In descending order, by date published.
Authors: Michelle Arnold
Anaplasmosis is a disease caused by Anaplasma marginale, an organism that invades cattle red blood cells (RBCs), resulting in severe anemia, weight loss, fever, abortion and death in adult cattle. Anaplasmosis is considered a "tick-borne" disease because ticks transmit the organism when feeding on cattle. However, spread of this disease can be by any method that moves fresh blood from infected to susceptible cattle. In addition to ticks, the Anaplasma organism may be spread by biting insects (mosquitoes, horse flies, stable flies) or using blood-contaminated tools such as dehorners, ear taggers, castration tools, and implant guns without disinfection between animals. A very common method of transmission is using the same hypodermic needle on multiple animals when administering vaccines to the herd. Transmission may also be from cow to calf during gestation.
Weaning is the process of separating suckling offspring from their dam. Weaning is a management procedure applied by the herd manager. Cattle are herd animals and their gregarious nature can lead to stress as a result of this separation. Managing the weaning process can aid in reducing stress for the animals and livestock managers.
Authors: Michelle Arnold
"Staggers" is an all-inclusive term for a group of nervous system disorders caused by indole-diterpenoid mycotoxins produced by various types of fungi on forages. These mycotoxins are collectively known as "tremorgens", and they may be found in several types of grasses at varying stages of maturity.
In the Southeastern United States, acute interstitial pneumonia has been produced by ingestion of the leaves and seeds of perilla mint (Perilla frutescens). Perilla ketone is the toxin absorbed from the rumen into the bloodstream and carried to the lungs where it damages the lung tissue in cattle.
Magnesium is a vital component of normal nerve conduction, muscle function, and bone mineral formation. Hypomagnesemic tetany or "grass tetany" is a disorder caused by an abnormally low blood concentration of the essential mineral magnesium (Mg). Synonyms for this disorder include spring tetany, grass staggers, wheat pasture poisoning, or lactation tetany.
Although infrequent, brassica crops can cause animal health disorders if grazing is managed improperly. Most brassica-related disorders in cattle tend to occur during the first two weeks of grazing while adjusting to the forage. The primary potential disorders are polioencephalomalcia or PEM, hemolytic anemia (mainly with kale), nitrate poisoning, and pulmonary emphysema. Other possible clinical disorders include bloat and rumen acidosis, and metabolic problems such as hypomagnesemia and hypothyroidism with goiter. Glucosinates present in brassicas are precursors of irritants that can cause colic and diarrhea. Large bulbs may lodge in the esophagus and lead to choking. Certain brassicas (specifically rape) can cause sunburn or "scald" on light-skinned animals, especially when grazed while the plants are immature. Other potential problems include oxalate poisoning and off-flavoring of meat and milk.
"Fescue toxicosis" is the general term used for the clinical diseases that can affect cattle consuming endophyte-infected tall fescue. Tall-fescue pastures containing ergot alkaloids are responsible for the toxic effects observed in livestock, including hyperthermia (elevated body temperature), gangrene of the extremities, decreased weight gain, and poor reproductive performance. Clinical signs vary depending on the cattle, the environmental conditions, and the level and duration of the exposure. Early clinical signs are often reversible after removal from contaminated pastures or hay.
Cyanide poisoning of livestock is commonly associated with johnsongrass, sorghum-sudangrass, and other forage sorghums. Choke-cherry or wild cherry, elderberry, and arrow grass are less frequent causes. Young plants, new shoots, and regrowth of plants after cutting often contain the highest levels of cyanogenic glycosides. The risk from potentially dangerous forages may be reduced by following the management practices in this publication.
In developing individual farm mastitis control and treatment strategies, it is often necessary to characterize the types of bacteria that are present on your farm. To answer this question, a microbiological analysis, or milk culture, must be performed on milk samples collected from cows showing clinical or subclinical signs of mastitis. Results of the milk cultures will help identify which bacteria are causing the mastitis. In turn, this information can be used to alter mastitis control, prevention, and treatment options to fit your herd's conditions.
Researchers at the University of Kentucky combined existing disease detection systems to produce a fresh cow examination system that may help producers detect diseases earlier by monitoring subtle changes every day during a cow's fresh period. Compiling daily information about each animal will enable producers to notice changes in health that may otherwise have been overlooked. These records may help producers detect illnesses early, thus reducing the long-term effects (reduced milk production or fertility) and costs (re-treatment, milk loss, or death) of a disease. Learning what diseases are common on a particular farm can focus producers' efforts towards preventive measures specific to their operation. Preventing disease, rather than treating, can save producers time and money and can improve overall cow well-being.
Authors: Michelle Arnold
Ergotism and fescue toxicosis are clinically similar syndromes caused by consuming plants containing ergot alkaloids. The toxic effects and mechanisms of action are similar in both syndromes although the alkaloids are produced by different species of fungi. It grows on rye, wheat, barley, triticale, oats, and various grasses. Rye and triticale are more susceptible than other grains because they require a longer period of pollination. Grasses potentially infected include tall fescue, bluegrass, brome, canarygrass, quackgrass, timothy, wild barley, and annual and perennial ryegrass. Shallow cultivation, no-till farming, and lack of crop rotation increase the likelihood of infection of crops. Environmental conditions of a cool, wet spring followed by hot early summer temperatures are ideal for the fungus to grow.
Few plants normally contain high nitrate levels, since under normal growing conditions the nitrates are converted to protein as quickly as they are absorbed from the roots. However, under certain conditions plants can develop dangerously high nitrate levels which can cause nitrate intoxication. Death or abortion may result. Care must be taken to recognize possible toxic forages and manage them appropriately to avoid animal loss.
Authors: Michelle Arnold
During gestation, the placenta of the cow effectively separates the blood of the fetus from that of the dam and prevents any transfer of protective immunity while in the uterus. Therefore, the calf is born completely dependent on the absorption of maternal antibodies from colostrum after birth. Colostrum is the milk produced from the mammary gland in the first 24 hours after birth. A calf's gastrointestinal tract is designed to temporarily allow the absorption of large molecules including antibodies from the small intestine, but only during the first 24 hours after birth. Although colostrum contains several different types of immunoglobulins, IgG accounts for roughly 85 percent of the total volume. IgG absorption is most efficient in the first four hours of life and declines rapidly after 12 hours of age. At 24 hours, the gut is completely closed and there is no further immunoglobulin absorption. These absorbed antibodies must be consumed in order to protect the calf from disease organisms until its own immune system becomes functional.
DHIA (Dairy Herd Improvement Association) records are an essential part of dairy herd management for many progressive dairy operations. However, for producers new to DHIA, interpreting the meaning of all this information can be a bit overwhelming. Even producers who have been DHIA members for many years may not fully understand all the value that DHIA records can provide for SCC management. What follows is a description and interpretation of SCC-related information available to dairy producers on DHIA test reports.
When it comes to minimizing mastitis and lowering somatic cell counts, the area where you have the most control is your milking procedures. Understanding and following proper milking procedures is a critical step to maintaining maximum milk quality.
As we move into a new era of lower acceptable somatic cell count levels, the prevention and control of mastitis takes on increased importance. For many years, the contagious mastitis pathogens including Staphylococcus aureus, Streptococcus agalactiae and Mycoplasma bovis were the focus of control measures primarily implemented in the milking parlor to stop the spread of these organisms from cow to cow. These contagious organisms often cause high individual somatic cell counts and ultimately high bulk tank somatic cell counts. As these high somatic cell count cows have been culled due to milk marketing regulations and more dairymen have adopted NMC recommended milking procedures, the contagious pathogens are decreasing.
Infectious Bovine Keratoconjunctivitis (IBK), also known as pinkeye, is a costly disease for the beef producer. Tremendous losses stem from poor weight gain and loss of appetite in affected animals suffering from visual impairment and ocular pain.
Staphylococcus aureus is an important bacterial cause of contagious mastitis on dairy farms worldwide. More importantly, it is often at the root of chronically high somatic cell counts, recurrent clinical mastitis, and damaged mammary gland tissue. It is considered to be a contagious udder pathogen that spreads within and between cows during milking. Because it is often subclinical (milk looks normal but with a potentially high somatic cell count), infected animals pose a risk of infection to herd mates during each milking.
Ruminal tympany, or bloat, can result in lost animal performance and in severe cases, death. It occurs as a result of a buildup of fermentation gases in the rumen. Bloat may be categorized as frothy bloat, which is caused by the formation of a stable foam in the rumen, or free gas bloat, which is due to excessive production of gaseous compounds from fermentation or as a result of an obstruction preventing the escape of gas compounds. Legume bloat is a frothy bloat condition.