The California mastitis test (CMT) is a simple cow-side indicator of the somatic cell count of milk. It operates by disrupting the cell membrane of any cells present in the milk sample, allowing the DNA in those cells to react with the test reagent, forming a gel. [1] It provides a useful technique for detecting subclinical cases of mastitis.
Whiteside described a reaction between sodium hydroxide and milk that resulted in the thickening of mastitic milk. [2] The utility of this reaction as a field test was limited by the fact that the reaction was sometimes difficult to observe, and would eventually occur even in normal milk. A refined version of the test, which enhanced its sensitivity, and eliminated the confounding effect of milk fat, uses an anionic surfactant, which forms a gel with the DNA in somatic cells in the milk. [3]
A four-well plastic paddle is used, one well being for each quarter of the cow to be tested. Foremilk is discarded, and then a little milk drawn into each well. An equal volume of test reagent is added, and gently agitated. The reaction is scored on a scale of 0 (mixture remains unchanged) to 3 (almost-solid gel forms), with a score of 2 or 3 being considered a positive result. [4] A special reagent for the test is marketed under the name 'CMT-Test', but domestic detergents are frequently used instead, being cheaper and more readily available. Fairy Liquid is as suitable as a reagent for the CMT, although many cheaper detergents are not. [5]
The polymerase chain reaction (PCR) is a method widely used to rapidly make millions to billions of copies of a specific DNA sample, allowing scientists to take a very small sample of DNA and amplify it to a large enough amount to study in detail. PCR was invented in 1983 by the American biochemist Kary Mullis at Cetus Corporation; Mullis and biochemist Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993.
The western blot, or western blotting, is a widely used analytical technique in molecular biology and immunogenetics to detect specific proteins in a sample of tissue homogenate or extract.
Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs within the first few months of delivery. Complications can include abscess formation.
Bovine somatotropin or bovine somatotrophin, or bovine growth hormone (BGH), is a peptide hormone produced by cows' pituitary glands.
Genotoxicity is the property of chemical agents that damage the genetic information within a cell causing mutations, which may lead to cancer. While genotoxicity is often confused with mutagenicity, all mutagens are genotoxic, but some genotoxic substances are not mutagenic. The alteration can have direct or indirect effects on the DNA: the induction of mutations, mistimed event activation, and direct DNA damage leading to mutations. The permanent, heritable changes can affect either somatic cells of the organism or germ cells to be passed on to future generations. Cells prevent expression of the genotoxic mutation by either DNA repair or apoptosis; however, the damage may not always be fixed leading to mutagenesis.
The University of California, Davis, School of Veterinary Medicine is the largest veterinary school in the United States. Established in 1948, the school is the primary health resource for California's various animal populations. In 2020, the school was again ranked No. 1 in the United States by U.S. News & World Report and in 2021, ranked No. 2 in the world by QS World University Rankings. The school is located in the southwest corner of the main campus of the University of California, Davis. The current Dean of Veterinary Medicine is Dr. Mark Stetter.
Dairy cattle are cattle bred for the ability to produce large quantities of milk, from which dairy products are made. Dairy cattle generally are of the species Bos taurus.
Nuclear transfer is a form of cloning. The step involves removing the DNA from an oocyte, and injecting the nucleus which contains the DNA to be cloned. In rare instances, the newly constructed cell will divide normally, replicating the new DNA while remaining in a pluripotent state. If the cloned cells are placed in the uterus of a female mammal, a cloned organism develops to term in rare instances. This is how Dolly the Sheep and many other species were cloned. Cows are commonly cloned to select those that have the best milk production. On 24 January 2018, two monkey clones were reported to have been created with the technique for the first time.
A somatic cell count (SCC) is a cell count of somatic cells in a fluid specimen, usually milk. In dairying, the SCC is an indicator of the quality of milk—specifically, its low likeliness to contain harmful bacteria, and thus its high food safety. White blood cells (leukocytes) constitute the majority of somatic cells in question. The number of somatic cells increases in response to pathogenic bacteria like Staphylococcus aureus, a cause of mastitis. The SCC is quantified as cells per milliliter. General agreement rests on a reference range of less than 100,000 cells/mL for uninfected cows and greater than 250,000 for cows infected with significant pathogen levels. Several tests like the PortaSCC milk test and The California mastitis test provide a cow-side measure of somatic cell count. The somatic cell count in the milk also increases after calving when colostrum is produced.
Cetrimonium bromide ([(C16H33)N(CH3)3]Br; cetyltrimethylammonium bromide; hexadecyltrimethylammonium bromide; CTAB) is a quaternary ammonium surfactant.
Buffalopox is caused by buffalopox virus (BPXV); it is a Poxviridae for which the natural host is buffalo. It mainly infects buffalo but has been known to infect cows and humans. It is classified in the Orthopoxvirus (OPV) genus and the subfamily Chordopoxvirinae. The appearance of buffalopox follows a pattern and is described as emerging and re-emerging, it commonly occurs in sporadic and epidemic forms in domestic and commercial farm settings.
Corynebacterium bovis is a pathogenic bacterium that causes mastitis and pyelonephritis in cattle.
Milk fever, postparturient hypocalcemia, or parturient paresis is a disease, primarily in dairy cattle but also seen in beef cattle and non-bovine domesticated animals, characterized by reduced blood calcium levels (hypocalcemia). It occurs following parturition, at onset of lactation, when demand for calcium for colostrum and milk production exceeds the body's ability to mobilize calcium. "Fever" is a misnomer, as body temperature during the disease is generally not elevated. Milk fever is more commonly seen in older animals and in certain breeds.
Bovine leukemia virus (BLV) is a retrovirus which causes enzootic bovine leukosis in cattle. It is closely related to the human T‑lymphotropic virus type 1 (HTLV-I). BLV may integrate into the genomic DNA of B‑lymphocytes as a DNA intermediate, or exist as unintegrated circular or linear forms. Besides structural and enzymatic genes required for virion production, BLV contains an oncogene coding for a protein called Tax and expresses microRNAs of unknown function. In cattle, most infected animals are asymptomatic; leukemia is rare, but lymphoproliferation is more frequent (30%).
The United States raw milk debate concerns issues of food safety and claimed health benefits of raw milk, and whether authorities responsible for regulating food safety should prohibit sale of raw milk for consumption.
The Lacaune is a breed of domestic sheep originating near Lacaune in southern France. The native region of these sheep is the Tarn and Aveyron departments and surrounding areas. This region is collectively known as the "Roquefort Sector" which references the milk collection area. The Lacaune is the most widely used dairying sheep breed in France, with a population of about 800,000 ewes. Notably, it is the predominant breed used in the production of Roquefort cheese in France.
Norwegian Red is a breed of dairy cattle developed in Norway since 1935. Since the 1970s, breeders strongly emphasized functional and production traits resulting in excellent production combined with world-leading performance in health and fertility traits. Norwegian Red cows can have either a red and white or black coat and have a high proportion of genetically polled animals.
Bovine mastitis is the persistent, inflammatory reaction of the udder tissue due to physical trauma or microorganisms infections. Mastitis, a potentially fatal mammary gland infection, is the most common disease in dairy cattle in the United States and worldwide. It is also the most costly disease to the dairy industry. Milk from cows suffering from mastitis has an increased somatic cell count. Prevention and control of mastitis requires consistency in sanitizing the cow barn facilities, proper milking procedure and segregation of infected animals. Treatment of the disease is carried out by penicillin injection in combination with sulphar drug.
Mycoplasma bovis is one of 126 species of genus Mycoplasma. It is the smallest living cell and anaerobic organism in nature. It does not contain any cell wall and is therefore resistant to penicillin and other beta lactam antibiotics.
A dry cow refers to a dairy cow that is in a stage of their lactation cycle where milk production ceases prior to calving. This part of their lactation cycle is referred to as the cows dry period and typically last between 40 and 65 days. Dry cows are typically divided into two groups: far-off and close-up. Once the cow has entered this stage, producers will seal the cows teat while following a veterinarian recommended, dry cow therapy for their herd. This dry period is a critical part of their lactation cycle and is important for the cows health, the newborn calf and future milk production, as it allows the cow time to rest, eat and prepare for birth. During this time, the cow will produce colostrum for the newly born calf.