N. R. ELLIS AND RICHARD D. SHUMAN.
NEARLY one-third of all pigs born each year die from various disorders and hazards.
Not all of the loss can be said to be due to diseases in the strict sense. The causes, which often are ill-defined and overlapping, include various management factors that involve housing, facilities, and care; various prenatal factors, which involve several variables such as genetics, physiology, disease organisms, and nutrition; and postnatal factors reflected in physiological well-being of dam and pig, nutrition, infections, parasites, numbers of pigs per litter, and others.
The multiple nature of the causes is evident in the cataloging of deaths outwardly apparent as due to mashing or injury. Many of the deaths are entirely physical. They are caused by the sow and often indirectly by inadequate housing and lack of protective guardrails, brooder lamps, and other pen facilities, of which the undersized, weak, and sick pigs are more prone to become victims.
The reasons why they are undersized, weak, and sick in turn are multiple. Hereditary, physiological, nutritional, and infectious-disease factors and parasitic infestations are involved. Bacterial and viral infections create a variable that may range from an extremely mild or latent contributing cause of weakness and unthriftiness to extremely virulent diseases of epidemic proportions. Some pigs that do not die from these causes often are permanently stunted or unthrifty in growth and use of feed. Examples of such diseases are the various enteric (intestinal) disorders, ranging from those forms that respond to antibiotics and other medication and to improved care and nutrition to the highly fatal transmissible gastroenteritis (T. G. E.).
Other diseases, such as pneumonia, cholera, erysipelas, atrophic rhinitis, and edema, add to the complexity of the possible causes of death.
Nutrition and management studies directed at the gestation and lactation periods at the Agricultural Research Center at Beltsville showed that the losses of young pigs are of various forms. Seasonal losses among farrowings of 350 to 500 baby pigs from 1949 to 1955 ranged from 30 percent to 10 percent of all pigs born. The average was about 20 percent.
Stillbirths averaged 3 percent between 1952 and 1954 a relatively low figure, compared to 5, 10, and 18 percent in some of the earlier studies, in which more severe dietary treatments were included in the tests.
Mashing or injury as the immediate cause of death averaged nearly 5 percent in 6 years, even though pen facilities and care were better than average.
Scours, especially in the first few days of life, claimed nearly 4 percent of the pigs.
Classifications of deaths due to other causes included chilling, 2 percent; starvation, more than 1 percent; uremia, 1 percent; and runtiness and weakness, about 1 percent. These totaled about 17 percent, leaving 3 percent as not further classified.
The studies at Beltsville emphasized the importance of good nutrition and good management. Inadequate care, overcrowding, unfavorable weather, related factors can nullify benefits of good nutrition, and vice versa. Good nutrition and good management can keep losses to 10 percent or less if there are no epidemics of a virulent nature.
So far we have considered the multiple nature of the causes of losses of baby pigs and the general nature of the more specific nutritional and infectious diseases that are involved. Let us consider now a number of the diseases with the object of bringing them to the attention of the swine raiser. Many are discussed in detail in other sections of this book.
ENTERIC DISORDERS are the predominant group of diseases of baby pigs. More than a dozen forms, both infectious and nutritional, have been listed, among them T. G. E., baby pig scours, bloody dysentery, salmonellosis (necro), hog cholera, influenza, pneumonia, swinepox, erysipelas, internal parasites, chemical fungi, molds, plant poisons, and the nutritional deficiencies.
Nutritional deficiencies or imbalances are important among these forms of diarrhea. Enteric disturbance often results from too little niacin, pantothenic acid, riboflavin, and other vitamins in the feed. Necrotic enteritis (necro) for many years was considered an important and baffling disease, which sometimes was helped by adding niacin and tryptophan (a crystalline amino acid) to the feed.
Young pigs are highly susceptible to enteritis. They can get sudden and severe diarrheas if the sanitation is neglected, the quality of the feed is low, and the manner of feeding the dam and the nursing pigs are below standard.
Practical treatments that involve improvements in nutrition, feeding, and care do much to clear up the trouble. Outbreaks of diarrheas often can be brought under control or prevented by such remedies as vitamin and mineral concentrates, sulfonamides, antibiotics, and arsanilates.
ANEMIA was a great hazard until the discovery that lack of iron and copper was responsible for nutritional anemia. Development of methods of providing iron, especially to young pigs, and widespread recognition and adoption of these methods has brought improvement. The recommended dosage is 10 to 15 milligrams of iron daily, preferably in the form of an iron salt. Commercial compounds are available and suggested directions for their use are printed on the containers. Neglect of these precautions can result in the development of weak, unthrifty pigs, and frequently is either the direct cause or at least a contributing cause of deaths.
ANOTHER DISORDER, goiter or hairlessness, is due to a deficiency of iodine. The general use of iodized salt in the mineral mixture or in the mixed diet of the sow in regions especially in those States bordering on the Great Lakes and westward to Montana that are deficient in iodine has brought about great improvement.
When the disease does occur, it is manifested by enlargement of the thyroid gland, hairlessness, and weakness. A high proportion of pigs may be dead at birth.
UREMIC POISONING often causes runtiness and the death of young pigs. It is also called toxemia-uremia syndrome. A study at the Agricultural Research Center revealed that the disorder is especially fatal among pigs less than a week old.
The onset is relatively sudden. Growth is interrupted. The pigs become sluggish and weak. Vomiting and diarrhea frequently occur. The hair becomes rough, and the pigs die or are accidentally crushed by the sow. A postmortem examination discloses emaciation and evidence of uremic poisoning, including precipitates of uric acid salts in the kidneys, an increase in urea and uric acid in the blood, and uric acid in the kidney.
The disease seems to have some connection with the amount and quality of the milk that the pigs get by nursing. Studies by W. W. Green and others in Minnesota in 1949 showed that a condition, characterized as a toxemia-uremia syndrome, similar to that seen in suckling pigs, could be induced by feeding young pigs on reconstituted skim milk simply fortified with a mineral mixture along with vitamins A and D. Addition of yeast generally prevented the symptoms.
Its sporadic and unpredictable nature has made study and control of the disorder difficult.
HYPOGLYCEMIA affects young pigs 1 to 3 days after birth. The blood sugar in affected pigs is much lower than in healthy pigs. It indicates some derangement of carbohydrate metabolism. The symptoms are sluggishness, weakness, convulsions, and failure to nurse. The amount of sugar in the blood is a measure of the severity of the trouble. The young pig in this condition may be crushed by the sow or it may burrow into the bedding, where it passes into a coma and dies. This condition may affect some or all pigs in a litter.
Pigs may be treated successfully in the early stages by injections of sugar, such as glucose, or by feeding them milk by bottle or by medicine dropper.