Domesticated animals rely on care providers to meet their physiological and behavioral needs. Consequently, management and nutrition are essential to animals' health and well-being. This is especially true in agriculture, in which production methods demand a high level of animal productivity. With continued advances, production systems have tended to become intensified, requiring continual adaptation in management and nutritional practices to ensure that they do not limit animal well-being, health, or production.
The tenets of biosecurity have been long recognized by veterinarians. However, throughout the past decades, interest in biosecurity as a scientific discipline has surged because of 1) disease outbreaks that have threatened to devastate agricultural economies, and 2) bioterrorism. In fact, the meaning of the term biosecurity and the structure and focus of biosecurity programs have evolved throughout time to more accurately reflect the scientific community’s evolving perception of disease as well as the needs of the consumer, the veterinary profession, and producers and owners.
The basic concept of cloning via nuclear transfer is that the nucleus of a cell, taken from a tissue sample of a donor individual, is transferred to an enucleated oocyte, and then the oocyte is stimulated to develop into an embryo. The embryo thus produced has the same genotype as the original donor individual.
Complementary and alternative veterinary medicine (CAVM) as defined in 2001 by the American Veterinary Medical Association, is “...a heterogeneous group of preventive, diagnostic, and therapeutic philosophies and practices. The theoretical bases and techniques of CAVM may diverge from veterinary medicine routinely taught in North American veterinary medical schools or may differ from current scientific knowledge, or both.” Although some of the myriad approaches have been used to treat animals for centuries, many have not. Instead, they have been extrapolated from human approaches without first undergoing assessment for safety and effectiveness in nonhuman animals.
Appropriate management in the peripartum period can substantially reduce morbidity and mortality for large animal dams and their offspring. As much as 5% of foals, 5%–10% of calves, and 10%–15% of the annual lamb crops die before weaning in the USA, with 50%–70% of neonatal mortality occurring in the first 3 days of life. A key aspect of managing the large animal dam includes appropriate nutrition and body conditioning in the pre- and postpartum periods to reduce the risk of pregnancy-related diseases such as pregnancy toxemia, hypocalcemia, and vaginal prolapse; as well as to optimize hygiene, colostrum quality, and fetal and neonatal growth. Appropriate anthelmintic therapy and vaccination of the dam several weeks before parturition will further protect dam and offspring from subsequent disease.
Pain delays recovery, impacts negatively on patient well-being, and can affect the client-veterinarian relationship. Behaviors suggestive of pain are routinely used to diagnose injuries and diseases, guide therapy, and provide prognostic information. Obvious signs of pain alert owners and veterinarians of a problem with the animal. Certainly, there is nothing novel about considering pain clinically relevant in the overall evaluation of an animal. What is relatively new is our understanding of the complexity of pain and the emphasis on ethical and medical obligations to treat pain in animals. Although limited survey data and anecdotal evidence suggest that the management of pain is receiving more attention in veterinary medicine than before, the assessment, prevention, and treatment of pain has yet to become an integral part of every physical examination and treatment plan.
Stray voltage is a low-level current in animal housing that most commonly affects dairy cows and swine. Behavioral changes, such as avoidance of the area affected, are the typical signs. Diagnosis is based on seeing behavioral changes and performing electrical testing. To prevent the problem, periodic inspection and testing of voltage/current levels by an electrician is recommended, especially when there are changes to the farm's electrical system.
Ventilation is often associated with respiratory health of animals; the quality of the air that animals breathe directly influences animal health and disease. Ventilation, directly and indirectly, impacts many other aspects of animal health as well. Good ventilation in the lying area of lactating animals helps bedding stay dry, a factor in favor of good mammary health. Good ventilation along alleys helps to keep walking surfaces dry, which contributes to healthy feet. Good ventilation may lead to greater productivity, eg, maintaining air movement in the eating area makes animals more comfortable, especially important during hot weather as an aid to maintaining dry matter intake. A comfortable, well-ventilated lying area encourages animals to lie down, an important contribution to many aspects of animal health.
Several managerial practices increase productivity within cow-calf herds when they can be implemented economically and practically. These practices are mostly associated with reproduction, because improvements in herd fertility generally offer potential for increased profitability in cow-calf operations. They include a restricted breeding season, identification of the optimal calving season, a good heifer replacement program, heifer reproductive tract scoring, proper nutrition, good herd health, bull breeding soundness examinations, crossbreeding, and maintaining good records. Other management practices associated with increased beef herd profitability include decreasing unit cost of production, use of growth promotants in calves, internal and external parasite control, improved calf management, management-intensive grazing, preconditioning of calves, and having a marketing plan.
The dairy industry is in a period of economic volatility of historic proportions. An era of modest fluctuation in milk and feed pricing in the late 1990s to the early 2000s was followed by increases in milk prices not seen before. The period of high dairy profitability in early 2008 was soon dampened as the global recession of 2008–2009 led to reduced exports. Since then, milk prices have rebounded and dropped several times. More recently, all-time high US milk prices in 2014 have been followed by 5 years of a severe, industry-wide economic downturn. In mid-2019, it was estimated that >7,000 dairies had closed because of milk prices remaining below the cost of production for too long.
Management of goats depends on the type (eg, dairy, pygmy, meat, mohair, or cashmere) and the reasons for which they are kept (eg, companionship or commercial enterprise). However, all are ruminants, and the basic principles of livestock husbandry are applicable. Dairy goats and pygmies are often raised intensively, with most of the feed being brought to the animals. Meat goats and fiber goats are usually raised extensively, with most of the diet coming from browse and occasionally from high-quality pasture at times of highest nutritional need, such as the last 6 wk of gestation and the first 18 mo of life. A pregnant Angora doe without adequate energy and protein continues to grow mohair, even if stressed until she aborts.
Proper management can reduce the incidence of many disease conditions in horses. Informed management of the environment and diet, routine foot and dental care, and adherence to an appropriate deworming and vaccination program form the basis of a preventive health program. Client education is important for compliance; owners are more likely to follow recommended changes in husbandry programs once they appreciate the advantages. Diet manipulation reduces the incidence of certain types of colic and exercise-induced myopathies, good dental care improves feed utilization, minimizing exposure to barn dusts and molds reduces the risk of recurrent airway obstruction (chronic obstructive pulmonary disease), and individually designed deworming and vaccination programs reduce morbidity and mortality due to parasitism and infectious disease. Owners should be aware of the normal vital signs and proper movement of a healthy horse, so that they will be better able to recognize when a health problem such as pneumonia, colic, or lameness develops. New modalities for prevention and treatment are always evolving. In addition, the use of complementary or alternative medicine such as acupuncture, acupressure, chiropractic procedures, photomodulation, and massage has grown in equine care (All.see chapter Complementary and Alternative Veterinary Medicine). Knowledgeable owners working with a veterinarian and a farrier can result in a productive and pleasant life for every horse.
Disease in pork production is generally caused by multiple factors. Microbial pathogens are rarely the sole cause of a health problem on a pig farm. Clinical disease is usually the interaction of a pathogen with errors in management and a variety of contributing influences such as environment and host factors. Many pathogens are endemic in the swine population and yet some farms suffer heavy losses from disease, whereas the impact on other farms is much less because of management differences.
Sheep and goats were first domesticated around 8,000 BC, making them the first of the domesticated food animals. Sheep are extremely adaptable and found all over the world, particularly in arid areas that do not support other types of livestock. Because sheep are raised in various environments, specific breeds have been developed to meet the needs of the environment and people. More than 100 breeds have been recorded. Different production systems are used in various areas of the world. Extensive year-round grazing, with large flocks (>1,000 sheep) and minimal sheep handling, is the typical system of sheep management where the climate and area to graze allow. Systems in New Zealand, South Africa, and Australia, where forage is available throughout the year, are prime examples of this type of management. Confinement and intensive feeding during the winter months, with access to range land pasture for the rest of the year, is a common system of large sheep flocks in parts of Europe, the UK, the western USA, and other countries that have snow and inclement weather seasonally.
Proper management to prevent and control disease has historically been a higher priority in production animal medicine than in small animal medicine. However, appropriate management is just as important for small animals, whether their environment is that of a single or multiple-pet household or a more intensive housing situation such as a kennel or cattery.
Dairy and beef producers should strive to increase reproductive efficiency as a key driver of economic efficiency in the sector. Reproductive efficiency, or "pregnancy rate," is defined as the proportion of cows eligible to be bred that become pregnant during an estrous cycle (or approximately 21 days), and which determines the calving to conception interval at the end of the voluntary waiting period. As pregnancy rate increases in dairy herds, the calving to conception interval decreases, and the herd status becomes, on average, less "days in milk" (DIM). This has the effect of increasing the potential amount of milk produced per day of herd lifetime, because yield classically declines at 0.3% per day after peak lactation production. A major and realistic goal of every beef cow/calf operator should be to raise or market 85 calves per 100 cows every year. Greater reproductive efficiency also reduces the number of cows culled for reproductive failure; collectively, these changes increase herd income.
Goats are spontaneously ovulating, seasonally polyestrous animals with peak breeding activity occurring in the fall when day length is shortening . As day length decreases, melatonin secretion from the pineal gland increases which activates pulsatile GnRH release from the hypothalamus. Hypothalamic GnRH secretion stimulates release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary and promotes the growth of follicles, stimulating the onset of the hypothalamic-pituitary-gonadal axis in short-day breeders.
Most mares are seasonally polyestrous and cycle when the length of daylight is long. Anestrus occurs during the winter when daylight length is short. During anestrus, the ovaries are inactive with no significant follicles >10 mm or corpora lutea, so plasma levels of estrogen and progesterone are low. Therefore, the uterus is flaccid and the cervix may be closed but not firm and tight, or it may be thin, short, and dilated. As the length of daylight increases, mares undergo a vernal transition and the ovaries become active, with 3–4 waves of numerous large (>25 mm) follicles. The cervix and uterus have minimal tone. Mares have 3 or 4 prolonged intervals of estrus (periods of sexual receptivity to the stallion) during the vernal transition, but ovulation does not occur. The end of vernal transition is marked by a surge of luteinizing hormone that stimulates ovulation, after which a regular, 21-day interovulatory estrous cycle is established.
Management of commercial swine breeding herds involves a thorough understanding of reproductive physiology, genetics, nutrition, immunology, disease control, environment, and other factors. (All.See also page Abortion in Pigs.) The closed-herd concept, which emphasizes preventive medicine strategies along with herd protection, minimizes the risk of disease loss when combined with intensive management, sound nutrition, and genetic selection. The breeding program should be evaluated at specified intervals to ensure that progress in both efficiency and productivity is being made. Several efficiency/production parameters to review when analyzing herd reproductive performance are shown in . The postweaning performance of a breeding herd's offspring can be measured through assessment of such parameters as feed conversion ratio, average daily gain, total days to market, and postweaning death loss.
Several key points are the basis of a sound flock reproduction health management program. First, sheep are short-day polyestrus breeders (ie, estrus occurs in response to shortening day length). Second, ovulatory season tends to be in fall and winter; anovulatory season during late winter, spring and early summer; the transition season occurs in the late summer months. Finally, there is considerable breed-to-breed variation in prolificacy and length of the ovulatory season.
A breeding soundness examination, which should take place before any dog or cat is purposefully bred, is the opportune time for veterinary input regarding good breeding practices. Because of pet overpopulation, dog and cat breeding should be left to educated and responsible breeders, to whom potential purebred puppy and kitten clients can be referred. Breeding soundness means a dog or cat is free from heritable defects based on phenotype evaluations such as radiography (eg, elbow dysplasia), ultrasonography (eg, renal dysplasia, tricuspid dysplasia), ophthalmoscopy (eg, cataract), physical examination (eg, patellar luxation) or specific DNA testing when available (eg, progressive rod-cone degeneration). Several resources are available to veterinarians negotiating purebred dog and cat genetic recommendations.
The breeding soundness examination (BSE) involves a complete and systematic evaluation of the reproductive potential of a given male, including mating ability and libido, general physical examination and inspection of the genital organs, and assessment of sperm production and quality. The BSE is not a direct evaluation of fertility: this can be confirmed only by successful production of offspring after breeding a fertile female. The specific male animal must be properly identified, and a detailed history is important because sub- or infertile males might require more exhaustive evaluation. The evaluation of mating ability and libido is possible only when collecting semen via artificial vagina or manual stimulation in the presence of a female in estrus. Therefore, mating ability is seldom evaluated in bulls and rams for routine BSE in which semen is typically collected via electroejaculation.
Embryo transfer has proved to be a powerful technology in genetic improvement of farm animals, primarily to propagate the genes of females of superior pedigree. In cattle, particularly in the dairy industry, breeding programs have been developed to promote genetic progress by strategic use of elite females via multiple ovulation embryo transfer (MOET) programs. In addition to conventional methods to produce embryos available for transfer, new technologies that produce embryos after cloning by somatic cell transfer or transgenesis are available; however, they are not widely used commercially.
Hormones are commonly used to manipulate the estrous cycle. The major indications for hormonal control of estrus are to induce luteolysis, induce ovulation of a mature follicle, suppress estrus, induce cyclicity in anestrous animals, and superovulate cyclic animals. Effective treatments for these manipulations of the estrous cycle vary between species. Additionally, a number of treatments currently lack regulatory approval; prescribing veterinarians should follow label instructions and adhere to relevant laws and regulations.
Beef cattle production, whether on range, improved pasture, or in the feedlot, is most economic when feedstuffs are used effectively. Young growing grass or other high-quality pasture crops usually supply ample nutrients, such that mature and young growing cattle can consume sufficient good-quality mixed pasture (grasses and legumes) for normal growth and maintenance. However, mature pasture, crop residues, or forage crops harvested in a manner that results in shattering, leaching, or spoilage may be so reduced in nutritive value (particularly energy, protein, phosphorus, and provitamin A or β-carotene) that they are suitable only in a maintenance ration for adult cattle. Such feedstuffs should be supplemented if used for any other purposes.
During lactation, dairy cows have very high nutritional requirements relative to most other species (). Meeting these requirements, especially for energy and protein, is challenging. Diets must have sufficient nutrient concentrations to support production and metabolic health, while also supporting rumen health and the efficiency of fermentative digestion.
The field of zoo and exotic animal nutrition continues to make advances that result in better diets. Exotic animal nutritionists in zoos and in the feed industry are studying problems and generating information on proper nutritional management for many species.
Although goats and sheep have several similarities, their nutrient requirements differ in several ways. Goats are predominantly browsing animals but will graze. Still, many of the principles useful for sheep feeding and nutrition are applicable for goats. Nutritional assessment, particularly as applied to energy intake, should be by body condition assessment. (Also All.see page Nutrition: Sheep.)
Horses are maintained for a much longer time than most farm animals and have more varied uses, as athletes and service and companion animals. Feeding programs, therefore, must sustain a long, productive, and athletic life and be varied according to individual needs, unlike food animal feeding programs. The feeding recommendations given below are based on both practical experience and scientific research. Detailed recommendations can be found in Nutrient Requirements of Horses, 6th Ed, published in 2007 by the National Research Council and Equine Applied and Clinical Nutrition, 2013, Geor RJ, Harris PA and Cohen M (eds), Saunders/Elsevier.
Pigs require a number of essential nutrients to meet their needs for maintenance, growth, reproduction, lactation, and other functions. The National Research Council (NRC), in its publication, Nutrient Requirements of Swine (updated in 2012), provides estimates of the amounts of these nutrients for various classes of swine under average conditions. However, factors such as genetic variation, environment, availability of nutrients in feedstuffs, disease levels, and other stressors may increase the needed level of some nutrients for optimal performance and reproduction. The NRC uses a modeling approach to take some of these factors into consideration in its estimates of requirements for energy, amino acids, calcium, and phosphorus, but requirements for other minerals and vitamins are estimated strictly from empirical data.
The economical and efficient production of sheep for meat, wool, show and/or pets is contingent on proper feeding, husbandry practices, and health care. All of these are influenced by dietary intake. Maintenance of breeding animals, a high percentage of the lamb crop weaned, growth of lambs, optimal weaning weights, and a heavy fleece weight and fleece quality are important to efficiency. The nutritional requirements for maintenance, reproduction, growth, finishing, and wool production are complex because sheep are maintained under a wide variety of environmental conditions; however, attempts should be made to ensure each production unit or individual sheep has adequate nutrient intake to be healthy and productive.
Domestic dogs and cats are both members of the order Carnivora. Observations of feral canids indicate that their feeding habits are broad and include various parts of plants as well as both small and large prey. By comparison, cats do not show omnivorous feeding behaviors and have a requirement for specific animal-derived sources of nutrients, such as preformed vitamin A, arachidonic acid, and taurine. As a result, dogs are classified nutritionally as omnivores, while cats are classified as true carnivores.