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Mortality or death loss often has been used as the only criterion to determine whether raising replacement heifers has been successful. A more sound approach might also include calculating the proportion of a farm's heifers that are well-grown and freshen by 24 months of age. The average heifer in Ohio DHI herds freshens for the first time when she is 28 months old. At least a portion of this time difference might be attributable to those bacterial and viral diseases that often occur in calves and heifers less than 12 months old.

Diarrhea (scours or enteritis) and pneumonia frequently occur together (pneumoenteritis) in young calves.


General Preventive Strategies

Birth through 4 weeks: The major health problem on many farms associated with calves in this age group is diarrhea. Many disease agents are capable of causing diarrhea in calves and research has indicated that many, if not all, of these agents may be present on the typical Ohio dairy farm. Actually, the occurrence of disease is dependent not only upon the presence of a particular infectious agent but also such factors as the dose of infectious agent, calf immunity, and the presence of other stresses on the calf. After the calf is born in a clean and dry environment, prevention and control of diarrhea should be concentrated in 3 areas:

  1. Early feeding of colostrum: Do not assume that the calf has nursed and received adequate colostrum. Feed at least 2 quarts of colostrum to large breed calves as soon as possible after birth. Promptness of the first feeding is very important. For example, colostrum fed 9 hours after birth will result in only 50 percent of the antibody level in the calf's bloodstream as compared to the same amount of colostrum fed during the first hour of life. Although it is not absorbed into the bloodstream after the first day, continued feeding of colostrum is suggested for the first 3 days of life. Such feeding will help provide local intestinal protection against diarrhea-causing viruses and bacteria.
    Colostrum from different cows frequently varies in antibody content. For example, if a cow leaks colostrum or has mastitis prior to freshening, colostrum that remains may be of lower antibody content. Also, when compared to cows, heifers often produce colostrum of lower antibody level. Fortunately, the antibody content of colostrum has been found to be correlated to it's specific gravity. In general, colostrum with a specific gravity of greater than 1.050 is of adequate antibody content. The specific gravity of colostrum may be determined either with a commercially available instrument called a colostrometer or an ordinary battery hygrometer.
  2. Reduction of exposure: Actual numbers of a disease agent (bacteria, virus, or protozoa), rather than the mere presence of a particular agent in the calf's environment may be the deciding factor in determining disease occurrence. One excellent way to reduce the level of exposure to disease agents is to house calves individually in hutches. For maximum benefit, hutches should be cleaned, disinfected and moved before putting calves in them. In Ohio, the open side of the hutch should face east. If hutches cannot be placed in a well-drained area, limestone bases may be required. During summer months shade or ventilation is suggested.
  3. Diagnosis/Control of Agent: Early colostrum feeding and rearing of calves in hutches can be safely recommended for use on all Ohio dairy farms. Unfortunately, even after these practices have been implemented occasional problems with calf diarrhea may still be expected. In these cases, working closely with a veterinarian to obtain an accurate diagnosis is necessary. For example, prevention of enterotoxigenic Escherichia coli (ETEC), enterotoxemia, and salmonellosis may be aided by vaccination of the pregnant dam. Management of other infectious agents may consist of medications given either at preventive or therapeutic levels (ea. coccidiosis) or rest primarily in the reduction of other stresses and the provision of good supportive care (ea. cryptosporidiosis, coronavirus,rotavirus).
    Disease agents that cause diarrhea early in life
    (E. coli, rotavirus, coronavirus) may result in rapid dehydration, shock and death of young calves. In addition to consulting your local veterinarian, the feeding of oral electrolyte solutions in place of milk or milk replacers is usually recommended during episodes of diarrhea in calves less than 2 weeks old. A number of effective commercial products are available. A homemade preparation that has proven satisfactory and economical is:

1 teaspoon diet salt (NaCl:KCI)
1 tablespoon baking soda (NaHCO3)
1 can beef consomme'
1 package jam and jelly pectin to 2 quarts of water

 

Both frequency and duration of feeding electrolyte solutions may vary according to the severity of diarrhea and is best determined by operator experience and consultation with a veterinarian.


Pneumonia

8 weeks through 8 months: Respiratory disease is frequently observed in calves of this age. During this time period, levels of colostrally acquired antibodies naturally decline. This decline is complicated by the fact that, although antibody levels that remain in the bloodstream may not be protective against natural disease exposure, they may interfere with attempts to induce active immunity by vaccination. Additional complications often occur after weaning when calves are moved and when mixing calves of different age groups occurs.

Cause—The formula that has been traditionally used to explain the occurrence of shipping fever in feeder calves (ie. Virus + Bacteria + Stress = Shipping Fever) may also be useful in understanding pneumonia in dairy heifers. Viruses that are frequently implicated in calf pneumonia include parainfluenza (Pl3), infectious bovine rhinotracheitis (IBR) and bovine respiratory syncytial virus (BRSV).

Currently, it is thought that these and other viruses may damage tissues and reduce defense mechanisms; thereby opening the way for bacterial invasion by such agents as Pasteurella sp. and Haemophilus somnus. Interactions by viruses and bacteria are thought to be aided and complicated by a variety of stress factors. Examples of stress include weather changes, poor ventilation, mixing groups of animals and inadequate nutrition. In any case, the end result is often pneumonia.

Prevention—Avoid mixing calves and heifers that differ greatly in age. After weaning, calves should be moved from individual hutches in groups of 6 to 8 to isolated facilities such as super hutches.

Ideally, heifers should remain in this isolated group until they are 6 to 8 months old. When 6 to 8 months old, heifers usually can be expected to respond favorably to active immunization against the common respiratory pathogens. Vaccination for IBR-PI3 is recommended throughout Ohio. Depending upon the prevalence of other infectious agents on a particular farm or in a community, a veterinarian may elect to vaccinate against other agents.

When heifers must be raised in a conventional barn, segregation by age group should still be attempted. Plywood barrier-walls between pens may be used to help prevent the spread of respiratory pathogens among age groups. At the very least, consider normal air movement patterns within a building. For example, young calves and heifers should not be housed downwind from older animals. Air movement patterns and proper ventilation are extremely important in the prevention of respiratory disease. Therefore, before building a new building or remodeling an existing one, it is wise to consult an agricultural engineer.

Treatment—Even after implementation of the above suggestions, occasional outbreaks of respiratory disease can be expected in young dairy heifers. Early in the course of the disease a veterinarian should be consulted regarding diagnosis and treatment. Too frequently, use of ineffective antibacterials or improper dosage schedules results in animals with residual lung damage. Animals treated improperly, even if they survive may be expected to exhibit poor growth and reduced performance. During an outbreak, in addition to prompt treatment, attempts should be made to correct underlying environmental problems, e.g. drafts and overcrowding. Sick animals should be isolated to help prevent spread of the disease and also to minimize further stress on the affected animals.


Specific Preventive Strategies

Ringworm—Ringworm is caused by a fungus that attacks the skin and forms ringlike or circular areas that are scabby or crusty in appearance. These areas may appear on the neck, shoulders or other parts of the body. It is contagious to both man and other animals upon direct contact. For treatment, scrub the infected areas with a stiff brush and soapy water. Then paint the areas with tincture of iodine or some other fungicide recommended by a veterinarian. Although not always successful, prevention should be attempted. Sunlight, adequate vitamin A supplementation, and cleaning and disinfection of animal facilities, all may be important in the prevention of ringworm.

Pinkeye—Pinkeye (infectious bovine keratoconjunctivitis) is an infectious disease of the eyes. It is characterized by a reddish inflammation of the eye. The disease is usually spread by contact between healthy and infected animals. Flies may also transmit the disease. Animals with Pinkeye are sensitive to light and should be isolated in a dark place away from other animals. Unless treated, blindness may result. Recently, several vaccines have been licensed for use in the prevention of pinkeye. Consult a veterinarian for specific recommendations regarding treatment and prevention.

Internal Parasites

Ostertagia ostertagi the brown stomach worm, is the most important internal parasite affecting Ohio dairy animals. Signs of infection include unthriftiness and poor growth. It is very cost effective to deworm heifers during their first grazing season. Several approved products are available. While most products require two treatments a sustained release product requiring dosing only at turn-out was licensed recently. A veterinarian should be consulted concerning the use of specific products and treatment schedules.

External Parasites

Lice are a common problem on dairy farms. Lice cause discomfort, a rough, unthrifty appearance and poor growth in affected heifers. With many of the commonly used dusting products, retreatment should be given 10 to 14 days following the initial treatment. However, as with all medications, care should be taken to carefully read and follow label directions.

Flies can be annoying to dairy cattle of all ages and cause reduced gain in young animals. Many are blood sucking such as the horn flies, stable flies, deer flies and other species. These flies not only remove blood but also may transmit other bacterial and parasitic diseases. Although daily use of insecticide sprays is of value when cattle are housed, the best control methods involve the destruction of breeding places.

Blackleg is an acute infectious disease that primarily affects young cattle. The disease results in depression, fever, lameness and death of nonvaccinated animals. Animals become infected by grazing on soils contaminated by the spore-forming Blackleg bacteria. A regular vaccination program should be instituted and maintained in areas where the disease is known to exist.

Selenium Deficiency Soils in Ohio are frequently deficient in selenium and calf losses can occur unless selenium is supplied. Selenium deficiency may be characterized by lameness, stiffness and labored breathing. It is recommended that calves in Ohio receive two injections of selenium (BoSe), one at birth and a second at two weeks of age as a preventive measure against possible deficiency.

Johne's Disease, also known as paratuberculosis, is characterized by chronic diarrhea, wasting and death. Although the disease is usually observed when the cattle are young adults the infection is actually contracted during calfhood. Because the disease is spread by ingestion of the feces of infected cattle, care should be taken to prevent fecal contamination of housing and feedstuffs used by young animals. Calves should be removed from their dams as soon as possible following birth and raised in isolation from adults as described previously.

Leukosis Enzootic bovine leukosis is caused by a virus carried in the blood of infected cattle. Once infected, an animal remains infected for the rest of it's life. Although tumors may develop later in life, currently the greatest loss is associated with the loss of export markets and semen sales. While a small percentage of animal's contract infection in-utero, the majority of new infections are thought to be acquired by the use of blood-contaminated instruments such as gouge dehorners, tatooing instruments, and common needles used for injection. Electric dehorning, proper disinfection of tatoo equipment between calves, and disposable single-use needles are suggested to help control the spread of leukosis.


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This page was last updated on November 16, 2002