Associations between use of electric cow-trainers and clinical diseases, reproductive performance and culling in Swedish dairy cattle

The aims of this follow-up study were: (a) to evaluate the role of ECT technology as a risk factor for several diseases; and (b) to determine if the effects of these diseases on cows' reproductive performance and as risk factors for culling are influenced by exposure to ECTs. Diseases considered were retained placenta, metritis, ketosis, cystic ovaries, silent heat, milk fever, clinical mastitis, and foot and leg problems. We used historical and contemporary controls (with control herds selected to match the experimental herds for size and location). Data consisted of 10264 Swedish Red and White (SRB) and 5461 Swedish Friesian (SLB) lactation records in 150 herds of which 33 used cow-trainers. Logistic regression was used to estimate the effects of parity and exposure to electric cow-trainers on the risks of diseases and the effects of diseases and exposure to electric cow-trainers on risk of culling. The least-squares procedure was used to estimate the effects of diseases on reproductive performance.

The dominant effects associated with use of electric cow-trainers were an increased risk for silent heat, clinical mastitis, ketosis and culling relative to cows in herds not using cow-trainers. Diseases had negative effects on reproductive performance and the effects were larger for cows in herds using cow-trainers. In herds using electric cow-trainers, the largest increase in the interval from first service to conception (58 days) was caused by the occurrences of silent heat, cystic ovaries and the combination of two or more diseases. Retained placenta, metritis, cystic ovaries, clinical mastitis and a combination of two or more diseases increased the risk of culling about two times relative to healthy primiparous cows with the increase being greater for cows in herds using cow-trainers. Silent heat did not increase risk of culling in control groups, but was the largest risk factor for culling in the exposed group. We concluded that exposure to electric cow-trainers increased the incidence risk of silent heat, clinical mastitis, and ketosis and changed silent heat from a neutral disease with respect to culling to a major risk factor. Finally, exposure to cow-trainers increased the general negative effect of diseases on the cows' reproductive performance and risk for culling.     

两种定性检测方法对围产期奶牛亚临床酮病的检测结果比较

采用酮粉法和试剂法检测贵南县两个奶牛场135头临床健康的围产期奶牛的尿酮和乳酮,结果表明,试剂法和酮粉法均可用于早期检测尿中酮体,临床上以粉剂法更佳;奶牛酮病的早期诊断应在产后10d左右开始,尿酮阳性率高而敏感,而乳酮阳性率低;尿酮阳性率集中在产后20d。     

The consequences of risk-based surveillance: Developing output-based standards for surveillance to demonstrate freedom from disease

Risk factors associated with high or low long-term incidence of displaced abomasum (DA) or clinical ketosis were studied in 60 Swedish dairy herds, using multivariable logistic regression modelling. Forty high-incidence herds were included as cases and 20 low-incidence herds as controls. Incidence rates were calculated based on veterinary records of clinical diagnoses. During the 3-year period preceding the herd classification, herds with a high incidence had a disease incidence of DA or clinical ketosis above the 3rd quartile in a national database for disease recordings. Control herds had no cows with DA or clinical ketosis. All herds were visited during the housing period and herdsmen were interviewed about management routines, housing, feeding, milk yield, and herd health. Target groups were heifers in late gestation, dry cows, and cows in early lactation. Univariable logistic regression was used to screen for factors associated with being a high-incidence herd. A multivariable logistic regression model was built using stepwise regression. A higher maximum daily milk yield in multiparous cows and a large herd size (p = 0.054 and p = 0.066, respectively) tended to be associated with being a high-incidence herd. Not cleaning the heifer feeding platform daily increased the odds of having a high-incidence herd twelvefold (p < 0.01). Keeping cows in only one group in the dry period increased the odds of having a high incidence herd eightfold (p = 0.03). Herd size was confounded with housing system. Housing system was therefore added to the final logistic regression model. In conclusion, a large herd size, a high maximum daily milk yield, keeping dry cows in one group, and not cleaning the feeding platform daily appear to be important risk factors for a high incidence of DA or clinical ketosis in Swedish dairy herds. These results confirm the importance of housing, management and feeding in the prevention of metabolic disorders in dairy cows around parturition and in early lactation.     

奶牛酮病红细胞膜上ATP酶活性变化的研究

为了深入研究酮病的发生机理,选择荷斯坦奶牛作为实验动物,应用酮粉法和改良式水杨醛比色法随机检测分组,Ⅰ组为10头对照牛、Ⅱ组为10 头阳性牛。应用试剂盒比色法测定红细胞膜上ATPase 的活性变化。结果表明,阳性组和对照组相比,红细胞膜上ATPase的活性显著下降(P <0.05)。说明奶牛酮病影响红细胞膜上ATPase的活性变化。     

酮病对荷斯坦奶牛抗氧化系统和一氧化氮含量的影响

[目的]研究新疆荷斯坦奶牛酮病血清中的部分生化指标的变化及其酮病致病机理的探讨。[方法]以新疆荷斯坦奶牛为试验动物,用酮粉法和改良的水杨醛检测法对其血清进行检测,应用硝酸还原酶法测定血清中一氧化氮(NO)含量和一氧化氮合酶(NOS)活性;应用DTNB显色法测定血清中GSH-Px活力,应用黄嘌呤氧化法测定血清中T-SOD活力,应用硫代巴比妥酸法测定血清中MDA含量。[结果]酮病奶牛血清中GSH-Px活力极显著降低(P0.01),T-SOD活力显著降低(P0.05),血清中MDA含量显著增高(P0.05);对照组奶牛血清中的NO含量和NOS活性均显著高于阳性组。[结论]酮病不但影响奶牛的抗氧化系统而且也会降低一氧化氮含量和一氧化氮酶的活性,对于揭示奶牛酮病的发生机理具有重要意义。     

酮病奶牛血清中NO含量及NOS活性变化的研究

为了深入研究酮病的发生机理,选择荷斯坦奶牛作实验动物,应用酮粉法和改良式水杨醛比色法随机检测分组,Ⅰ组为10头阳性牛、Ⅱ组为10头对照牛。应用硝酸还原酶法测定血清中一氧化氮(NO)含量和一氧化氮合酶(NOS)活性。实验结果表明对照组奶牛血清中的NO含量及NOS活性均显著大于阳性组。由此可知,酮病可导致奶牛血清中NO含量降低、NOS活性下降。     

应用MIR预测牛健康状况的研究进展

在牛遗传育种研究中,健康性状越来越受到人们关注,但大规模健康状况数据收集难度较大,故很难对其进行遗传评估。在过去近二十年中,国外研究人员探索了基于MIR的预测牛健康状况方法,其是一种高效、经济的工具。本文现从其对牛的酮病、亚临床酮病、能量平衡和其他疾病的预测几方面进行一个总结,为我国研究人员进行相关工作提供借鉴。     

Relationship between ketosis and dairy cows’ blood metabolites in intensive production farms of the periurban area of Dakar

This study which involved 140 Holstein and Montbeliard was carried out in the periurban area of Dakar with the aim to establish the relationship between ketosis, milk production and biochemical blood metabolites. The results showed that ketosis is a real problem in periurban farms around the city of Dakar with high proportions of 33.57% for subclinical ketosis and 6.43% for clinical ketosis. In their second month of milking, cows with subclinical ketosis had a decrease of 12.4 and 15.,6% in milk yield respectively for Montbeliard and Holstein, whereas cows with clinical ketosis had a decrease of 18.6 and 26%. Ketogenic cows (subclinical and clinical) have significantly lower average levels of blood glucose (p<0.05) and significantly higher average levels of blood urea (p<0.05) than cows with normal blood beta-Hydroxy Butyrate (BbHB) levels. Also, from one farm to another, significant difference was recorded with concentration of total proteins and globulin, calcium and magnesium.