共查询到20条相似文献，搜索用时 62 毫秒
1.
夏季的奶牛场,由于温度和湿度上升,奶牛普遍经历着“热应激”。母牛舒适度是奶牛生产性能能否达到最大的关键。一般来说,当温度超过20℃、湿度高于85%,母牛开始遭受热应激,其具体表现为牛场70%以上的奶牛呼吸频率超过80次/分钟,直肠温度超过39℃,干物质采食量降低10%以上,产奶量降低10%以上。泌乳母牛自身产生大量体热,如果畜舍内空气流通不利,母牛自身体温就与周围空气的温度十分接近,那么高温高湿就会降低奶牛的采食量,造成奶牛产奶量下降,进而降低奶牛繁殖性能。除此之外,在夏季新的饲草料的供应变化(饲料种类变化包括高浓度精饲料、新刈… 相似文献
2.
奶牛养殖的适宜温度范围是-4～18℃.一旦气温高于26℃,奶牛便出现采食量下降,产奶量减少;气温达到或超过38℃,湿度为20%时,奶牛会出现热应激;38℃气温,湿度为80%时,可能导致奶牛死亡.夏季减少高温对奶牛生产造成的不利影响是获得全年高产的关键. 相似文献
3.
浙江地区夏季高温高湿,奶牛极易发生热应激反应。热应激时,奶牛采食量降低、产奶量下降、乳品质降低、繁殖性能下降,给奶牛业夏季生产造成巨大的经济损失。本文结合现有文献,分析了热应激对奶牛造成的危害,提出了缓解奶牛热应激的思路及措施。旨在探索解决奶牛热应激的技术和方法,为减少夏季奶业损失提供科学依据。 相似文献
4.
黑白花奶牛是耐寒怕热的家畜，适宜温度范围44～211℃，产奶最适宜温度10℃，当环境温度自21℃升高至35℃，产奶量将大幅下降，乳的组成亦发生变化。合肥地区属于亚热带季风气候，夏季温度高达35℃以上，极端最高温度达40℃，奶牛长时期处于这种环境中，高温引起热应激反应，散热困难，体温升高，采食量减少，增加散热的能量消耗和体蛋白质的分解，造成内分泌活动和酸碱平衡失调乃至死亡。为降低热应激对奶牛生产的影响，我场在夏季采用强制通风和喷雾的措施，可提高奶牛单产达20％的显著效果。1 材料与方法11 喷雾设备111 加压泵… 相似文献
5.
奶牛热应激是指奶牛对于不利于生理条件的高温环境产生的非特异性应答反应的总和。奶牛正常体温为38．5℃,适宜的饲养环境温度为10-20℃,当环境温度超过25℃时便会出现应激反应。热应激严重影响奶牛采食量,据报道,奶牛在环境温度为22～25℃时采食量开始下降,30℃以上时采食量明显下降,40℃时采食量不会超过正常时的60％,40℃以上时耐热性差的奶牛品种将停止采食。 相似文献
6.
夏季高温高湿．由于奶牛汗腺不发达．对高温炎热的耐受性很差,极易产生热应激反应。奶牛在热应激时表现采食量减少,产奶量下降．发情紊乱．日射病、热射病（中暑）发病率增高,稍不注意就会造成很大的经济损失。通过加强饲养管理．可以减少热应激程度,保持奶牛在夏季的高产稳产。现将高温高湿对奶牛生产的影响及应对措施介绍如下．供参考。 相似文献
7.
荷斯坦奶牛耐寒不耐热,最适宜的温度为9～16℃,当温度达到25℃以上即影响其产奶量。在炎热的夏季,高温和高湿一同作用时,会加重奶牛的热应激反应,导致产奶量下降,这是由于干物质采食量的减少造成的。在环境温度为20℃的情况下,1头600 kg的奶牛日产27 kg的奶,需要消耗18.7 kg的干物质,而环境温度达到35℃时,干物质采食量下降到16 kg。 相似文献
8.
热应激是指鸡在高温环境下,由于体温调节及生理机能趋于紊乱而发生的一系列异常反应,对鸡的采食量、生产性能、饲料转换率等造成不同程度的影响,甚至鸡出现热休克和死亡。1热应激产生的原因主要有3方面原因:①夏季高温天气,②规模化养殖,饲养密度大;③舍内通风不良。2热应激对鸡的危害2.1干扰鸡只的正常生理机能。热应激可使鸡的心跳加快,血压下降、呼吸加快、喘息严重时可出现呼吸性碱中毒,血液pH值上升,钠钾比例失调。2.2降低鸡只的生产性能。①高温时,采食量下降,试验表明,环境温度在21~31℃时,每上升1℃,采食量下降1.7%,在32~38℃范围… 相似文献
9.
在炎热的夏季,由于奶牛的排汗速度慢,当受到高温刺激时,牛体温升高,呼吸加快,皮肤代谢发生障碍,食欲下降,采食量减少;体内营养呈负平衡,造成奶牛体重减轻,体况下降;产奶量和乳脂率同时下降,繁殖率下降,患病和死亡率增加.温度一旦超过27℃,奶牛的采食量就会下降,开始对奶牛产生不利影响.当温度达到或超过32℃时,其产奶量会明显下降,减产3~20%.高温、高湿对奶牛生产性能的影响更大. 相似文献
10.
在夏季高温环境下,由于奶牛汗腺不发达,对高温炎热的耐受性很差,极易产生热应激反应。尤其当外界温度超过30℃以上时,奶牛就会表现采食量减少,易造成奶牛的产奶量下降,,发情紊乱、热射病发病率增高,稍不注意就会造成很大的经济损失,降低经济效益。为确保奶牛的健康,保持产奶量的稳定,安全度过炎热夏季,在奶牛饲养过程中应正确分析夏季影响奶牛产奶量的原因并围绕提高产奶量认真做好预防控制措施。 相似文献
11.
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. 相似文献
12.
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%). 相似文献
13.
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. 相似文献
15.
In late November 1991, 1883 clinics in Canada were sent a questionnaire to assess the status of Dirofilaria immitis in dogs in 1991 and there was a 60.0% response. There were 344,031 dogs tested for heart-worm (HW), 627 were found infected and the prevalence of HW infection was 0.18%. There were 417 dogs with HW in Ontario, 116 in Manitoba, 38 in Quebec, 53 in British Columbia, three in Alberta, and one in Nova Scotia. In British Columbia, all of the infected dogs but one were from the Okanagan valley which, as from 1991, is a new focus of infection in Canada. Most dogs with HW had not been on preventive medication in 1990, and the prevalence among dogs tested and unprotected was 0.59%. That prevalence was considerably higher in endemic areas. Companion dogs, over three years of age and maintained primarily outdoors in rural areas, were most frequently infected. One cat was diagnosed with D. immitis and 33 dogs had Dipetalonema reconditium. 相似文献
16.
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. 相似文献
17.
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%). 相似文献
18.
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. 相似文献
20.
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. 相似文献
|
