Stability and storage characteristics of enzymes in cattle blood

The stability and storage characteristics were studied of 11 bovine enzymes of potential clinical significance, namely, aldolase, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, acetylcholinesterase, creatine kinase, gamma glutamyltransferase, glutathione peroxidase (GSH-Px), alpha-hydroxybutyrate dehydrogenase, lactate dehydrogenase and superoxide dismutase (SOD). Enzyme activities in fresh serum were compared with those in plasma containing various anticoagulants including lithium heparin, EDTA and oxalate/fluoride. The same preservatives were assessed for their effects on the whole blood activities of GSH-Px and SOD. Stabilities of enzymes in plasma and serum stored at room (+20 degrees C), refrigerator (4 degrees C) or deep freeze (-20 degrees C) temperatures were also compared. In addition, SOD and GSH-Px activities in samples stored, at the same temperatures, as whole blood or aqueous lysates were monitored.     

Dynamics and diagnostic use of ALP activity in the blood of cattle exposed to a temperature of 56 degrees C

Possibilities of the diagnostic utilization of determined thermostable portion of the ALP activity in bovine serum were studied. The work is based on the finding that the total ALP activity is formed by two fractions with different sensitivity to the temperature of 56 degrees C. Dynamics of the loss of ALP activity during serum heating was of an equal character in all four tested groups. The loss was always highest during the first minutes of heating, after 15 to 20 minutes it became equal. A period of 15 minutes of the serum heating is sufficient for obtaining information on the size of the ALP thermostable fraction. The ALP activity and its residue after 15-minute thermal inhibition (thermostable portion) were tested in the sera of 163 head of cattle divided into seven groups. The size of this residue was related to the age of animals, degree of gravidity did not affect the residue. The thermostable portion in 6 to 10 months old bullocks was 14.86 +/- 4.93%, in 2.5 to 5 years old heifers 41.20 +/- 20.37% and in clinically healthy dairy cows 54.35 +/- 18.26%. In a group of calved breeding cows 44.13 +/- 19.74% of the initial activity remained. Determination of the thermostable ALP fraction can be applied with certain limitation in pre-clinical diagnostics of disorders of mineral metabolism in bones of cattle. In herds of healthy dairy cows the value of thermostable portion should not be lower than 45% of the original ALP activity. In 2.5 to 3 years old heifers this level is considered to be 35%.     

日粮铜水平对兔血铜含量及两种酶活性的影响

在含铜10.56mg/kg的基础日粮中添加0、10、20、100、200mg/kg铜，分别饲喂五组90日龄的安哥拉兔，研究日粮铜水平对兔血铜含量及两种酶活性的影响。结果表明，不同铜处理组间，兔体内SOD酶和铜兰蛋白酶的活性以及兔血浆铜含量差异不显著（P＞0.05)；但血浆铜兰蛋白酶的活性明显地随铜添加量的增加而增加，试验期末高铜E组该酶活力平均比对照组提高60％；肝SOD酶活力也有随日粮铜水平增加而增加的趋势；血浆、红细胞中的含铜量及红细胞中SOD酶活性没有明显的变化规律。     

The blood vessels of the mesonephros of domestic cattle (Bos taurus), a corrosion cast study

The blood vessels of the bovine mesonephros - a corrosion cast study Using scanning electron microscopy plastoid corrosion cast specimens of the mesonephros of 30-45-day-old bovine foetuses were investigated. The studies showed that the blood vessels of the mesonephros are organized in two separate networks similar to these of the teleosts and amphibians. The glomerula mesonephrica originate from the aorta implying that they belong to the high pressure system. The tubuli mesonephrici are surrounded by a filamentous independent capillary network which is shown for the first time in these studies. This capillary network originates from the caudal cardinal veins and represents a mesonephric portal system with a relatively low blood pressure. The blood from the two capillary networks diverts into terminal veins and into the subcardinal veins. The questions of haemodynamics in the mesonephros are discussed.     

Blood vessels in cattle teats

The behaviours of arteries and veins in the teats of cattle of different age groups is described against the background of general formation and development of the vessels. Growing age was found to have been accompanied by numerical growth of veins (rather than arteries) towards the teat tip and by some thickening of the median vein region. No correlations were established between those vascular changes, on the one hand, and milkability, on the other.     

Hepatic steroid inactivating enzymes,hepatic portal blood flow and corpus luteum blood perfusion in cattle

Production from the corpus luteum (CL) and/or hepatic steroid inactivation impacts peripheral concentrations of P4, which can alter reproductive performance. Our primary objective was to examine hepatic steroid inactivating enzymes, portal blood flow, and luteal blood perfusion at 10 days post‐insemination in pregnant versus non‐pregnant beef and dairy cows. Twenty early lactation Holstein cows and 20 lactating commercial beef cows were utilized for this study. At day 10 post‐insemination, hepatic portal blood flow and CL blood perfusion were measured via Doppler ultrasonography. Liver biopsies were collected and frozen for later determination of cytochrome P450 1A (CYP1A), 2C (CYP2C), 3A (CYP3A), uridine diphosphate‐glucuronosyltransferase (UGT) and aldo‐keto reductase 1C (AKR1C) activities. Pregnancy was determined at day 30 post‐insemination and treatment groups were retrospectively assigned as pregnant or non‐pregnant. Data were analyzed using the mixed procedure of SAS. Steroid metabolizing enzyme activity was not different (p > .10) between pregnant versus non‐pregnant beef or dairy cows. Hepatic portal blood flow tended (p < .10) to be increased in pregnant versus non‐pregnant dairy cows. Luteal blood perfusion was increased (p < .05) in pregnant versus non‐pregnant dairy cows. Pregnant dairy cows appear to have an increased rate of hepatic clearance of P4 in combination with increased synthesis from the CL. This could account for the lack of difference in peripheral P4 concentrations between pregnant and non‐pregnant dairy cows. This study highlights the relevance of further investigation into steroid secretion and inactivation and their impact on the maintenance of pregnancy in cattle.     

Relation between selenium content and glutathione-peroxidase activity in blood of cattle

To identify a simple method for assessing the selenium demand in cattle, the relationship between selenium content in whole blood and the concentration of the selenium containing enzyme glutathione peroxidase (EC 1.11.1.9; GSH-Px) in red blood cells was studied. On six farms with suspected low soil selenium content, blood samples were collected from groups of calves, yearlings and adults at the end of the housing period and of the grazing period. The data obtained showed a highly significant correlation between the parameters mentioned: GSH-Px (U/g Hb) = 3.261 * Se (micrograms/kg) - 40.553. In growing animals there was a decline in Se supply with age, followed by a gradual recovery in heifers. This was most pronounced on some sandy soils and on peat soil. Seasonal effects could not be demonstrated.     

Serum haptoglobin concentration in cattle

To obtain a basal concentration of serum Haptoglobin (Hp) in cattle in Taiwan, Hp concentrations were measured from serum samples collected from 10 healthy heifers, every week for one year. The values were also compared with those collected from 15 cows diagnosed with postpartum metritis. The heifers were successfully impregnated by artificial insemination six months after the tests. Hp concentrations were also measured in the serum collected from 11 other cows within 3 weeks after parturition. The Hp assay developed in this study gave a good correlation (r=0.893)with Western blotting. The Hp concentration of 454 serum samples from the 10 heifers had a mean value of 83.6 +/- 34.1 mg/l, and there was no significant difference among individual heifers. The basal value of Hp in heifers was calculated as less than 73.6 mg/l. No significant difference in Hp concentration was observed among the 10 heifers during cold and warm seasons (19.8 +/- 2.2 degrees C vs 27.3 +/- 1.4 degrees C), or before and after pregnancy. The mean serum Hp concentration from cows suffering from postpartum reproductive disorders was 1133.5 +/- 627.1 mg/l, which was significantly greater than the serum of healthy heifers and postpartum cows (104.6 +/- 61.0 mg/l) (P<0.05). These results demonstrate that Hp concentration may be a useful indicator for cows with postpartum reproductive disorders.     

Effects of protozoa on the antioxidant activity in the ruminal fluid and blood plasma of cattle

The objective of this study was to investigate the antioxidant status in ruminal fluid and blood plasma among three faunated and two defaunated (protozoa‐free) cattle (average bodyweight of 225 kg), fed hay plus concentrate. The extra cellular antioxidant activity of the mixed protozoa and bacteria suspensions were also studied in vitro. The antioxidant activity was detected by means of the free radical scavenging ability. The activity (units/microbial nitrogen) of the protozoal suspension increased from 59 (0 h) to 318 (18 h), and decreased to 40 (24 h) during incubation. The activity of the bacterial suspension also increased from 111 (0 h) to 644 (18 h), and decreased to 533 (24 h). The antioxidant activity (units/mL, U/mL) in the ruminal fluid of faunated (ranging from 116 to 254) and defaunated (ranging from 66 to 110) cattle was increased after 2 h and decreased after 5 h of feeding, being significantly higher in the faunated cattle. The antioxidant activity of blood plasma (U/mL) ranged from 248 to 316 in the faunated and 121–170 in the defaunated cattle during 0–5 h after feeding, being significantly higher in the faunated cattle. Therefore, defaunation possibly causes a decrease in the antioxidant level in the ruminal fluid, and may impair the health and performance of ruminants through an oxidant–antioxidant imbalance.