉率(除约×梅长51.14%外)均高于55%.结果表明,在主要生产性能上各组合差异不显著,杜洛克、汉普夏、约克夏均可作为三元杂交的终端父本.     

不同猪种ESR基因多态性的PCR-RFLP分析

运用PCR-RFLP方法,检测了杜洛克、约克夏、长白猪、皮特兰、梅山猪、二花脸猪、枫泾猪、荣昌猪、苏太猪等9个国内外猪种的ESR基因PvuⅡ位点多态性.结果表明,在约克夏猪、二花脸猪、枫泾猪和苏太猪中检测到了AA、AB、BB 3种基因型,在杜洛克猪、皮特兰猪中检测到AB、BB 2种基因型,在长白猪、梅山猪、荣昌猪中只检测到了AB基因型.在本研究中不同品种的A、B基因频率差异显著,总体上在国外猪群体中A等位基因为优势等位基因,而地方猪种中B等位基因为优势等位基因.     

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.     

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     

Evaluation of the Microbiological Status of Milk and Various Structures in Mammary Glands from Naturally Infected Dairy Cows

A knowledge of the microbiological status of milk and of the different structures in the mammary glands has great importance in elucidating the pathogenesis of mammary gland infections. The objective of this study was to evaluate the microbiological status of various structures in the mammary glands from naturally infected dairy cows following slaughter. A total of 94 samples of milk, 184 samples of mammary parenchyma, 168 samples of gland cisterns, and 168 samples of teat cisterns were collected for microbiological examination. Microorganisms were detected in 59.9% of all samples, 67.0% of the milk samples, 70.1% of the mammary parenchymas, 55.9% of the gland cisterns and 48.8% of the teat cistern samples. When all samples were considered, coagulase-negative Staphylococcus were the most prevalent (35.7%) followed by coagulase-positive Staphylococcus (12.2%), Corynebacterium bovis (2.4%), Prototheca sp. (1.9%), and Streptococcus dysgalactiae (1.5%). There was a significantly higher occurrence of microorganisms in the milk and mammary parenchyma compared to the gland cisterns and teat cisterns. This revised version was published online in July 2006 with corrections to the Cover Date.     

Development and survival of free-living stages of gastrointestinal nematodes of sheep and goats on pasture in the Nigerian derived savanna

Four grass plots were sequentially contaminated with goat faeces containing known numbers of unembryonated eggs of predominantly Haemonchus contortus and Trichostrongylus spp. between October 1982 and April 1983. Four other plots were similarly contaminated with sheep faeces between February and May 1987. An additional plot was repeatedly contaminated with sheep faeces from February to April 1987. Populations of free-living stages in faeces and of infective larvae (L₃) in the herbage were subsequently monitored until the end of April and June of 1983 and 1987 respectively. During February and May 1987 two control cultures of sheep faeces were incubated in the laboratory at 25°C–30°C and at a constant temperature of 50°C and the free-living development was also monitored. L₃ developed very readily in the faeces cultured at 25°C–30°C and in those spread on a grass plot in October, at the end of the wet season, but developed less on the plot contaminated in May at the start of the wet season. Worm eggs in faeces deposited on plots during the hot dry season (December to April) or incubated at 50°C died and disintegrated after 24–48 h exposure to the high environmental temperatures. The results indicate that it is unlikely that gastrointestinal nematodes of sheep and goats can develop or survive on open pasture during the dry season in the Nigerian derived savanna zone.