影响家兔人工授精效果的因素

1　激素的影响在家兔人工授精中 ,使用的主要是蛋白质激素 ,这类激素有 :促性腺激素释放激素 (ＧｎＲＨ)、促性腺激素 (ＦＳＨ和ＬＨ)、人绒毛膜促性腺激素 (ＨＣＧ)、孕马血清促性腺激素 (ＰＭＳＧ)以及现在人工合成的促排 2号和促排 3号 (ＬＲＨ -Ａ2和ＬＲＨ -Ａ3 )。这些激素主要影响排卵效果 ,而排卵效果与人工授精的受胎率和产仔数直接相关 ,所以研究人工授精的受胎率和产仔数的重点是研究激素对促排效果的影响。家兔作为哺乳动物 ,在生殖活动中 ,与其他哺乳动物不同 ,属刺激性排卵。家兔一年四季均可发情 ,但发情后若不交配 ,则卵巢…     

外源生殖激素调控母猪生殖能力的研究

对注射外源生殖激素对后备母猪、断奶母猪生殖能力的影响进行了探讨、研究。试验选择9月龄健康纯种大白和长白母猪,分析外源生殖激素(或者激素组合)对母猪发情及产仔情况的影响。结果表明,肌肉注射800IU和1000IU绒毛膜促性腺激素(HCG)均能显著提高后备母猪受孕率;肌注孕马血清促性腺激素(PMSG)800IU+HCG400IU可显著提高大白纯种母猪的发情、受孕及产仔率;使用氯前列烯醇(PG)或者与PMSG、HCG组合使用,在发情率和受孕率、产仔数等方面都有较好的效果。研究指出注射外源生殖激素的方法可以有效调控母猪的生殖能力,诱发后备母猪和断奶乏情母猪发情面具有实际应用价值。     

猪的繁殖试验(十三)

青年母猪初情期前的诱导排卵和繁殖力美国格思里(1977)取160日龄青年母猪28头,分为5组: 第1组,每头注射赋形剂。第2组,每头注射合成GnRH类似物(AY.25205)500微克(GnRH系促性腺激素释放激素—译者)。第3组,每头注射孕马血清促性腺激素400国际单位、人绒毛膜促性腺激素200国际单位。     

不同激素药物促进后备猪同期发情试验报告

本研究综合应用烯丙孕素、孕马血清促性腺激素等对某商品猪场8~9月龄的400头长大二元杂后备母猪进行同期发情试验,以进一步研究外源激素产品对后备母猪同期发情和繁殖性能等方面的影响。结果表明烯丙孕素+低剂量的孕马血清促性腺激素组合配种利用率最佳。     

母猪定时输精常用激素与应用效果的研究进展

母猪定时输精是通过对母猪发情、排卵过程实施同步化调控,在预定的时间对母猪进行人工输精,最终达到批次化生产目的的一项繁殖新技术,具有降低成本、避免漏配、便于管理、提高生产效率等优点。其中调控母猪发情常用的激素包括烯丙孕素、PMSG/eCG、PG600;调控母猪排卵常用激素包括GnRH及其类似物、hCG、pLH等。本文主要对母猪定时输精中常用激素进行介绍并综述了该技术的应用效果及其对母猪繁殖性能的影响,以期为生产实践提供借鉴。     

提高母猪繁殖性能的技术措施

1提高产仔数的措施1.1增加母猪排卵数实践证明,对空怀母猪在配种前进行短期优饲,有促进发情排卵和容易受胎的良好作用。另外,给母猪一次注射750～1 500 IU的孕马血清,并配合使用500～1 000 IU的人绒毛促性腺激素,可诱导母猪发情并刺激母猪超数排卵。     

后备母猪培育和管理

自20世纪50年代起,基因选择、营养、饲养设施和疾病控制等诸多研究进展已经被应用到现代猪肉生产中,从而产生了高产母猪和相关的管理措施与技术。本文的目的是综述应用于繁殖管理方面的文献和最新的行业生产技术,尤其是重点评述辅助繁殖技术及其在提高母猪生产力上的应用情况。与20年前的母猪相比,现代母系猪种食欲较低,但瘦肉的生长潜力较高。因此,会影响后备母猪发育和使用年限的营养需求、管理技术和生产工艺需要持续的更新。不能准确地确定母猪的发情会严重影响母猪的分娩率和窝产仔数。然而,即使能够准确地确定母猪发情也不能消除由发情开始至实际排卵之间的时间间隔差异所造成的影响。然而,在停用烯丙孕素之后,给断奶母猪和后备母猪服用促性腺激素释放激素类似物,能克服这种差异,因此能够引发母猪同步排卵,这使养猪场能够对繁育母猪定期进行人工授精。受温度和光周期调控影响的季节性不孕是养猪生产中一个持续存在的问题。随着消费者对动物福利越来越重视,对养殖场员工进行技能培训显得越来越重要。用于后备母猪同步发情的烯丙孕素可以使母猪的妊娠期延长2 d～3 d,以使群内母猪能够同步分娩和推迟断奶后的发情。P.G.600可以用来诱导初情期前的后备母猪发情,并可治疗季节性乏情。与子宫颈授精相比,子宫内授精(即深部输精)对每份精液或每次授精所需的精子数明显减少。在人工授精后3～5周,实时超声检查可以查明母猪是否妊娠。在正常的预产期前2 d,前列腺素F2α能有效诱导母猪分娩。同步排卵、单次定期人工授精和诱导生产可使母猪同步分娩,这有助于养猪场进行生产管理,并可减少死胎,降低仔猪死亡率。人工接产和助产对确保仔猪在出生后能够及时吃到充足数量的初乳是非常重要的。本综述还提出了新的性能术语。     

利用激素诱导青年母猪发情及人工授精的受胎效果观察

孕马血清促性腺激素（血促性素）PMSG具有促卵泡素（FSH）和促黄体素（LH）的功能,主要是FSH功能,能促卵泡发育、成熟。人绒毛膜促性腺激素（绒促性素）hCG具有促黄体素（LH）和促卵泡素（FSH）的功能,主要是LH功能,能促卵泡成熟、排卵。二者协调可以使处于卵巢静止的青年母猪卵泡发育、成熟、排卵。     

母猪乏情的处理方法

在养猪生产中，母猪乏情是一个常见问题。使这些乏情母猪发情、配种并受胎，对提高母猪的经济效益意义极大。乏情的主要原因是卵巢处于相对静止状态。垂体不能分泌足够的促性腺激素以促进卵泡发育成熟及排卵。在这种情况下，只要增加体内促性腺激素(Gn)、促性腺激素释放激素(GnRH)及其类似物，基本上可促进卵泡发育成熟，使乏情母猪发情。而对于卵巢上有持久黄体或黄体囊肿的母猪，适时给予氯前列烯醇钠(PGF2α)，就可消除黄体使母猪发情。     

集约化养猪场繁殖控制技术

1同期发情1.1青年母猪的同期发情1.1.1未进入初情期的青年母猪的发情同期化——促性腺激素 PGF2法:每4～6头青年母猪为一群进行群养,根据经验预测青年母猪初次发情的时间,在青年母猪初次发情前20～40天,每头母猪一次注射200IU的人绒毛膜促性腺激素(hCG)和400IU孕马血清促性腺激素eCG或PG600。一般在注射3～6天后母猪表现发情,但发情时间差异较大。如果从注射当日开始,每天让青年母猪与试情公猪直接接触,可增强激素的效果。在禁闭栏内饲养的青年母猪同期发情处理效果不及群养母猪。第一次激素处理尽管能使绝大多数青年母猪在一定时间内…     

Heartworm in dogs in Canada in 1985

In late December 1985, 1485 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1985 and 44% of them responded. Veterinarians reported that 137,300 dogs were blood-tested to check for microfilariae and 1210 dogs were found with heartworm. Another 36 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number diagnosed in 1985 as 1247 (0.91%).

Heartworm was reported from all provinces except Prince Edward Island, Newfoundland and Saskatchewan but most (1126) of the cases were in Ontario. Southwestern Ontario continued to be the primary focus of the infection in Canada. From Quebec, 91 cases were reported mostly from and around Montreal. From Manitoba, 19 cases were reported from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 28% of the cases were observed with clinical signs of heartworm disease and 78% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1988

In late November 1988, 1581 small and mixed animal clinics and institutional veterinarians across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1988, and 46% of them responded. Veterinarians reported that 181,577 dogs were blood-tested for heartworm disease and 367 dogs were found with D. immitis microfilariae. Another 60 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1988 as 441 (0.24%).     

Heartworm in dogs in Canada in 1984

In late December 1984, 1853 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1984 and 35% of them responded. Veterinarians reported that 97,794 dogs were blood-tested to check for microfilariae and 1417 dogs (1.45% of those tested) were found with heartworm. Another 34 dogs were amicrofilaremic, but were diagnosed as having heartworm disease, to give the total number diagnosed in 1984 as 1451 (1.48%). Heartworm was reported from all provinces except Prince Edward Island and Newfoundland but most (1310) of the cases were in Ontario. In Quebec, 126 cases were reported mostly from west of Montreal.

Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 27% of the cases were observed with clinical signs of heartworm disease and 72% had a history of not having left Canada. Southwestern Ontario continued to be the primary focus of the infection.

     

Heartworm in dogs in Canada in 1989

In late November 1989, 1732 clinics and institutional veterinarians were sent a questionnaire to assess the status of Dirofilaria immitis, and 51.7% responded. Of 247,716 dogs tested, 394 had D. immitis microfilariae and 51 were amicrofilaremic for a total of 445 cases and heartworm prevalence of 0.17%. Most (408) of these dogs had no preventive medication and the prevalence among dogs tested and unprotected was 1.01%. That prevalence was considerably higher in endemic areas. Thirty-seven dogs with heartworm had preventive medication. Heartworm was most frequent in companion dogs over three years of age maintained outdoors in rural areas. About 75% of the cases had never left Canada, 26% had clinical signs and 125 were not treated.

Heartworm was reported from British Columbia, Manitoba, Ontario, Quebec, Nova Scotia and Newfoundland, but 383 cases were in Ontario. South-western Ontario was the primary focus of infection. There were 33 cases in Quebec and 24 in Manitoba, mainly found in and around Metropolitan Montreal and Winnipeg respectively.

     

Heartworm in dogs in Canada in 1987

In late November 1987, 1246 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1987, and 50% of them responded. Veterinarians reported that 165,428 dogs were blood tested for heartworm disease and 511 dogs were found with D. immitis microfilariae. Another 78 dogs were amicrofilaremic but diagnosed with heartworm disease to give the total number of cases diagnosed in 1987 as 589 (0.35%).     

Heartworm in dogs in Canada in 1986

In late December 1986, 1224 institutional veterinarians and small and mixed animal clinics across Canada were sent a questionnaire in order to assess the status of Dirofilaria immitis in Canada in 1986; 46% of them responded. Veterinarians reported that 150,989 dogs were blood-tested for microfilariae and 869 dogs were found with heartworm. Another 65 dogs were amicrofilaremic but diagnosed with heartworm disease and one was found with heartworm at necropsy to give the total number diagnosed in 1986 as 935 (0.62%).

Heartworm was reported from Manitoba, New Brunswick, Ontario and Quebec, but most (810) of the cases were from Ontario. South-western Ontario continued to be the primary focus of the infection in Canada. There were 103 cases reported from Quebec, mostly from and around Montreal, and 21 cases from Manitoba, from Winnipeg and surrounding areas. Heartworm was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 33% of the cases were observed with clinical signs of heartworm disease and 81% had a history of not having left Canada.

     

Heartworm in dogs in Canada in 1983

In late December 1983, 2 800 veterinarians across Canada were sent a questionnaire in order to assess the status of heartworm disease in Canada in 1983 and 26% of them responded. Veterinarians reported that 59 504 dogs were blood-tested to check for microfilariae and 771 dogs (1.30% of those tested) were found with Dirofilaria immitis. Heartworm disease was diagnosed in all provinces except New Brunswick and Newfoundland but most (733) of the cases were in Ontario.

Heartworm disease was found most frequently in companion dogs over three years of age maintained mainly outdoors in rural areas. About 31% of the cases were observed with clinical signs of heartworm disease and 64% had a history of not having left Canada. Southwestern Ontario continues to be the focus of the infection and most of the dogs there had not left the province previously.