Reduced lymphoid response to skin allotransplants in cows with hepatic lipidosis.

The immune responsiveness of cows with hepatic lipidosis (fatty liver) in comparison to control cows with a normal liver fat content was tested by applying skin allotransplants to the skin of the back of cows on day 3 after parturition. Immunoreactivity was determined by semiquantitative counting of the number of infiltrating lymphocytes in the recipient skin adjacent to the allotransplants during a period of 21 days. There were more invading lymphocytes in samples from control cows than there were in samples from cows with hepatic lipidosis. It was concluded that cows with hepatic lipidosis have a reduced lymphoid response to skin allotransplants.     

Serum Bile Acid Concentrations in Dairy Cattle With Hepatic Lipidosis

This study was designed to evaluate serum bile acid measurements as indicatory, of liver function and/or hepatic fat infiltration in dairy cattle. Serum bile acid concentrations were measured in healthy dairy cattle at different stages of lactation after fasting or feeding. Bile acid concentrations were compared with liver fat content and sulfobromophthalein (BSP) half-life (T 1/2). Serum bile acid concentrations were higher in cows in early lactation and with higher daily milk production. Compared with prefasting values, bile acid concentrations were decreased at 8,14, and 24 hours of fasting. Blood samples from fed cows at 1 - to 2-hour intervals had wide and inconsistent variations in bile acid concentration. Because serum bile acids correlated well with BSP T 1/2, it is suggested that both measurements evaluate a similar aspect of liver function. Neither bile acids nor BSP T I correlated with differences in liver fat content among cows. Because of large variability in serum bile acid concentrations in fed cows and the lack of correlation of measured values with liver fat content, bile acid determinations do not appear useful for showing changes in hepatic function in fed cows with subclinical hepatic lipidosis nor serve as a screening test for this condition.     

Studies on liver sufficiency of cows fed on food with unbalanced mineral composition

In 90 cows of black white and red white race, aged 3-9 years and of 450 kg mean body weight fed on food with low level of Ca, P, and Na, several parameters of protein, carbohydrates and lipid liver metabolism before and after supply of special mineral mixtures were evaluated. After the supply the increased concentration of total protein, urea and cholesterol esters and decrease of AspAT, AlAT, and AP activities were recorded in the blood. Cholesterol esters: total cholesterol ratio improved and a slight increase of milk yield and content of fat in milk was observed. Food mineral mixtures favourably influenced the stabilization of liver metabolism.     

An Abattoir Survey on the Frequency of Fatty Liver Syndrome in Dairy Cows from the Suburbs of Tehran

One hundred and six Holstein and Holstein x native cows were inspected before and after slaughter, and liver samples were taken. The fat content of all the liver samples was estimated by an extraction method (Soxhlet). The livers of 29 cows (27%) were classified as fatty. Seventeen of the animals were newly calved, 47 were non-pregnant, 33 were pregnant and 9 were dry, the median values for the fat content of their livers being 60.6, 34.4, 34.7 and 33.8 mg/g, respectively. The median concentration of liver fat in the first group was significantly different from that in each of the other groups (p < 0.01).     

Total serum bile acid concentrations in dairy cows with fatty liver and liver failure

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.     

The use biochemical and hepatic parameters to predict treatment outcome of dairy cows suffering from displacement of the abomasum

In this prospective study the impact of fatty liver and an impaired liver function on the treatment outcome of displacement of the abomasum (DA) was investigated. In a yearlong period, all cows suffering from DA submitted to the clinic were included in this study. All cows were clinically examined before surgery and a serum sample was taken to measure the following parameters: ASAT, bilirubin, urea. Liver biopsy was performed in all cows. Liver fat content was measured gravimetrically and concentrations of triglycerides were measured using a commercial test kit. Reposition of DA was done using the method by Dirksen. A total of 365 cows with DA entered the study, 326 (89.3%) suffered from LDA and 39 (10.7%) from RDA. RDA-cows had significantly (p = 0.002) more days in milk than LDA-cows. RDA-cows had significantly (p < 0.001) higher urea concentrations than LDA-cows. Bilirubin concentrations (p = 0.008) and liver fat content, triglyceride concentrations and the ratio of triglycerides to fat (TRI/FAT) (p < 0.001) were significantly higher in LDA-cows. The majority of LDA-cows showed at least a mild fatty liver. Comparing the cows with successful and failed treatment showed that ASAT-activity (p = 0.021), bilirubin concentration (p = 0.001), triglyceride concentration in liver and TRI/FAT (all p < 0.001) were significantly higher in the unsuccessfully treated cows. In RDA cows, significant differences between successfully and unsuccessfully treated cows were only seen in urea concentration (p = 0.004). ROC-analysis was performed to determine whether any parameter is suitable for a prediction of treatment outcome. In RDA-cows no threshold value was traceable for urea concentration. In LDA cows, TRI/FAT showed the best curve progression. The threshold value of 53.5 % had a sensitivity of 0.720 and a specificity of 0.700. LDA-cows exceeding this threshold had a 2.4 higher risk of an unsuccessful treatment. Due to the good overall treatment success (92.3 %) the positive predictive value for an unsuccessful or ineffective treatment was 0.368 only. The results of our study clearly show that impaired liver function plays an important role in the outcome of treatment of LDA but not RDA. In spite of this no laboratory parameter provides sufficient power to make a predictive statement of treatment outcome.     

胆碱对奶牛肝脏脂肪代谢的调控作用及机制

围产期奶牛脂肪肝等营养代谢性疾病的防治和调控是提高生产性能和效益的关键.胆碱作为一种动物生长发育必需的营养素,在奶牛肝脏脂肪代谢调控方面发挥着重要的作用.饲粮中适当补充胆碱可以有效降低肝脏脂肪含量和预防脂肪肝,并维持肝脏的正常生理功能.胆碱主要通过上调脂肪分解和下调脂肪生成途径的基因和蛋白的表达水平来调节脂肪代谢,从而减少脂肪沉积,缓解脂肪肝.本研究在已有文献报道基础上,阐述了胆碱的特性和功能,围绕胆碱对动物肝脏脂肪代谢的调节作用及机制进行了综述,旨在为奶牛维持机体健康、提高反刍动物生产性能提供理论依据.     

Relationship between fat accumulation in the liver and energy intake, milk fat yield and blood metabolites in dairy cows

In the present study, 42 multiparous Holstein cows were used to investigate the relationship between fat accumulation in the liver and dry matter intake, milk yield and blood metabolites. Based on the percentage of fat in the liver cell at 2 weeks post‐parturition, the cows were classified into three groups. These groups were: (i) less than 10% of fat (normal group, n = 29); (ii) 10–20% of fat (mild group, n = 6); and (iii) more than 20% of fat (moderate group, n = 7). The bodyweight of the moderate group was high (771 kg) before calving. The sufficiency rates of total digestible nutrients (TDN) were remarkably decreased (approximately 65%) in early lactation. The milk fat yield and milk fat composition of the moderate group were higher (P < 0.05) than the other groups at 1 and 2 weeks post‐parturition. It was suggested that non‐esterified fatty acids (NEFA) mobilized from adipose tissues was directly used by the mammary gland for synthesis of milk fat. The percentage of bromsulfalein (BSP) retention of the moderate group was high (21.1%) at 30 min, and it showed that the BSP clearance function was significantly decreased. The concentrations of NEFA, β‐hydroxybutyric acid and glucose were appropriate indicators of energy status; however, aspartate aminotransferase, γ‐glutamyl transpeptidase and total bilirubin were not sensitive indicators of a moderate fatty liver. Thus, high‐yielding cows that calve in an overweight condition are more likely to develop excessive fat accumulation in the liver because of great mobilization from adipose tissues post‐parturition. In cows with a moderately fatty liver, a decrease in TDN sufficiency rates, an increase of milk fat yield and a reduction of liver function were observed in early lactation. The increase of serum NEFA and milk fat composition resulting from mobilization of adipose tissues helped to diagnose moderate fatty liver.     

Reduced fertility associated with fatty liver in high-yielding dairy cows

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.     

Reduction of serum triacylglycerol-rich lipoprotein concentrations in cows with hepatic lipidosis

The hepatic and serum lipid concentrations in 49 dairy cows with displaced abomasum, 7 postpartum cows fasted for 6 days, and 14 healthy postpartum cows were studied. The cows with displaced abomasums were retrospectively allotted to 2 groups: those with greater than 15% liver fat (DAHF) and those with less than 15% liver fat (DALF). Liver total lipid concentrations were high in the DAHF group, exceeding these values in the fasted cows by 30% and in the healthy and DALF cows by 63% on the average. In contrast, the liver phospholipid concentrations were low in the DAHF group, intermediate in the fasted and DALF groups and high in the healthy group. On a group basis, an inverse relationship was observed between serum and liver lipid concentrations. The serum concentrations of both total and dextran-sulfate-precipitable (DSP) lipids were high in the fasted cows and were less in the DALF and healthy cows and in the DAHF cows (lowest). The between-group differences in serum total and serum DSP concentrations of triacylglycerol, cholesterol, and phospholipid followed the same quantitative pattern as the total lipids. However, the relative difference between groups was greater for each of the DSP lipid fractions. These results support the hypothesis that severe hepatic lipidosis in cattle occurs due to impaired hepatic lipoprotein synthesis and secretion.     

The effects of a single injection of dexamethasone-21-isonicotinate on the lymphocyte functions of dairy cows at two weeks post partum

Dexamethasone is a potent therapeutic for treatment of the fatty liver syndrome or primary ketosis in post partum dairy cows. Reservations exist, however, among practitioners with respect to the risk of immunosuppression induced by corticosteroids. The aim of this study was to investigate the effect of a single injection of dexamethasone-21-isonicotinate on distinct immune functions of postpartum dairy cows because only scarce information is available on the effects of corticosteroid preparations when administered at a dosage and frequency for treatment of the fatty liver syndrome or primary ketosis. Sixteen Swedish red-pied dairy cows, between days 9 and 15 post partum, were allotted to either a control group (n = 8) or a treatment group (n = 8). The cows in the treatment group received a single intramuscular injection of a dexamethasone-21-isonicotinate suspension at a dosage of 0.02 mg/kg i.m. at the start of the experiment. White blood cell counts and selected lymphocyte functions (lymphocyte proliferation, expression of lymphocyte markers and the b2 and a4 chain of adhesion molecules belonging to the integrin family) and some parameters of the energy metabolism (glucose, insulin) were determined before the administration of corticosteroids (day 0) and subsequently at days 2, 4, 7 and 9 of the experiment. Changes in glucose and insulin were within the target range for treatment of the fatty liver syndrome or primary ketosis. Significant (P < 0.05) increases in the number of circulating white blood cells were observed in treated cows on the second day following treatment which was exclusively caused by an increase in the number of circulating neutrophils. Lymphocyte blastogenesis in response to ConA and the percentages of lymphocytes positive for CD2, CD4, CD8, CD49d and CD18 as well as the intensity of CD49d expression did not differ between the treatment and control groups. There was, however, a significant reduction (P < 0.01) in the intensity of CD18 expression on lymphocytes in the treated animals on the fourth day after treatment. In conclusion, a single administration of dexamethasone-21-isonicotinate in a dosage of 0.02 mg/kg i.m. at two weeks post partum in healthy cows had a significant but highly transient effect on CD18 expression on lymphocytes and the number of peripheral blood neutrophils, but did not affect lymphocyte blastogenesis or lymphocyte subpopulation patterns in peripheral blood.     

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。     

Relationship between occurrence of white diarrhea and changes of properties and components of blood and milk in their dams after parturition in Japanese Black calves.

We investigated the diet content and properties of blood and milk in 11 pairs of Japanese Black cows and their calves for the one month following delivery. Four pairs (group A) had been no cases of white diarrhea during the year prior to this study, and 7 pairs (group B) had been a high occurrence of white diarrhea in calves during the same period. Properties of dams' diet in groups A and B before the onset of white diarrhea in calves were as follows: TDN fullness rate 98 +/- 2% vs. 110 +/- 5%, DCP fullness rate 151 +/- 2% vs. 200 +/- 33%, and starch content 5 +/- 2% vs. 14 +/- 3%. Blood and milk samples were collected from cows weekly and at the onset of white diarrhea in calves. No calves in group A had white diarrhea, while 5 out of 7 calves in group B had the diarrhea in this study. All cows were fed mixed hay, but 3 out of 5 cows whose calves had white diarrhea had been additionally given 3.0-3.5 kg of corn-silage a day from 4-5 days before onset. In all cows in the white diarrhea development group, the fat content of milk increased by 2.94 +/- 1.82% at the day of onset in comparison before. Serum TG and BUN, respectively, increased by 3.8 +/- 1.3 mg/dl and 3.7 +/- 2.0 mg/dl. Feeding cows a low-starch diet and additional corn-silage may induce a transient increase in blood TG, BUN and milk fat, which may contribute to the occurrence of white diarrhea in calves.     

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 various dietary fat supplementations on liver lipid and glycogen of high-yielding dairy cows in the peripartal period

In a model experiment, Holstein-Friesian dairy cows were fed on a corn-silage-based diet supplemented with 11.75 MJ NE1 per day of calcium soaps of palm oil fatty acids (CAS) or hydrogenated triglyceride (HTG) or without fat supplementation (control). All diets were fed to the cows over a period from 21 +/- 3 days (d) prior to the expected calving to d 100 +/- 5 postpartum. On d 25 (basal sample) and d 14 prepartum as well as on d 5 and 25 postpartum liver samples were collected by percutaneous biopsy. Total lipid content, fatty acid composition and glycogen of liver tissues were determined. At d 5 postpartum, both control and CAS cows had higher liver lipid (P < 0.05) and lower glycogen (P < 0.05) concentrations than cows in the HTG group. No significant (P < 0.05) differences were detected in liver fat content among the groups at d 14 prepartum or d 25 postpartum. The glycogen concentration slightly decreased in the liver of cows in each treatment group from d 14 prepartum to d 5 postpartum; however, this decrease was more intensive in both the control and CAS groups than in the HTG group. The variations in liver lipid concentrations were accompanied by significant changes in the proportion of C16:0, C16:1n-7, C18:0, C18:1n-9, C18:2n-6 and C20:4n-6 fatty acids in the liver lipids. The results show that HTG supplementation exerted more advantageous effects on liver lipid and glycogen metabolism than did CAS supplementation.     

Experimental studies on the ketogenic effect of high doses of proteins in dairy cows]

A 14-month feeding experiment was conducted with 16 high-yielding cows, each given a daily supplement of 2 kg soya meal regardless of milk yield or the stage of lactation, in comparison with 8 normally-fed cows. At monthly intervals various parameters of carbohydrate, fat and protein metabolism and of liver function were determined. At the end of the trial, samples of liver were obtained by biopsy for morphological and histochemical examination. Supplementation had a pronounced effect on milk yield and fat content, averaging over 900 kg of milk and 0.2% fat content more than during the preceding year. The parameters of metabolism revealed clear signs of subclinical ketosis, particularly during the first third of the trial period. Changes were greatest during the 3rd and 4th months of the trial, when the protein content of the ration was particularly high (over 3 kg) and when the energy supply ratio was particularly unfavourable (PEQ 300). At the end of the trial some abnormalities were detected in individual animals in the biochemical properties of blood and urine, and the morphological, histochemical and ultrastructural appearance of the liver. These changes included increases in KK, BTS and bilirubin concentrations in the blood; ketonuria, proteinuria; perilobular fat infiltration with glycogen depletion; changes in succinate dehydrogenase and acid phosphatase activities. In most animals the liver seemed to have become adapted to a high protein intake.     

Decrease in stearic acid proportions in adipose tissues and liver lipids in fatty liver of dairy cows

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.     

Variations in parameters of liver function and plasma progesterone related to underfeeding and ketosis in a dairy herd

Twenty-eight Norwegian Red Cattle dairy cows were fed silage ad libitum and restricted amounts of concentrates. Blood samples were collected before morning feeding, once or twice weekly, from 2 weeks before to 12 weeks after calving. Parameters of liver function, carbohydrate status and fertility were recorded in order to assess their interrelationships. Eight cows were treated for clinical ketosis. Four of these had to be treated 2 or 3 times. Aspartate aminotransferase and bilirubin showed the highest within-animal coefficients of correlation with acetoacetate. Analysis of variance revealed a significant effect of carbohydrate status (indicated by plasma acetoacetate levels) on the levels of aspartate aminotransferase, glutamate dehydrogenase and sorbitol dehydrogenase, though only a small part of the total variation was explained by this factor. The estimated volume density of liver fat in the 4th week of lactation averaged 6.0 +/- 6.4% (+/- SD) ranging from 0.1-25.1%. Liver fat content at this stage of lactation was not significantly correlated with other indicators of liver function or carbohydrate status. Cows treated for clinical ketosis had significantly lower plasma progesterone values at the time of first ketosis treatment than untreated multiparous cows. The frequency of high progesterone values (greater than 3 ng/ml) being significantly lower in treated than in untreated cows during the period from 3-5 weeks post partum, though not at later stages. In conclusion, the results revealed a significant relationship between carbohydrate status and liver function, and also between clinical ketosis and luteal function.     

Efficacy of sodium borate in the prevention of fatty liver in dairy cows

The effects of sodium borate (100 mg/kg body weight, p.o., 15 days) from a month before expected calving until a month after calving were evaluated in dairy cows susceptible to fatty liver. Cows received either sodium borate (n = 13) or no treatment (n = 10). All cows had mild fatty livers and increased plasma triglycerides and very low density lipoprotein (VLDL) concentrations at the beginning of the experiment. The control group of cows developed significant fatty liver after calving, and 2 of them had severe fatty liver associated with clinical and biochemical abnormalities. There were no clinicopathological signs related to sodium borate administration. Serum triglycerides and VLDL concentrations before calving decreased significantly at calving and after calving in controls, and they were within the normal range only after calving. There were significant alterations during the experiment in some hematological and chemical variables between groups, within period, but they were within the normal range. Unlike treated cows, serum triglycerides and VLDL concentrations correlated with liver fat content after calving in untreated cows. Our results document that sodium borate decreases the degree of fatty liver in dairy cows during early lactation.