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1.
In forty-five Holstein Frisian dairy cows (1-6 weeks post partum; mean age: 5.1 +/- 1.2 years) the serum total bile acid concentrations (SBA) were measured enzymatically. In all cows a left sided abomasal displacement was corrected surgically by right side laparotomy and omentopexy three days before investigation. The liver fat content was determined in all cows histologically. Liver failure was assumed if typical clinical signs (ataxia, general depression, recumbency or coma), an increased venous plasma ammonia level (> 35 mumol/l) and a decreased plasma amino acid index (< 4.0) were found. Cows without liver failure (N = 29) were grouped according to the liver fat content as cows with mild (N = 5), moderate (N = 19) or severe hepatosteatosis (N = 5). Histological examination of liver biopsies in cows with liver failure (N = 16) revealed in twelve cases a severe fatty liver and in four cases a hydropic degeneration of the liver tissue. Although in cows without liver failure mean SBA concentrations were higher in the group with moderate (47.3 +/- 30.9 mumol/l) or severe fatty liver (32.9 +/- 21.7 mumol/l) than in that with mild lipidosis (18.0 (16.8 mumol/l), differences were not significant. The mean SBA concentration in cows with liver failure (70.5 +/- 49.5 mumol/l) was only significantly (p < 0.05) increased compared to cows with uncomplicated mild hepatic lipidosis. In conclusion, the determination of SBA concentrations is of little value in the recognition of fatty liver or even liver failure due to the considerable variance of SBA concentrations in dairy cows.  相似文献   

2.
Samples of liver and perirenal, mesenteric and subcutaneous fat were collected from 16 sick necropsied dairy cows to evaluate the fatty acid profiles in the hepatic and adipose tissues associated with advanced fatty liver or hepatic lipidosis. Hepatic triglyceride and eight fatty acids were measured in the hepatic and adipose tissues. Six cows had more than 3% triglyceride on fresh weight in their livers and were classified as having fatty liver. Stearic and linoleic acid proportions in the liver decreased markedly with increased hepatic triglyceride levels, while the proportion of palmitic and oleic acids increased. The most striking fluctuations in hepatic lipidosis were manifested as decreased stearic acid in the adipose tissues including subcutaneous fat with the trend of decreasing stearic acid. Palmitic acid was elevated in hepatic and perirenal fat in fatty liver cows. In instances of advanced hepatic lipidosis, palmitoleic acid increased in only subcutaneous fat and not in perirenal or mesenteric fat. In addition to the proportions of hepatic fatty acids in fatty liver, this study also clarified the fluctuations observed in the profiles of fatty acids of the adipose tissues in cows with advanced hepatic lipidosis, particularly the decline in the proportions of stearic acid.  相似文献   

3.
To elucidate possible relationships between triglyceride (TG) levels and fatty acid composition in bovine liver, hepatic TG and seven individual fatty acids were measured in 23 Holstein dairy cows, of them 6 are healthy. Liver TG level was greater than 3 % in 12 cows which were ruled fatty liver. Palmitic and oleic acid proportions were significantly higher in fatty liver cows than in the healthy cows, while stearic acid was lower in fatty liver cows. With increased liver TG, stearic acid proportions decreased dramatically. Results indicate that hepatic lipidosis markedly alters the proportions of the various fatty acids in the liver of dairy cows.  相似文献   

4.
Glucagon as a potential therapy for ketosis and fatty liver.   总被引：4，自引：0，他引：4  
An experiment demonstrating the usefulness of glucagon as a treatment for fatty liver and ketosis in early-lactation dairy cows has been described. This is the first report of the ability of glucagon, or any agent, to promote clearance of lipid from livers of animals suffering hepatic lipidosis. The development and use of glucagon as a therapeutic agent for the fatty-liver complex in dairy cows may provide a powerful management tool to enhance the profitability of the high-producing dairy cow.  相似文献   

5.
In dairy cows, overfeeding during the dry period leads to overcondition at calving and to depression of appetite after calving. As a consequence, at calving overconditioned high-producing dairy cows inevitably go into a more severe negative energy balance (NEB) postpartum than cows that have a normal appetite. During the period of NEB, the energy requirements of the cow are satisfied by lipolysis and proteolysis. Lipolysis results in an increased concentration of non esterified fatty acids (NEFA) in the blood. In the liver, these NEFA are predominantly esterified to triacylglycerols (TAG) that are secreted in very low density lipoproteins (VLDL). In early lactation in cows with a severe NEB, the capacity of the liver to maintain the export of the TAG in the form of VLDL in balance with the hepatic TAG production is not always adequate. As a result, the excess amount of TAG accumulates in the liver, leading to fatty infiltration of the liver (hepatic lipidosis or fatty liver). The NEB and/or fatty liver postpartum are frequently associated with postparturient problems. In general, a severe NEB induces changes in biochemical, endocrinological, and metabolic pathways that are responsible for production, maintenance of health, and reproduction of the postparturient dairy cow. These changes include a decrease in blood glucose and insulin concentrations, and an increase in blood NEFA concentrations. High NEFA concentrations caused by intensive lipolysis are accompanied by impairment of the immune system, making the cows more vulnerable to infections. Metabolic diseases such as ketosis, milk fever, and displaced abomasum are related to overcondition at calving. The changes in biochemical, endocrinological, and metabolic pathways are associated with delay of the first visible signs of oestrus, an increase in the interval from calving to first ovulation, a decrease in conception rate, and a prolonged calving interval. It is possible that the increased blood NEFA concentration directly impairs ovarian function.  相似文献   

6.
Plasma lipoproteins and fatty liver in dairy cows   总被引：1，自引：0，他引：1  
Dairy cows were classified on the basis of a histological study after a hepatic biopsy conducted in the second week post partum (mild fatty liver, moderate fatty liver, severe fatty liver). Plasma lipoproteins were separated into various density classes by repeated ultracentrifugation. The results indicate that the beginning of lactation is associated with a low concentration of the 1.006 to 1.063 g ml-1 lipoprotein fraction. The lowest concentrations occurred in cows with severe steatosis or during the evolution of moderate steatosis.  相似文献   

7.
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.  相似文献   

8.
Summary

In dairy cows, overfeeding during the dry period leads to overcondition at calving and to depression of appetite after calving. As a consequence, at calving overconditioned high‐producing dairy cows inevitably go into a more severe negative energy balance (NEB) postpartum than cows that have a normal appetite. During the period of NEB, the energy requirements of the cow are satisfied by lipolysis and proteolysis. Lipolysis results in an increased concentration of non esterified fatty acids (NEFA) in the blood. In the liver, these NEFA are predominantly esterified to triacylglycerols (TAG) that are secreted in very low density lipoproteins (VLDL). In early lactation in cows with a severe NEB, the capacity of the liver to maintain the export of the TAG in the form of VLDL in balance with the hepatic TAG production is not always adequate. As a result, the excess amount of TAG accumulates in the liver, leading to fatty infiltration of the liver (hepatic lipidosis or fatty liver). The NEB and/or fatty liver postpartum are frequently associated with postparturient problems. In general, a severe NEB induces changes in biochemical, endocrinological, and metabolic pathways that are responsible for production, maintenance of health, and reproduction of the postparturient dairy cow. These changes include a decrease in blood glucose and insulin concentrations, and an increase in blood NEFA concentrations. High NEFA concentrations caused by intensive lipolysis are accompanied by impairment of the immune system, making the cows more vulnerable to infections. Metabolic diseases such as ketosis, milk fever, and displaced abomasum are related to overcondition at calving. The changes in biochemical, endocrinological, and metabolic pathways are associated with delay of the first visible signs of oestrus, an increase in the interval from calving to first ovulation, a decrease in conception rate, and a prolonged calving interval. It is possible that the increased blood NEFA concentration directly impairs ovarian function.  相似文献   

9.
Fatty liver in dairy cows   总被引：3，自引：0，他引：3  
An increase in liver fat concentration during the peripartum period is extremely common in dairy cows and, to some degree, is probably normal. When severe, it is associated with clinical problems including increased morbidity and mortality and reduced breeding efficiency. Fatty liver develops when serum NEFA concentrations rise and hepatic uptake of NEFA exceeds the liver's ability to synthesize and secrete lipoproteins. In most cases, hepatic lipid accumulation appears to commence prepartum, in association with rising serum NEFA concentrations and declining serum lipoprotein concentrations. Commonly used clinicopathologic tests of liver function do not yield clearly abnormal results except in animals with extremely high concentrations of liver fat. Clinically useful estimates of hepatic lipid concentration can be obtained in the field by determining the buoyancy of needle biopsy samples in liquids of various specific gravities. Clinically ill animals with liver fat concentrations of greater than 35 per cent by weight have a poor prognosis, and those that do survive will have a protracted convalescence. Treatment of dairy cows with clinical fatty liver should be aimed at reducing further adipose lipid mobilization and promoting hepatic lipoprotein synthesis; however, protocols for therapy have not as yet been evaluated critically. Prevention of fatty liver is more rewarding than treatment. Dry cows should be maintained in a moderately fat condition and fed high-quality, palatable feeds in amounts necessary to met or slightly exceed their energy requirements. Free-choice feeding of high-energy feeds should be avoided in late lactation and during the nonlactating period.  相似文献   

10.
The objective was to examine the effects of insulin under euglycaemic conditions on liver long chain fatty acids (LCFA) metabolism with special focus on the aetiology of hepatic lipidosis in early lactation. A 4-day hyperinsulinaemic-euglycaemic clamp (clamp) was conducted on four dairy cows starting in weeks 4 and 17 postpartum. Insulin was infused continuously (1 microg/kg BW per h) and a 50% glucose solution was infused to maintain euglycaemia. Liver biopsies were taken 6 days before, the last day of, and 5 days after the clamp, and blood samples were taken in the same period. In the liver tissue, the relative triglyceride content decreased (P < 0.01) and the glycogen content increased (P < 0.0001) in response to the clamp. Hepatic in vitro palmitate oxidation capacity was lowest during the clamp period and could be explained by a significant decrease in incomplete oxidation (ketogenesis) (P < 0.04) and a tendency to a decreased complete oxidation of palmitate (P < 0.10). Plasma non-esterified fatty acids concentration was decreased during the clamp in early lactation (P < 0.05) but there was no effect on the mid-lactation clamp. The present study shows that increased insulin under euglycaemic conditions seems to depress hepatic LCFA oxidation capacity. However, in terms of preventing hepatic lipidosis, the anti-lipolytic effect of insulin on adipose tissue, which results in decreased mobilization of and hence hepatic load with LCFA, appears more important.  相似文献   

11.
A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period. After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.  相似文献   

12.
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%。  相似文献   

13.
Summary

A syndrome very similar to hepatic lipidosis is described in dairy cows during the dry period.

After being sent to pasture the animals did not eat well for undetermined reasons. The disease phenomena were mainly observed in animals carrying twins. At post mortem examination severe falty infiltration was found in the 3 animals made available for post mortem examination. Increase of the energy supply to the dry cows by addition of maize silage to the ration prevented new cases.  相似文献   

14.
It was the aim of this study to investigate the effect of a supplementation with beta-carotene administered systemically (Carofertin) on the reproductive performance in dairy cows. One hundred cows received three injections of 20 ml Carofertin 3 to 4 weeks ante partum, 1 to 2 weeks post partum and 6 to 8 weeks post partum. Control cows (n = 101) were treated simultaneously with 20 ml 0.9% NaCl-solution. Serum concentrations of beta-carotene were determined before the first and the second beta-carotene injection, and at the time of first insemination. For all animals, serum concentrations of beta-carotene, results of puerperal controls, culling rate, culling reason, fertility parameters, progesterone production during the luteal phase, and cost per pregnancy were evaluated. Clinical examination during the puerperal phase revealed that cyclicity had started statistically significantly more often in control cows than in the cows receiving Carofertin. With regard to the other parameters, no significant group differences were found. Cost per pregnancy were higher in the Carofertin group (241.78 [symbol: see text]) than in the control group (171.40 [symbol: see text]). These results suggest that the use of Carofertin in dairy cows under the given experimental conditions for therapy or prophylaxis of fertility disorders might not be recommendable.  相似文献   

15.
Relationship of hepatic lipidosis to health and performance in dairy cattle   总被引：2，自引：0，他引：2  
In a field study of 80 cows in 9 dairy herds, serial liver biopsies were performed over the peripartum period to determine degree of hepatic lipidosis. Cattle were separated into categories of mild, moderate, and severe hepatic lipidosis on the basis of maximal amounts of hepatic triglyceride that accumulated during this period. Number of cattle with mild, moderate, and severe hepatic lipidosis were 52, 16, and 12, respectively. Cattle with severe hepatic lipidosis had greater concentrations of hepatic triglyceride before calving and after parturition, and greater serum nonesterified fatty acid concentrations and body condition loss after parturition than cattle with mild hepatic lipidosis. Rate of disease and culling and death rate because of disease were greater in cattle with severe hepatic lipidosis. Cattle with severe hepatic lipidosis had reproductive performance equal to clinically normal cattle; however, cattle with moderate hepatic lipidosis had increased days to conception, possibly related to greater milk production.  相似文献   

16.
In a group of 20 high-yielding dairy cows, 10 with mild and 10 with severe fatty liver one week after calving, there was an association between fatty liver and reduced fertility. The 10 cows with severe fatty liver had a significantly longer calving interval to the next lactation compared to the cows with mild fatty liver. In addition there was a significant positive correlation between the amount of fat in the liver and calving interval. The results support the concept that liver dysfunction at calving adversely affects subsequent fertility.  相似文献   

17.
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.  相似文献   

18.
The objective of the present study was to analyse the apoptotic process of liver cells in dairy cows with fatty infiltration of the liver using indicators of DNA damage and immunohistochemistry. For this purpose, sixteen dairy cows with fatty liver were examined. On clinical examination, the physical condition of the animals was fair in nine and poor in seven cows. The most dominant clinical signs were reduced ruminal motility, inappetance and/or anorexia and recumbency. Postmortem examination, in seven cases, revealed enlarged liver (18-33kg), icteric carcasses and distended gallbladder. Laboratory results included neutrophilia, hypochloraemia, decreased concentrations of total bilirubin and increased concentrations of β-hydroxy butyric acid, non-esterified fatty acids and insulin. The activities of aspartate aminotransferase, γ-glutamyl transpeptidase, creatine kinase and lactate dehydrogenase were high. Histopathological examination of hepatic specimen showed lipid drops in cytosol with indistinct cellular membranes. In control hepatic cells, the DNA was tightly compressed and maintained the circular disposition of the normal nucleus. However, in the diseased cows, the damaged DNA migrated from the core toward the anode, forming a tail of a comet. Compared to controls, numerous ssDNA and caspase-3-positive cells were detected in the liver. To the authors' knowledge, this is the first study to document accelerated apoptosis of hepatocytes in dairy cows with fatty infiltration of the liver.  相似文献   

19.
The objective of the present study was to analyse the apoptotic process of liver cells in dairy cows with fatty infiltration of the liver using indicators of DNA damage and immunohistochemistry. For this purpose, sixteen dairy cows with fatty liver were examined. On clinical examination, the physical condition of the animals was fair in nine and poor in seven cows. The most dominant clinical signs were reduced ruminal motility, inappetance and/or anorexia and recumbency. Postmortem examination, in seven cases, revealed enlarged liver (18–33 kg), icteric carcasses and distended gallbladder. Laboratory results included neutrophilia, hypochloraemia, decreased concentrations of total bilirubin and increased concentrations of β-hydroxy butyric acid, non-esterified fatty acids and insulin. The activities of aspartate aminotransferase, γ-glutamyl transpeptidase, creatine kinase and lactate dehydrogenase were high. Histopathological examination of hepatic specimen showed lipid drops in cytosol with indistinct cellular membranes. In control hepatic cells, the DNA was tightly compressed and maintained the circular disposition of the normal nucleus. However, in the diseased cows, the damaged DNA migrated from the core toward the anode, forming a tail of a comet. Compared to controls, numerous ssDNA and caspase-3-positive cells were detected in the liver. To the authors’ knowledge, this is the first study to document accelerated apoptosis of hepatocytes in dairy cows with fatty infiltration of the liver.  相似文献   

20.
Fatty liver syndrome or hepatic lipidosis (HL) is a condition thought to contribute to an increased incidence of peripartum disease, reduced response to therapy and decreased fertility in dairy cows. This syndrome is characterized by excess triglyceride (TG) accumulation in the liver and apparent decreased hepatic lipoprotein output. In lactating rats, a similar condition results from feeding an inositol-deficient diet. It is also characterized by excess hepatic TG accumulation and decreased hepatic lipoprotein output. Myo-inositol is a necessary component of the phospholipid phosphatidyl-inositol, which is an important membrane constituent. Myo-inositol occurs in feed mainly as the inositol hexaphosphate phytic acid. Phytic acid is undigestible by the monogastric but rumen phytases are assumed to adequately hydrolyze it. In early lactation dairy cows, lipid mobilization is intense, and the myo-inositol requirement may exceed the dietary supply or availability. Myo-inositol is being tested in a field trial as a potential lipotropic agent for dairy cows. Preliminary results suggest no lipotropic benefit from added myo-inositol.  相似文献   

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