Blindness in dairy cows

Extract

Blindness in dairy cows due to various causes has often been observed. This report instances threecases occurring on one property within a period of two months. Of the animals concerned, all Jersey cows, one was home bred and the other two were purchased.     

Fatty liver in dairy cows

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.     

Abomasal fistulas in dairy cows

Abomasal fistulas were corrected surgically in 9 adult Holstein cows. Six cows had a history of right paramedian abomasopexy (RPA), and 2 cows had had a percutaneous abomasopexy using the blind-stitch technique (BSA). Fistulas developed from 2 weeks to 12 months after the RPA or BSA. In 1 cow, history was not available beyond 2 years, and no surgery had been performed in that time. All fistulas were in the right paramedian area and were draining blood and/or ingesta from necrotic abomasal tissue (8 cows) or ruminal tissue (1 cow). Surgery was performed immediately in cows with consistent hemorrhage from the fistulated tissue (4 cows). Surgery was delayed to reduce rumen contents if bleeding was absent or considered negligible (4 cows) or to stabilize the patient (1 cow). General anesthesia was used in 7 cows, local anesthesia in 2 cows. Outcome following the fistula resection was successful in the 7 cows discharged from the clinic. The occurrence of abomasal fistulation is probably related to nonabsorbable sutures penetrating the abomasal lumen during the abomasopexy procedure resulting in infection of the incision or body wall.     

Heat synchronization in dairy cows

Dairy cows were heat synchronized with two injections of cloprostenol (PG1/PG2) with an interval of 13 days and inseminated 72 hours after PG2. The total pregnancy rate obtained was 42% The probability of achieving luteal phase at PG2, the probability of undergoing luteolysis after PG2 and the probability of achieving pregnancy were all equal whether the cows were in luteal phase, follicular phase, had follicular cysts or small ovaries at PG1. Close correlations were found between the signs of heat at the insemination and the interval from calving to PG1 to the pregnancy rates.     

Follicular cysts in dairy cows

Follicular cysts are the most critical reproductive disorder in dairy cows and disturb the normal ovarian cycle, resulting in a prolonged interval from calving to conception. Therefore, this condition causes significant economic losses to the dairy industry. Two direct causal factors for cysts are suggested in this review; ovulation disorder and the delay of regression. Ovulation disorder has been accepted to be a main etiology of cystic follicle. This seems to be caused by the deficiency of positive feedback of estrogen to the hypothalamus, leading to the lack of luteinizing hormone surge. On the other hand, if a large anovulatory follicle is regressed immediately after the failure of ovulation, its follicle does not continue to grow, resulting in no cystic follicle being formed. Therefore, it is proposed that another cause of a cystic follicle is the delay (or absence) of the degeneration system of the follicle. This review will introduce these two causes separately, referring to recent advances in understanding the follicular cyst in dairy cows.     

Amyloidosis in six dairy cows

Amyloidosis was diagnosed in 6 Holstein cows that were examined because of chronic intractable diarrhea. Besides diarrhea, the chief finding was a nephrotic-like syndrome, in that there was edema, hypoproteinemia, and proteinuria. Other consistent clinicopathologic abnormalities were hyperfibrinogenemia, low-normal serum calcium content or hypocalcemia, hypomagnesemia, prolonged bromosulphalein half time, high serum urea nitrogen concentration, high serum creatinine concentration, and low urine specific gravity. Foci of inflammation including traumatic reticuloperitonitis, traumatic pericarditis, salpingitis, mastitis, and metritis were found. There was histologic evidence of amyloid in the kidneys, liver, adrenal glands, and spleen. The iodine-sulfuric acid test for amyloid was positive in 2 cows. The Congo red dye test for amyloid was positive in 2 other cows. In spite of supportive care, all the cows either died naturally or were euthanatized. Because foci of inflammation were found in each cow, it was concluded that the most likely classification of amyloidosis in these cases would be reactive systemic amyloidosis and that the major amyloid fibril protein would be type AA.     

Nutritional myodegeneration in dairy cows

A syndrome is described in which parturient dairy cows showed clinical signs consistent with milk fever but failed to respond to conventional therapy. The affected cows were reluctant to walk, moved stiffy and in severe cases became recumbent. The condition was apparently precipitated by low vitaimin E and selenium intake, stress of pregnancy and in one outbreak erratic feeding. Skeletal and cardiac myodegeneration were observed grossly and histologically but an almost full term fetus from an affected cow showed no muscle lesions. A high incidence of retained placentae was also recorded.     

Subclinical ketosis in dairy cows

Subclinical ketosis is defined as a preclinical stage of ketosis. The peak prevalence of subclinical ketosis occurs during the fourth week of lactation. Herd-related factors, breed, parity, and season are other important determinants. Subclinical ketosis can be revealed by determining levels of plasma glucose, plasma NEFA and blood, and milk or urine ketone body concentration. There are theoretical and practical advantages of using milk ketone bodies. Most authors are agreed on approximate lower and upper borderlines for subclinical ketosis. The risk of an outbreak of clinical symptoms has been evaluated by some authors. Most authors have found significant negative relationships between energy balance and ketone body concentration. Some disagreement may be attributable to the fact that the diets used in different experiments can have different glucogenic potential, even if the energy content is the same. This affects the relationship between energy balance and ketone body concentration, as the ketone body level is influenced by both the energy balance and plasma glucose. Feeding silage with high butyric acid content increases the risk of subclinical ketosis. There are indications that cows with the highest milk yield directly after calving are at greatest risk for developing ketosis. Increased ketone body level secondarily reduces milk production, a decrease that has been quantified by some authors. Subclinical ketosis causes delayed reproductive functions return to normal after calving, increased intervals from calving to first and last service, and an increased frequency of ovarian cysts. The routine determination of milk acetone levels in control programs can be used to evaluate the status of individual cows, to indicate the energy feeding in early lactation at a herd level, and to evaluate sires for breeding. The heritability and the tendency toward a positive genetic correlation between milk acetone and milk yield have also been discussed, as have aspects of nutritional prevention. Factors such as energy- and protein-rich roughage, tasty high-energy concentrates, suitable feeding during the dry period, and division of the concentrates into at least four meals are considered to be important.     

Blood sugar in dairy cows

Glycemia was found in 1270 cows and high-pregnant heifers fed summer feed rations and in 1981 cows fed winter feed rations, with the known levels of energy-yielding nutrients in feed rations for cows in the first (I) and in the second (II) lactation phases and cows and heifers in the eighth to ninth and a half month of pregnancy (III). The levels of glycemia were significantly lower after the summer feed rations than after the winter feed rations, both in the whole population and in all groups. The basic type of feed rations has a stronger influence on the level of glycemia than the phase of the reproduction cycle. In all groups, hypoglycemic deviations prevail over hyperglycemic ones. Hypoglycemia is most expressive in group I, least expressive in group III. The coefficient of glycemia variability is high (26.5 to 34.6); it is higher after the winter feed rations. Covering of the nutrient need is significantly higher in the summer period than in the winter period, the narrow calorie-protein ratio prevails over the increased ratio and is most obvious in groups II and III. Gaussian character of the glycemia distribution curves suggests a large number of independently acting factors, none of them prevailing over the others; the effects of these factors are mostly additive. This phenomenon limits strongly the employment of glycemic values as indicators of the energy balance in the organism. Glycemia is to be judged within the framework of the metabolic profile and nutritive indicators. Further study of glycemia should be performed by means of multivariate statistical methods.     

Bleeding abomasal ulcers in dairy cows

The clinical signs and changes in blood and rumen fluid, and the results of therapy are described in 35 cows suffering from bleeding abomasal ulcer. The most important pathological findings were moderate to severe anaemia with pale mucous membranes and tachycardia, dark coloured to black faeces, a disturbed general condition and anorexia. Two of the cows were slaughtered immediately. The others were treated by the transfusion of several litres of blood and the intravenous administration of a solution containing sodium chloride and glucose and other drugs such as calcium solution, vitamin K, vitamin C and metoclopramide. Two animals died in spite of the treatment and three had to be slaughtered because of the deterioration in their condition. The other 28 cows recovered within a few days and their general condition, appetite and defecation returned to normal.     

奶牛乳房炎的治疗方法

奶牛乳房炎是乳腺受到物理、化学、微生物刺激所发生的一种炎性变化.本病以乳汁的理化性改变为主,由多种非特定的病原微生物引起,不仅影响产奶量、牛乳质量、延长产后发情和妊娠时间,严重时还能使奶牛泌乳机能丧失而被淘汰,是世界奶牛业的主要危害因素之一[1-3].笔者根据多年的治疗经验,总结如下.     

Nutrition and reproduction in dairy cows

Diagnosis of nutritional effects on herd fertility requires a systematic analysis of reproductive records in addition to quantifying the feeding program on the farm. Corroborative laboratory tests for specific deficiencies may be useful.