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阴离子盐酸化日粮钙、镁水平对围产期奶牛血清离子平衡及生产性能的影响 总被引：1，自引：0，他引：1
为了研究阴离子盐酸化日粮钙、镁水平对奶牛血清离子平衡及生产性能的影响,选择12头二胎以上围产期奶牛,采用配对试验设计分成4组(高钙高镁组、高钙低镁组、低钙高镁组、低钙低镁组),从产前3周开始饲喂4种阴离子盐添加剂日粮,日粮阴阳离子差(DCAD)值均为-65 mEq/kg.结果表明:各试验组奶牛的干物质采食量不同程度下降(P>0.05);尿液pH值在5.5～6.5之间变化(P>0.05).产犊当天、产后1天和产后3天,阴离子盐酸化日粮中钙水平对围产期奶牛血清Ca2+浓度有显著影响(P<0.05);产犊当天,阴离子盐酸化日粮中镁水平对奶牛血清Ca2+浓度有显著影响(P<0.05);在产后3天,阴离子盐日粮钙、镁互作对奶牛血清Ca2+浓度有显著影响(P<0.05).各试验组奶牛产奶量差异不显著(P>0.05). 相似文献
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选取2胎以上12头围产期奶牛,采用配对试验设计分成4组,从产前3周开始随机饲喂4种阴离子盐添加剂日粮(高钙高镁组、高钙低镁组、低钙高镁组和低钙低镁组),饲粮阴阳离子差(DCAD)值均为-6.5mEq/100 g DM.研究阴离子盐酸化日粮Ca2+和镁水平对奶牛血清离子平衡及生产性能的影响.结果表明,各试验组奶牛的干物质采食量(DMI)有不同程度下降(P>0.05).尿液pH在5.5～6.5变化(P>0.05).产犊当天、产后1 d和产后3 d,阴离子盐酸化日粮中钙水平对围产期奶牛血清Ca2+浓度有显著影响;产犊当天,阴离子盐酸化日粮中镁水平对血清Ca2+浓度有显著影响;产后3 d,阴离子盐日粮钙和镁互作对奶牛血清Ca2+浓度有显著影响.产犊当天、产后1 d和产后3 d高钙高镁组血清Ca2+浓度均高于其他3组,并显著高于低钙低镁组.产后1 d及产后3 d高钙低镁组和低钙高镁组血清Ca2+浓度也显著高于低钙低镁组.各试验组奶牛产奶量差异不显著. 相似文献
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本试验选用1日龄艾维茵(AA)肉仔鸡120只,随机分为对照和试验二个组,每组6个重复,每重复10只鸡。试验组采用低温(low ambient temperature,LAT)和饲粮添加1．5mg/kg 3,3’,5-三碘甲状原氨酸(3,3’,5-triiodothyronine,T3)的方法诱导产生腹水综合征(ascites syndrome,AS)考察AS对肉鸡生产性能、营养物质利用率、组织钙磷存留、生长激素及AS发病率和死亡率的影响。结果表明：(1)试验组肉鸡生产性能显著降低(p＜0．05),其AS发病率和死亡率分别高达66．7%和23．3%,心脏指数显著升高(p＜0．05);(2)试验组肉鸡在第二周龄时对能量、粗脂肪、粗蛋白、必需氨基酸及大多数氨基酸、钙磷的利用率均极显著或显著低于对照组(p＜0．01或p＜0．05),而对精氨酸和脯氨酸的利用率却分别升高了22．62%和3．87%;第三周,除精氨酸外,试验组肉鸡对营养物质的利用率与第二周的变化相似;试验组肉鸡生长激素的分泌量极显著低于对照组(p＜0．01);(3)试验组肉鸡心脏、肝脏、十二指肠中的钙含量显著提高(p＜0．05),十二指肠磷含量极显著提高(p＜0．01)．心脏磷含量极显著降低(p＜0．01)。由此可知T3与LAT能成功诱发AS,使肉鸡生产性能下降,营养物质利用率降低,血清GH水平下降,生长缓慢,组织钙沉积增加。 相似文献
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本试验选用1日龄艾维茵(AA)肉仔鸡120只,随机分为对照和试验二个组,每组6个重复,每重复10只鸡。试验组采用低温(low ambient temperature,LAT)和饲粮添加1．5mg/kg 3,3′,5-三碘甲状原氨酸(3,3′,5-triiodothyronine,T3)的方法诱导产生腹水综合征(ascites syndrome,AS)考察AS对肉鸡生产性能、营养物质利用率、组织钙磷存留、生长激素及AS发病率和死亡率的影响。结果表明:(1)试验组肉鸡生产性能显著降低(p＜0．05),其AS发病率和死亡率分别高达66．7％和23．3％,心脏指数显著升高(p＜0．05);(2)试验组肉鸡在第二周龄时对能量、粗脂肪、粗蛋白、必需氨基酸及大多数氨基酸、钙磷的利用率均板显著或显著低于对照组(p＜0．01或p＜0．05),而对精氨酸和脯氨酸的利用率却分别升高了22．62％和3．87％;第三周,除精氨酸外,试验组肉鸡对营养物质的利用率与第二周的变化相似;试验组肉鸡生长激素的分泌量极显著低于对照组(p＜0．01);(3)试验组肉鸡心脏、肝脏、十二指肠中的钙含量显著提高(p＜0．05),十二指肠磷含量极显著提高(p＜0．01),心脏磷含量极显著降低(p＜0．01)。由此可知T3与LAT能成功诱发AS,使肉鸡生产性能下降,营养物质利用率降低,血清GH水平下降,生长缓慢,组织钙沉积增加。 相似文献
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缓释钙弹丸博威钙对预防奶牛产后低血钙的影响 总被引：1，自引：1，他引：0
本试验目的是研究缓释钙弹丸博威钙对预防奶牛低血钙的影响。选择二胎及以上胎次的健康母牛30头,根据配对原则随机分为对照组和试验组,每组15头。对照组在产犊前后进行常规饲喂,不喂任何含钙添加剂;试验组在产犊后0h和12h分别投喂一颗缓释钙弹丸。所有试验奶牛分别在产前6h、产犊0h、产后1h、产后13h采集血样、尿样,检测其中钙离子、碱性磷酸酶及其他生化指标的浓度。结果表明,与对照组相比,在两次投喂缓释钙弹丸后各1h(即产后1h及13h),奶牛血钙离子浓度分别提高16.8%和21.1%(P0.05),尿钙离子浓度分别提高77.0%和168.2%(P0.01),但其他血液生化指标如碱性磷酸酶、血糖等无显著变化(P0.05),表明博威钙具有显著提高奶牛血钙离子浓度和尿钙离子浓度的功效。同时,投喂博威钙趋于降低大群奶牛胎衣不下及真胃移位的发生率。 相似文献
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阴离子盐对奶牛围产期血浆离子平衡的影响 总被引：1，自引：0，他引：1
采用20头荷斯坦经产奶牛按配对试验设计,研究在干奶后期(产前约3周)添加阴离子盐添加剂对奶牛产前1周、2周和产后1周、2周及分娩当日血浆离子浓度、胎衣不下发病率以及产乳热发病情况的影响。结果表明,饲喂阴离子盐日粮4d后可使尿液pH值显著降低(P<0.05),试验组与对照组比较产前一周和产后一周血浆钙离子浓度有上升的趋势,分别为(7.98vs7.26)和(7.81vs7.19),距分娩1周血浆镁离子浓度有降低趋势(1.96vs2.16),在分娩当日试验组血浆镁离了浓度低于对照组(1.90vs2.01),产前1周和分娩当日血浆钠离子浓度低于对照组,分别为(123.90vs126.43,P<0.05)和(124.28vs125.93,P<0.05)。在本试验条件下添加阴离子盐对血浆其他离子浓度没有显著影响(P>0.05),通过对胎衣不下发生情况的统计表明,饲喂阴离子盐能够减少胎衣不下的发生。 相似文献
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为了研究过瘤胃复合维生素对围生期奶牛血清生化指标的影响,试验选择围生期健康的荷斯坦奶牛119头,分为2组,对照组奶牛饲喂基础日粮,试验组在基础日粮中添加过瘤胃复合维生素50 g/(d·头),试验期为51 d,分别测定奶牛产前7天、分娩当天和产后30天的血清生化指标。结果表明:与对照组比较,试验组奶牛在产前7天血清中Ca的浓度和产后30天血清中丙氨酸氨基转移酶、天门冬氨酸氨基转移酶、肌酸激酶活性及尿素氮和葡萄糖的浓度均极显著升高(P0. 01),球蛋白、白球比、三酰甘油浓度显著升高(P0. 05)。说明添加过瘤胃复合维生素可提高奶牛产后葡萄糖的浓度,缓解能量负平衡,对预防肝脏疾病和改善蛋白质代谢无显著影响。 相似文献
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试验旨在研究阴离子盐对围产期奶牛产后健康和生产性能的影响。试验选取24头围产前期经产奶牛分为对照组和试验组,对照组饲喂牧场原饲料、试验组于产前21 d饲喂含阴离子盐颗粒料,产犊后统一饲喂牧场原有日粮。结果显示,试验组奶牛尿液pH值维持在5.7~6.9;与对照组相比,试验组血液pH值显著降低（P<0.05）,血钙含量、血糖水平、碱性磷酸酶活性在产后1 d显著升高（P<0.05）;试验组低血钙、产乳热、胎衣不下、真胃移位和乳房炎等疾病的发生率降低,其中胎衣不下发病率显著降低（P<0.05）;但两组间产奶量无显著差异（P>0.05）。综上所述,饲喂阴离子盐颗粒料可提高奶牛的健康状况,维持血钙平衡。 相似文献
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Abbas Rajaeerad Gholam R. Ghorbani Mohammad Khorvash Ali Sadeghi-Sefidmazgi Amir H. Mahdavi Mirja R. Wilkens 《Journal of animal physiology and animal nutrition》2021,105(1):14-25
This study investigated the effects of low potassium diets with different levels of Ca compared to two diets low in dietary cation–anion difference (DCAD) fed prepartum as a strategy to prevent hypocalcemia on sorting behaviour, total tract digestibility, oxidative status and energy and protein metabolism of transition cows. Forty-eight pregnant dairy cows were assigned to 4 treatment groups: Low Ca, low K (LCLK), High Ca, low K (HCLK), Supplementation with anionic mineral mixture (AMS) supplementation with SoyChlor (CAS). After parturition, all animals were fed a standard postpartum diet. Data were collected until 21 DIM. Prepartum urinary pH was significantly reduced by the low DCAD diets, while postpartum Ca homeostasis was affected by the HCLK ration. Feeding AMS induced sorting against particles <1.18 mm in favour of particles >19 mm prepartum. In contrast, cows fed CAS showed an increase in selective consumption of fine particles and sorted against longer particles similar to the HCLK and LCLK groups. Postpartum sorting activity was not affected by the dietary treatments. After calving, apparent digestibility of NDF was significantly reduced in the HCLK group. Prepartum, we observed effects on serum concentrations of non-esterified fatty acids were higher and insulin sensitivity was lower in the AMS group. Blood urea nitrogen (BUN) was decreased in cows fed the CAS ration. Postpartum, we found serum protein to be decreased with the low DCAD diets while BUN was decreased in the CAS group. The low DCAD rations increased prepartum serum malondialdehyde concentrations, while postpartum total antioxidant capacity was lower in the HCLK and the AMS group. From these data, we conclude that AMS decreased prepartum intake due to compromised palatability. Intermediate protein metabolism was affected by the low DCAD diets, while parameters of oxidative stress were probably affected by acid–base balance and Ca homeostasis. 相似文献
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Renan Braga Paiano Daniela Becker Birgel Jeannine Bonilla Eduardo Harry Birgel Junior 《Reproduction in domestic animals》2020,55(11):1599-1606
The aim of the present study was to evaluate the biochemical profile and reproductive performance in postpartum dairy cows with clinical metritis. The research was carried out using performed on 213 pluriparous lactating cows from two dairy herds in southeast Brazil. Dairy cows were assigned into a group of healthy cows (n = 147) and cows with metritis (n = 66). Blood samples to assess serum albumin, cholesterol, fibrinogen, calcium, gamma-glutammyltransferase (GGT), aspartate aminotransferase (AST) and β-hydroxybutyrate (BHBA) concentrations were performed on day 8 ± 2 postpartum. Metritic cows had lower (p < .05) serum albumin, cholesterol and calcium concentration, and higher (p < .05) GGT and AST activity, and BHBA and fibrinogen concentrations when compared to the healthy group. The calving-to-conception interval and services per pregnancy were higher in metritic cows (p < .01) than in healthy cows and the conception rate at first service was lower in metric group (p < .01). Variable importance in projection plots demonstrated that cholesterol was the main discriminator between metritic and healthy cows. Our results indicated alterations in the biochemical profile and impaired reproduction performance in metritic cows. 相似文献
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本试验旨在研究围产前期饲粮阴阳离子差(DCAD)对产后奶牛血清生理生化指标及犊牛血清抗氧化指标的影响。试验采取单因子随机区组试验设计,选取2~4胎次、体重相近、预产期相近的围产前期(产前28天)中国荷斯坦奶牛20头,分为4组,每组5头。4组分别在围产前期饲喂DCAD为+262.31、+130.26、+78.51、+6.67 mmol/kg(干物质基础)的饲粮,阴离子盐的添加量分别为0、15.0、21.9、29.1 g/kg。试验期49 d,其中预试期7 d,正试期42 d。结果表明:降低奶牛产前饲粮DCAD能显著提高其血清钙含量(P0.05);显著降低尿液p H(P0.05);显著提高产后血清维生素D含量(P0.05);显著提高犊牛血清抗氧化能力(P0.05);但对奶牛血清肿瘤坏死因子、甲状旁腺素、降钙素和β-羟丁酸含量没有显著影响(P0.05)。因此,添加阴离子盐降低产前奶牛饲粮的DCAD可以促进其血清钙稳态,诱发机体轻度代谢性碱中毒从而减少产褥热的发病率,并提高犊牛的抗氧化能力。本试验条件下,15.0 g/kg(干物质基础)为阴离子盐最佳添加量。 相似文献
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Elizabeth Schwegler Augusto Schneider Paula Montagner Diego Andres Velasco Acosta Luiz Francisco Machado Pfeifer Eduardo Schmitt Viviane Rohrig Rabassa Francisco Augusto Burkert Del Pino Helenice de Lima Gonzalez Cláudio Dias Timm Marcio Nunes Corrêa 《Tropical animal health and production》2013,45(7):1549-1555
The aim of this study was to measure changes in biochemical markers in the peripartum period of primiparous Holstein cows diagnosed with subclinical and clinical mastitis. In this study, 37 dairy cows were monitored daily during milking until 60 days postpartum and were categorized according to the occurrence of clinical mastitis (group mastitis (GM), n?=?9) or subclinical mastitis (group subclinical mastitis (GSUB), n?=?10) or absence of symptoms (control group (CG), n?=?18). Blood samples were collected weekly from ?30 to 60 days from calving. Samples were grouped for prepartum (?30 to 0 days from calving), early postpartum (0 to 30 days from calving), and late postpartum (30 to 60 days from calving) periods. Prepartum serum non-esterified fatty acid (NEFA) concentration was higher in GM than in CG (P?<?0.01). In addition, CG had higher prepartum serum glucose concentration than GM (P?=?0.03). In the early postpartum period, aspartate aminotransferase (AST) activity was lower in CG than in GSUB (P?<?0.05), and in the late postpartum period, AST activity was lower in CG than GSUB and GM (P?=?0.01). Somatic cell count was higher during the early and late postpartum periods for GM and GSUB when compared to CG (P?<?0.01). In this study, primiparous cows with low glucose and higher NEFA in the prepartum were more susceptible for mastitis in the early postpartum, probably due to low immune function associated to a more negative energy balance. In sum, increased prepartum serum NEFA concentration and decreased glucose in primiparous cows were associated with clinical mastitis incidence in the postpartum period. 相似文献
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阴离子型日粮及补Ca对围产期奶牛代谢与健康及其生产性能的影响 总被引：3，自引：0，他引：3
将36头干奶后期中国荷斯坦奶牛随机分为对照组、试验Ⅰ组、试验Ⅱ组（每组12头）．分别饲喂常规日粮、阴离子型日粮及在此基础上朴Ca日粮，探讨其对奶牛体内代谢状况、健康状况及生产性能的影响。与饲喂常规日粮相比，饲喂阴离子型日粮可降低奶牛尿液pH值（P〈0．01）和血液HCO2^-浓度（P〉0．05）；增加奶牛产后12h（P〈0．05）、2d（P〈0．05）血清总钙含量．对血清无机磷、镁含量没有显著影响；明显降低奶牛亚临床性低血钙率（33％）、胎衣不下率（33％）和乳房水肿率（17％）；增加牛奶乳糖率（P〈0．05），对其他奶成分和奶产量没有显著影响（P〉0．05）。在阴离子型日粮中补Ca后．与饲喂阴离子型日粮相比．除增加奶牛产后血清镁含量外（P〈0．05）．对其他各项指标没有明显影响。 相似文献
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《The Professional Animal Scientist》1999,15(4):278-285
Twenty multiparous and four primigravid Holstein cows were utilized in a completely random design to characterize the influence of decreasing prepartum dietary cation-anion difference (DCAD) from +388 to +183 meq/kg diet on DMI, prepartum blood profiles, and postpartum milk yield and composition of dairy cows grazed during the prepartum period. Treatments began on wk −4 prepartum, continued through calving, and consisted of 1) pasture and grain pellet without anionic salts (control; +388 meq/kg) or 2) pasture and grain pellet containing anionic salts (AS) (+183 meq/kg). Prepartum cows were rotationally grazed as a single group and individually fed pellets twice daily at a rate of 0.5% of BW/d. Blood and urine samples were collected on wk −4, −2.5, and −1 prepartum and analyzed for Ca, Mg, K, Na, and Cl concentrations. Urine samples were also analyzed for pH. Chromic oxide was dosed twice daily during the last 4 wk of gestation and again for 10 d during wk 4 and 12 postpartum for estimation of intake. Cows calved on pasture and were then integrated into the regular milking herd and fed a total mixed ration (TMR). Daily milk yield and weekly milk samples were collected through wk 14 of lactation. Prepartum and postpartum DMI, milk yield and composition, and plasma minerals were not affected by treatment. No clinical cases of milk fever were observed for either treatment group. Reducing prepartum DCAD from +388 to +183 meq/kg DM did not improve prepartum blood profiles or postpartum milk yield or composition; therefore, this type of supplementation was not economical. 相似文献
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AIMS: To compare the effect of two partial mixed ration diets containing either sulfate or chloride-based anionic salts, fed to grazing prepartum dairy cows, on concentrations of Ca, Mg, P and beta-hydroxybutyrate (BHB) in plasma, disease incidence and milk yield during the early postpartum period.
METHODS: The study was conducted on a seasonal-calving grazing dairy farm located in Benton (MO, USA). In August 2016, two groups of 200 cows were randomly assigned at 30 days before expected parturition to receive either a sulfate or chloride-based anionic diet, to achieve a dietary cation–anion difference (DCAD) of ?25?mEq/kg DM. Cows were fed partial mixed rations to provide 50% of their DM intake, with 50% provided by grazing fescue pasture. Urine samples were collected from 20 cows from each group once a week for 5 weeks until calving for pH assessment. At parturition, 42 cows per group were selected at random and blood samples collected on Days 1, 2, 3 and 7 postpartum. The study continued until 100 cows per group calved. Health events and cumulative milk yield until 30 days postpartum were recorded. Concentrations of Ca, P, and Mg in plasma at Days 1, 2, 3, and 7, and BHB in plasma at Day 7 postpartum were assessed.
RESULTS: Mean urine pH was lower in cows in the chloride than sulfate group (p≤0.06) on four of five sampling occasions. Mean concentrations of Ca in plasma on Day 1 were 2.00 (95% CI=1.94–2.05) and 1.91 (95% CI=1.88–1.97) mmol/L for the chloride and sulfate groups, respectively (p=0.15), and on Day 3 were 2.03 (95% CI=1.97–2.08) and 1.90 (95% CI=1.84–1.96) mmol/L, respectively (p=0.038). Concentrations of Mg, P and BHB in plasma and incidence of diseases postpartum were similar in both groups (p>0.05). There were no cases of clinical hypocalcaemia in either group.
CONCLUSIONS AND CLINICAL RELEVANCE: Prepartum cows fed a partial mixed ration with a negative DCAD containing chloride-based anionic salts and free access to a fescue pasture had lower prepartum urine pH, and higher concentrations of total Ca in plasma during the first week postpartum, than cows receiving a partial mixed ration containing sulfate-based anionic salts. 相似文献
18.
Mellau LS Jørgensen RJ Kambarage DM 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2002,49(5):225-229
The objective of this experiment was to induce acidification by anion salt supplementation for 2 days or 10 days and to study the prophylactic effects of such supplementation in preventing hypocalcaemia in cows. It was further attempted to monitor the extent to which any effect on the calcium-regulating mechanisms would persist following a 10-day period of acidification with anion salts. Study animals were three untreated control cows and three cows supplemented with ammonium chloride and ammonium sulphate in their ration for 2 days or 10 days through the rumen cannula. The basic ration of hay was dominated by Urochloa spp. The pH of the urine of the control cows was around 8.00 throughout the experiment and was considered normal. Anion-supplemented cows produced urine with a daily mean pH between 5.5 and 7.0, possibly due to anion salt exposure. The ability to withstand hypocalcaemic challenges was tested by a standardized intravenous infusion of disodium ethylenediaminetetraacetate (Na2EDTA). The calcium regaining time (CRT), expressed as time spent to reach 1.00 mmol/l of ionized calcium during recovery from the EDTA-induced hypocalcaemia, was used to compare cow responses. In the control cows the unexpectedly short CRT, especially during the weekly EDTA tests, could be a result of the repeated induced episodes of hypocalcaemia caused by the EDTA infusions. The improved CRT in the anion-supplemented cows may thus be interpreted as the combined effect of the repeated hypocalcaemic episodes due to EDTA infusions and probably the effect of anion-induced metabolic acidosis on endocrine-regulated calcium homeostatic mechanisms. The effect of anion salt exposure for 10 days on the improvement of calcium-regulating mechanisms was not clear due to the unexpected improvement of CRT that was exhibited by the untreated control cows as well. An on-farm trial of the effect of a 2-day or 10-day anion exposure of dry cows on calcium-regulating mechanisms is suggested. 相似文献
19.
Preventive effect of mildly altering dietary cation-anion difference on milk fever in dairy cows 总被引：1，自引：0，他引：1
Kurosaki N Yamato O Mori F Imoto S Maede Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(2):185-192
In the present study, we examined whether mildly altering dietary cation-anion difference (DCAD) contributes to the prevention of milk fever in dairy cows. Thirty multiparous cows and ten primiparous cows (heifer group) were used in this study and the multiparous cows were randomly divided into three groups of ten animals each (anion, non-anion and control groups). The cows in the anion group were given supplemental salts that slightly lowered DCAD. These salts consisted of 115 g of CaCO3, 42 g of CaHPO4, 65 g of MgSO4 x 7 H2O and 80 g of CaCl2 x 2 H2O as a daily dose for each cow, using a catheter from 21 days before the expected date of parturition until parturition. The cows in the non-anion group were given only the same Ca, Mg and ip supplement but no sulfate and chloride salts as that in the anion group. The cows in the control and heifer groups were not given any additional supplement. The incidence of hypocalcemia in the anion group decreased to approximately half of those in the non-anion and control groups, while the heifer group did not develop hypocalcemia at all. In addition, the number of days spent for the treatment of hypocalcemia and the number of drug bottles (calcium borogluconate solution) used for the treatment decreased to less than half in the anion group compared with those in the non-anion and control groups. At parturition, the serum Ca concentration in the control (6.2 +/- 1.9 mg/dl, mean +/- standard deviation) and non-anion groups (6.4 +/- 1.7 mg/dl) were significantly lower than that in the heifer group (8.3 +/- 0.4 mg/dl), and the level in the anion group was intermediate (7.3 +/- 1.3 mg/dl). The change in ionized Ca concentration was almost the same as that in serum Ca concentration, but only the concentration in the anion group tended to increase slightly from a week before parturition and was significantly higher than that in all other groups three days before parturition. Urinary pH in the anion group was maintained at a mildly acidic level (6.8-7.0) for the last two weeks before parturition, compared with those in the control (7.3-7.5) and non-anion groups (7.9-8.1), and similar to that in the heifer group (6.3-7.3). The urinary Ca excretion was the highest in the anion group among all groups during the prepartum period. There were no specific changes in the excretion of parathyroid hormone and 1,25-dihydroxyvitamin D in all groups of multiparous cows while the levels of these hormones remained low in the heifer group throughout the experimental period. The data in the present study indicates that the administration of anion salts that slightly lowered DCAD in the preparum period was effective for preventing milk fever in multiparous cows. Safe and mild metabolic acidosis induced by the anion salts could be evaluated by urinary pH (6.8-7.0), and might increase the responsiveness to Ca requirement at parturition through some complex mechanisms unrelated to the excretion of Ca-related hormones. In addition, it was clarified that primiparous cows have a high potential to respond to sudden Ca demand unrelated to hormone excretion, and their Ca metabolism was in some respects similar to that in multiparous cows fed anion salts. Therefore, manipulating mildly DCAD is expected to be an effective, safe and natural method for preventing milk fever in dairy cows. 相似文献
20.
L. Avendao-Reyes F.D. Alvarez-Valenzuela A. Correa-Caldern J.S. Saucedo-Quintero P.H. Robinson J.G. Fadel 《Livestock Science》2006,105(1-3):198-206
Two experiments were completed to determine whether cooling Holstein cows during their 60-day prepartum period improved their immediate physiological status as well as subsequent postpartum performance. In Experiment 1, 38 cows were divided into two pens that were not cooled, or where the cows were moved twice daily to be cooled by soaking until their body was completely wet. Prepartum respiration rate (RR) and rectal temperatures (RT) did not differ between groups, indicating that the cooling system was largely ineffective, which was consistent with differences that only numerically favored the treated group in postpartum productive (milk production, milk fat content and related response variables), and reproductive (services per conception and days open) performance. In Experiment 2, 52 Holstein cows were used over 3 years (n = 24 in year one; n = 12 in year two; n = 16 in year three) and cows were housed in pens either not cooled or cooled with water spray and fans. Cooled cows had lower RR and RT prepartum at 14:00 and 18:00 h vs. non-cooled cows, indicating that the cooling system was effective, and this was consistent with improved productive (milk production, milk fat content and related response variables), and reproductive (services per conception and days open) performance postpartum. In addition, there was a trend (P = 0.10) to higher birth weights of calves from cooled mothers (which was consistent with a numeric difference in Experiment 1). Use of effective cooling systems under hot and dry conditions during the dry period can improve postpartum productive and reproductive performance of Holstein cows. 相似文献