奶牛围产期低血钙发生状况及其调控措施

<正>奶牛围产期指的是奶牛在产前的21 d和产后的21 d,一般将产前称为围产前期,而产后称为围产后期,在这个阶段由于奶牛生理、日粮和生活环境等变化,很可能会对奶牛的营养代谢、内分泌等造成影响,使得奶牛出现围产期低血钙的症状,这对于奶牛的成长和发育极其不利,必须要做好相应的防控措施。1奶牛围产期低血钙发生的危害1.1不利于小奶牛的发育和成长在奶牛围产期发生低血钙症会使得奶牛的抵     

围产期奶牛低血钙症的发生及预防措施研究进展

围产期奶牛经历妊娠后期、分娩和泌乳等一系列生理变化,抵抗力下降,容易诱发奶牛产后诸多疾病,其中低血钙症就是本阶段易发的疾病之一.本文就围产期奶牛低血钙症的发生原因、危害、影响因素及目前的预防措施进行了总结,为奶牛围产期的饲养管理提供相应的理论参考.     

奶牛低血钙症营养管理的研究进展

低血钙症是常发生于围生期奶牛的营养代谢病，由血钙浓度降低引起。机体钙具有构成机体骨骼、调节肌肉收缩、参与免疫调节等功能，因此低血钙症会继发多种疾病，影响奶牛生产效益，是国内外研究的热点。随着研究的深入和新技术的应用，奶牛低血钙症在预防、诊断、营养调控等方面的研究不断取得突破。文章从发病机理的角度阐述了低血钙症引起的全身性疾病，叙述了奶牛低血钙症的诊断方式，并总结了奶牛低血钙症的营养管理手段，以期为奶牛低血钙症的营养管理提供新的思路和参考。     

奶牛围产期低血钙及酮病的营养调控

本文针对以产后低血钙、酮病为代表的奶牛围产期营养代谢病,从发病机理、临床表现、预防控制突破点和营养调控关键点等方面进行阐述,以期为围产期营养代谢病的综合调控提供依据。     

奶牛营养与围产期疾病预防

奶牛围产期的营养管理是其泌乳、繁殖和预防围产期疾病发生的关键。围产期疾病与营养代谢密切相关,其中营养不平衡造成的低血钙症是引起围产期相关疾病的根本原因。在保证围产期其它营养需要的同时,根据离子平衡理论给予阴离子盐,使体液偏酸性,可有效动员骨钙,使血钙浓度上升,达到预防围产期疾病的目的。     

再给苜蓿增加一个“缺陷”

<正> 近期,由于"奶牛围产期饲喂阴离子"措施的兴起,苜蓿又增加了一个不容忽视的"缺陷"。笔者特就此作一阐述,以便养殖者更好的了解苜蓿的营养效果。1 从奶牛产后低血钙症说起1.1 分娩和泌乳使奶牛的血钙平衡发生紊乱,奶牛产后,每分泌10千克初乳,需耗钙23克,这相当于奶牛血钙储存量的9倍,因而分娩后的奶牛有67%发生低血钙症。1.2 奶牛产后低血钙症的危害:可诱发许多产后疾病,如胎衣滞留、产后瘫痪、酮病、泌乳减少、子宫炎、乳房炎、真胃变位、胎次减少等。     

奶牛围产期血浆Ca、P、AKP和HYP的变化

为了解健康奶牛围产期钙代谢特点,本试验选取围产期健康奶牛20头,分别在产前7d、3d,分娩当天,产后3d、7d对试验奶牛血浆Ca、P、ALP、HYP浓度进行测定。按每个时间点血钙水平将试验奶牛分为血钙正常组(C)和低血钙组(L)。结果显示:奶牛在产前7d至产后7d低血钙发生率分别为45%、20%、80%、25%、15%。产前7d到产后7d,C组奶牛血浆Ca、ALP、HYP水平均显著高于L组(P0.05)。两组奶牛血浆P浓度围产期无显著差异(P0.05)。结论:奶牛围产期易发生低血钙,以分娩时发生率最高;围产期奶牛低血钙症的发生可能与骨钙动员能力低有关。     

奶牛低血钙症与阴阳离子平衡

低血钙症是经产奶牛围产期非常容易发生的代谢性疾病.据报道,美国7.2%的高产奶牛患有产后瘫痪(Jordan和Fouldraine,1993),芬兰9%的奶牛患有产后瘫痪(Forger,1999);60%的经产奶牛产犊后患有亚急性低血钙(Breed等,1992),患有产后瘫痪的奶牛,产奶量会降低14%(Block,1984)[1].同时患有低血钙症的奶牛还常常伴有其他产后疾病,如酮病、代偿性碱中毒、胎衣滞留、乳房炎和真胃移位等疾病.     

围产期奶牛主要血液生化指标的监测

为了解围产期奶牛血液生化指标的实时变化,从而为围产期常见营养代谢类疾病的防控提供理论依据,本研究拟对吴忠市某奶牛场26头待产荷斯坦奶牛进行为期30d的围产期循环血液生化监测,后用GraphPad Prism 7绘图软件对各项数据变化趋势作图并加以分析。结果显示:生产过程对肝、肾负担极大,产前血清谷丙转氨酶(ALT)、总胆固醇(TC)、甘油三酯(TG)、总蛋白(TP)、球蛋白(GLB)、尿素氮(UREA)、肌酐(Crea)浓度均呈下降趋势,产后血糖(Glu)、血钙(Ca)、血磷(P)浓度下降较为明显,围产期内低血糖症、低血钙症、低血磷症发病率较高。围产期内奶牛各项生理代谢旺盛,给肝、肾等器官造成了严重负担,极易诱发高酮血症、低血糖症、低血钙症、低血磷症等营养代谢类疾病。     

奶牛低血钙症的预防

<正>一、低血钙症和产后疾病的关系低血钙症可以导致很多围产期疾病(图1)。钙有收缩肌肉的功能,可以让平滑肌机能下降和骨骼肌松驰,而低血钙症主要是由于平滑肌机能下降导致的。低血钙症还会导致子宫内膜炎,这主要是由于子宫收缩机能下降引起的。对于产后奶牛,只要看到它无法站立,就可以判断可能是低血钙症。但事实上,不仅是无法站立的奶牛有低血钙症的可能性,最近的研究报告显示,40%的二胎奶牛都有低血钙症,三胎奶牛中大概90%有潜在的低血钙症。     

Effect of Anionic Salts on Health and Production Performance of Holstein Cows in Peripartum

This study was to determine the effect of anionic salts on health and production performance of Holstein cows during the peripartum period. Twenty-four Holstein cows during the peripartum period were selected and divided into control group and experimental group. Twelve Holstein dairy cows in control group were fed diets with original concentrate,while twelve cows in experimental group were fed diets with concentrates adding anionic salts for the last 21 days before expected calving. All animals were ad libitum fed with the same diets after calving. The results showed that urine pH maintained 5.7 to 6.9,and blood pH was decreased significantly compared to control group (P<0.05). However,the contents of plasma Ca,glucose and alkaline phosphatase (ALP) activity in experimental group were significantly increased in 1 d after calving (P<0.05). What's more, the incidences of hypocalcemia,milk fever,retained placenta,displaced abomasum and mastitis were reduced in experimental group and the incidences of retained placenta was significantly decreased (P<0.05). No significant difference was detected in milk yield between two groups (P>0.05). In summary,supplementation of anionic salts concentrate could help to keep the health and plasma Ca homeostasis of Holstein cows.     

Relationship between blood calcium level and ST peak interval of electrocardiographic variables in peripartum Holstein cows

The association between blood calcium levels and electrocardiographic variables was compared in 137 normal parturient and 36 peripartum recumbent Holstein cows to determine whether hypocalcemia in peripartum dairy cows can be rapidly diagnosed using electrocardiograph. Inverse of STc (ST peak interval/SS interval^0.5) and blood ionized calcium or serum calcium concentrations were strongly correlated, and both correlation coefficients were 0.81 (P<0.001). The 95% prediction interval indicated that cows with STc >0.385 ± 0.001 sec are very likely to be hypocalcemic (blood ionized or serum calcium concentrations of <0.9 mmol/l or <7.5 mg/dl, respectively). These findings indicate that hypocalcemia in parturient cows can be non-invasively estimated using the STc.     

阴离子盐对围产期奶牛健康和生产性能的影响

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。     

Effect of reproductive disorders and parity on repeat breeder status and culling of dairy cows in Quebec

This study quantified the effect of peripartum reproductive disorders and parity on repeat breeder status and involuntary culling of dairy cows. Reproductive data of 418 383 lactations were taken from a computerized databank of health records for dairy cows. A logistic regression model was used with dystocia, retained placenta (RP), metritis complex, and parity as fixed effect risk factors and herd entered as the random effect. Of the peripartum problems studied, dystocia had the greatest effect on future fertility. Dystocia increased the odds of a cow being a repeat breeder by 44% [odds ratio (OR): 1.44; confidence interval (CI): 1.37 to 1.51]. Compared to first-parity cows, cows in second, third, and fourth parities had significantly higher odds of being a repeat breeder: 18% (OR: 1.18; CI: 1.16 to 1.20); 24% (OR: 1.24; CI: 1.21 to 1.26); and 42% (OR: 1.42; CI: 1.39 to 1.45), respectively. The odds for second-, third-, or fourth-parity repeat breeders being culled were 24% (OR: 1.24; CI: 1.20 to 1.28); 39% (OR: 1.39; CI: 1.35 to 1.43); and 67% (OR: 1.67; CI: 1.62 to 1.71) respectively, while peripartum reproductive problems had less of an effect.     

奶牛酮病发病原因及其对生产性能影响调查分析

探索奶牛酮病发病原因、发病规律及其对生产性能的影响,对986头围产期奶牛进行跟踪调查分析。结果表明,奶牛酮病发病率为31.74%,死亡率为4.15%;秋季发病率最高,可达37.4%,其次是冬季和夏季,春季发病率最低;随着胎次、年龄和产乳量的增加,奶牛酮病的发病率明显增高;在第1个泌乳月奶牛酮病的发病率最高,可达50.43%;日粮种类和微量元素越少,奶牛酮病就越容易发生;奶牛发病后受胎率明显降低;发病后产乳量、乳脂率、乳蛋白率、乳糖率和乳干物质比发病前均明显降低,差异显著（P〈0.05）。奶牛酮病发病具有一定的规律性,且可降低奶牛的繁殖性能、产奶量和乳品质。     

Slow recovery of blood glucose in the insulin tolerance test during the prepartum transition period negatively impacts the nutritional status and reproductive performance postpartum of dairy cows

In peripartum dairy cows, insulin resistance (IR) increases to adjust the direction of energy to lactation after calving. To investigate the effect of prepartum IR on postpartum reproductive performance, the insulin tolerance test (ITT) was applied to 15 cows at 3 weeks (Pre21) and 10 days (Pre10) before the predicted calving date. Blood glucose area under the curve (AUC(glu)) within 120 min after administration of 0.05 IU/kg-BW insulin was calculated. The occurrence of first ovulation, days to first artificial insemination (AI) and first AI conception rate were recorded. Nutritional status postpartum was evaluated by blood chemical analysis. Based on AUC(glu) changes from Pre21 to Pre10, cows were classified into either the AUC-up group (AUC(glu) increase, n=5) or the AUC-down group (AUC(glu) decrease, n=10). There was no difference in the decrease in blood glucose at 30 min after insulin injection between groups, although glucose recovery from 30 to 60 min during the ITT was slow at Pre10 in the AUC-up group. The AUC-up group had a higher number of days to first AI and high glucose, total protein, globulin, γ-glutamyltransferase, triacylglycerol levels and a low albumin-globulin ratio at the 14th day postpartum. The present study infers that prepartum slow glucose recovery rather than insulin sensitivity might increase the potential for subclinical health problems postpartum and thus suppress reproductive performance. During the prepartum transition period, glucose dynamics in the ITT can be considered as a new indicator for the postpartum metabolic status and reproductive performance of dairy cows.     

Parturient paresis and hypocalcemia in ruminant livestock

Parturient paresis (hypocalcemia) is most likely to affect dairy cattle around the time of parturition. It causes progressive neuromuscular dysfunction and flaccid paralysis. Older dairy cows, cows with a history of parturient paresis during a previous lactation, high-producing cows, and cows from the Jersey and Guernsey breeds are at highest risk for developing parturient paresis. Nonparturient hypocalcemia may also occur and is related to events other than parturition, such as severe stress, that temporarily overwhelm the mechanisms of calcium homeostasis. Beef cattle, sheep, and goats are affected less frequently by hypocalcemia than are dairy cows. Because these species are not as stressed for milk production as dairy cattle, nonparturient hypocalcemia makes up a higher proportion of cases in nondairy ruminants. Clinical signs of hypocalcemia in beef cattle, sheep, and goats tend toward hyperesthesia and tetany rather than the classic flaccid paralysis that occurs in dairy cattle with parturient hypocalcemia. Prompt and effective treatment of hypocalcemia helps to reduce the incidence of secondary complications, such as muscle damage or mastitis. The standard treatment regimen of 500 ml of 23 per cent calcium gluconate, administered intravenously, will elicit a favorable response in approximately 75 per cent of recumbent cows within 2 hours of treatment. Relapses following successful initial therapy are common and may be prevented in part by supplementation of intravenous treatment with an additional 500 ml of 23 per cent calcium gluconate administered subcutaneously. Proper nursing care following treatment speeds recovery and reduces the incidence of secondary complications owing to hypocalcemia.     

Relationship between haptoglobin, serum amyloid A, and clinical status in a survey of dairy herds during a 6-month period

BACKGROUND: Haptoglobin and serum amyloid A are major acute phase proteins in cattle. Dairy cattle often develop pathologic conditions in the peripartum period; acute phase proteins may be useful in their diagnosis. OBJECTIVES: The purpose of this study was to compare the accuracy of serum haptoglobin (Hp) and serum amyloid A (SAA) concentrations with clinical health status for diagnosing disease during the peripartum period in dairy cattle. METHODS: Dairy cows from 4 herds were evaluated every 15 days over a 6-month period. Health status was determined by thorough clinical examination. Haptoglobin and SAA concentrations were measured in serum using validated methods and the results were classified as positive or negative based on defined cutoff points. Disease prevalence, sensitivity, and specificity were compared using clinical examination as the gold standard. RESULTS: A total of 1896 samples from 158 cows were analyzed. Significant increases in mean Hp and SAA concentrations were observed in the week following parturition in both primiparous and multiparous cows, although high interindividual variability was observed. Both Hp and SAA had low sensitivity but higher specificity in determining disease status compared with clinical examination. Increased concentrations of Hp and SAA were found in <10% of samples from clinically healthy cows, except in the week after parturition. CONCLUSIONS: Haptoglobin and serum amyloid A should be used with caution as markers of inflammation in the week after calving. Poor sensitivity in other postpartum periods could be related to the higher incidence of chronic (vs acute) inflammation. Haptoglobin may be appropriate for routine screening, but further work needs to be done to assess its value as an indicator of herd health.     

Udder health: the influence of BVD-free status

The effect of BVD v-free certification of BVD v-infected dairy herds on udder health was determined, by comparing parameters of udder health in 319 cases and 629 controls. Cases were dairy herds that originally had at least one BVD V antigen-positive animal but which subsequently became BVD v-free and maintained this certified status for at least 2 years. Controls had an unknown BVD V status. Each case was matched with two controls by region and herd size. The three udder health parameters were bulk-milk somatic cell count (scc), the proportion of cows with a high scc, and the proportion of cows with a high scc after previously having a normal scc (these cows were considered to have a new intramammary infection). Udder health was better in the cases in the 2 years preceding the BVD V-free period than in the controls. BVD V-free status was not associated with bulk-milk scc or the proportion of cows with a high scc but was associated with occurrence of a new intramammary infection:fewer case cows had a new intramammary infection than control cows (difference 0.6%; P < 0.05).