Information that covers MCF in ruminants.

Testing for trichomoniasis is performed daily at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL). If submitted properly, a sample can be accurately and efficiently tested, and results reported to the submitting veterinarian in a timely manner.  All samples must be incubated 48 hrs (36-38°C) prior to rtPCR testing; please plan accordingly. Clearly indicate on […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) offers timely and accurate diagnostic tests for Tritrichomonas foetus, the parasite that causes bovine trichomoniasis, or trich.  Trich causes abortions and infertility, and unless properly identified with diagnostic testing, can cost the state’s cattle producers millions.  TVMDL employs the most current technology available utilizing real-time polymerase chain […]

Photosensitization is a serious skin condition in horses and cattle caused by a hazardous combination of certain plants and ultraviolet (UV) light. Certain plants contain photodynamic agents, which then cause a reaction in the animal’s body that leads to ultra-sensitive skin. This condition is specific to lightly or non-pigmented animals or areas of an animal […]

Neonatal calf diarrhea also known as scours is a primary cause of illness and death in young, unweaned calves. Of the several viral, bacterial and protozoal intestinal pathogens associated with calf diarrhea, the most recognized pathogens include Cryptosporidium species, bovine coronavirus and bovine rotavirus group A1. Prevalence of infections by these pathogens varies due to […]

TVMDL offers a range of tests to detect bovine viral diarrhea virus (BVDV). BVDV threatens the global cattle industry and negatively impacts producers in the form of decreased or lost productivity.  Despite vaccines and an array of diagnostic tests, this expensive disease continues to impact cattle producers. About 70 to 90% of all infections go […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) offers digital toxicology to account-holding clients. Digital toxicology provides evaluation of photos taken with smart phones, or other digital cameras, and an official report identifying items photographed (where possible) including an attachment with labeled photos for later reference – an advantage over shipping items to the laboratory […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) Analytical Chemistry Section has the ability to offer toxicology and drug testing services to livestock producers and practitioners. The lab offers a variety of tests to aid in diagnosing many conditions of both toxic and nutritional origin. Our highly trained and qualified personnel use state-of-the-art analytical techniques […]

Fumonisin B1 is the most prevalent of several fumonisin mycotoxins (B1, B2, B3) produced by Fusarium molds in corn. Corn contamination can occur at very high levels when permissive environmental conditions coincide with vulnerable points in corn kernel production. Equine Leukoencephalomalacia (ELEM) Horses and other equids, as well as rabbits, are the most fumonisin-sensitive species. […]

Prior to diagnostic testing, it’s important to determine what factors would lead to the most comprehensive assessment of an animal’s condition. Each case must be evaluated individually in order to establish the most practical diagnostic testing route.  Collection Guidelines What is an ideal serum sample? Since most serologic testing utilizes serum, blood should be collected […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) performs numerous tests using serum. Proper collection, preparation, and packaging for transportation is imperative to obtaining a quality serum sample. Serum samples that arrive at TVMDL which are hemolyzed and/or lipemic may not be acceptable for testing. Accurate results start with an ideal sample. Ideal Sample Clear […]

Hundreds of samples arrive daily at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. Testing accuracy often depends on submission of the proper specimen for the assay, particularly for molecular diagnostics.  To ensure the appropriate sample is submitted for molecular diagnostics at TVMDL, please consult the website for specific details associated with the […]

Hundreds of samples arrive daily at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. Testing accuracy often depends on the submission of the proper specimen for the assay, particularly for molecular diagnostics. With the proper sample, we can perform the assay and provide the most timely and accurate results without delay.  While results […]

A forensic or legal necropsy as defined by the purposes of the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) is a necropsy done to attempt to determine the cause of death in cases where the death is known or suspected to be non-natural, there are suspicious circumstances, or there is evidence of foul play. They […]

Click to Skip: Autolysis | Cautery Artifact | Freezing Artifact | Crush Artifact | Sponge Artifact Pathologic artifacts are any structures or features that are not normally present in the living animal. Some are minor, easy to distinguish from normal or diseased tissue, and/or do not interfere with the pathologists’ ability to provide an accurate […]

Vaccination programs are integral to the overall health and profitability of a cattle operation. Without vaccinations, diseases such as Bovine Respiratory Disease (BRD) and Bovine Viral Diarrhea (BVD) can decimate a cattle herd. The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) team includes experienced veterinary diagnosticians available to help veterinarians and producers with a vaccination […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) has seen quite a few cattle testing positive for Johne’s Disease. Clinically affected cattle are usually mature adults that are gradually losing body condition despite having a normal appetite. Chronic watery diarrhea is also usually recognized, but it can be sporadic during the syndrome. The causative organism […]

A male-castrated, crossbred steer was noted to have a severe and locally extensive skin disease involving the perineal and inguinal areas with other scattered individual nodular skin masses on other portions of the body (Figure 1). The animal was otherwise healthy and displayed no discomfort from the skin lesions. Fresh and fixed skin lesions were […]

Recently, seventeen cows died within twenty-four hours after consuming new hay. All of the cows died within 100 yards of the hay. A sample of the hay, along with tissue samples and ocular fluid from one of the cows were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. Toxic levels of […]

Approximately 200 head of cattle were grazing on improved native Bermuda grass pastures in the Colorado River bottom. Vegetation also included a large number of oak trees, and a low number of nightshade, cocklebur, and coffee senna plants. Two 400 to 500 lb. calves were found down and unable to rise. Both calves died within […]

Click to Skip Tips for Collecting Needle and Core Bone Biopsy | Tips for Submitting and Entire Leg | Clinical History Submitting samples of bone for histopathological analysis is essential to definitively diagnose most primary bone diseases (e.g., osteosarcoma). However, collecting representative bone biopsy specimens and their histopathological interpretations presents several challenges for the clinician […]

Dermatology cases are one of the most common types of cases seen by general practitioners. A crucial diagnostic tool in these cases is the skin biopsy. They are indicated in cases that do not respond to normal therapy, pustular, or ulcerative disease, and suspected neoplasia.  Before Taking a Skin Biopsy Prior treatment should also be […]

Diagnosing animal diseases frequently requires a veterinarian or a technician to collect specimens in the field. This can be difficult without having the right tools on hand. For these occasions, the Texas A&M Veterinary Medical Diagnostic Laboratory suggests assembling a necropsy field kit. The kit should include the following tools and materials, all of which […]

Click to Skip: Bone Marrow Aspirate Procedure | Bone Marrow Core Biopsy Procedure Bone marrow testing is used to diagnose and monitor bone marrow diseases and CBC abnormalities. Full evaluation of bone marrow requires a CBC the day of the bone marrow collection, bone marrow aspiration, and a bone marrow core biopsy.  Indications for bone […]

Although there have been substantial advances in benchtop hematology instrumentation for veterinary species, manual evaluation of a blood smear remains a vital part of a complete blood count (CBC). At the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL), all CBCs include manual blood smear examination by a highly skilled clinical pathology technician, a clinical pathologist, […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) offers digital cytology to account-holding clients. Digital cytology provides rapid evaluation of photos taken with microscope cameras or smart phones. This service provides an official report and cytologic interpretation, typically within one hour of submission (during business hours). To enhance this service, submission of glass slides for […]

A veterinarian was called to examine a 5-month-old Angus calf due to weight loss and lethargy. On physical examination the calf had a temperature of 105˚F and all external lymph nodes were enlarged. Blood was collected and lymph nodes were aspirated. The samples were sent to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for a […]

This assay utilizes rtPCR technology on E. coli isolates recovered from ruminant samples. Samples are recovered by the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) bacteriology section to further characterize the potential of the isolate to be participating in the current patient clinical syndrome.  The significance of the detected genes should be interpreted with the […]

Anthrax is caused by a gram positive, rod-shaped bacteria called Bacillus anthracis. This is a spore forming bacteria that can persist in dry, alkaline soil of endemic areas such as southwest Texas. Cattle, sheep, goats, deer, and horses are more susceptible to infection than pigs, birds and carnivores, like dogs and cats. In herbivores, anthrax […]

Pre-weaning calf diarrhea is a common concern in the beef and dairy industry and the cause may be difficult to determine. This is due to the multifactorial nature of calf diarrhea. Multiple etiologies, both infectious and non-infectious, can result in diarrhea. Disease is caused by an interaction between a host, an agent, and the environment […]

Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) offers a variety of testing to assist in working up calf diarrhea cases. The calf diarrhea multiplex PCR—which targets bovine coronavirus, bovina rotavirus A, and Cryptosporidium—has been requested by Texas veterinarians over 1,000 times since 2019. Using TVMDL test results gathered between March 2019 and October 2023, this article […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) has been providing drug testing services for livestock shows across the country for more than 30 years. The agency tests in excess of 3,500 samples for more than 90 shows across the United States annually. TVMDL’s drug testing laboratory is an ISO 17025 accredited lab with state-of-the-art […]

Many Texans rely upon the weather for a variety of reasons. From crops to cattle, Texans are often at the mercy of Mother Nature. Although droughts can have a dire impact on animal health, floods can also contribute to widespread issues among animal owners. Excessive rainfall can contribute to mosquito-borne diseases, toxic plants, dermatologic conditions, […]

Drought conditions can create two deadly dangers for a herd: water deprivation and water (salt) intoxication. Poor water quality will worsen these conditions. Water DeprivationHigh temperatures combined with a lack of fresh water or green forage can lead to dehydration and death. During a drought, a poorly managed herd may lack access to enough fresh […]

Tissue samples from a three-week old, Charolais mix, male intact calf were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. According to the submitting veterinarian, the animal exhibited acute, non-specific neurological deficits that progressed rapidly. No information was provided regarding whether this animal died naturally or by euthanasia. Tests requested by […]

Infectious bovine keratoconjunctivitis (IBK) or pinkeye can be very problematic at times in cattle herds. It is manifested as an inflammation/infection of the cornea and conjunctiva of one or both eyes in affected cattle. Signs range from mild to severe and are characterized by blepharospasm, epiphora, and discoloration of the cornea. Cattle suffering from severe […]

The body of a midterm bovine fetus and the attached placenta were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for necropsy and gross examination. Upon examination, the entire fetus and placenta exhibited severe mummification. Tissues of this fetus were submitted to the molecular section for bovine herpesvirus (BHV)-1, BVDV, Leptospira spp. and Neospora caninum rtPCRs. […]

A 21 day-old calf with a history of multiple leg fractures and no evidence of external injuries was euthanized and sent into the TVMDL for evaluation of the hind limbs and mandible. On gross necropsy examination the mandible contained incisor teeth that were erupted but were all pink, translucent, mobile, and when transected contained pink […]

In previous cases of listeriosis in cattle, veterinarians submitting samples to the Texas A&M Veterinary Medical Diagnostic Laboratory have reported profound neurological signs that have caused them to include rabies high on their list of differential diagnoses. The primary organism responsible is Listeria monocytogenes, an organism that is common in the environment both as free-living bacteria as […]

Any animal demonstrating neurological signs localized to the brain or spinal cord before death may benefit from testing of cerebral spinal fluid (CSF) collected at necropsy. If rabies is a differential, careful CSF sampling prior to removal of the head and/or brain allows for the potential of further diagnostic investigation if the brain tests negative […]

A seven-day-old angus bull calf with a history of diarrhea was necropsied by the submitting veterinarian. The small intestine, liver, kidney and the lymph node were submitted as fresh and formalin-fixed tissues to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for further testing. The tests requested by the submitting veterinarian included microscopic evaluation (histopathology), […]

Grain is certainly an important feedstuff for livestock, but it can also be deadly if not fed correctly. Grains are rich in carbohydrates and provide energy for the animals consuming them. Commonly fed grains include corn, milo, grain sorghum, oats, wheat, and barley. The carbohydrates in grain are metabolized to produce energy, which is especially […]

Anaplasmosis is a blood cell parasite of cattle with a worldwide distribution, but the disease is most common in tropical and subtropical areas. Anaplasma marginale is the most common organism involved in cattle, and it is transmitted through the bite of Dermacentor spp. ticks or tabanid flies, as well as through the use of blood-contaminated instruments. As a result, […]

Bovine thrombotic meningoencephalitis (TEM), formerly known as thromboembolic meningoencephalitis (TEME), is a neurological disease, primarily of feedlot cattle between the ages of 6 to 12 months. The condition is caused by Histophilus somni (previously known as Haemophilus somnus), a Gram-negative opportunistic bacterium that can be cultured very commonly from the respiratory and reproductive tracts of normal cattle. Calves […]

An adult, female, 800 lb., Brangus cow in poor body condition was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for necropsy. The animal was part of a herd that reported multiple losses in the previous weeks and days. The clinical signs exhibited by other animals was not reported by the owner or […]

Two hundred and forty straight stocker cattle were on a wheat and grass pasture with access to old barns filled with moldy hay, chemicals, fertilizers, and other substances. Six percent of the animals reportedly died within a 24-hour period. Two 7-month-old calves were necropsied on site and were noted to have melting abdominal fat, hemorrhage […]

Anaplasma marginale is a rickettsial bacterium that invades the red blood cells (RBCs) of ruminants, primarily cattle, and is considered the most common tick-borne infection of cattle.  In addition to tick vectors (Dermacentor spp., Rhipicephalus spp.), biting flies and blood-tainted fomites can also transmit this organism.  Anaplasma marginale is typically a clinical disease of adult cattle.  Calves infected with the organisms usually […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) has seen quite a few cattle testing positive for Johne’s Disease in the last several months. Clinically affected cattle are usually mature adults that are gradually losing body condition despite having a normal appetite. Chronic watery diarrhea is also usually recognized, but it can be sporadic during […]

Recently, bovine conjoined twin calves were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL). Both the dam and sire were angus crosses from a herd of 250 head in the eastern region of Texas. There had been no prior occurrences of conjoined twins or other congenital abnormalities on the property. The dam had […]

Neospora caninum is a protozoal organism that is associated with abortion in cattle and the birth of weak calves.  Dogs are the definitive hosts for this organism, and the organism is spread in the feces of infected dogs.  Cattle become infected by ingesting the organism in feedstuffs contaminated with infected dog feces, but vertical transmission from […]

Between the months of August to December, the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) performs drug testing on more than 1,000 urine, blood, fecal, and feather samples from approximately 45 different livestock shows and fairs across the country. As officials and volunteers prepare for these events, please remember TVMDL offers the following collection supplies: […]

Tissue from a cross-bred bovine fetus in the third trimester of gestation was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) to investigate the cause of abortion. According to the history provided by the submitting veterinarian, this animal was the second of two full term fetuses that had been born dead in the […]

A two-month-old, 150-pound, Brahman-cross heifer calf was observed with neurologic signs following application of what was believed to be a permethrin-based insecticide. The calf died following symptomatic treatment. Fresh and fixed tissue samples were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. A portion of fresh brain was extracted and analyzed […]

A cattle owner in eastern Texas noticed several of the 50 weaned calves in his coastal pasture had diarrhea and didn’t seem to want to eat. The pasture had been sprayed with monosodium methyl arsenate (MSMA) to kill weeds about 10 days prior and was fertilized at 300 lbs per acre three days before the […]

Approximately 40 head of Hereford cows were grazing on 12 sections of land with oil production activity present. In one particular section, four to five cows were found dead within 12-24 hours. Another cow was observed by the owner to be shaking and trembling, had fallen and gotten up, fell a second time and became […]

The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) frequently works on Bovine Respiratory Disease (BRD) cases. Multiple factors lead to a BRD diagnosis, leading many to refer to the syndrome as Bovine Respiratory Disease Complex (BRDC). Affected cattle commonly display signs of fever, lethargy, nasal discharge, and coughing. Some of the factors involved in BRDC are stressors […]

A 1-year-old heifer became weak and went off by herself in mid-April.  The heifer was examined by the submitting veterinarian a few days later and was described as being lethargic, having a drooped head, oculonasal discharge, conjunctivitis/scleritis, mild mucosal petechiations, and frank blood in the urine. The heifer was weak and ataxic and would fall down […]

Since the onset of winter, the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) has seen quite a few cases of intoxication in cattle that have consumed the coffee senna (Senna occidentalis) plant. Most of the cases involved adult cattle that were found dead by the owners. The diagnosis was made by finding evidence of the plant in the […]

A herd of 14, six-month-old crossbred cattle was turned out into a new pasture. Within five days, five head died suddenly. An old barn with various abandoned and discarded metal and equipment was noted to be in the pasture. Chemical poisoning of an unknown origin was suspected. A 500-pound steer was submitted to the Texas […]

A biopsy from a 7-month-old cross breed bovine steer with a large mass was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in Canyon. The mass had been surgically removed from the right cervical region just in front of the shoulder. The mass had dimensions of 8-10 inches in diameter, very firm and […]

As part of the process for weaning, a group of 400 calves were given a parenteral injection of a mineral preparation. Four calves were unexpectedly found dead within 24 hours following treatment. Due to marked pulmonary congestion, there was a suspicion of acute pneumonia. Fresh and fixed tissues (liver spleen, lung, and kidney) were submitted […]

In early December, livestock submitted for necropsy at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in College Station demonstrated various signs of declining nutrition.  Not coincidentally, most of Texas received the first frosts and freezes of the year within this same time period. Despite the fact that generous rains in Texas produced an abundance […]

Too often the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) receives samples where there is a concern for rabies testing but the brain tissue submitted is not suitable for testing by the Department of State Health Services (DSHS) in Austin. Usually the problem is an incomplete sample where only half the brain is submitted.  Less commonly, […]

A 12-month-old crossbred bull was submitted to the Texas A&M Veterinary Diagnostic Laboratory (TVMDL) in College Station for necropsy.  The clinical history indicated that this animal had periodic seizures and bouts of ataxia for two days.  The animal would appear to be normal between these neurologic episodes.  The referring veterinarian indicated that the neurologic signs […]

A veterinarian was investigating the cause of increased non-respiratory disease mortalities in beef feeder cattle. The cattle were 100-200 days on feed and had signs of systemic compromise before acute death. On necropsy, the animals had advanced autolysis of the peritoneal organs, especially the liver and kidneys, and bladder distention. The bladders contained clotted blood […]

During the winter, the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) typically sees submissions in newborn calves described as “weak”, “dummy”, “maladjusted”, and “poor doer”. Most commonly, these animals are born alive but lack normal vigor and die within the first week of life. Postmortem exam and ancillary diagnostic testing has shown vitamin and trace […]

A veterinarian was called in to investigate the cause of abortion in a group of 60 well-managed 2-year-old brangus heifers. Four heifers aborted before the investigation was initiated. The herd is closed with a reportedly good biosecurity program and good nutrition. All of the animals are well-vaccinated. A fresh mid-term female fetus and fetal tissues […]

A producer reported a sudden death loss of six head of cattle. Two of the animals were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for necropsy to determine the cause of sudden death. Upon arrival at TVMDL, the owner indicated there had been a history of pneumonia and some of the animals […]

Fifteen crossbred calves were placed in a pasture with a burn-pile. The day after they were provided with Johnson grass hay, one calf was found dead. Two days later, three calves were walking abnormally and had diarrhea. Feces from those calves was submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) for testing. Fecal […]

A 500 lb. steer from a 30,000 head capacity feedlot was recognized as ill and pulled to a “sick pen”. The steer was from a pen of 45 head that had been on feed for approximately 45 days and appeared normal until recently.  The steer was discovered on a routine daily pen check to be […]

A herd of steers, weighing approximately 700 lbs. and roughly 8 months old, was moved onto a ryegrass/native pasture. After about a month, four steers were found dead while 17 steers exhibited peeling and crusting noses with thickening of ear and eye margins. The animals did not exhibit any clinical signs of illness and were […]

An adult angus bull was presented to a veterinarian for lethargy and weakness. The bull died shortly after blood collection. Blood and tissue samples were submitted to the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL). The complete blood count revealed a marked leukocytosis characterized by a lymphocytosis at 43,000 lymphocytes/µL (reference interval 1,800 – 9,000 […]

Blackleg is an infectious, non-contagious disease caused by Clostridium chauvoei.  Infection occurs when animals ingest bacterial spores while grazing. The bacterial spores penetrate the intestine and are disseminated via the bloodstream to the skeletal muscle, where the spores remain dormant. Following an event that causes low oxygen conditions (i.e. bruising or damage to the muscle) in […]