สอบถามปัญหาออนไลน์
Live chat by BoldChat
Live chat by Boldchat


BECOME A MEMBER
สมัคร ! สมาชิกชมรม
รักสุขภาพ   ฟรี ข่าว
สาระความรู้เรื่องสุขภาพ

Animal Health Division : Reagent test Strips

แถบตรวจวัดระดับสารเคมีในสัตว์เลี้ยง ตรวจสุขภาพสัตว์ จากปัสสาวะ เลือด น้ำนม
สอบถามรายละเอียดเพิ่มเติมได้ที่ 02 803 7310, 02 803 7311,02 803 7747

Healthcare Products 
and supplies for
Animal Health

เครื่องมือ/อุปกรณ์ดูแลสุขภาพ
สัตว์เลี้ยง

  VET Reagent Strips
  products designed 
  specifically for use in
  the diagnosis of animal
  health.
  
 
Glucose
 
BUN
 
Ketone
 
β-Hydroxybutyrate 

  กลับหน้าแรก AnimalHealth
Browser คุณไม่ support Java / your browser does not support JAVA
จึงไม่สามารถแสดงผลได้


 

 

 

สนใจรายละเอียดเพิ่มเติม
กรุณาแจ้งให้ทึมงานเพื่อ
จัดเตรียมหาสาระให้


 Contact : ติดต่อ
 
info@thailabonline.com
ชมรมเรารักสุขภาพ


We subscribe to the
HONcode principle of 
the Health on the
Net Foundation


 

   β-Hydroxybutyrate ( BHB )  
  

 แถบตรวจหาสารเคมีสำหรับสัตว์เลี้ยง
  VET 10 :  Ascorbic acid
                       Urobilinogen
                       Protein
                       Specific gravity (Sp.gr.)
                       Ketone
                       Bilirubin
                       Glucose
                       Blood
                       Nitrite
                       Leukocyte

 VET-BUN whole blood Test strip
 VET-BUN in milk Test strip
 VET-BHB in milk Test strip
                       (
β-Hydroxybutyrate )

 

  β-Hydroxybutyrate ( BHB )

β-hydroxybutyrate (BHB or 3-hydroxybutyrate), along with acetone and acetoacetate, is considered a ketone. Ketones are produced from the metabolism of non-esterified fatty acids (NEFAs) and volatile fatty acids. In monogastric animals (dogs, cats), the main source of ketones is NEFAs, which are released from fat stores in the body during states of negative energy balance where fat, and not carbohydrates (glucose) become the energy source. In ruminants, both NEFAs and volatile fatty acids produced from rumen metabolism can be used to form ketones. Proprionate, butyrate and acetate are volatile fatty acids that are produced by rumen fermentation. Of these, mainly butyrate is converted to BHB in the rumen epithelium and the liver. Camelids, despite having a rumen-like forestomach, do not produce much BHB from the gastrointestinal tract. The primary ketone produced by the liver from NEFAs is acetoacetate. This is reduced to BHB within the mitochondria and spontaneously decarboxylates to acetone. The ketones are excreted into the circulation, taken up by other tissues (e.g. skeletal muscle, mammary gland), where they are oxidized to yield energy or, in the case of the mammary gland, incorporated into milk fat. An increase in ketones in the blood is called ketosis. Since ketones are acids, increased concentrations can result in a primary metabolic acidosis when values are high enough to overcome normal body buffers (primarily bicarbonate, concentrations of which decrease in blood). This is called ketoacidosis but it is not always present in states of ketosis. Ketones are freely filtered by the glomerulus and, since renal absorptive thresholds are low, they are readily found in the urine during ketosis.

Increased BHB concentrations in blood indicates stimulation of lipolysis (all species) or excess absorption of butyrate (ruminants) from feeding spoiled silage (also called alimentary ketosis). Lipolysis is stimulated by any condition leading to negative energy balance (starvation/anorexia, late pregnancy or lactation, insulin lack/inhibition) and exercise (dogs, horses). In late pregnancy, negative energy balance may be compounded by a state of insulin resistance (due to progesterone). This promotes ketogenesis by causing a shift in energy metabolism from glucose to fat, decreasing conversion of dietary or endogenous triglycerides to stored fat, and by decreasing fatty acid oxidation in hepatocyte mitochondria (thus more acetyl CoA is available to form ketones (see below)). Note that horses have poorly developed ketogenic pathways, so ketosis is rare in this species.

The building block of ketones is NEFAs, which are released from fat stores by lipolysis. NEFAs are esterified in the liver, transported to mitochondria, and are oxidized to acetyl CoA. Within mitochrondria, acetyl CoA can be oxidized in the Kreb's cycle, producing ATP (energy), or converted to ketones. Oxidation within the Kreb's cycle is dependent on the availability of cycle intermediates, particularly oxaloacetate (which is also used to produce glucose). In conditions associated with insulin resistance (e.g. hyperadrenocorticism, pregnancy) or deficiency (Type 1 diabetes mellitus) and states of negative energy balance (which stimulates glucose production), oxaloacetate is shunted out of the Kreb's cycle for gluconeogenesis, thus causing less acetyl CoA to be oxidized for energy and promoting ketogenesis. In the cytoplasm, excess NEFAs can also be packaged into very low density lipoproteins (VLDL) which are transported into plasma or stored in the liver. In excess, this causes hepatic lipidosis. Thus, in states of negative energy balance (provides more NEFAs from lipolysis) or conditions causing insulin resistance (which decreases NEFA oxidation), ketogenesis is promoted, which can lead to clinical ketosis.

Sample collection guidelines for serum/plasma BHB

  • Collection tube: A red top tube is recommended for sample collection. EDTA- (purple top) and heparin- (green top) anticoagulant tubes can be used as well. Separate serum or plasma from cells ASAP after collection.
  • Sample storage: BHB in bovine blood samples is relatively stable in samples kept cool or frozen in a dedicated freezer.
  • Pooled samples: Pooling of individual samples from cows to assess energy status of a herd is NOT recommended. Studies at Cornell University have shown that results from pooled samples are insensitive when using prepartum or postpartum NEFA for the detection of excessive negative energy balance in transition dairy cows.

Measurement of BHB

Ketones can be measured in blood, milk or urine. Most animal-side tests are based on the ability of ketones (acetoacetate in particular) to react with nitroprusside to form a purple color. This is the method used to detect ketones in urine on urine dipsticks. It does not, however, detect BHB, which is the dominant ketone produced in disease states. BHB can be measured specifically in milk and blood, using an enzymatic method (BHB dehydrogenase) which converts BHB to acetoacetate. This is the method used at Cornell University to measure BHB concentrations in blood, serum and plasma. Bovine BHB values are quite stable (24 hours in whole blood and 72 hours in separated serum or plasma, regardless of anticoagulant or storage temperature). Values are also unaffected by hemolysis.


Disease conditions

Bovine ketosis

Ketosis primarily occurs in postcalving dairy cows, who are undergoing extensive lipolysis due to a combination of decreased dry matter intake and increased energy demands (from the fetus and milk production). Many transition dairy cows are also thought to be insulin resistant, which favors lipolysis and ketogenesis. VLDL transportation from the liver is inefficient in ruminants, which contributes to hepatic lipidosis in affected animals. Ketosis can be initiated by underlying diseases, which cause decreased dry matter intake and subsequent negative energy balance. Ketosis can also be subclinical or clinical. Note that any cow (not only transition cows) can develop alimentary ketosis (excess rumen butyrate production).

Subclinical ketosis

Postcalving dairy cows with increased BHB, but no clinical signs of ketosis (off feed, decreased milk yield), are considered to be in a state of subclinical ketosis. Associations have been made between subclinical ketosis and an increased incidence of inflammatory (metritis, mastitis) and metabolic (displaced abomasum, clinical ketosis) diseases postcalving. Subclinical ketosis is also thought to reflect underlying hepatic lipidosis. Dairy practitioners have begun to monitor dairy herds for subclinical ketosis (which is an indirect indicator of excess negative energy balance) by testing for BHBs in the postcalving period, either alone or in combination with other tests (UN, albumin, NEFA, AST) as part of transition cow energy metabolite assessment. Results of these tests can be interpreted at the individual cow level (i.e. a BHB value above a certain cut-off indicates subclinical or clinical ketosis) or at the herd level (i.e. the proportion of tested cows that have BHB values over a certain cut-off value).

For transition cow energy metabolite assessment, we recommend the following sample collection guidelines (in addition to those given above):

  • Time of collection,: Collect samples from cows that are 3-14 days in milk. Also sample cows as they are coming into the feeding stalls.
  • Number of cows: A minimum of 12 animals per herd should be sampled for herd level testing. This can be a mixture of heifers and >2 parity cows.

The following intepretation guidelines are based on studies done at Cornell University and are valid for samples collected from 'at risk' TMR-fed cows between 3-14 days post-calving.

  • Cow level testing: Post-calving BHB > 10 mg/dL is associated with a significant risk of post-calving metabolic or infectious diseases (displaced abomasum, clinical ketosis and metritis), decreased milk yield and decreased reproductive performance in individual TMR-fed Holstein cows.
  • Herd level testing: At the herd-level, there is a significantly increased risk of these post-calving diseases, decreased milk production or decreased reproductive performance if >10% of tested post-calving cows have BHB values > 10 mg/dL. Note, that as indicated above, pooling samples from individual cows is not recommended for herd-level testing.

Clinical ketosis

Clinical ketosis typically occurs in cows during early lactation (usually the first 2-4 weeks). This is also called lactation or spontaneous ketosis and is a consequence of excess negative energy balance due to stresses of calving and lactation. Occasionally, dairy cows in late lactation can also develop clinical ketosis (pregnancy ketosis) due to negative energy balance. Affected cows are dull, inappetant, lose weight and have decreased milk yield. Cows with clinical ketosis in dairy herds fed concentrate rations are frequently concurrently hypoglycemc. This worsens the state of negative energy balance Blood, urine and milk BHB values are often quite high. Blood BHB values >27 mg/dL are considered compatible with clinical ketosis. Cows with underlying hepatic lipidosis may have concurrent elevations in liver leakage enzymes (AST, SDH, GLDH) or cholestatic enzymes (GGT, ALP).

Pregnancy toxemia in small ruminants

Clinical ketosis due to excess energy demands from the fetus (particulary with twins) also occurs in sheep and goats. Since, these animals are not farmed intensively and are not selected for high milk production, subclinical ketosis is less of an issue, in terms of herd management, in these species.

Clinical ketosis in camelids

Clinical ketosis occurs in states of negative energy balance (stress, anorexia, pregnancy, lactation) and as a complication of hepatic lipidosis in llamas and alpacas. Both males and females can develop hepatic lipidosis and ketosis; females are often in late pregnancy (called pregnancy toxemia) or early lactation. The syndrome of hepatic lipidosis develops when dietary needs are insufficient or feed intake is inadequate to meet energy demands (which are naturally increased in pregnant or lactating females). Hepatic lipidosis mostly occurs in older animals, with weight loss and anorexia being the most frequently observed clinical signs. Clinical pathology testing demonstrates increases in liver leakage (AST, SDH, GLDH) and cholestatic (GGT, ALP) enzymes. Some animals are icteric (due to cholestasis) and increased bile acids are seen due to cholestasis and decreased hepatic function. High NEFA concentrations reflect negative energy balance, as do high triglycerides (and is associated with visible lipemia in some animals). In one study, none of the affected camelids were hypoglycemic, but several were hyperglycemic (suggesting underlying insulin resistance).

Diabetic ketoacidosis in small animals

Clinical ketosis is seen primarily in small animals as a consequence of diabetes mellitus. Lack of insulin or insulin resistance creates a state of negative energy balance due to decreased ability of cells to take up and use glucose. This is compounded by decreased metabolism of triglycerides (decreased activity of lipoprotein lipase), unopposed stimulation of hormone sensitive lipase, and (stimulates lipolysis) and stimulation of gluconeogenesis (which decreases oxaloacetate in hepatocyte mitochondria, facilitating ketogenesis). The concentrations of lipolytic hormones (glucagon, epinephrine norepinephrine, cortisol and growth hormone) are often increased in diabetic animals. Ketosis is thought to develop in diabetic animals due to additional hormonal and metabolic stresses imposed by underlying diseases (infection, pancreatitis, renal insufficiency). Affected animals usually have a high anion gap metabolic acidosis (from accumulation of ketones) and ketonuria. BHB concentrations (which are typically very low in health) are markedly increased.

 

  

 

  
About Us | Add URL I Privacy Policy | Member Register | Health Shop | Contact Us | Health Board | Advertising
Disease / Condition | Head Line News | Healthcare | Diagnostic | Alternative Medicine | Aromatherapy |
Health Game Zone


1999-2009 Thailabonline.com. All rights reserved. 
เลขทะเบียนพาณิชย์อิเล็กทรอนิกส์  e-Commerce Registration Number  7100803000130
By using this information service,    you accept the terms of our Visitor Agreement. Please read it. 
The material on Thailabonline.com and iHealthsite.net are for informational purposes only and is not 
a substitute for medical advice or treatment for any medical conditions.   You should promptly seek 
professional medical care if you have any concern about your health, and you should always consult 
your physician before starting a fitness regimen.
”Thailabonline.com” and “ihealthsite.net” and ”AromaEssence” and ”MedHealthMart” are trademarks of Crystal Diagnostics Co.,Ltd.