Reference Library

Health and Management Techniques
Roy Burns and Patricia Scharko

Several management techniques, including identifying, implanting, vaccinating, castrating, and dehorning, should he done in as timely and humane a manner as possible. As discussed in Section 3, adequate handling facilities are required to properly restrain the animals for treatment.

Before moving or processing animals, it is useful to have some knowledge of animal behavior. Animals generally respond to the way they are handled. They remember bad experiences. If you handle cattle gently, they will be less excitable when you handle them in the future.

Cattle have a flight zone - the area around them which they do not like for people to enter. The size of the flight zone depends on how wild an animal is. This area can be very large in range cattle; however, it might be only 5 to 20 feet in cattle accustomed to people. Extremely tame cattle can he difficult to drive because they have no flight zone. These cattle are best moved by leading them with a feed bucket.

When a person penetrates the animal's flight zone, it moves away. You can use this behavior to your advantage when moving cattle. Approach an animal slowly; when you enter its flight zone, it will move away from you. If you move too rapidly or try to get too close, the animal will turn back or break and run away. The best place to be is on the edge of the flight zone. This causes the animal to move away slowly. Cattle stop moving when they get a comfortable distance away. Don't crowd them or make sudden moves until you have them through the gate and in the corral. Cattle have a strong herding instinct and do not like to be isolated. Occasionally, a Brahman-type or exotic breed animal becomes excited if it is left alone in the crowding area of the working facility after others have entered the single-file working chute.

When processing cattle, work carefully. If you try to set a record for speed, you might end up unduly stressing or injuring your cattle. Cattle can be worked rapidly enough when they are handled skillfully and gently and when the handling facility is constructed so that cattle flow through it easily. Remember that animal health products, such as vaccines and implants, must be administered properly to be effective. Therefore, emphasize proper technique, rather than speed.

A healthy, disease-free herd is a goal of all beef producers. Your cow-calf herd health program will be most successful when you and your veterinarian customize it to your herd's needs. Local veterinarians are knowledgeable about diseases in your area and should be able to make cost-effective recommendations. Plan a program that prevent diseases and disorders; don't depend on your veterinarian just to treat problems.

Requirements for a successful herd health program include:

controlled breeding season
adequate handling facilities
adequate nutrition
working relationship between producer and veterinarian
willingness to follow a program once it is established management level that reduces stress in cattle

Contagious Diseases

Several contagious diseases can be problems in Kentucky beef herds. If you understand these diseases, you might be able to prevent them in your herd.

Anaplasmosis is caused by a microscopic parasite that destroys red blood cells. Horseflies, mosquitoes, and ticks are the principal blood-sucking insects that spread anaplasmosis. Since the infection is easily transmitted by the transfer of infected blood, outbreaks can be caused by mass operations, such as bleeding, dehorning, castrating, ear-tagging, and vaccinating. Disinfect equipment to minimize spread of the disease.

Signs of anaplasmosis include anemia. pale mucous membranes, dehydration, and constipation. Death can occur in older cattle. Most cases occur in late summer or early fall and occur in older cattle.

Oxytetracycline is the drug of choice for treating anaplasmosis. Treatment to clear the carrier state requires injections of 5 mg of oxytetracycline per pound body weight daily for 10 days or feeding 5 mg chlortetracycline per pound body weight daily for 60 days. One method of prevention is a low-level feeding of chlortetracycline at 0.5 mg per pound bodyweight daily during the insect vector season.

A vaccine is available for controlling anaplasmosis. Discuss a vaccination program with your veterinarian since special precautions may be necessary. The vaccine protects cattle against an acute attack of anaplasmosis, but it does not clear up the carrier state.

Blackleg and malignant edema are similar and are part of the Clostridium complex. They are caused by Clostridial organisms that live in the ground and enter calves through wounds, ingestion, and navel cords. The bacteria are not spread directly from animal to animal, but from the soil. These organisms produce toxins in the animal's body that are rapidly fatal. Blackleg usually occurs in cattle 6 months to 2 years of age; malignant edema can occur at an older age.

The vaccine is inexpensive, effective, and economical. All calves should be vaccinated at about 4 months of age. A booster in four to six weeks is always recommended. Calves that receive the vaccine at less than 2 months of age should
be revaccinated.

Bovine Virus Diarrhea (BVD) affects cattle by causing abortions, diarrhea, weak calves at birth, and death. BVD is frequently diagnosed in Kentucky herds. BVD can create persistently infected cattle, animals that do not appear sick and shed BVD sporadically in the herd. Bulls can introduce BVD into a closed herd of cattle. Treatment for cattle with BVD is generally not effective. The vaccines available are killed or modified-live virus products. Do not use the modified-live vaccine in pregnant animals. The killed vaccines require a booster two to four weeks after the first vaccination. Annual revaccination with a single dose is then recommended. Use these vaccines only after discussing them with a veterinarian.

Brucellosis (Bang's disease) affects cattle primarily by reproductive losses, such as abortions. An important point is that brucellosis can cause disease in humans called "undulant fever." Cows with brucellosis shed large numbers of infectious organisms at calving. Calves receiving milk from infected cows shed live organisms in the feces.

There is no cure for brucellosis in cattle. Efforts are directed at control and prevention. Test and slaughter of infected animals is the only choice available for control. Prevention is best accomplished by calfhood vaccination of heifer calves. It is permissible to vaccinate calves between 4 to 10 months of age, preferably between 4 and 7 months. Heifer calves must be vaccinated by an accredited veterinarian. Upon vaccinating a calf the veterinarian will place an official tattoo in the right ear and record the vaccination with the state veterinarian. It is recommended that you work with your veterinarian to have your herd certified brucellosis free.

Footrot is an infectious disease characterized by sudden lameness and inflammation of the subcutaneous tissues of the interdigital space. It is caused by interdigital trauma and infection with the bacteria Fusobacterium necrophorum and Bacteriodes melaninogenicus. Treatment consists of systemic antibiotics (penicillin, oxytetracycline, Naxcel, etc.) and local treatment of the interdigital area (copper sulfate, zinc sulfate, etc.). Prevention includes adequate nutrition and irninunization with B. nodosus. The vaccine appears to reduce the severity of interdigital dermatitis.

Haemophilus somnus causes an infectious disease of the central nervous system. It is also associated with bovine respiratory disease, especially in feedlot cattle. Additionally, it is recognized by veterinarians in Kentucky as an infection that can affect reproduction. Vaccines are available; they require two doses initially and an annual booster.

Infectious Bovine Rhinotracheitis (IBR) can cause respiratory infections, abortion in cows exposed during pregnancy, and eye inflammation similar to pinkeye. All forms of IBR can be prevented by vaccination with products for intranasal or intramuscular use. Modified live virus vaccines, in combination with BVD and PI3 for intramuscular injection, are most effective but can cause abortion in pregnant animals. Calves should be vaccinated 30 days before weaning. Replacement heifers should be vaccinated at least 30 days before breeding.

Johne's Disease (pronounced yo-knees) is a contagious bacterial infection of the intestinal tract of ruminants caused by the bacterium Mycohacterium parataberculosis. The bacteria can survive for more than a year in contaminated soil or water because they are resistant to heat, cold, and drying. Individual animals become infected at a very early age by exposure to fecal material or colostrum milk from infected cattle. Young cattle are more susceptible to infection than adults. The incubation for disease is usually two to eight years. Infected cattle develop diarrhea and rapidly lose weight. They continue to eat but appear unthrifty; they do not have a fever. The disease typically enters a herd when infected but healthy cattle are purchased. Several years later, the producer begins to see signs of Johne's in the herd.

There is no effective treatment for Johue's. Cattle become subclinical shedders of the bacteria before they show clinical signs. Cattle can be tested for M. paratuberca/osis. The feces can be cultured, but it can take as long as 16 weeks to get results. Fecal culture is the most definitive test. Blood tests can be done quickly. There are few false positives, but a negative test does not guarantee the animal is negative. Some animals with infection are never positive to the test.

Leptospirosis (Lepto) is a bacterial disease that produces abortions, stillbirths. weak calves, and death in nursing calves. L. hardjo and pomona are the two strains of primary concern for cattle. The infection occurs in the kidneys, and the urine infects other animals, including humans. Prevention of leptospirosis is a good reason to keep cattle out of ponds. Lepto is also spread by natural breeding. All cattle older than 4 months of age should be vaccinated for all available strains of Lepto. Annual revaccination is highly recommended. Some areas are forced to vaccinate every three to four months to maintain adequate herd immunity.

Listeriosis (circling disease, silage disease) is caused by the bacterium Listeria monocytogenes which has worldwide distribution but is most frequent in temperate climates. Animals show neurologic disease with head pressing, drooped ear, and/or compulsive circling. The recovery rate is best if treatment is administered early in the course of the disease. Prolonged treatment with antibiotics of oxytetracycline or penicillin is recommended. Prevention includes discarding moldy feed, especially silage, and preventing access to contaminated areas. Rule out other diseases that can cause similar signs, especially rabies.

Parainfluenza type 3 (P13) primarily causes respiratory problems in cattle. It is considered to be a secondary factor in a lot of shipping fever outbreaks. Vaccines are available in combination with IBR, and sometimes BVD, for use in immunization programs.

Pinkeye in cattle is characterized by inflammation and watering of the eye, painful sensitivity to light, and varying degrees of corneal damage. Research in Kentucky indicates a severe decrease in weaning weight of calves with pinkeye. This decreased performance, coupled with a decrease in selling price of affected calves, can mean severe losses for Kentucky beef producers.

The common cause of pinkeye is the bacterium Moraxella bovis. The bacteria are generally spread by face flies but may not produce the disease until irritation of the eye occurs. During the summer months, tall grass with seedheads, dust, and pollen can cause trauma to the eye, thereby increasing the risk of penetration by M. bovis. Viral infections, such as that caused by IBR, are also thought to sometimes trigger an outbreak of pinkeye.

Be alert for early signs of pinkeye. Usually the first indication of the disease is watering of the eye. A short time later, the face on the affected side might be wet. The animal might try to stay in the shade, stand with the affected side away from sunlight, blink repeatedly, or keep the eye closed. As the disease progresses, the redness of the eye intensifies and a whitish-opaque spot might appear in the center of the eye. If the eye is untreated, the white area enlarges and may rupture and ulcerate.

Treat pinkeye as early as possible. Early cases might respond to a variety of antibacterial preparations placed in the mucous membranes surrounding the eyes. It is important to place the topical medication in the eye; repeated applications are necessary. If the eye is seriously damaged, cattle are frequently treated with a subconjunctival (under the eyelid) injection of antibiotic and corticosteroid. Affected eyes should be protected from irritants and flies. You can cement a patch over the eye to provide shade and avoid flies. Leave the patch on for one to two weeks.

Intramuscular injections of a long-acting oxytetracycline antibiotic are also effective in treating pinkeye cases. This intramuscular injection should stop cattle from shedding M. bovis. If the pinkeye is caused by other agents (e.g., the virus IBR), more cases could be expected to occur.

A Kentucky study also indicated a significant reduction in incidence of pinkeye when an antibiotic was included in the salt-mineral mixture.

Don't look for a single, easy solution to control pink-eye. Instead, follow these suggestions to reduce costly outbreaks of the disease:

Develop a program to control face flies.

Reduce eye irritation by keeping pastures clipped. Keep cattle out of dusty lots, and provide plenty of shade.

Consult with your veterinarian to develop a treatment or control plan; consider vaccinating for pinkeye. All cattle herds should be routinely vaccinated for IBR.

Observe herds regularly for early detection and treat problems as they arise.

Treating the cow herd with antibiotics may be needed in an outbreak of pinkeye to clear up the M. bovis infection and eliminate the carrier state. This is an expensive option.

Salmonella is a disease that causes diarrhea in calves and/or adults. It can lead to multiple deaths in a herd. Salmonellae are invasive bacteria that can penetrate intestinal, oral, ocular, or nasal mucous membranes. Cattle are primarily infected with salmonellae by three methods:

Transmission by wildlife. Rodents and birds can bring in salmonellae from outside sources or act to maintain the infection by infecting cattle feed.

Being fed contaminated animal protein by-products (40 percent are reported to be contaminated in the United States). The bacteria can rapidly multiply in high moisture feeds after contamination by birds, rodents, or equipment.

Transmission by cattle and other livestock. Asymptomatic and sick cattle can shed large numbers of the bacteria in the feces. Carrier cattle are especially important with S. dublin since they shed numerous bacteria into the environment while appearing healthy.

There appears to be an association between intensive management practices, such as crowded conditions and high protein diets, with an increased incidence of Salmonella. Stress factors play an integral part in the disease. Stresses include transportation of animals, inadequate nutrition, bad weather, overcrowding, parturition, and concurrent disease. Salmonella frequently affects calves already diseased with rota virus, corona virus, or cryptosporidia. If the challenge dose of Salmonella is large enough, salmonellosis may occur as a primary disease in healthy cattle. The risk may be greatest when the infection occurs in a herd that is under environmental or nutritional stress and is close to calving.

Salmonellae survive for months in moist areas out of direct sunlight and in lagoons and drainage areas. Composting can decrease on-farm Salmonella. Survival of salmonellae in composted cattle manure was less than seven days. Freezing feces at ~4o F kills 85 percent of Salmonella in two days and more than 95 percent by one month. In cold manure, Salmonella can survive longer than 200 days.

The primary Salmonella isolated in Kentucky is Salmonella typhimurium. Salmonella typhimurium infection does not usually produce chronic carriers. Cattle typically eliminate S. lyphimurium within three months after infection. Salmonella spp. can persist in the environment.

Existing killed vaccines have limited efficacy against salmonellosis. The calf protection from passive colostral antibodies lasts only three weeks. Vaccines could be used to decrease clinical illness only in the early phases of a control program. Vaccination of cattle 3 months of age or older with two doses of killed Salmonella bacterins is likely to be useful for preventing salmonellosis. 15 E. co/i bacterin can be protective in calves vaccinated at 3 and 10 days of age. Ryperimmune serum can be given to neonate calves in immediate danger during an outbreak.

Adverse reactions to Salmonella vaccines can result in death. Adverse reactions commonly occur on the first dose, are more likely to occur if given during hot weather, and can occur if given with other gram negative bacterial vaccines. Therefore, Salmonella vaccines should be given in cool weather (mornings are much better than evenings) and not given with other E. co/i bacterins or Bruce/la abortus vaccine. Epinephrine should be used in case of anaphylactic reactions.

Calf scours/diarrhea is a clinical sign, NOT a disease.

Noninfectious causes:
inadequate nutrition or overabundant nutrition
inclement weather

Infectious causes: Age affected
E. coli < 10 days
Clostridium penfringens > 2 to 3 weeks
Salmonella > 3 weeks
Rota virus - 1 day to 3 weeks
Corona virus - 7 days to 3 weeks
BVD > 7 months
Cryptosporidia - 7 days to 5 weeks
Coccidia> 3 to 4 weeks
Combination of all of the above

Treatment:

1. ID and isolate.
2. Electrolytes-use esophageal tube feeder if weak calf. Feed electrolytes full dose for one day. Make sure that electrolyte will not affect the milk clot in the abomasum (not sodium bicarbonate).
3. Use Pepto-bismol or other binders; can mix with electrolytes.
4. Use antibiotics if E. coil diarrhea.

Prevention:

1. Decrease numbers of organisms in environment with pasture management. Reduce stress: avoid crowding, provide adequate shelter
2. Provide adequate amount of colostrum at birth.
3. Vaccinate dam at end of gestation to protect calf through colostrum, or
4. Vaccinate calf at birth BEFORE ingestion of colostrum.

Vibriosis (Vibrio or Campylobacter) is a sexually transmitted disease that causes early abortions and infertility in the cow. Treatment is difficult. Prevention is accomplished by vaccinating cattle 30 to 60 days before the start of breeding. Bulls should also be vaccinated. Take precautions to prevent adding infected breeding stock to the herd and thus introducing the disease.

Your veterinarian should develop a vaccination program to prevent contagious diseases for your particular herd. The time of year you work your cattle and the number of times you work them will influence the program for your herd. Table 6-1 is an example of a "Cattle Working Schedule" in which cattle are corralled four times a year.

Forage-related Disorders

Bloat is caused by an abnormal collection of gas in the rumen. Bloat results when an animal cannot "belch up" gases produced in the process of rumen fermentation. Pasture bloat usually occurs in cattle grazing lush legumes, such as alfalfa, ladino, or red clover. The danger of pasture (frothy) bloat is greatest when pasture plants are young, lush, and high in soluble protein. Frothy bloat results from the production of a stable foam that does not allow gas bubbles to form free gas and be "belched" off. The disorder is due to the foaming properties of soluble leaf proteins, which are more prevalent in legumes.

A cow's inability to expel the gas allows pressure to build up in the rumen. As the pressure increases, the rumen becomes distended on the cow's upper left side between the last rib and the point of the hip. As the bloat becomes more severe, breathing becomes difficult. After the cow is no longer able to stand, death follows within a few minutes.

In these severe cases, a 34-inch to 1-inch rubber hose can be passed through the throat into the rumen to provide relief. However, since pasture bloat is frothy, this may not be sufficient. If it is not, a defoaming agent (vegetable oil or detergent) may be added through the tube. As a last resort, relief can be obtained by making a hole in the rumen large enough to release the foam. An incision is made at a point halfway between the last rib and the hook bone on the left side. The incision must be sutured, and antibiotics must be administered.

The best plan is to prevent bloat. Bloat preventing products, such as Bloatguard&REG; and Bloat Blox&REG;, are effective if consumed with regularity and in adequate amounts. These other management practices also can help prevent bloat:

Fill cattle with hay or grass pasture before turning on to alfalfa or clover pasture. Don't turn hungry cattle on lush, immature alfalfa or clover.

Once cattle are turned onto pasture, don't remove them at the first signs of bloat. Mild sub-acute bloat occurs frequently on alfalfa pasture, unless a bloat preventative is fed.

Provide a grass-legume mixture for pasture.

Feed grain or a grain-roughage mixture to reduce pasture intake.

Fear of bloat should not keep you from using high quality legumes, such as alfalfa and clover, in your pasture program.

Fescue toxicosis and summer syndrome are terms widely used to denote poor performance of animals grazing tall fescue during the summer. This poor performance is due to the presence of high levels of a fungus in the fescue-the endophytic fun gus Acrernonium coenophialum-sometimes referred to simply as the endophyte.

Cattle consuming fescue infected with high levels of the fescue endophyte show some or all of the following symptoms:
lower feed intake
lower weight gains
lower milk production
decreased pregnancy rates
rough hair coat
more time spent in the shade and higher body temperature

Hot, humid weather worsens the effects. In Kentucky research, pregnancy rates in beef cows grazing low-endophyte and high-endophyte fescue averaged about 90 percent and 65 percent, respectively, over four years. Weaning weight of calves was decreased by about 50 pounds.

Table 6-1. Cattle Working Schedule Time

Time Calves Cows
Birth
(March, April) Identify
Record birth date, dam
Castrate, implant male feeder calves
Prebreeding
(May) Vaccinate &SHY; IBR-P13
(killed or modified-live)
Clostridial diseases (4-way)
Dehorn, if needed Vaccinate-Lepto (5-way)
IBR-BVD (killed)
Hemophilus somnus,
Vibriosis
Deworm
Sort into breeding groups
Midsummer1
(July) Deworm2
Reimplant steers
Calfhood vaccinate heifer calves for
brucellosis Deworm2
Pre-weaning-
3-4 wk
(September) Vaccinate &SHY; IBR-P13
Clostridial diseases, BVD,
H. somnus, BRSV Pregnancy exam
Weaning
(October) Vaccination booster
Treat for internal/external parasites Sell open and cull cows

1 Avoid working cattle during periods of extreme heat-early morning is best.
2 Use a dewormer that is effective against inhibited Ostertagia larvae.

Note: The Kentucky Cooperative Extension Service publication ID-14, "Management Calendar for Spring-Calving cows," contains additional management recommendations.

At least three areas should be considered to avoid or minimize the effect of the endophyte in animal production:

1. Manage to minimize the effect. Clipping seedheads eliminates a concentrated source of the endophyte and helps keep the plants vegetative. Hay harvested at the proper stage of maturity also gives better animal performance than late-cut hay.
2. Dilute out the endophyte. The most practical way is to add legumes, such as clovers, to the fescue pasture. Even small amounts of legumes can increase animal gains.
3. Replace infected stands with low-endophyte varieties. Several low-endophyte or endophyte-free varieties are now available. When you consider new varieties, pay attention to adaptability, forage production, animal performance, persistence, and pest resistance. These new varieties require good grazing management to persist in a stand.

Grass tetany is a disorder caused by an abnormally low amount of magnesium in the animal's blood. Beef cattle producers in Kentucky have generally been successful in reducing the incidence of tetany. However, the potential still exists in most herds for this disorder to be a problem.

Grass tetany occurs most often in cows grazing lush spring forages-especially small grains and cool-season perennials, such as fescue. It is most common in spring calving cows, especially if they are high producers in their third to fifth lactation. Several factors contribute to the increased incidence of tetany at this time. The magnesium requirement of cows doubles from late gestation to early lactation (from 9 grams to 21 to 22 grams).

When this rapid change in magnesium needed by the cow is coupled with lowered magnesium in the plant, along with certain components that lower the availability of magnesium (such as high applications of nitrogen and potassium fertilizers), tetany can develop. Weather can also have an effect; the greatest threat is when temperatures are between 400F and 60~F. Temperatures in excess of 600F for a week markedly decrease the incidence of tetany. When all of these factors are combined, the risk can be high.

Cattle affected with grass tetany might isolate themselves from the herd and stagger. As the disease progresses, they may exhibit extreme nervousness, rapid breathing, and muscle trembling. They might become aggressive and charge anyone in the pasture. In the most severe stage, the animal collapses to the ground with muscular spasms. Treatment must be given rapidly as death can occur within an hour after the onset of convulsions.

For the cow down with tetany, treatment is the only option. Treatment consists of an intravenous injection of solutions containing magnesium, calcium, and glucose. This must be done correctly. If the IV solution is administered too rapidly, death can result. Consult a veterinarian familiar with the herd and its management about treatment procedures and whether you should keep emergency medication and equipment on hand. To prevent relapse, recovered animals should be removed from the pasture and fed a hay/ concentrate mixture supplemented with magnesium oxide for at least a week.

As a producer, you should be concerned with preventing tetany. About 2 ounces of magnesium oxide (22 grams of magnesium) is recommended to meet the magnesium needs of lactating beef cows. Since legumes are higher in magnesium than grasses, feeding cows legume hay during the early spring may supply some magnesium. Cows grazing spring grass pasture should have magnesium in the mineral mixture; in 'high risk" situations, it may be supplied in a supplement.

Many commercial mixtures are available in various forms to prevent tetany. Before you make a purchase, determine if the product will give adequate magnesium intake. This depends on the magnesium content and the expected consumption of the product. Both should be listed on the tag. If it appears that magnesium intake will not be adequate, a product with more magnesium or greater intake should be used.

In "high risk" situations where tetany is a frequent problem, it might be necessary to force feed the daily magnesium needs. Magnesium oxide can be included in a grain or protein supplement. Supplements for "high risk" situations are shown in Table 6-2.

Nitrate toxicity can affect cattle that consume forages containing excessive amounts of nitrate. It also might occur if animals (especially those hungry for salt) have access to nitrate fertilizer. Under normal conditions, low levels of nitrate consumed by cattle are converted to ammonia and then to protein. However, high levels of nitrate interfere with the ability of red blood cells to carry oxygen. Thus, the animal dies from nitrate poisoning, but the death is caused by lack of oxygen.

Forage crops most likely to collect nitrates are warm-season annual grasses, such as sorghum, sorghum-sudan hybrids, sudangrass, corn, and johnsongrass. Avoid grazing these warm-season grasses, especially those heavily fertilized with high amounts of nitrogen, when growth ceases due to drought or cold damage. Suspect forage should be tested for nitrate level. Consult your county Extension agent for agriculture or veterinarian for information concerning sampling and how to send samples to a diagnostic lab.

The chart below should help you interpret laboratory results. Results are generally reported on a percentage or parts per million (ppm) of nitrate on a dry matter basis. Be sure results are reported as nitrate levels.

Cattle being fed or grazed on suspect forages should be watched closely for these signs:
labored breathing
frothing at the mouth
diarrhea
frequent voiding of colorless urine
staggering
convulsions
brown color of the membranes
Nitrate Levels in Forages (dry matter basis)

Percent (%) nitrate PPM nitrate Comments

0 to 0.25 0 to 2,500 Safe

0.25 to 0.50 2,500 to 5,000 Caution. Generally safe when fed with a balanced ration. For pregnant animals limit to one-half of total dry ration. Make certain water is low in nitrates. Prolonged feeding may result in a Vitamin A deficiency. Do not feed with liquid feed of other nonprotein (NPN supplements. Be cautious with pregnant and young animals.

0.50 to 1.50 5,000 to 15,000 Danger. Limit to one-fourth of ration. Should be well fortified with energy, minerals, and Vitamin A. May experience decreased milk production in 4 to 5 days, possible occurrence of reproductive problems.

Remove animals showing symptoms from the feed or pasture, and feed them a high concentrate diet. A solution of methylene blue can be given intravenously to help restore the oxygen-carrying ability of the red blood cells.

Do not bale forage that tests high in nitrate. The nitrate content of cured forage is stable. Corn fodder or sorghum-type plants have about the same nitrate content when fed as they did when baled. Properly fermented silage loses about half of its nitrate content. Do not enter the silo during the ensiling process; gases that are given off are toxic. Ground limestone added to the silage as it enters the silo, at the rate of 20 pounds per ton, can cause more nitrate to be lost.

Ray that tests high in nitrate can be diluted with low-nitrate feeds. Feed a ration high in carbohydrates (such as grain). This especially applies to feed that is marginal in its nitrate content.

Caution. Generally safe when fed with a balanced ration. For pregnant animals limit to one-half of total dry ration. Make certain water is low in nitrates. Prolonged feeding may result in a Vitamin A deficiency. Do not feed with liquid feed or other nonprotein (NPN) supplements. Be cautious with pregnant and young animals.

Danger. Limit to one-fourth of ration. Should be well fortified with energy, minerals, and vitamin A. May experience decreased milk production in 4 to 5 days, possible occurrence of reproductive problems.

Toxic. Do not feed free choice. Feed containing such high levels can only be used if ground and mixed with other feed. Limit to 15% of total ration.

Source: D.M. Ball, C.S. Hoveland, and G.D. Lace field. Southern Forages. 1991. Atlanta, GA: Potash and Phosphate Institute.

These are management guidelines for feed and forages that contain high levels of nitrates:

Leave drought-damaged forage in the field as long as practical before harvest since nitrate diminishes as plants mature.

Cut suspect forage higher than usual to avoid the higher nitrate-containing portion of the plant. Don't force cattle to eat the lower portion of the stalk during grazing.

Avoid use of drought-stricken forage until three to five days after a rain.

Regulate the intake of nitrate-containing feeds so that small amounts are fed initially and increases are gradual. Run an analysis on suspect feed to determine nitrate level.

Prussic acid poisoning occurs in animals that have consumed plants containing cyanide-yielding compounds. The prussic acid (hydrocyanic acid) poisoning potential is affected by species and variety of plants, along with weather and soil fertility. Plants of the sorghum family and leaves of wild cherry trees have the potential to produce prussic acid poisoning. Some sudangrasses are low in prussic acid, and pearl millet is free of toxic amounts of prussic acid.

The first sign of trouble might be a dead animal. Symptoms from small amounts of prussic acid can be labored breathing, frothing at the mouth, and staggering.

You can lower the risk of prussic acid poisoning by following these management practices:
Don't graze sorghum or sorghum-cross plants until they are at least 15 inches tall.
Don't graze wilted plants.
Don't graze these plants during or shortly after drought periods when growth is retarded.
Don't graze for two weeks after a non-killing frost.
Don't graze until about 48 hours after a killing frost (until plant material is dry).
Don't graze at night when a frost is forecast.
Don't allow cattle access to wild cherry leaves.
Do check pastures after storms for fallen wild cherry trees or limbs.

Parasites

Internal parasites are present in most beef herds in Kentucky. The condition is often subclinical and results in hidden losses. Reduced gain and feed efficiency occur in what appear to be healthy cattle. Cattle infected with a heavy load of internal parasites may show many of the following symptoms:
anemia
rough hair coat
"bottle jaw"
progressive weight loss
persistent diarrhea
unthriftiness

This is how the cycle works: mature female worms that live in the gut of animals produce a large number of eggs which pass out of the animal in the manure. The moisture and warmth of the manure pad helps the eggs hatch and develop into larvae. When they reach the infective stage, the larvae of most species crawl onto the forage where they are ingested by cattle. Once inside the animal, they grow to maturity and the cycle begins again.

The medium brown stomach worm (Ostertagia ostertagia) is different in that the larvae enter digestive glands in the stomach lining and can become inhibited (hibernate) for as long as four months. This period of inactivity generally occurs in the summer and winter. The hibernation is a method of survival for the worms because the eggs are not deposited on hot, dry summer pastures or frozen ground where they would die quickly. However, when favorable weather resumes for development of worms on pasture, the larvae become active in the stomach lining. They develop into adult worms and break out of the glands, damaging them as they leave. They can emerge gradually or suddenly, causing much damage to the stomach lining.

Several products help control internal worms in cattle. They are in the forms of injectables, pour-ons, drenches, pastes, boluses, blocks, crumbles, and feed additives. Select the appropriate product based on your management practices and your veterinarian's recommendations. Dewormers used during the hot summer and cold winter should be effective against inhibited Ostertagia ostertagia larvae. Albendazole (Valbazen&REG;), doramectin (Dectomax&REG;), ivermectin (Ivomec&REG;), oxfendazole (Synanthic&REG;), or a double dose (10 mg/kg) of fenbendazole (Safe-Guard&REG;, Panacur&REG;) removes the adult and inhibited Ostertagia.

Cattle are typically dewormed in the fall at weaning time, spring at pasture turn out, or both. If you deworm in the spring, keep the animals in a confined pasture for 24 to 48 hours after treatment and before turning out onto the spring/ summer pasture. This time allows the anthelmintics (dewormers) to kill the worms and discard them onto a "contaminated" pasture. The cattle can then be turned out onto "clean" pastures.

Strategic deworming programs should be designed to work with the natural rise and fall of infective larval populations on pastures at various times of the year. The most important part of strategic deworming is timing. Timing for deworming is dependent on the weather, grass growth, and management. Strategic deworming coordinates grazing pastures with several strategic dewormings in the spring! summer. The timing between dewormings depends on the type of anthelmintic used.

Chemical control of internal parasites should be accompanied by other measures, such as not overstocking pastures, pasture rotation, feed bunk management and sanitati on, and an adequate level of nutrition. Pastures on which cattle have been concentrated can be harrowed with a chain-link harrow to expose eggs and larvae to the effects of drying and heat or cold.

External parasites, such as flies, lice, and cattle grubs, cause losses to beef producers from lowered weight gains, reduced milk production, and diseases transmitted by parasites. Animals that are severely infested with parasites are more susceptible to disease.

Lice occur primarily during the winter months when cattle have longer coats and less oily skin. Two types of lice infest cattle in Kentucky: biting lice and sucking lice. Biting lice (little red lice) do not suck blood but use their chewing mouthparts to feed on dead skin, hair, and skin secretions. These lice are very active and cause irritation to animals by their movement and feeding. Biting lice are usually found around the tailhead and the top of the shoulder. Sucking lice have piercing mouthparts which they use to feed on blood. Sucking lice are bluish or slate-gray in color. They are often found in colonies, which look like patches of dirt or manure against light colored hair.

Symptoms of lice infestation are licking the hair to soothe the irritation, rubbing, and scratching. Severely infested cattle often rub off patches of hair. The rubbing can cause damage to fences or injury to the cattle.

Lice can be controlled easily in the winter by using pour-on or spot-on insecticides, either those used for cattle grub control or those designed specifically for lice control. Keep lice in check by using backrubbers or dustbags throughout the year. Some forms of dewormers (ivermectin, doramectin) kill sucking lice and grubs.

When treating for lice, treat all animals in the herd to prevent reinfestation from untreated cattle. To rid the herd of lice completely, you will need a second insecticide treatment 14 to 21 days after the first (to kill lice that have hatched from unkilled eggs).

Flies are pests of beef cattle and cause most problems during the warmer months. Most flies have either sponging or piercing-sucking mouthparts. Face flies have sponging mouthparts; hornflies, stable flies, and horseflies have piercing-sucking mouthparts.

Faceflies usually feed on mucus secreted from the eyes of cattle. They spread the bacteria Moraxe/la bovis, which causes pinkeye in cattle.

Hornflies are blood-sucking pests that stay on cattle continuously, leaving only when disturbed or when they move to fresh manure to deposit their eggs. They are usually found on the shoulders and backs of cattle. Since hornflies stay on the cattle, they are easy to control.

Horseflies are severe blood-sucking pests of cattle that cause problems usually during late summer. Horseflies greatly irritate cattle by feeding on them, and they can spread anaplasmosis. The control of horseflies is difficult since they spend little time on the cattle.

You can control face flies and hornflies by using insecticide sprays, backrubbing devices, dust bags, insecticide-impregnated ear tags, and feed-through insecticides. Insecticide-impregnated ear tags have been used effectively for several years. Tags give the best fly control when you use two tags per animal, apply them in late May or early June when the fly population builds up, and put tags on all animals in the herd.

Flies can become resistant to chemicals used in insecticide ear tags when they have been used for long periods. In these cases, alternate the types of insecticide and/or methods of control to eliminate insecticide-resistant populations of flies.

Cattle grubs are the immature or larval form of heel flies. Producers are likely to be aware of these parasites at two stages of their life cycle: first, when heel flies try to deposit their eggs on cattle, causing them to run with their tails up (this is sometimes called "gadding") and, second, when grubs appear in the cattle's backs after nine months or so in the animals' bodies.

Control of these insects is important because of losses due to disturbed or "gadding" cattle, reduced vigor of cattle while larvae are migrating through the body, and damage to loin muscle and hide when slaughtered. Control can be accomplished while the larvae are small and in the "wandering" stage in the body. In Kentucky, this is from mid July until the end of October. Systemic insecticides are applied as pour-ons, spot-ons, and sprays. The injectable dewormers ivermectin and doramectin also kill cattle grubs.

Administering Drugs to Cattle

Drugs used by producers and veterinarians are generally classified broadly as pharmaceuticals (used for treatment) or biologicals (used for prevention). Both are necessary for a herd health program.

Types of pharmaceuticals used for treatment include antibiotics, coccidiostats, and steroids. An example of a biological used for prevention is a vaccine, which stimulates immunity against specific diseases. [Note: Vaccines should be refrigerated and are sensitive to light. Do not reconstitute them until they are to be used. Observe the expiration dates printed on the labels.]

No matter which method you use to administer drugs, always use proper animal restraint to do a good job. Since most drugs are relatively expensive, take your time and do the job right. If your technique is sloppy, your biggest loss will be caused by a lack of response to the drug.

Injections are probably the most common method of administering drugs. Drugs that are injected act rapidly, are used efficiently, and may act longer than those given orally or applied topically. For the best results, take care to properly prepare the injection site, equipment, and product.

There are three types of hypodermic syringes: plastic disposable, glass reusable, and metal pistol-grip reusable. Be sure to keep extras in case of breakage or malfunction. Convenient sizes to have available are 5, 10, and 20 cc. Larger sizes (about 50 cc) can be used in administering large doses or for multiple doses (like pistol-grip syringes). When loading the syringe, pull back the plunger and fill with an amount of air equal to the drug to be put in the syringe. Then inject the air into the bottle and withdraw the drug.

Needles also come in many lengths and sizes; remember, the diameter becomes smaller as the gauge number gets larger (for example, 14 gauge is larger in diameter than 22 gauge). Consider both length and gauge when you prepare to give various types of injections. Generally, 16 and 18 gauge needles are required for most injections. Smaller diameter needles may not allow thick liquids to flow easily and may bend. Larger diameter needles make a large hole and might let the product flow back out.

The most commonly used types of injections are subcutaneous (SC), intramuscular (IM), intravenous (IV), sub-conjunctival, and intranasal.

Subcutaneous injections are made just under the skin but not into the muscle tissue. The side of the neck is a good area to make injections in cattle. Behind the point of the elbow where the skin is loose can also be used. To properly administer the injection, lift the skin with your free hand and insert the needle into the raised fold of skin. Needles of 16 to 18 gauge and + to 1 inch are usually used. A +-inch needle is needed when the skin is not lifted with the free hand during injection. Do not give more than 10 cc at a single injection site. Separate injection sites by at least 5 inches.

Intramuscular injections are made directly into muscle tissue, generally with a 1- to I +-inch needle. Absorption of the drug is more rapid here than under the skin because of the good blood supply to muscle tissue. After the injection site is chosen, distract the animal by slapping the injection site firmly. Immediately insert the needle with a quick thrust. Do not inject more than 10 cc at an injection site. Too much drug in one area can cause muscle damage. Do not make injections in the rump (see Figure 6-3 for proper injection sites).

Intravenous injections are useful when a large volume must be given, when the drug must not be deposited outside the vein, or when it might be irritating to tissues. These are made directly into a blood vessel, usually the jugular vein. An injection site can be found on the side of the animal's neck by placing the thumb or forefinger of your free hand firmly onto the area where the jugular vein is located. The vein should bulge between your thumb and the animal's head so that it can be seen and felt. The needle must be sharp and inserted with a quick thrust to hit the vein. Don't stick the needle in until you can see the vein.

Because some knowledge of anatomy and experience is needed, intravenous injections should be performed only by an experienced person following recommendations and instructions by a veterinarian.

Subconjunctival injections involve injection of a drug into the eyelid. This type of injection might be needed for treating pinkeye. Invert the top eyelid of the infected eye and make an injection under the pink lining of the eyelid.

Intranasal refers to inside the nostril; drugs administered intranasally (such as IBR vaccine) are "squirted" inside the nostril. Only a small amount of the product needs to come in contact with the mucous membranes to cause the animal to develop immunity.

Precautions

When using injectable drugs:
· Never exceed the recommended volume per injection site.

This could cause:
· tissue damage
· soreness
· extended withdrawal times
· altered absorption
· increased possibility of "leakage" of the product

Never use a needle on an animal and then insert it back into the bottle. Leave a clean needle in the bottle for withdrawing the drug.
Always take your time, handle drugs properly, and make injections correctly.

Administering drugs orally

Another way to administer drugs is orally. In this case, the product is fed or given directly through the mouth. Feeding of drugs requires that all animals eat an adequate amount. Therefore, the product must be palatable, and adequate feeding space must be allowed so that all animals eat the proper amount in the required time. Balling guns are used to give boluses, capsules, and tablets. Drenching can also be used to give liquid to cattle.

Identification of Cattle

Animal identification is important in beef cattle herds for effective record-keeping, performance testing, and artificial insemination, as well as routine observations. The three most common methods of identification are ear-tagging, tattooing, and branding.

Regardless of the method you use, you must decide on a numbering scheme if your records are to be meaningful. Each animal should have a unique number. Herd size determines how many digits are necessary, but each digit should have some meaning.

In a four-character number, you could use this common scheme: the first number or letter denotes the year of birth; the second character identifies the sire or breed crossed; and the last two numbers are the order of birth. Or, a letter can be used to denote the year of birth using the international year/letter designation (see Table 6-3).

For example, the tattoo "7 2 14," read from the left, could be:

7 = 1997 birth year

2 = sire No.2

14 = 14th calf born in 1997

Or, the calf could be tattooed G214 and have the same meaning.

Ear-tagging is probably the most common method of identification. It is not permanent, because tags are frequently lost. Ear tags are best used in combination with a permanent form of identification, such as a tattoo or brand. You can purchase pre-numbered tags. If you number your own, be sure to use ink that will bond to the tag and allow adequate time for it
to dry.

Step-by-step procedure for ear-tagging

1. Select the tag and numbering system to be used.
2. Number plastic ear tags with a marking fluid or ink that bonds to the ear tag. Number tags no later than the day before they are to be used.
3. Insert the ear tag into the appropriate applicator. When two-part tags are used, be sure they line up correctly and that you are using the correct pin for the type of tag.
4. Select the tagging site on the ear. Place one-piece plastic tags between the cartilage ribs, approximately one-half the distance from the base to the tip of the ear. You may place two-piece tags between the cartilage ribs or below the ribs. Place metal tags into the top of the ear near the ear's base.
5. Insert the ear tag. Apply the two-part tag with the plier-type applicator by squeezing the handles until the ear tag snaps together. Metal types are applied in the same manner. The knife-like applicators (for one-piece tags) are forced through the ear using extreme care. Be sure the knife is turned so that the tag hangs straight down or at an angle away from the base of the ear.
6. Treat the wound with an antiseptic to prevent infection.

Tattooing is a permanent means of identification, but it cannot be read from a distance. Most purebred organizations require that animals be tattooed in one or both ears before registration. The tattooing instrument consists of a pliers-type device with numbers and/or letters. These numbers or letters are made of needle-like projections that pierce into the ear when the handles of the tattoo instrument are squeezed together. An indelible ink is then rubbed into the small punctures. After healing, the tattoo is permanent.

Step-by-step procedure for tattooing

1. Restrain the animal.

2. Locate the area of the ear you wish to tattoo. Two ribs of cartilage divide the ear into top, middle, and lower thirds. Place the tattoo in the top of the ear just above the cartilage rib. It is generally best not to tattoo between the two cartilage ribs as this area is frequently used for ear tags. Also, the area between the two ribs on the right ears of heifers is reserved for brucellosis vaccination tattoos.
3. Clean the inside of the ear where the tattoo is to be placed with a cloth soaked in alcohol.
4 Position the tattooing instrument so that the numbers are in the proper position. Squeeze the handles together completely and quickly.
5 Rub tattoo ink into all needle marks. You can apply the ink with a roll-on applicator or rub it in with your thumb or an old toothbrush.

Hot-branding is used for two basic reasons: to establish ownership of an animal and to identify an individual animal. Like many states, Kentucky registers ownership brands through the Department of Agriculture. The use of a registered ownership brand helps discourage cattle rustling and serves as the cattleman's trademark. It has the disadvantage of lowering the value of the hide and is considered by some as inhumane.

Brands used for individual animal identification usually consist of three or four numbers. Hot-branding permits quick identification of an animal from a distance. The most common locations of brands are the hip, rib, thigh, and shoulder. Brands can be applied easily to these locations when animals are restrained in a squeeze chute, and the brand is easy to see from a distance. Each character is generally 3 or 4 inches high. Numbers that are 3 inches are generally used on young cattle; 4-inch numbers are used on mature cattle.

Step-by-step procedure for hot-branding

1. Restrain the animal. Place the animal in a squeeze chute with a head gate. Apply tension to the squeeze mechanism to prevent the animal from moving.
2. Heat the irons. Electric irons may be used; these require a 110-volt outlet. Electric irons heat in about 90 seconds and maintain a constant heat. A set of electric irons consists of three irons with three numbers on each iron; thus, three outlets are required to keep all irons hot. Regular irons (iron or steel) may be heated with a propane gas burner or a wood fire. The gas burner is usually built inside a drum to help contain the heat and is hooked to a propane tank for a constant fuel source.
3. Check temperature of irons. A properly heated iron looks ash-gray in daylight but glows when held in a dark place, such as the bottom of a five-gallon bucket. A black iron is too cold. It might be hot enough to burn the hair but will not form a permanent brand. A red hot iron is too hot and should be allowed to cool until the ash-gray color appears.
4. Apply the iron. Firmly press the branding iron against the hide and rock the handle gently to vary the pressure and obtain uniform application of the entire character. The iron should be applied to the hide just long enough to burn the hair and outer layer of skin. This generally requires about five seconds, depending on the age, hair cover, and iron temperature. New brands should be the color of saddle leather (light tan).

Repeat this step until the animal is branded with all the desired characters.

Tips for better brands

Do not brand wet animals. An iron applied to wet hair loses temperature rapidly and tends to scald rather than burn the hide; this results in a scar that is slow healing and hard to read.

Do not permit the iron to slip or slide during application or a blotch will result.

Clip hair over the brands in fall or winter before the calving season begins.

Freeze-branding of cattle with super-chilled irons (copper or copper alloy) is considered more humane than hot-branding. When applied properly, the cold brand destroys the color-producing cells in the hide and the hair grows out white. The visibility of these brands is much better on black or dark colored cattle, and not as good on white or light colored cattle.

Step-by-step procedure for freeze-branding

1. Prepare the branders. They should be made of copper or copper alloy.
2. Cool the irons in a refrigerant. One method of doing this is to place the branders in liquid nitrogen(-3200F). Place 3 to 4 inches of liquid nitrogen in a Styrofoam cooler or insulated bucket before the irons are added. It takes about 5 quarts of liquid nitrogen for 20 head of cattle. The second method of cooling branders involves placing them in a mixture of 99 percent isopropyl alcohol and dry ice. The recipe for 20 head of cattle is 1 gallon of 99 percent isopropyl alcohol plus 20 pounds of dry ice placed in a Styrofoam cooler. The ratio of alcohol to dry ice is not critical, but one pound of dry ice per animal branded is a good rule of thumb. Both methods require more refrigerant to cool the branders initially than to rechill between animals. Add refrigerant (liquid nitrogen or alcohol and dry ice) as needed to ensure the branders are covered by refrigerant.
3. Fill a quart squeeze bottle with 99 percent isopropyl alcohol.
4. Restrain the animal in a squeeze chute.
5. The irons are ready for use when the refrigerant stops boiling. Initially, this takes about 20 minutes and depends on how many branders you are trying to cool at one time. When the boiling stops, the brander has reached the temperature of the surrounding refrigerant.
6. Clip the area to be branded as closely as possible. This can best be done by using a No.40 surgical clipper to remove the hair and "underfur," which acts as insulation and increases the time required for proper branding. If necessary, a stiff-bristled grooming brush can be used after clipping to remove dirt, hair, and dandruff.
7. Liberally apply 99 percent isopropyl alcohol from the squeeze bottle over the branding site. Soak the area but don't waste alcohol. It need not be rubbed in.
8. Put on a pair of leather gloves, take the brander out of the refrigerant, and check the character to be used to be sure it is the right one.
9. Check the clock to ensure the proper brand application time.
10. Apply the brander to the clipped, alcohol-soaked area, and apply pressure to the brander by leaning on it.

When either liquid nitrogen or alcohol-dry ice are used as refrigerants, the minimum time of application is 30 seconds. When liquid nitrogen is used in the winter, hold the iron on black calves for 45 seconds and on red calves for 60 seconds. When dry ice and alcohol are used during the winter, hold the brander in place for at least 60 seconds.

The calf usually jumps and squirms for the first 10 seconds after the brander is applied to the hide. The reason for this is that the extreme cold activates the nerve endings. After about 10 seconds, the nerve endings are frozen and inactivated and the animal usually stops moving. You should be ready for this and keep the brander in the same position the entire time to ensure a good, clear freeze brand.

Implants for Beef Calves

Growth-stimulating implants offer the commercial producer a fast, easy-to-use method of increasing weight gain of calves. They have been proven effective through research as well as in the beef industry.

Implants are placed underneath the skin on the back of the ear. They appear to exert a positive effect by increasing growth hormone and insulin, resulting in increased formation of muscle tissue and decreased fat. Growth hormone is naturally produced by the pituitary gland and is an important regulator of growth. Implants generally increase the rate of gain by 4 percent to 8 percent.

As a general recommendation, male calves should be implanted when they are castrated. Do not implant bull calves that you intend to save for breeding. Research has shown that suckling male calves implanted at castration weighed as much at weaning as non-implanted bull calves of the same age. While bull calves weigh more at weaning than non-implanted steers of the same age, they generally bring a Tower price per pound when sold as feeders.

Compudose&REG; is cleared for use in suckling steers. The implant is a 1.18-inch long, 3/16-inch thick silicone rubber cylinder that contains 24 rug of crystalline estradiol 1713. This provides for a controlled release of the product for 200 days. Individual implants are contained in a 20-dose hard plastic cylinder designed for use in the Compudose implant gun. Each implant is coated with oxytetracycline powder to minimize ear infections and consequent loss of the implant.

The active ingredient in Ralgro&REG; is zeranol, derived from a mold commonly found in corn. Although it functions through the hormonal system, it is not a hormone itself. Ralgro is approved for suckling calves (from birth) of either sex that are not intended for use as breeding animals. One dose of Ralgro consists of 36 mg zeranol regardless of size or sex of calf. It is available in 24-dose cartridges made for the Ralgro implant gun.

Magnum contains 72 rug of zeranol and is for use in feedlot steers.

Revalor&REG;-G is for weaned pasture cattle. Each implant contains 40 mg trenbolone acetate (TBA) and 8 rug estradiol and provides for improved average daily gain.

Synovex&REG;-C is cleared for steer or heifer calves ranging from 45 days old to 400 pounds. It can also be used on heifers intended for later breeding, if used during this period. An individual dose of Synovex-C&REG; consists of four cylindrical pellets contained in a clear plastic implant cylinder. Synovex-S is for steers weighing more than 400 pounds. Each implant contains 200 mg progesterone and 20 rug estradiol in eight cylindrical pellets. Synovex-H is for heifers weighing more than 400 pounds. Each implant contains 200 mg testosterone and 20 mg estradiol in eight cylindrical pellets. Each implant cylinder contains 10 doses and is made for use in a Synovex implanter. There are two types of Synovex implanters, one of which has a retractable needle to improve implant retention and absorption.

Calf-oid, Implus H, and Implus S have the same ingredients and labeled uses as Synovex-C, Synovex-H, and Synovex-S, respectively.

Research has shown that calves respond to reimplanting. With the exception of Compudose, calves should be implanted every 90 to 100 days. UK data indicates that 97 percent of the gain stimulation from Ralgro occurred in the first 84 days. Your best approach is to implant calves at or near birth when the males are castrated and reimplant midway through the suckling phase, unless Compudose is used.

Step-by-step procedure for administering implants

1. Properly restrain the animal.
2. Determine which ear you want to implant and adjust the implant instrument so the needle can be positioned next to and parallel to the ear, with the slant side of the needle facing outward. Implant all calves in the same ear to minimize confusion.
3. Select the proper implant site on the back of the ear (Figures 6-1 and 6-2). Put the implant between the skin and cartilage on the back of the ear.
4. Clean the needle and implant site with cotton dipped in alcohol to reduce contamination of the needle wound.
5. Grasp the ear with one hand while the other hand positions the instrument parallel to and nearly flush with the ear. Put the point of the needle against the ear with the beveled part facing you.
6. Use the tip of the needle to prick the skin, lift slightly, and completely insert the needle under the skin.
7. Pull the instrument and needle back to create a space for the implant, unless using an implanter with a retractable needle.
8. Depress the plunger of the implant gun and withdraw the needle.
9. Feel the ear for the implant under the skin to see that it is inserted properly.

Precautions

When the ear is grasped and the needle inserted, the animal may throw its head. This can be prevented by using a nose lead, halter, or a headgate equipped with a head and nose bar.

Avoid piercing or cutting ear veins with the needle.

Do not allow the needle to gouge or pierce through the cartilage. If you feel resistance as you insert the needle, it is quite probable that the cartilage has been gouged, and pellets may be covered with scar tissue and 'walled off," resulting in poor drug absorption and decreased gain.

Never sacrifice a careful implantation technique for speed.

The products named in this section should be available through animal health and farm supply stores or your veterinarian.

Castration of Bull Calves

Castration is the removal or destruction of the testicles of a bull by surgical or nonsurgical methods. The castrated male calf is then referred to as a steer. Steers are preferred in the marketplace and bring more per pound than bull calves because they have a better disposition and their meat is preferred over that from bulls. Implanted steer calves weigh as much at weaning as hull calves.

Bull calves should be castrated as soon after birth as possible. You can castrate calves at birth when they are ear-tagged and implanted. In some herds, it is not practical to castrate that early because herd sire prospects will not be selected until weaning. However, older and heavier bulls generally bleed more and suffer more setback.

There are several methods of castration. All of the surgical methods accomplish successful removal of the testicles, but not all of them permit the scrotum to drain properly while healing.

Knife castration is the most common method used. Two variations are generally used: cutting off the lower third of the scrotum or slitting the scrotum down the side. A sharp and sterile pocket knife works fine for making the incision. However, specially designed castration knives are available. After the incision is made, squeeze the testicles one at a time through the incision. Pull on the testicle and, with the thumb and index finger of the other hand, separate the testicle and cord from surrounding connective tissue. Sever the spermatic cord as high as possible by scraping with the knife blade, or use an emasculator which crushes as it cuts (this prevents hemorrhage in older calves). Apply an effective antiseptic, and a fly repellent if needed.

The bloodless emasculator (Burdizzo&REG;) is the preferred method of nonsurgical castration. It can be used at any time of year without concern for an open wound. "Clamped" bull calves may become staggy (have some of the physical characteristics of a bull) if the procedure isn't done properly.

Clamping is best done with the calf standing and a tail-hold applied (grasp the tail near the base and bend it sharply upward and over the back toward the calf's head). Be sure the emasculatome closes properly. Each cord should be crushed separately. Position one cord against the outside of the scrotum. Clamp approximately 2 inches above the testicle. The emasculatome should be left in place for about a minute. The crushing of the cord should make the testicle atrophy and become nonfunctional.

It is a good practice to clamp each cord twice. Repeat the procedure on the other cord, making sure to leave the middle (septum) unclamped for adequate circulation to the scrotum. If you clamp all the way across (including the septum), the scrotum can slough off and expose the testicles.

The elastrator method should only be used on calves less than 1 month old. In this method, a special rubber band is placed around the scrotum at its neck. You apply the rubber band with a forceps-like instrument. Expand the rubber ring and press both testicles through the band. Release the rubber band and remove the elastrator. The testicles and scrotum will fall off in about two weeks. Elastrators can be used only before the testicles become too large to pass through the band.

The elastrator method has some serious disadvantages: tetanus can be a problem when the bottom of the scrotum atrophies and sloughs off; also, the rubber band sometimes breaks and voids the operation. Complete removal of the scrotum is also objectionable to some producers.

Dehorning Calves

Buyers of feeder calves prefer calves without horns. Dehorning reduces the possibility of injury and bruising of animals. Hornless cattle require less space at the feed bunk and in transit. Horned animals are more difficult to catch in a headgate and more likely to injure the handler during processing.

It is best to dehorn animals as early as possible to minimize stress, preferably at less than 2 months of age. As calves get older, the process causes more trauma, more bleeding, and an increased chance of infection. When calves have matured enough to have a "horn" sinus, cutting the horn out leaves an open hole into the sinuses of the head. Do it early when little or no cutting is required!

It is also best not to dehorn cattle by a method requiring cutting during either the fly season or extremely cold weather. Maggots can be a problem during hot weather, and the exposed sinuses can lead to respiratory problems during extremely cold weather.

Calves can be dehorned genetically with the use of polled animals in the breeding herd. If calves are born with horns, however, dehorn them as early and humanely as possible, using one of the following methods.

A caustic paste or stick can be used on very young calves (up to 2 or 3 weeks of age), where only a button can be felt. Clip the hair around the base of the horn. Then clip off the end of the horn button with a sharp pocket knife so the dehorning chemical can penetrate the horn. Apply a ring of petroleum jelly around the base of the horn button to protect the skin. Apply the caustic stick or paste according to label directions. Rub the caustic stick on the horn until blood appears. Keep the calf away from its dam until the treated area has hardened and dried.

Spoon, tube, or knife dehorning works on horn buttons or small horns just emerging. These tools separate the horn from the adjoining tissue with very little bleeding. Clean the area around the horn with a disinfectant. The cut should be made around the base of the horn to include about /8 inch of skin and should be about % to + inch deep. After removing the horn, apply an antiseptic, and insect repellent if needed.

An electric dehorner is an excellent tool for removing horns from calves of any age when the horn is still small. Most electric dehorners have cupped ends of different sizes which are placed over the horn. Select the "cup" that fits best over the base of the horn and hold it on long enough to destroy the ring of growth cells around the base of the horn. The skin will look copper or bronze colored when completed. The horn or button can then be knocked off with the hot iron or it will drop off in a few weeks.

Barnes-type dehorners may be necessary if dehorning is delayed until weaning. The instrument should fit over the horn plus a ring of skin and hair. The dehomers are available in calf and yearling sizes. The older the calf, the greater the potential for complications with this method.

Close the handles to fit the blades around the base of the horn; then spread the handles and twist while applying considerable pressure. Control bleeding by using forceps to pull exposed arteries. Pick up the artery (bleeder) with the forceps, twist and pull the artery until it breaks and retracts into surrounding tissue. A hot iron (electric dehorner) may be used to cauterize small blood vessels. Treat the wound with an antiseptic spray, and fly repellent if needed. Do not use blood-clotting powders if there are openings into the sinus cavity. Place a thin layer of cotton over the exposed cavity to keep out foreign particles, like dust.

Estimating Age of Cattle by Their Teeth

If you don't know how old a cow is, it is sometimes helpful to estimate its age. Decisions on purchasing or culling commercial cattle are best when based on age. For example, if you were to purchase a group of "4- or 5-year-old" cows, it would be an expensive lesson to learn they were actually 10 or older. The appearance of the teeth gives an indication of how old cattle are.

Only the front "cutting" teeth (incisors) are important in calculating age. Of course, the cow has no upper incisors. The eight incisors on the lower jaw appear at different times and exhibit varying degrees of wear depending on age.

By the time a calf is about a month old, it has eight temporary incisors. These temporary teeth are shed and replaced by permanent teeth, in pairs. The first pair is the two central incisors in front. The second pair is the two teeth on either side of them, and so on for the third and fourth pairs.

At 19 to 20 months of age, the first permanent incisor tooth appears. By 24 months, the center incisors are fully erupted and in line. The following pattern of growth and wear appears after 2 years of age.

2 years -the central permanent incisors (pinchers) attain full development.

2+ years -the second set of incisors (one on each side of the pinchers) is cut. They are fully developed by age 3.

3+ years -the third set of incisors is cut. They are fully developed and begin to wear at age 4.

41/2 years -the fourth set (corner teeth) is replaced. By age 5, they are fully developed.

Age determination past 4 + years is less accurate and is mainly related to wear on the surface of the eight incisor teeth. The center pair begins to show wear at 5, the second pair at 6, the third pair at 7, and the corners at 8 years. The teeth begin to take on a "pegged" appearance at age 7; that is, the gum begins to recede from the base of the teeth. By the 10th year, the corner teeth show noticeable wear. By the 12th year, the row of teeth appears to be in a nearly straight line, as opposed to the normal arch, and shows progressive wearing to stubs. The animal may then become "smooth-mouthed," when the teeth are worn to the gums, or 'broken-mouthed," when some teeth are lost.