Left-side displacement of the abomasum in dairy cows at pasture

The presentation of approximately 40 dairy cows affected with left-side displacement of the abomasum (LDA) per annum in a cattle practice in East Gippsland, Victoria provided an opportunity to conduct a survey and case-control study of the disease in a grazing environment. The study, involving 37 dairy cows at pasture, revealed significant differences from the pattern of the disease occurring in the northern hemisphere where cows in older age groups, of larger frame size, higher production and fed high grain rations are at increased risk. Affected cows were diagnosed over a 10-month period and represented approximately 0.06% of the dairy cow population. Most cases were diagnosed in the early lactation period. Evidence for a genetic predisposition was suggested by the discovery that one sire generated a disproportionately large number (9) of the cows with LDA. Although affected cows were average producers in their herds, being a member of a high-producing herd was a significant risk factor.     

奶牛真胃变位发病规律的研究

为了阐明奶牛真胃变位的发病规律，对263例奶牛患有真胃变位的自然病例进行了研究。结果表明：真胃变位的发生与过食精料和高产奶牛有密切关系，2－4胎次体格健壮的、产后30天内的、11月份到来年的5月份奶牛发病率高。     

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.     

Position of the abomasum in dairy cows during the first six weeks after calving

The position of the abomasum in six cows was examined by ultrasonography at regular intervals for six weeks after they had calved. Its position was established by determining the distance between the margin of the left side of the abomasum and the ventral midline at two sites. During the last weeks of pregnancy, the abomasum was positioned in a small region of the left ventral side of the abdominal cavity. At parturition it was positioned high on the left side and then descended. The abomasum was furthest from the midline immediately after parturition. Its position was related to the interval after calving, the cow's feed intake, and the pH and osmotic pressure of the rumen fluid. There was considerable variation between the cows in the position of the abomasum, which was in part due to analytical variation, and in individual cows it had a circadian rhythm.     

Origin of abomasum gas in the cows with displaced abomasum

The gas composition of the rumen and the abomasum were investigated in 71 cows including 25 cows with displaced abomasum. The ratio of methane (CH4) to CO2 in the abomasum gas was higher than that in the rumen. In the incubated mixtures of fresh rumen fluid, CH4 was detected at a high concentration, while a small amount of CO2 and CH4 was found in incubated mixtures of fresh abomasum fluids. Hence, it was suggested that the gas in the abomasum originated not from the abomasum itself but from the rumen. In cows fed with mixed roughages and concentrates, the rumen CO2:CH4 ratio was higher compared with cows fed with roughages alone. Marked changes in rumen gas composition were presumed to be associated with changes in abomasum gas composition. Consequently, it is possible that feeding a large quantity of concentrates may increase the flow rate of the ingesta through the forestomach, so that the return rate of gas separated from the ingesta in the abomasum to the forestomach may also increase. Therefore, the frequent accumulation of a large amount of gas with concomitant changes in the total volatile fatty acid (VFA) concentration in the abomasum caused abomasal atony and subsequently displaced abomasum.     

Peritoneal fluid analysis in dairy cows with left displaced abomasum and abomasal volvulus

Peritoneal fluid (PF) was evaluated in 40 cows with left displaced abomasum (LDA) and 15 cows with abomasal volvulus (AV). PF was obtained by abdominocentesis at the right ventral abdomen at admission. Simultaneously, a blood sample was taken from the jugular vein. Biochemical and cytological variables in blood and PF specific for ischaemia, inflammation and cell damage were compared. Total protein, albumin, glucose and cholesterol were normal in PF of cows with LDA and AV. Although L-lactate increased in both groups, cows with AV had significantly higher values (LDA: 1.47/0.69/2.68 mmol/l; AV: 6.45/4.55/12.89 mmol/l (median/1. quartile/3. quartile)). D-dimer (LDA: 0.50/0.22/0.88 mg/l; AV: 1.11/0.40/1.85 mg/l) and LDH (LDA: 663/437/943 U/l; AV: 1099/750/1439 U/l) were only increased in PF of cows with AV. The number of leucocytes was normal; however, significantly more peritoneal neutrophils appeared necrotic or apoptotic after AV. PF of cows with abomasal displacement showed distinctive features of ischaemia and inflammation. Characteristics of haemostatic dysfunction and cell damage were mainly evident in PF of cows with AV. The results suggest that anti-inflammatory therapy is indicated in each cow with abomasal displacement. Additionally, medical treatment should be directed to prevent complications of ischaemia and reperfusion in cows with AV.     

One-step laparoscopic abomasopexy for correction of left-sided displacement of the abomasum in dairy cows

Four adult dairy cows in which a diagnosis of left-displaced abomasum (LDA) had been made underwent a 1-step laparoscopic abomasopexy (LA). The technique was performed with each cow positioned in dorsal recumbency. Two laparoscopic portals were created in the right paramedian area to identify the abomasum and direct insertion of the steel trocar and cannula into the abomasal lumen. A stainless steel toggle pin (with 2 lengths of suture attached to its midpoint) was inserted via the cannula into the abomasal lumen while the excess suture material remained exterior to the abdomen. The abomasum was deflated, and the excess suture material was withdrawn up to a preset marker on the suture to position the abomasum adjacent to the body wall. The suture was then tied to secure the abomasum in place. By use of this 1-step LA technique, LDA was successfully corrected in all 4 cows. The procedure is minimally invasive and allows viewing of the abomasum for correct positioning and fixation; it can be accomplished with the speed associated with the blind roll-and-tack technique. The 1-step LA technique may reduce the incidence of complications associated with traditional laparotomy and the blind roll-and-tack technique and could be a useful alternative procedure for the treatment of LDA in dairy cows.     

Factors influencing the survival of dairy cows after correction of left displaced abomasum

OBJECTIVE: To determine factors that influenced culling or death of cows with left displaced abomasum (LDA) subsequent to correction by a roll-and-toggle (R&T) procedure or via laparotomy. DESIGN: Cohort study. ANIMALS: 810 Holstein dairy cows with LDA. PROCEDURES: Data regarding method of repair and risk factors for survival after correction of LDA were collected during a 1-year period. Outcomes were compared at days 14 and 60 after LDA correction for 3 groups of cattle (veterinarians performed R&T [V-R&T], herd personnel performed R&T [H-R&T], and veterinarians performed surgical repair via laparotomy [V-Surg]). RESULTS: Survival rates 14 days after LDA correction for the V-R&T, H-R&T, and V-Surg groups were 87% (286/329), 81% (327/403), and 85% (66/78), respectively. At 60 days after LDA correction, survival rates for the V-R&T, H-R&T, and V-Surg groups were 79% (260/329), 71% (286/403), and 73% (57/78), respectively. Multivariable analysis indicated that factors positively associated with failure to remain in the herd at 60 days after LDA correction included current mastitis status, history of a previous LDA, high preoperative risk, and correction of LDA by herd personnel rather than by a veterinarian. CONCLUSIONS AND CLINICAL RELEVANCE: Correction of LDA by veterinarians via an R&T procedure yielded results that were generally comparable to those for correction by veterinarians via laparotomy. Although survival rates at days 14 and 60 after surgery differed significantly between the V-R&T and H-R&T groups, herd personnel in this study used the R&T procedure to correct LDA and achieved survival rates within the range for those of practicing veterinarians.     

Prevalence of endotoxemia in healthy postparturient dairy cows and cows with abomasal volvulus or left displaced abomasum

Left displaced abomasum (LDA) and abomasal volvulus (AV) occur most commonly in postparturient dairy cows. Our main hypothesis was that endotoxemia occurred more frequently in the peripheral blood of cows with LDA or AV than in healthy cows because increased luminal pressure in AV or LDA, or the presence of a hemorrhagic strangulating obstruction in AV, may have injured the abomasal mucosa, thereby facilitating translocation of luminal endotoxin into the circulation. Therefore, our main objective was to compare the prevalence and magnitude of endotoxemia in healthy postparturient cows with the prevalence and magnitude of endotoxemia in cows with AV and LDA. We examined 60 adult dairy cows in early lactation that were diagnosed with AV (n = 15) or LDA (n = 15) or were healthy on physical examination (control group, n = 30). Jugular venous blood was obtained from cows in all 3 groups, and right gastroepiploic venous blood was obtained during surgical correction of AV and LDA immediately after repositioning of the abomasum. Platelet-rich plasma endotoxin concentrations were measured with a chromogenic limulus amoebocyte lysate assay. Endotoxin was detected in jugular vein plasma in 50% (15/30) of control cows; however, the prevalence of endotoxemia was significantly lower (P < .05) in cows with AV (7%, 1/15) or LDA (20%, 3/15). Endotoxin was detected simultaneously in right gastroepiploic and jugular vein plasma in only 1 cow with LDA and 0 cows with AV. Contrary to our hypothesis, we conclude that endotoxemia is infrequently present in postparturient dairy cows with AV or LDA.     

Animal-based measurements of the severity of mastitis in dairy cows

A range of clinical parameters were studied to assess their usefulness as objective markers of the severity of clinical mastitis in dairy cows. Cows with moderate clinical mastitis had significantly higher rectal temperatures and heart and respiratory rates than cows with mild clinical mastitis or control cows. The difference in temperature between quarters did not vary significantly between the control cows and the cows with mastitis, but there was a larger difference between quarter temperatures in the cows with moderate mastitis than in the cows with mild mastitis or the control cows. The hock-to-hock distance in the control cows was significantly smaller than in the cows with mild to moderate mastitis, but there was no significant difference in the distance either between the cows with mild mastitis and those with moderate mastitis, or between the cows with mastitis in the front quarters and those with mastitis in the hind quarters. The mechanical threshold to pain of the cows with mild and moderate mastitis was significantly lower than that of the control cows.     

Comparison of abomasal luminal gas pressure and volume and perfusion of the abomasum in dairy cows with left displaced abomasum or abomasal volvulus

OBJECTIVE: To compare abomasal luminal gas pressure and volume and perfusion of the abomasum in dairy cows with a left displaced abomasum (LDA) or abomasal volvulus (AV). ANIMALS: 40 lactating dairy cows (25 with an LDA and 15 with an AV). PROCEDURE: Abomasal luminal gas pressure and volume and pulse oximetry values for the caudal portion of the dorsal ruminal sac and abomasal wall were measured during laparotomy. Abomasal perfusion was assessed on the basis of abomasal O2 saturation (pulse oximetry) before correction of the LDA or AV. Abomasal perfusion was also assessed after correction of the LDA or AV by measuring venous O2 saturation in the right gastroepiploic vein and calculating the abomasal oxygen-extraction ratio. RESULTS: Abomasal luminal gas pressure and volume were higher in cattle with an AV than in cattle with an LDA. Abomasal O2 saturation was lower and abomasal oxygen-extraction ratio higher in cattle with an AV, compared with values in cattle with an LDA. In cows with an AV, lactate concentration in the gastroepiploic vein was greater than that in a jugular vein, whereas no difference in lactate concentrations was detected in cows with an LDA. Abomasal luminal gas pressure was positively correlated (r, 0.51) with plasma lactate concentration in the gastroepiploic vein and negatively correlated (r, -0.32) with abomasal O2 saturation determined by use of pulse oximetry. CONCLUSIONS AND CLINICAL RELEVANCE: Abomasal perfusion decreases as luminal pressure increases in cattle with an AV or LDA.     

Right displacement of the abomasum and abomasal volvulus in dairy cows: 458 cases (1980-1987)

Clinical and surgical findings in 458 dairy cows with right displacement of the abomasum or abomasal volvulus (AV) were analyzed to determine the association between these variables and the outcome (productive, salvaged, or terminal) of the affected cow. Heart rate at initial examination was higher in the salvaged and terminal groups of cows (P less than 0.0001) than in the productive group. The plasma Na+ concentration was lower in the salvaged and terminal groups of cows (P less than 0.0001) than in the productive group. The plasma C1- concentration was lower in the salvaged group of cows than in cows with either productive or terminal outcomes (P less than 0.0001). Anion gap was significantly higher (P less than 0.0001) in the salvaged and terminal groups than in cows classified as productive. On the basis of surgical findings, cattle with right displacement of the abomasum were more likely to survive than cows with AV. Cows that required fluid decompression of the abomasum via abomasotomy were less likely to survive than those in which gaseous decompression was performed. Cows with evidence of vascular compromise of the abomasal wall were less likely to survive than those with normal abomasal serosa. Preoperative heart rate and anion gap had positive correlations with the presence of abomasal necrosis, whereas temperature, venous blood pH, plasma bicarbonate, and base excess concentrations had negative correlations. Cows in terminal stages of AV were likely to have a mixed primary acid-base disturbance, consisting of metabolic alkalosis with superimposed metabolic acidosis. These findings were highly correlated with abomasal necrosis.     

The association between first DHI milk-test parameters and subsequent displaced abomasum diagnosis in dairy cows

First Dairy Herd Improvement Corporation (DHI) test milk that was sampled prior to displaced abomasum (DA) diagnosis was used to examine the association between milk yield (kg), fat (%), protein (%), or fat/protein ratio and DA in dairy cows. 27 DA cases were matched to 3 controls per case by herd and calving date. Logistic regression was used to examine the effect of each milk parameter on the odds of DA, adjusting for lactation number and days in milk (DIM) at test. Higher odds of DA diagnosis was found with lower milk yield, higher milk fat percentage, lower milk protein percentage and higher fat/protein ratio. We conclude that milk yield, fat percentage, protein percentage and fat/protein ratio may be used to detect cows at risk for DA. Our findings also indicate that cows diagnosed with DA were energy deficient prior to DA diagnosis.     

Evaluation of ornithine carbamoyl transferase and other serum and liver-derived analytes in diagnosis of fatty liver and postsurgical outcome of left-displaced abomasum in dairy cows

OBJECTIVE: To evaluate postsurgical outcome in dairy cows with left-displaced abomasum (LDA) with regard to severity of fatty liver and assess the usefulness of preoperative determination of serum ornithine carbamoyl transferase (OCT) activity, bile acids concentration, and other variables for evaluating liver function during the postsurgical convalescence period. DESIGN: Prospective study. ANIMALS: 68 Holstein cows. PROCEDURES: Blood and liver biopsy specimens were obtained during standing LDA surgery. Liver tissue was examined histologically and classified by severity of fatty change. Serum activities of liver-derived enzymes and concentrations of total lipids, triglycerides, bile acids, glucose, beta-hydroxybutyric acid, bilirubin, and nonesterified fatty acids were determined. RESULTS: Most cows with LDA and cows with severe fatty liver were detected within the first month after calving. Postsurgical outcome was related to severity of fatty liver. All cows that died had severe fatty liver. Serum activities of OCT, aspartate aminotransferase, and glutamate dehydrogenase and serum total bilirubin concentration were sensitive indicators of fatty liver. Serum bile acids concentration was not an accurate indicator of fatty liver. CONCLUSIONS AND CLINICAL RELEVANCE: Postsurgical outcome of cows undergoing surgery to correct LDA was related to fatty liver severity. Assessment of serum activities of OCT, aspartate aminotransferase, and glutamate dehydrogenase and serum total bilirubin concentration is recommended for diagnosis of fatty liver in dairy cows with LDA, whereas determination of bile acids concentration is not. The strong correlation between OCT activity and degree of hepatocellular damage supports use of this enzyme for assessing severity of fatty liver and predicting postsurgical outcome in cows with LDA.     

An evaluation of protein/fat ratio in first DHI test milk for prediction of subsequent displaced abomasum in dairy cows.

First DHI test milk that was sampled prior to displaced abomasum (DA) diagnosis was used to evaluate milk protein/fat ratio (PFR) for prediction of subsequent DA in dairy cows. Odds ratio, sensitivity, specificity, and likelihood ratio were determined. Twenty-seven DA cases were matched to 3 controls per case by herd and calving date. Milk was tested at a median of 19 d after calving, which was 8 d prior to the median time of DA diagnosis. Adjusted for parity and days in milk, a protein/fat ratio < or = 0.72 was 8.2 times more likely to come from a cow subsequently diagnosed with DA than a protein/fat ratio > 0.72. Using the cut off value of 0.72, the sensitivity of PFR for DA was 80% and the specificity was 68%. A receiver operating characteristics curve indicated that the minimum sum of false negative and false positive results was at a PFR cut off value of 0.72. The likelihood ratio indicated that protein/fat ratios < or = 0.62 are 3.8 times more likely to come from cows that are diagnosed subsequently with DA than from cows without DA. The protein/fat ratio in 1st DHI test milk may predict subsequent DA in dairy cows.     

奶牛真胃左方变位手术前后血液生化参数的变化

为了解奶牛真胃左方变位(LDA)手术前后血液生化指标的变化,跟踪采集了100头围产期奶牛产后7、14、21和28 d尾静脉血液,后经确诊6例LDA患牛进行手术整复,并随机选择6头相应的健康牛为对照。通过检测12头牛手术前后1周血清中游离脂肪酸(NEFA)和β-羟丁酸(BHBA)等21项生化指标,调查患LDA奶牛机体能量代谢、肝功能和电解质状况,并分析手术前、后生化指标的变化。结果显示:术前多数患LDA奶牛机体能量负平衡指标升高,肝功能指标不同程度的升高,电解质变化不一;术后牛机体能量代谢指标多数恢复正常,肝功能指标部分恢复正常,部分仍升高,电解质多恢复正常。     

Minimally invasive field abomasopexy techniques for correction and fixation of left displacement of the abomasum in dairy cows.

To reduce the potential drawbacks associated with laparotomy techniques for correction and fixation of left displaced abomasums (LDA), minimally invasive techniques have been developed. This chapter reviews the toggle pin suture (TPS) and the laparoscopic abomasopexy procedures used in the field for correction and fixation of the abomasum for correction of left-displacement of the abomasum in dairy cows. The importance of case selection cannot be overestimated. By combining laparoscopy with the principle of the TPS procedure, the lack of visual control associated with the TPS procedure is eliminated, while the advantage of the speed of completion and minimal invasiveness provided by both procedures are maintained. Successful LDA treatment includes not only early detection and treatment of the LDA, but also the prevention of secondary ketosis and aggressive treatment of concurrent disease.