Suppression of interferon response of bovine leukocytes during clinical and subclinical ketosis in lactating cows.

The influence of spontaneous ketosis on interferon alpha and gamma production in blood leucocytes and on PHA induced lymphocyte blastogenic response was investigated. Twenty three cows 4.13 +/- 2.8 weeks after calving were divided into three experimental groups on the basis of blood ketone bodies, glucose and free fatty acids concentrations. The leukocytes of cows with clinical symptoms and the highest concentration of ketones and free fatty acids in blood responded with the lowest levels of interferons alpha and gamma to three interferon inducers: Newcastle Disease Virus (NDV), phytohemagglutinin (PHA) and concanavalin A (ConA). Depression in interferon PHA stimulated synthesis correlated with a very low mitogenic response of blood lymphocytes. Blood leukocytes of cows with subclinical ketosis, characterized by mild clinical symptoms and a lower concentration of ketones in blood in comparison to cows with clinical ketosis, responded better to interferon and mitogenic stimulation; however, the interferon titer and blastogenesis were still lower than in leukocytes of healthy cows. Correlation between the stage of ketosis and the level of interferon production in milk leukocytes was also observed. A possible relationship between the suppression of interferon production in blood leukocytes and the increased concentration of ketone bodies in blood is discussed.     

Studies on hepatic lipidosis and coinciding health and fertility problems of high-producing dairy cows using the "Utrecht fatty liver model of dairy cows". A review

Fatty liver or hepatic lipidosis is a major metabolic disorder of high-producing dairy cows that occurs rather frequently in early lactation and is associated with decreased health, production and fertility. A background section of the review explores reasons why high-producing dairy cows are prone to develop fatty liver post partum. Hepatic lipidosis and coinciding health and fertility problems seriously endanger profitability and longevity of the dairy cow. Results from a great number of earlier epidemiological and clinical studies made it clear that a different approach was needed for elucidation of pathogenesis and etiology of this complex of health problems. There was a need for an adequate animal model in which hepatic lipidosis and production, health and fertility problems could be provoked under controlled conditions. It was hypothesized that overconditioning ante partum and feed restriction post partum might induce lipolysis in adipose tissue and triacylglycerol accumulation in the liver following calving. This consideration formed the basis for the experiments, which resulted in the "Utrecht fatty liver model of dairy cows". In this model, post partum triacylglycerol-lipidosis as well as the whole complex of health and fertility problems are induced under well-controlled conditions. The experimental protocol based on this hypothesis produced in all cases (10 feeding trials with over 150 dairy cattle) the intended result, i.e. all experimental cows developed post partum higher hepatic triacylglycerol concentrations than did control cows. The model was evaluated in biochemical, clinical pathology, immunological, clinical and fertility terms. It turned out that in this model, post partum triacylglycerol-lipidosis as well as the whole complex of health and fertility problems were induced under well-controlled conditions.     

Longitudinal evaluation of CD4+ and CD8+ peripheral blood and mammary gland lymphocytes in cows experimentally inoculated with Staphylococcus aureus.

Staphylococcus aureus is a major pathogen associated with mastitis, a disease affecting both women and dairy cows. The longitudinal profiles of bovine peripheral blood and mammary gland lymphocyte phenotypes in response to S. aureus-induced mastitis were investigated in dairy cows. Increased percentage of CD4 lymphocytes in the mammary gland between 1 and 8 days post-inoculation, increased milk CD4 protein density per cell between 1-8 days post-inoculation, and a statistically significant negative correlation between post-inoculation bacterial counts in milk and blood lymphocyte CD4 protein density were found. Together with blood and milk leukocyte counts, the milk lymphocyte CD4/CD8 ratio and the milk lymphocyte CD4 protein density were more informative indicators than milk somatic cell counts and bacteriology for identification of early vs. late inflammatory phases. These findings suggest that CD4+ lymphocytes play a protective role in the early stages of S. aureus-induced mastitis.     

Blood and milk cellular immune responses of mastitic non-periparturient cows inoculated with Staphylococcus aureus

Lymphocyte function and phenotype of peripheral blood and mammary gland cells were evaluated in non-periparturient cows before and at 1, 4 to 8 and 9 to 14 d after inoculation with Staphylococcus aureus, as expressed by percentage of CD3+, CD2+, and CD45R+ cells, antigen density of these markers per lymphocyte, and mitogen-induced blastogenesis. Milk bacterial counts and somatic cell counts (SCC) were also assessed. Mitogen-induced blastogenic responses were strong in blood and weak in mammary gland cells in all observations and positively correlated with the percent of CD45R+ cells. Significantly greater percentages of milk CD3+ lymphocytes and increased CD3, CD2, and CD45R antigen density per cell were observed after challenge. The blood CD3 and CD2 antigen density per lymphocyte and the milk CD2+ lymphocyte percent were negatively correlated with SCC (P ≤ 0.01). No mastitis (SCC ≤ 500 000 cells/mL) was observed in cows showing blood lymphocyte CD2 and CD3 antigen density indices ≥ 2.5 and 6, respectively. Forty-one percent of SCC values were predicted by the combined blood CD2 and milk CD3 antigen density (P ≤ 0.01). These findings support the hypotheses that mitogen-induced lymphocyte blastogenesis is not a valid test to assess mammary gland immunocompetence and that CD2 expression may facilitate immune responses by decreasing the number of T cell receptors required to achieve full activation.     

Relationship between overfeeding, metritis and ketosis in high yielding dairy cows

The association between overfeeding before calving, metritis and ketosis in seven dairy herds was investigated. The overall rate of ketonuria in 695 adult cows tested routinely between seven and 14 days post partum was 18 per cent and that of post parturient uterine diseases was 56.5 per cent. Eighty per cent of all cows with ketonuria concurrently suffered from post parturient uterine diseases. Ketonuria was found by a retrospective analysis to be independently associated with both overfeeding before calving and post parturient uterine diseases. In view of the additional risks of both metritis and ketonuria associated with overfeeding before calving and the fact that the risk of ketonuria in cows which had metritis was also found to be associated with overfeeding, it is argued that the term 'complicated' rather than 'secondary' ketosis should be applied to such cases, and that appropriate therapeutic measures should be taken accordingly.     

泌乳奶牛脂肪肝早期诊断的研究

为了寻找泌乳奶牛脂肪肝早期诊断方法,本研究从某千头奶牛场随机选取了30头乳酮阳性的奶牛,其中临床酮病牛10头,亚临床酮病牛20头,测定其肝脂含量以及血中代谢指标和肝功指标。试验结果表明,脂肪肝的奶牛存在能量负平衡现象,机体呈现高游离脂肪酸血症、高酮血症,肝脂浸润越重,能量代谢障碍越严重;乳酮阳性出现时间的早晚与脂肪肝的严重程度密切相关,乳酮阳性产后出现的越早,乳酮阳性越明显,肝脂浸润越重;随肝脂浸润程度的加重,肝功多个指标会出现异常,重度的脂肪肝会引发肝功能不全。本试验证明,酮粉法可以作为早期诊断奶牛脂肪肝的初选方法,肝功指标异常可作为诊断脂肪肝的辅助方法,两者结合可作为奶牛脂肪肝的实用、有效和准确的早期诊断方法,准确率可达80%。     

Effect of dietary chromium supplementation on productive and reproductive performance of early lactating dairy cows under heat stress

One hundred and twenty early lactating Holstein dairy cows were assigned to investigate the effect of dietary chromium (Cr) supplementation (0 or 6 mg Cr/head/day from organic preparation) on the productive and reproductive performance as well as on some blood serum parameters under heat stress (35–40 °C). Cows received treatment from 3 weeks pre‐partum through 12 weeks post‐partum. Chromium supplemented diet had lower body weight loss and improved dry matter intake with consequent reduction in the energy balance deficits during the first period after calving when compared with the control group. Chromium supplementation increased (p < 0.05) milk yield by 6.7%, 12.3% and 16.5% at 4, 8 and 12 weeks post‐partum, respectively, whereas milk composition and milk to feed ratio were unaffected (p > 0.05) when compared with the control. Moreover, dietary Cr supplementation had no effect (p > 0.05) on blood serum glucose, calcium and phosphorus concentrations. A reduction (p < 0.05) of non‐esterified fatty acids at 1 week pre‐partum, 2 and 4 weeks post‐partum was also observed. Serum insulin concentration increased whereas cortisol concentration decreased, when compared with the control group, throughout the whole experimental period. Also Cr supplementation showed a trend towards improving reproductive performance as indicated by increased percentage of pregnant cows in the first 28 days of breeding. It could be concluded that dietary Cr supplementation at level of 6 mg/head/day may offer a potential protective management practice to lessen the effect of heat stress in dairy cattle.     

Expression of fibroblast growth factor 21 in the liver of dairy cows in the transition period and during lactation

Fibroblast growth factor 21 (FGF21) has been identified as a novel hormonal factor involved in the regulation of metabolic adaptations during energy deprivation. The present study aimed to investigate the expression of the FGF21 gene in the liver of dairy cows during the transition from pregnancy to lactation. Therefore, the relative mRNA abundance of FGF21 in liver biopsy samples of 20 dairy cows in late pregnancy (3 weeks pre‐partum) and early lactation (1, 5, 14 weeks post‐partum) was determined. It was observed that hepatic mRNA abundance of FGF21 at 1 week post‐partum was dramatically increased (110‐fold) compared to 3 weeks pre‐partum (p < 0.001). With progress of lactation, mRNA concentration of FGF21 was declining; nevertheless, mRNA abundance at 5 and 14 weeks post‐partum remained 25‐ and 10‐fold increased compared to 3 weeks pre‐partum (p < 0.001). Using a gene array technique, it was found that many genes involved in fatty acid oxidation, gluconeogenesis and ketogenesis were up‐regulated during early lactation compared to late pregnancy. Moreover, there were positive linear correlations between hepatic mRNA concentration of FGF21 and mRNA concentrations of genes involved in ketogenesis as well as carnitine synthesis and carnitine uptake at various time‐points during lactation, indicating that FGF21 could play a role in ketogenesis and carnitine metabolism in the liver of dairy cows (p < 0.05). In overall, the present study shows that expression of the FGF21 gene is strongly up‐regulated during the transition period. It is assumed that the up‐regulation of FGF21 might play an important role in the adaptation of liver metabolism during early lactation in dairy cows such as in other species.     

产后酮病奶牛血液生化指征分析

为了比较产后一段时期内酮病奶牛与健康奶牛血液生化指标的差异,为奶牛酮病的防控及兽医临床诊治提供理论依据。本研究选取吴忠市某集约化奶牛场待产奶牛共30头进行为期3周的血液生化指标监测,根据β-羟丁酸（BHBA）的浓度将奶牛分为酮病组和对照组并进行比较研究。结果显示,酮病组与对照组在生产当天（0 d）各项检测指标未出现显著性差异;酮病组奶牛β-羟丁酸浓度在产后7 d时较对照组极显著升高（P<0.01）;天门冬氨酸氨基转移酶（AST）和总胆红素（T-bil）浓度在产后7 d和14 d时显著升高（P<0.05）;血糖（Glu）浓度在产后7 d时显著降低（P<0.05）,产后14 d时极显著降低（P<0.01）;钙（Ca）、磷（P）浓度无显著性差异,但均低于正常参考值范围,出现低血钙、低血磷症。经分析发现,本场奶牛所患酮病为Ⅱ型酮病,酮病牛高发胎次为3~6胎,产后低血钙、低血磷、低血糖现象严重,同时奶牛酮病引发了机体肝脏功能损伤,影响母牛生产性能。     

一例奶牛酮病的诊断与防治

奶牛酮血病简称酮病,是由于奶牛体内碳水化合物及挥发性脂肪酸代谢紊乱所引起的一种全身性功能失调的代谢性疾病,本文结合病例,介绍了奶牛酮病的发病原因和临床症状,给出了几种诊疗方法。     

Pre‐ and Post‐Partum Mild Underfeeding Influences Gene Expression in the Reproductive Tract of Cyclic Dairy Cows

Undernutrition before and after calving has a detrimental effect on the fertility of dairy cows. The effect of nutritional stress was previously reported to influence gene expression in key tissues for metabolic health and reproduction such as the liver and the genital tract early after calving, but not at breeding, that is, between 70 and 90 days post‐partum. This study investigated the effects of pre‐ and post‐partum mild underfeeding on global gene expression in the oviduct, endometrium and corpus luteum of eight multiparous Holstein cows during the early and middle phases of an induced cycle 80 days post‐partum. Four control cows received 100% of energy and protein requirements during the dry period and after calving, while four underfed received 80% of control diet. Oestrous synchronization treatment was used to induce ovulation on D80 post‐partum. Oviducts, ovaries and the anterior part of each uterine horn were recovered surgically 4, 8, 12 and 15 days after ovulation. Corpora lutea were dissected from the ovaries, and the endometrium was separated from the stroma and myometrium in each uterine horn. The oviduct segments were comprised of ampulla and isthmus. RNAs from ipsi‐ and contralateral samples were pooled on an equal weight basis. In each tissue, gene expression was assessed on a custom bovine 10K array. No differentially expressed gene (DEG) in the corpus luteum was identified between underfed and control, conversely to 293 DEGs in the oviduct vs 1 in the endometrium under a false discovery rate (FDR) < 0.10 and 1370 DEGs vs 3, respectively, under FDR < 0.15. Additionally, we used dedicated statistics (regularized canonical correlation analysis) to correlate the post‐partum patterns of six plasma metabolites and hormones related to energy metabolism measured weekly between calving and D80 with gene expression. High correlations were observed between post‐partum patterns of IGF‐1, insulin, β‐hydroxybutyrate and the expression in the oviduct of genes related to reproductive system disease, connective tissue disorders and metabolic disease. Moreover, we found special interest in the literature to retinoic acid‐related genes (e.g. FABP5/CRABP2) that might indicate abnormalities in post‐partum tissue repair mechanisms. In conclusion, this experiment highlights relationships between underfeeding and gene expression in the oviduct and endometrium after ovulation in cyclic Holstein cows. This might help to explain the effect of mild undernutrition on fertilization failure and early embryonic mortality in post‐partum dairy cows.     

Expression of adhesion molecules on milk and blood lymphocytes from periparturient dairy cattle with Johne's disease

Twelve dairy cows infected with Mycobacterium avium subsp. paratuberculosis were monitored for lymphocyte subsets and expression of adhesion molecules on cells in blood and milk at parturition and at intervals up to 21 days post-partum. Using fluorescent antibody labeling of cells and analysis by flow cytometry, we determined percentages of T cell subsets (CD4+, CD8+, gammadelta+) and expression of adhesion molecules (CD62L, LFA-1, LPAM-1, and CD44) on cells from blood and milk of these cows. Significantly higher percentages of CD8+ cells were found in milk than in blood at all time points; there were no significant differences in percentages of CD4+ or gammadelta+ cells. CD62L, LFA-1, and LPAM-1 were expressed on a significantly higher percentage of all T cell subsets in milk than in blood at various times after parturition. No differences were seen in expression of CD44. Increased percentages of T lymphocytes expressing adhesion molecules in milk compared to blood suggest that a migratory population of cells is being selectively recruited to the mammary gland from the circulation.     

Lymphocyte subsets and adhesion molecule expression in milk and blood of periparturient dairy cattle

Fifteen Holstein dairy cattle were monitored for lymphocyte subsets and expression of adhesion molecules on cells in milk and blood at parturition and at intervals up to 21 days post-partum. Using flow cytometry, we determined percentages of T cells (CD4+, CD8+, gammadelta) and B cells from milk and blood of these cows. We also measured expression of adhesion molecules (CD62L, LFA-1, LPAM-1, and CD44) on lymphocytes in milk and blood. Significantly higher percentages of CD8+ cells were found in milk than in blood at all time points while significantly higher percentages of B cells were found in blood than in milk at all time points. There were minimal to no significant differences in percentages of CD4+ or gammadelta+ cells between milk and blood. Expression of adhesion molecules was consistently higher on all subsets of milk lymphocytes compared with blood lymphocytes. These differences were most pronounced and statistically significant at calving and in the first week following calving. CD62L, LPAM-1 and CD44 were expressed on a significantly higher percentage of lymphocytes in milk at calving than in milk at subsequent sampling times, while LFA-1 expression on lymphocytes in milk was significantly lower at calving than at subsequent times.     

我国规模化牧场奶牛酮病防治状况调查分析

[目的]为了解2021年我国规模化牧场奶牛酮病发病情况和防控状况。[方法]本文选择105个规模化牧场进行调查,包括酮病发病率、诊断和监测方法、治疗方法、治愈率、防控方法和治疗成本等。[结果]牧场奶牛平均单产为9.7 t,酮病平均发病率为17.9%,高于国外控制目标。大多数牧场奶牛酮病诊断和监测,主要采用检测血液中β-羟丁酸浓度的方法,奶牛酮病治愈率无论单一或综合措施都达90%以上,奶牛酮病综合防控效果明显好于单一措施。[结论]目前我国规模化牧场奶牛酮病发病率控制目标、诊断和监测、治疗和防控仍需更多研究,完善和制定相应的技术规范,为规模化牧场奶牛酮病的高效防控提供技术支撑。     

Effect of supplementation of vitamin E,copper and zinc on the in vitro phagocytic activity and lymphocyte proliferation index of peripartum Sahiwal (Bos indicus) cows

To study the effect of vitamin E (VE), copper (Cu) and zinc (Zn) supplementation on the in vitro phagocytic activity (PA) and lymphocyte proliferation response (LPR) of blood neutrophils and lymphocytes, thirty Sahiwal pregnant cows (six in each group) in their late gestation at 30 days before the expected date of calving were selected from the NDRI experimental herd and supplemented with various micronutrients from 30 days before calving to 45 days after calving. Cows were supplemented individually with VE (1000 IU/cow/day), Cu (20 ppm/cow/day) and Zn (80 ppm/cow/day) and also with a combination of VE, Cu and Zn to study cumulative effect of all micronutrients. One group without any supplementation acted as a control. Blood neutrophils and lymphocytes were isolated and studied for their PA and LPR. Supplementation of micronutrients like VE, Cu, Zn and a combination of all these nutrients significantly (p < 0.01) increased the PA of experimental cows as compared to control (unsupplemented) cows during the pre‐partum period. During post‐partum, all the micronutrients (VE, Cu, Zn and their combination) showed a significant (p < 0.01) increase in the PA of experimental cows as compared to control cows. Of all the groups, significant (p < 0.01) and maximum PA was observed in the combination group followed by Zn‐supplemented group during both the pre‐ and post‐partum period. A significant (p < 0.01) increase in LPR of B lymphocytes was observed in combination‐supplemented group during the pre‐partum period and during both the pre‐ and post‐partum period in the Cu‐supplemented group.     

In vitro depression of bovine lymphocyte function by treatment of cultured bovine lymphocytes with physiologic concentrations of hydrocortisone

The effect of hydrocortisone (hydrocortisone sodium succinate) on bovine lymphocyte blastogenesis in response to Staphylococcus aureus antigens and phytohemagglutinin was measured in vitro. Lymphocytes isolated from the blood of cows were treated for 6 to 8 days with physiologic hydrocortisone concentrations known to be inducible by environmental stress (10 ng/ml), acute clinical mastitis (25 ng/ml), or adrenocorticotropin treatment (45 ng/ml). All 3 concentrations of hydrocortisone caused a depression (P less than 0.01) in lymphocyte blastogenesis in response to phytohemagglutinin and S aureus antigen extract. Hydrocortisone concentrations as low as 10 pg/ml caused a depression in the lymphocyte blastogenic response to phytohemagglutinin. Marked variation existed among cows in the normal response of their nontreated lymphocytes and in the degree of depression of lymphocyte function after the in vitro treatment with hydrocortisone. Macrophage depletion experiments showed that the suppressive effect of hydrocortisone was not mediated by induction of suppressor macrophages. The data suggest that T-cell function was impaired directly by hydrocortisone treatment.     

Relationships between body weight and milk yield during the early postpartum period and bull and technician and the reproductive performance of high producing dairy cows

The aim of this study was to evaluate the effect of body weight (BW) change during the early postpartum period and BW on day 50 post partum on the subsequent expression of estrus and fertility at first insemination before day 90 post partum. The data were derived from 1036 postpartum cows reaching 90 days in milk. The following data were recorded for each animal: lactation number, daily milk production at day 50 post partum, calving date, days in milk at estrus and at AI, insemination date, insemination number, inseminating bull, AI technician and body weight at calving, at day 50 post partum and at AI. Of the 1036 cows registered, 817 (78.9%) showed first estrus before day 90 post partum and were inseminated. Using logistic regression procedures and based on the odds ratio a one unit (kg) increase in the daily milk production at day 50 post partum and a one unit (kg) decrease in the BW between calving and day 50 post partum were related to a 1.03-fold increase and a 0.97-fold decrease in the estrus expression rate before day 90 post partum, respectively. Of the 817 cows inseminated before day 90 post partum, 437 became pregnant (53.5%). A one unit increase in the BW at day 50 post partum produced a 1.003-fold increase in the early fertility rate. Pregnancy rate before day 90 was also influenced by the season at calving, bull providing semen and technician. In conclusion, the register of BW during the postpartum period may be a useful tool for evaluating the nutritional status and its relationship with the subsequent reproductive efficiency in dairy cows.     

Ketosis treatment and milk yield in dairy cows related to milk acetoacetate levels

Milk yield and milk acetoacetate (M-acac) were measured weekly for the first 6 weeks of lactation in 5 herds with a ketosis problem. Ketosis treatments and the corresponding ketotest score, were also recorded. The treatment rate was highest 7-16 days after calving. Most of these early cases were associated with low ketone levels in milk, whereas the treatment rate for cows with high ketone levels was highest 17-31 days after calving. Nearly half of the treated cows were low-ketone animals. They were classified as ketosis cases in the cow health card records, although probably suffering from other post partum disturbances in many instances. About 40% of the cows with high ketone levels recovered spontaneously. Reduction in milk yield associated with peak M-acac levels was transient and moderate. It was concluded that health card statistics overestimates the severity of the ketosis problem in Norway.     

酮病、脂肪肝奶牛胰岛素受体mRNA丰度

选择自然发生的酮病奶牛、脂肪肝奶牛和正常围产期荷斯坦奶牛（对照）各5头，通过手术方法采取其肝脏样品，采用半定量RT—PCR方法检测了这3组奶牛肝胜样品胰岛素受体（InsR）mRNA丰度的变化。结果表明，酮痛奶牛InsRmRNA相对表达量低于正常对照奶牛，而高于脂肪肝奶牛；脂肪肝奶牛InsR mRNA相对表达量低于正常对照奶牛和酮病奶牛（P〈0．05）。可见，酮病奶牛InsR mRNA相对表达量下降，提示此有利于酮病奶牛糖异生和脂肪动员，从而缓解能量负平衡；脂肪肝奶牛InsR mRNA相对表达量降低，提示奶牛胰岛素应答显著减弱，此时奶牛可能发生了胰岛素抵抗。     

Activity of hepatic but not skeletal muscle carnitine palmitoyltransferase enzyme is depressed by intravenous glucose infusions in lactating dairy cows*

A positive energy balance in dairy cows pre‐partum may decrease hepatic carnitine palmitoyltransferase (CPT) enzyme activity, which might contribute to disturbances of lipid metabolism post‐partum. The purpose of this study was to investigate whether skeletal muscle CPT activity can also be downregulated during positive energy balance. Mid‐lactating dairy cows were maintained on intravenous infusion of either saline (control) or glucose solutions that increased linearly over 24 days, remained at the 24‐day level until day 28 and were suspended thereafter. Liver and skeletal muscle biopsies, as well as four diurnal blood samples, were taken on days 0, 8, 16, 24, and 32, representing infusion levels equivalent to 0%, 10%, 20%, 30% and 0% of the net energy for lactation (NE_L) requirement respectively. Glucose infusion increased serum insulin concentrations on day 16 and 24 while plasma glucose levels were increased at only a single time point on day 24. Serum beta‐hydroxybutyric acid concentrations decreased between day 8 and 24; whereas changes in non‐esterified fatty acids were mostly insignificant. Total lipid contents of liver and skeletal muscle were not affected by treatment. Hepatic CPT activity decreased with glucose infusion (by 35% on day 24) and remained decreased on day 32. Hepatic expression levels of CPT‐1A and CPT‐2 mRNA were not significantly altered but tended to reflect the changes in enzyme activity. In contrast to the liver, no effect of glucose infusion was observed on skeletal muscle CPT activity. We conclude that suppression of CPT activity by positive energy balance appears to be specific for the liver in mid‐lactating dairy cows.